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KEYS: Fix up comments in key management code 

Fix up comments in the key management code.  No functional changes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2011-01-20 16:38:33 +00:00 committed by Linus Torvalds
parent a8b17ed019
commit 973c9f4f49
11 changed files with 777 additions and 366 deletions
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13
security/keys/compat.c
View File

@ -1,4 +1,4 @@
/* compat.c: 32-bit compatibility syscall for 64-bit systems /* 32-bit compatibility syscall for 64-bit systems
* *
* Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -15,11 +15,12 @@
#include "internal.h" #include "internal.h"
/* /*
* the key control system call, 32-bit compatibility version for 64-bit archs * The key control system call, 32-bit compatibility version for 64-bit archs
* - this should only be called if the 64-bit arch uses weird pointers in *
* 32-bit mode or doesn't guarantee that the top 32-bits of the argument * This should only be called if the 64-bit arch uses weird pointers in 32-bit
* registers on taking a 32-bit syscall are zero * mode or doesn't guarantee that the top 32-bits of the argument registers on
* - if you can, you should call sys_keyctl directly * taking a 32-bit syscall are zero. If you can, you should call sys_keyctl()
* directly.
*/ */
asmlinkage long compat_sys_keyctl(u32 option, asmlinkage long compat_sys_keyctl(u32 option,
u32 arg2, u32 arg3, u32 arg4, u32 arg5) u32 arg2, u32 arg3, u32 arg4, u32 arg5)

14
security/keys/gc.c
View File

@ -32,8 +32,8 @@ static time_t key_gc_next_run = LONG_MAX;
static time_t key_gc_new_timer; static time_t key_gc_new_timer;
/* /*
* Schedule a garbage collection run * Schedule a garbage collection run.
* - precision isn't particularly important * - time precision isn't particularly important
*/ */
void key_schedule_gc(time_t gc_at) void key_schedule_gc(time_t gc_at)
{ {
@ -61,8 +61,9 @@ static void key_gc_timer_func(unsigned long data)
} }
/* /*
* Garbage collect pointers from a keyring * Garbage collect pointers from a keyring.
* - return true if we altered the keyring *
* Return true if we altered the keyring.
*/ */
static bool key_gc_keyring(struct key *keyring, time_t limit) static bool key_gc_keyring(struct key *keyring, time_t limit)
__releases(key_serial_lock) __releases(key_serial_lock)
@ -107,9 +108,8 @@ do_gc:
} }
/* /*
* Garbage collector for keys * Garbage collector for keys. This involves scanning the keyrings for dead,
* - this involves scanning the keyrings for dead, expired and revoked keys * expired and revoked keys that have overstayed their welcome
* that have overstayed their welcome
*/ */
static void key_garbage_collector(struct work_struct *work) static void key_garbage_collector(struct work_struct *work)
{ {

26
security/keys/internal.h
View File

@ -1,4 +1,4 @@
/* internal.h: authentication token and access key management internal defs /* Authentication token and access key management internal defs
* *
* Copyright (C) 2003-5, 2007 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2003-5, 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -35,10 +35,12 @@ extern struct key_type key_type_user;
/*****************************************************************************/ /*****************************************************************************/
/* /*
* keep track of keys for a user * Keep track of keys for a user.
* - this needs to be separate to user_struct to avoid a refcount-loop *
* (user_struct pins some keyrings which pin this struct) * This needs to be separate to user_struct to avoid a refcount-loop
* - this also keeps track of keys under request from userspace for this UID * (user_struct pins some keyrings which pin this struct).
*
* We also keep track of keys under request from userspace for this UID here.
*/ */
struct key_user { struct key_user {
struct rb_node node; struct rb_node node;
@ -62,7 +64,7 @@ extern struct key_user *key_user_lookup(uid_t uid,
extern void key_user_put(struct key_user *user); extern void key_user_put(struct key_user *user);
/* /*
* key quota limits * Key quota limits.
* - root has its own separate limits to everyone else * - root has its own separate limits to everyone else
*/ */
extern unsigned key_quota_root_maxkeys; extern unsigned key_quota_root_maxkeys;
@ -146,13 +148,13 @@ extern unsigned key_gc_delay;
extern void keyring_gc(struct key *keyring, time_t limit); extern void keyring_gc(struct key *keyring, time_t limit);
extern void key_schedule_gc(time_t expiry_at); extern void key_schedule_gc(time_t expiry_at);
/*
* check to see whether permission is granted to use a key in the desired way
*/
extern int key_task_permission(const key_ref_t key_ref, extern int key_task_permission(const key_ref_t key_ref,
const struct cred *cred, const struct cred *cred,
key_perm_t perm); key_perm_t perm);
/*
* Check to see whether permission is granted to use a key in the desired way.
*/
static inline int key_permission(const key_ref_t key_ref, key_perm_t perm) static inline int key_permission(const key_ref_t key_ref, key_perm_t perm)
{ {
return key_task_permission(key_ref, current_cred(), perm); return key_task_permission(key_ref, current_cred(), perm);
@ -168,7 +170,7 @@ static inline int key_permission(const key_ref_t key_ref, key_perm_t perm)
#define KEY_ALL 0x3f /* all the above permissions */ #define KEY_ALL 0x3f /* all the above permissions */
/* /*
* request_key authorisation * Authorisation record for request_key().
*/ */
struct request_key_auth { struct request_key_auth {
struct key *target_key; struct key *target_key;
@ -188,7 +190,7 @@ extern struct key *request_key_auth_new(struct key *target,
extern struct key *key_get_instantiation_authkey(key_serial_t target_id); extern struct key *key_get_instantiation_authkey(key_serial_t target_id);
/* /*
* keyctl functions * keyctl() functions
*/ */
extern long keyctl_get_keyring_ID(key_serial_t, int); extern long keyctl_get_keyring_ID(key_serial_t, int);
extern long keyctl_join_session_keyring(const char __user *); extern long keyctl_join_session_keyring(const char __user *);
@ -214,7 +216,7 @@ extern long keyctl_get_security(key_serial_t keyid, char __user *buffer,
extern long keyctl_session_to_parent(void); extern long keyctl_session_to_parent(void);
/* /*
* debugging key validation * Debugging key validation
*/ */
#ifdef KEY_DEBUGGING #ifdef KEY_DEBUGGING
extern void __key_check(const struct key *); extern void __key_check(const struct key *);

240
security/keys/key.c
View File

@ -39,10 +39,10 @@ static DECLARE_RWSEM(key_types_sem);
static void key_cleanup(struct work_struct *work); static void key_cleanup(struct work_struct *work);
static DECLARE_WORK(key_cleanup_task, key_cleanup); static DECLARE_WORK(key_cleanup_task, key_cleanup);
/* we serialise key instantiation and link */ /* We serialise key instantiation and link */
DEFINE_MUTEX(key_construction_mutex); DEFINE_MUTEX(key_construction_mutex);
/* any key who's type gets unegistered will be re-typed to this */ /* Any key who's type gets unegistered will be re-typed to this */
static struct key_type key_type_dead = { static struct key_type key_type_dead = {
.name = "dead", .name = "dead",
}; };
@ -57,8 +57,8 @@ void __key_check(const struct key *key)
#endif #endif
/* /*
* get the key quota record for a user, allocating a new record if one doesn't * Get the key quota record for a user, allocating a new record if one doesn't
* already exist * already exist.
*/ */
struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
{ {
@ -66,7 +66,7 @@ struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
struct rb_node *parent = NULL; struct rb_node *parent = NULL;
struct rb_node **p; struct rb_node **p;
try_again: try_again:
p = &key_user_tree.rb_node; p = &key_user_tree.rb_node;
spin_lock(&key_user_lock); spin_lock(&key_user_lock);
@ -123,16 +123,16 @@ struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
goto out; goto out;
/* okay - we found a user record for this UID */ /* okay - we found a user record for this UID */
found: found:
atomic_inc(&user->usage); atomic_inc(&user->usage);
spin_unlock(&key_user_lock); spin_unlock(&key_user_lock);
kfree(candidate); kfree(candidate);
out: out:
return user; return user;
} }
/* /*
* dispose of a user structure * Dispose of a user structure
*/ */
void key_user_put(struct key_user *user) void key_user_put(struct key_user *user)
{ {
@ -146,9 +146,8 @@ void key_user_put(struct key_user *user)
} }
/* /*
* assign a key the next unique serial number * Allocate a serial number for a key. These are assigned randomly to avoid
* - these are assigned randomly to avoid security issues through covert * security issues through covert channel problems.
* channel problems
*/ */
static inline void key_alloc_serial(struct key *key) static inline void key_alloc_serial(struct key *key)
{ {
@ -208,14 +207,34 @@ serial_exists:
} }
} }
/* /**
* allocate a key of the specified type * key_alloc - Allocate a key of the specified type.
* - update the user's quota to reflect the existence of the key * @type: The type of key to allocate.
* - called from a key-type operation with key_types_sem read-locked by * @desc: The key description to allow the key to be searched out.
* key_create_or_update() * @uid: The owner of the new key.
* - this prevents unregistration of the key type * @gid: The group ID for the new key's group permissions.
* - upon return the key is as yet uninstantiated; the caller needs to either * @cred: The credentials specifying UID namespace.
* instantiate the key or discard it before returning * @perm: The permissions mask of the new key.
* @flags: Flags specifying quota properties.
*
* Allocate a key of the specified type with the attributes given. The key is
* returned in an uninstantiated state and the caller needs to instantiate the
* key before returning.
*
* The user's key count quota is updated to reflect the creation of the key and
* the user's key data quota has the default for the key type reserved. The
* instantiation function should amend this as necessary. If insufficient
* quota is available, -EDQUOT will be returned.
*
* The LSM security modules can prevent a key being created, in which case
* -EACCES will be returned.
*
* Returns a pointer to the new key if successful and an error code otherwise.
*
* Note that the caller needs to ensure the key type isn't uninstantiated.
* Internally this can be done by locking key_types_sem. Externally, this can
* be done by either never unregistering the key type, or making sure
* key_alloc() calls don't race with module unloading.
*/ */
struct key *key_alloc(struct key_type *type, const char *desc, struct key *key_alloc(struct key_type *type, const char *desc,
uid_t uid, gid_t gid, const struct cred *cred, uid_t uid, gid_t gid, const struct cred *cred,
@ -338,11 +357,18 @@ no_quota:
key = ERR_PTR(-EDQUOT); key = ERR_PTR(-EDQUOT);
goto error; goto error;
} }
EXPORT_SYMBOL(key_alloc); EXPORT_SYMBOL(key_alloc);
/* /**
* reserve an amount of quota for the key's payload * key_payload_reserve - Adjust data quota reservation for the key's payload
* @key: The key to make the reservation for.
* @datalen: The amount of data payload the caller now wants.
*
* Adjust the amount of the owning user's key data quota that a key reserves.
* If the amount is increased, then -EDQUOT may be returned if there isn't
* enough free quota available.
*
* If successful, 0 is returned.
*/ */
int key_payload_reserve(struct key *key, size_t datalen) int key_payload_reserve(struct key *key, size_t datalen)
{ {
@ -376,12 +402,13 @@ int key_payload_reserve(struct key *key, size_t datalen)
return ret; return ret;
} }
EXPORT_SYMBOL(key_payload_reserve); EXPORT_SYMBOL(key_payload_reserve);
/* /*
* instantiate a key and link it into the target keyring atomically * Instantiate a key and link it into the target keyring atomically. Must be
* - called with the target keyring's semaphore writelocked * called with the target keyring's semaphore writelocked. The target key's
* semaphore need not be locked as instantiation is serialised by
* key_construction_mutex.
*/ */
static int __key_instantiate_and_link(struct key *key, static int __key_instantiate_and_link(struct key *key,
const void *data, const void *data,
@ -432,8 +459,21 @@ static int __key_instantiate_and_link(struct key *key,
return ret; return ret;
} }
/* /**
* instantiate a key and link it into the target keyring atomically * key_instantiate_and_link - Instantiate a key and link it into the keyring.
* @key: The key to instantiate.
* @data: The data to use to instantiate the keyring.
* @datalen: The length of @data.
* @keyring: Keyring to create a link in on success (or NULL).
* @authkey: The authorisation token permitting instantiation.
*
* Instantiate a key that's in the uninstantiated state using the provided data
* and, if successful, link it in to the destination keyring if one is
* supplied.
*
* If successful, 0 is returned, the authorisation token is revoked and anyone
* waiting for the key is woken up. If the key was already instantiated,
* -EBUSY will be returned.
*/ */
int key_instantiate_and_link(struct key *key, int key_instantiate_and_link(struct key *key,
const void *data, const void *data,
@ -462,8 +502,24 @@ int key_instantiate_and_link(struct key *key,
EXPORT_SYMBOL(key_instantiate_and_link); EXPORT_SYMBOL(key_instantiate_and_link);
/* /**
* negatively instantiate a key and link it into the target keyring atomically * key_negate_and_link - Negatively instantiate a key and link it into the keyring.
* @key: The key to instantiate.
* @timeout: The timeout on the negative key.
* @keyring: Keyring to create a link in on success (or NULL).
* @authkey: The authorisation token permitting instantiation.
*
* Negatively instantiate a key that's in the uninstantiated state and, if
* successful, set its timeout and link it in to the destination keyring if one
* is supplied. The key and any links to the key will be automatically garbage
* collected after the timeout expires.
*
* Negative keys are used to rate limit repeated request_key() calls by causing
* them to return -ENOKEY until the negative key expires.
*
* If successful, 0 is returned, the authorisation token is revoked and anyone
* waiting for the key is woken up. If the key was already instantiated,
* -EBUSY will be returned.
*/ */
int key_negate_and_link(struct key *key, int key_negate_and_link(struct key *key,
unsigned timeout, unsigned timeout,
@ -525,15 +581,18 @@ int key_negate_and_link(struct key *key,
EXPORT_SYMBOL(key_negate_and_link); EXPORT_SYMBOL(key_negate_and_link);
/* /*
* do cleaning up in process context so that we don't have to disable * Garbage collect keys in process context so that we don't have to disable
* interrupts all over the place * interrupts all over the place.
*
* key_put() schedules this rather than trying to do the cleanup itself, which
* means key_put() doesn't have to sleep.
*/ */
static void key_cleanup(struct work_struct *work) static void key_cleanup(struct work_struct *work)
{ {
struct rb_node *_n; struct rb_node *_n;
struct key *key; struct key *key;
go_again: go_again:
/* look for a dead key in the tree */ /* look for a dead key in the tree */
spin_lock(&key_serial_lock); spin_lock(&key_serial_lock);
@ -547,7 +606,7 @@ static void key_cleanup(struct work_struct *work)
spin_unlock(&key_serial_lock); spin_unlock(&key_serial_lock);
return; return;
found_dead_key: found_dead_key:
/* we found a dead key - once we've removed it from the tree, we can /* we found a dead key - once we've removed it from the tree, we can
* drop the lock */ * drop the lock */
rb_erase(&key->serial_node, &key_serial_tree); rb_erase(&key->serial_node, &key_serial_tree);
@ -586,10 +645,13 @@ static void key_cleanup(struct work_struct *work)
goto go_again; goto go_again;
} }
/* /**
* dispose of a reference to a key * key_put - Discard a reference to a key.
* - when all the references are gone, we schedule the cleanup task to come and * @key: The key to discard a reference from.
* pull it out of the tree in definite process context *
* Discard a reference to a key, and when all the references are gone, we
* schedule the cleanup task to come and pull it out of the tree in process
* context at some later time.
*/ */
void key_put(struct key *key) void key_put(struct key *key)
{ {
@ -600,11 +662,10 @@ void key_put(struct key *key)
schedule_work(&key_cleanup_task); schedule_work(&key_cleanup_task);
} }
} }
EXPORT_SYMBOL(key_put); EXPORT_SYMBOL(key_put);
/* /*
* find a key by its serial number * Find a key by its serial number.
*/ */
struct key *key_lookup(key_serial_t id) struct key *key_lookup(key_serial_t id)
{ {
@ -626,11 +687,11 @@ struct key *key_lookup(key_serial_t id)
goto found; goto found;
} }
not_found: not_found:
key = ERR_PTR(-ENOKEY); key = ERR_PTR(-ENOKEY);
goto error; goto error;
found: found:
/* pretend it doesn't exist if it is awaiting deletion */ /* pretend it doesn't exist if it is awaiting deletion */
if (atomic_read(&key->usage) == 0) if (atomic_read(&key->usage) == 0)
goto not_found; goto not_found;
@ -640,14 +701,16 @@ struct key *key_lookup(key_serial_t id)
*/ */
atomic_inc(&key->usage); atomic_inc(&key->usage);
error: error:
spin_unlock(&key_serial_lock); spin_unlock(&key_serial_lock);
return key; return key;
} }
/* /*
* find and lock the specified key type against removal * Find and lock the specified key type against removal.
* - we return with the sem readlocked *
* We return with the sem read-locked if successful. If the type wasn't
* available -ENOKEY is returned instead.
*/ */
struct key_type *key_type_lookup(const char *type) struct key_type *key_type_lookup(const char *type)
{ {
@ -665,12 +728,12 @@ struct key_type *key_type_lookup(const char *type)
up_read(&key_types_sem); up_read(&key_types_sem);
ktype = ERR_PTR(-ENOKEY); ktype = ERR_PTR(-ENOKEY);
found_kernel_type: found_kernel_type:
return ktype; return ktype;
} }
/* /*
* unlock a key type * Unlock a key type locked by key_type_lookup().
*/ */
void key_type_put(struct key_type *ktype) void key_type_put(struct key_type *ktype)
{ {
@ -678,9 +741,10 @@ void key_type_put(struct key_type *ktype)
} }
/* /*
* attempt to update an existing key * Attempt to update an existing key.
* - the key has an incremented refcount *
* - we need to put the key if we get an error * The key is given to us with an incremented refcount that we need to discard
* if we get an error.
*/ */
static inline key_ref_t __key_update(key_ref_t key_ref, static inline key_ref_t __key_update(key_ref_t key_ref,
const void *payload, size_t plen) const void *payload, size_t plen)
@ -717,9 +781,30 @@ error:
goto out; goto out;
} }
/* /**
* search the specified keyring for a key of the same description; if one is * key_create_or_update - Update or create and instantiate a key.
* found, update it, otherwise add a new one * @keyring_ref: A pointer to the destination keyring with possession flag.
* @type: The type of key.
* @description: The searchable description for the key.
* @payload: The data to use to instantiate or update the key.
* @plen: The length of @payload.
* @perm: The permissions mask for a new key.
* @flags: The quota flags for a new key.
*
* Search the destination keyring for a key of the same description and if one
* is found, update it, otherwise create and instantiate a new one and create a
* link to it from that keyring.
*
* If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
* concocted.
*
* Returns a pointer to the new key if successful, -ENODEV if the key type
* wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
* caller isn't permitted to modify the keyring or the LSM did not permit
* creation of the key.
*
* On success, the possession flag from the keyring ref will be tacked on to
* the key ref before it is returned.
*/ */
key_ref_t key_create_or_update(key_ref_t keyring_ref, key_ref_t key_create_or_update(key_ref_t keyring_ref,
const char *type, const char *type,
@ -827,11 +912,20 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
key_ref = __key_update(key_ref, payload, plen); key_ref = __key_update(key_ref, payload, plen);
goto error; goto error;
} }
EXPORT_SYMBOL(key_create_or_update); EXPORT_SYMBOL(key_create_or_update);
/* /**
* update a key * key_update - Update a key's contents.
* @key_ref: The pointer (plus possession flag) to the key.
* @payload: The data to be used to update the key.
* @plen: The length of @payload.
*
* Attempt to update the contents of a key with the given payload data. The
* caller must be granted Write permission on the key. Negative keys can be
* instantiated by this method.
*
* Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
* type does not support updating. The key type may return other errors.
*/ */
int key_update(key_ref_t key_ref, const void *payload, size_t plen) int key_update(key_ref_t key_ref, const void *payload, size_t plen)
{ {
@ -861,11 +955,16 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
error: error:
return ret; return ret;
} }
EXPORT_SYMBOL(key_update); EXPORT_SYMBOL(key_update);
/* /**
* revoke a key * key_revoke - Revoke a key.
* @key: The key to be revoked.
*
* Mark a key as being revoked and ask the type to free up its resources. The
* revocation timeout is set and the key and all its links will be
* automatically garbage collected after key_gc_delay amount of time if they
* are not manually dealt with first.
*/ */
void key_revoke(struct key *key) void key_revoke(struct key *key)
{ {
@ -894,11 +993,15 @@ void key_revoke(struct key *key)
up_write(&key->sem); up_write(&key->sem);
} }
EXPORT_SYMBOL(key_revoke); EXPORT_SYMBOL(key_revoke);
/* /**
* register a type of key * register_key_type - Register a type of key.
* @ktype: The new key type.
*
* Register a new key type.
*
* Returns 0 on success or -EEXIST if a type of this name already exists.
*/ */
int register_key_type(struct key_type *ktype) int register_key_type(struct key_type *ktype)
{ {
@ -918,15 +1021,19 @@ int register_key_type(struct key_type *ktype)
list_add(&ktype->link, &key_types_list); list_add(&ktype->link, &key_types_list);
ret = 0; ret = 0;
out: out:
up_write(&key_types_sem); up_write(&key_types_sem);
return ret; return ret;
} }
EXPORT_SYMBOL(register_key_type); EXPORT_SYMBOL(register_key_type);
/* /**
* unregister a type of key * unregister_key_type - Unregister a type of key.
* @ktype: The key type.
*
* Unregister a key type and mark all the extant keys of this type as dead.
* Those keys of this type are then destroyed to get rid of their payloads and
* they and their links will be garbage collected as soon as possible.
*/ */
void unregister_key_type(struct key_type *ktype) void unregister_key_type(struct key_type *ktype)
{ {
@ -974,11 +1081,10 @@ void unregister_key_type(struct key_type *ktype)
key_schedule_gc(0); key_schedule_gc(0);
} }
EXPORT_SYMBOL(unregister_key_type); EXPORT_SYMBOL(unregister_key_type);
/* /*
* initialise the key management stuff * Initialise the key management state.
*/ */
void __init key_init(void) void __init key_init(void)
{ {

278
security/keys/keyctl.c
View File

@ -1,4 +1,4 @@
/* keyctl.c: userspace keyctl operations /* Userspace key control operations
* *
* Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -31,27 +31,24 @@ static int key_get_type_from_user(char *type,
int ret; int ret;
ret = strncpy_from_user(type, _type, len); ret = strncpy_from_user(type, _type, len);
if (ret < 0) if (ret < 0)
return ret; return ret;
if (ret == 0 || ret >= len) if (ret == 0 || ret >= len)
return -EINVAL; return -EINVAL;
if (type[0] == '.') if (type[0] == '.')
return -EPERM; return -EPERM;
type[len - 1] = '\0'; type[len - 1] = '\0';
return 0; return 0;
} }
/* /*
* extract the description of a new key from userspace and either add it as a * Extract the description of a new key from userspace and either add it as a
* new key to the specified keyring or update a matching key in that keyring * new key to the specified keyring or update a matching key in that keyring.
* - the keyring must be writable *
* - returns the new key's serial number * The keyring must be writable so that we can attach the key to it.
* - implements add_key() *
* If successful, the new key's serial number is returned, otherwise an error
* code is returned.
*/ */
SYSCALL_DEFINE5(add_key, const char __user *, _type, SYSCALL_DEFINE5(add_key, const char __user *, _type,
const char __user *, _description, const char __user *, _description,
@ -134,14 +131,17 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
} }
/* /*
* search the process keyrings for a matching key * Search the process keyrings and keyring trees linked from those for a
* - nested keyrings may also be searched if they have Search permission * matching key. Keyrings must have appropriate Search permission to be
* - if a key is found, it will be attached to the destination keyring if * searched.
* there's one specified *
* - /sbin/request-key will be invoked if _callout_info is non-NULL * If a key is found, it will be attached to the destination keyring if there's
* - the _callout_info string will be passed to /sbin/request-key * one specified and the serial number of the key will be returned.
* - if the _callout_info string is empty, it will be rendered as "-" *
* - implements request_key() * If no key is found, /sbin/request-key will be invoked if _callout_info is
* non-NULL in an attempt to create a key. The _callout_info string will be
* passed to /sbin/request-key to aid with completing the request. If the
* _callout_info string is "" then it will be changed to "-".
*/ */
SYSCALL_DEFINE4(request_key, const char __user *, _type, SYSCALL_DEFINE4(request_key, const char __user *, _type,
const char __user *, _description, const char __user *, _description,
@ -222,9 +222,11 @@ error:
} }
/* /*
* get the ID of the specified process keyring * Get the ID of the specified process keyring.
* - the keyring must have search permission to be found *
* - implements keyctl(KEYCTL_GET_KEYRING_ID) * The requested keyring must have search permission to be found.
*
* If successful, the ID of the requested keyring will be returned.
*/ */
long keyctl_get_keyring_ID(key_serial_t id, int create) long keyctl_get_keyring_ID(key_serial_t id, int create)
{ {
@ -243,12 +245,17 @@ long keyctl_get_keyring_ID(key_serial_t id, int create)
key_ref_put(key_ref); key_ref_put(key_ref);
error: error:
return ret; return ret;
}
} /* end keyctl_get_keyring_ID() */
/* /*
* join the session keyring * Join a (named) session keyring.
* - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING) *
* Create and join an anonymous session keyring or join a named session
* keyring, creating it if necessary. A named session keyring must have Search
* permission for it to be joined. Session keyrings without this permit will
* be skipped over.
*
* If successful, the ID of the joined session keyring will be returned.
*/ */
long keyctl_join_session_keyring(const char __user *_name) long keyctl_join_session_keyring(const char __user *_name)
{ {
@ -274,9 +281,14 @@ error:
} }
/* /*
* update a key's data payload * Update a key's data payload from the given data.
* - the key must be writable *
* - implements keyctl(KEYCTL_UPDATE) * The key must grant the caller Write permission and the key type must support
* updating for this to work. A negative key can be positively instantiated
* with this call.
*
* If successful, 0 will be returned. If the key type does not support
* updating, then -EOPNOTSUPP will be returned.
*/ */
long keyctl_update_key(key_serial_t id, long keyctl_update_key(key_serial_t id,
const void __user *_payload, const void __user *_payload,
@ -321,9 +333,14 @@ error:
} }
/* /*
* revoke a key * Revoke a key.
* - the key must be writable *
* - implements keyctl(KEYCTL_REVOKE) * The key must be grant the caller Write or Setattr permission for this to
* work. The key type should give up its quota claim when revoked. The key
* and any links to the key will be automatically garbage collected after a
* certain amount of time (/proc/sys/kernel/keys/gc_delay).
*
* If successful, 0 is returned.
*/ */
long keyctl_revoke_key(key_serial_t id) long keyctl_revoke_key(key_serial_t id)
{ {
@ -351,9 +368,11 @@ error:
} }
/* /*
* clear the specified process keyring * Clear the specified keyring, creating an empty process keyring if one of the
* - the keyring must be writable * special keyring IDs is used.
* - implements keyctl(KEYCTL_CLEAR) *
* The keyring must grant the caller Write permission for this to work. If
* successful, 0 will be returned.
*/ */
long keyctl_keyring_clear(key_serial_t ringid) long keyctl_keyring_clear(key_serial_t ringid)
{ {
@ -374,10 +393,15 @@ error:
} }
/* /*
* link a key into a keyring * Create a link from a keyring to a key if there's no matching key in the
* - the keyring must be writable * keyring, otherwise replace the link to the matching key with a link to the
* - the key must be linkable * new key.
* - implements keyctl(KEYCTL_LINK) *
* The key must grant the caller Link permission and the the keyring must grant
* the caller Write permission. Furthermore, if an additional link is created,
* the keyring's quota will be extended.
*
* If successful, 0 will be returned.
*/ */
long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
{ {
@ -406,10 +430,13 @@ error:
} }
/* /*
* unlink the first attachment of a key from a keyring * Unlink a key from a keyring.
* - the keyring must be writable *
* - we don't need any permissions on the key * The keyring must grant the caller Write permission for this to work; the key
* - implements keyctl(KEYCTL_UNLINK) * itself need not grant the caller anything. If the last link to a key is
* removed then that key will be scheduled for destruction.
*
* If successful, 0 will be returned.
*/ */
long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
{ {
@ -438,14 +465,17 @@ error:
} }
/* /*
* describe a user key * Return a description of a key to userspace.
* - the key must have view permission *
* - if there's a buffer, we place up to buflen bytes of data into it * The key must grant the caller View permission for this to work.
* - unless there's an error, we return the amount of description available, *
* irrespective of how much we may have copied * If there's a buffer, we place up to buflen bytes of data into it formatted
* - the description is formatted thus: * in the following way:
*
* type;uid;gid;perm;description<NUL> * type;uid;gid;perm;description<NUL>
* - implements keyctl(KEYCTL_DESCRIBE) *
* If successful, we return the amount of description available, irrespective
* of how much we may have copied into the buffer.
*/ */
long keyctl_describe_key(key_serial_t keyid, long keyctl_describe_key(key_serial_t keyid,
char __user *buffer, char __user *buffer,
@ -516,13 +546,14 @@ error:
} }
/* /*
* search the specified keyring for a matching key * Search the specified keyring and any keyrings it links to for a matching
* - the start keyring must be searchable * key. Only keyrings that grant the caller Search permission will be searched
* - nested keyrings may also be searched if they are searchable * (this includes the starting keyring). Only keys with Search permission can
* - only keys with search permission may be found * be found.
* - if a key is found, it will be attached to the destination keyring if *
* there's one specified * If successful, the found key will be linked to the destination keyring if
* - implements keyctl(KEYCTL_SEARCH) * supplied and the key has Link permission, and the found key ID will be
* returned.
*/ */
long keyctl_keyring_search(key_serial_t ringid, long keyctl_keyring_search(key_serial_t ringid,
const char __user *_type, const char __user *_type,
@ -609,13 +640,14 @@ error:
} }
/* /*
* read a user key's payload * Read a key's payload.
* - the keyring must be readable or the key must be searchable from the *
* process's keyrings * The key must either grant the caller Read permission, or it must grant the
* - if there's a buffer, we place up to buflen bytes of data into it * caller Search permission when searched for from the process keyrings.
* - unless there's an error, we return the amount of data in the key, *
* irrespective of how much we may have copied * If successful, we place up to buflen bytes of data into the buffer, if one
* - implements keyctl(KEYCTL_READ) * is provided, and return the amount of data that is available in the key,
* irrespective of how much we copied into the buffer.
*/ */
long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
{ {
@ -669,10 +701,19 @@ error:
} }
/* /*
* change the ownership of a key * Change the ownership of a key
* - the keyring owned by the changer *
* - if the uid or gid is -1, then that parameter is not changed * The key must grant the caller Setattr permission for this to work, though
* - implements keyctl(KEYCTL_CHOWN) * the key need not be fully instantiated yet. For the UID to be changed, or
* for the GID to be changed to a group the caller is not a member of, the
* caller must have sysadmin capability. If either uid or gid is -1 then that
* attribute is not changed.
*
* If the UID is to be changed, the new user must have sufficient quota to
* accept the key. The quota deduction will be removed from the old user to
* the new user should the attribute be changed.
*
* If successful, 0 will be returned.
*/ */
long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{ {
@ -775,9 +816,11 @@ quota_overrun:
} }
/* /*
* change the permission mask on a key * Change the permission mask on a key.
* - the keyring owned by the changer *
* - implements keyctl(KEYCTL_SETPERM) * The key must grant the caller Setattr permission for this to work, though
* the key need not be fully instantiated yet. If the caller does not have
* sysadmin capability, it may only change the permission on keys that it owns.
*/ */
long keyctl_setperm_key(key_serial_t id, key_perm_t perm) long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
{ {
@ -815,7 +858,8 @@ error:
} }
/* /*
* get the destination keyring for instantiation * Get the destination keyring for instantiation and check that the caller has
* Write permission on it.
*/ */
static long get_instantiation_keyring(key_serial_t ringid, static long get_instantiation_keyring(key_serial_t ringid,
struct request_key_auth *rka, struct request_key_auth *rka,
@ -852,7 +896,7 @@ static long get_instantiation_keyring(key_serial_t ringid,
} }
/* /*
* change the request_key authorisation key on the current process * Change the request_key authorisation key on the current process.
*/ */
static int keyctl_change_reqkey_auth(struct key *key) static int keyctl_change_reqkey_auth(struct key *key)
{ {
@ -869,8 +913,13 @@ static int keyctl_change_reqkey_auth(struct key *key)
} }
/* /*
* instantiate the key with the specified payload, and, if one is given, link * Instantiate a key with the specified payload and link the key into the
* the key into the keyring * destination keyring if one is given.
*
* The caller must have the appropriate instantiation permit set for this to
* work (see keyctl_assume_authority). No other permissions are required.
*
* If successful, 0 will be returned.
*/ */
long keyctl_instantiate_key(key_serial_t id, long keyctl_instantiate_key(key_serial_t id,
const void __user *_payload, const void __user *_payload,
@ -948,8 +997,19 @@ error:
} }
/* /*
* negatively instantiate the key with the given timeout (in seconds), and, if * Negatively instantiate the key with the given timeout (in seconds) and link
* one is given, link the key into the keyring * the key into the destination keyring if one is given.
*
* The caller must have the appropriate instantiation permit set for this to
* work (see keyctl_assume_authority). No other permissions are required.
*
* The key and any links to the key will be automatically garbage collected
* after the timeout expires.
*
* Negative keys are used to rate limit repeated request_key() calls by causing
* them to return -ENOKEY until the negative key expires.
*
* If successful, 0 will be returned.
*/ */
long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
{ {
@ -993,8 +1053,11 @@ error:
} }
/* /*
* set the default keyring in which request_key() will cache keys * Read or set the default keyring in which request_key() will cache keys and
* - return the old setting * return the old setting.
*
* If a process keyring is specified then this will be created if it doesn't
* yet exist. The old setting will be returned if successful.
*/ */
long keyctl_set_reqkey_keyring(int reqkey_defl) long keyctl_set_reqkey_keyring(int reqkey_defl)
{ {
@ -1050,7 +1113,16 @@ error:
} }
/* /*
* set or clear the timeout for a key * Set or clear the timeout on a key.
*
* Either the key must grant the caller Setattr permission or else the caller
* must hold an instantiation authorisation token for the key.
*
* The timeout is either 0 to clear the timeout, or a number of seconds from
* the current time. The key and any links to the key will be automatically
* garbage collected after the timeout expires.
*
* If successful, 0 is returned.
*/ */
long keyctl_set_timeout(key_serial_t id, unsigned timeout) long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{ {
@ -1105,7 +1177,21 @@ error:
} }
/* /*
* assume the authority to instantiate the specified key * Assume (or clear) the authority to instantiate the specified key.
*
* This sets the authoritative token currently in force for key instantiation.
* This must be done for a key to be instantiated. It has the effect of making
* available all the keys from the caller of the request_key() that created a
* key to request_key() calls made by the caller of this function.
*
* The caller must have the instantiation key in their process keyrings with a
* Search permission grant available to the caller.
*
* If the ID given is 0, then the setting will be cleared and 0 returned.
*
* If the ID given has a matching an authorisation key, then that key will be
* set and its ID will be returned. The authorisation key can be read to get
* the callout information passed to request_key().
*/ */
long keyctl_assume_authority(key_serial_t id) long keyctl_assume_authority(key_serial_t id)
{ {
@ -1145,12 +1231,14 @@ error:
} }
/* /*
* get the security label of a key * Get a key's the LSM security label.
* - the key must grant us view permission *
* - if there's a buffer, we place up to buflen bytes of data into it * The key must grant the caller View permission for this to work.
* - unless there's an error, we return the amount of information available, *
* irrespective of how much we may have copied (including the terminal NUL) * If there's a buffer, then up to buflen bytes of data will be placed into it.
* - implements keyctl(KEYCTL_GET_SECURITY) *
* If successful, the amount of information available will be returned,
* irrespective of how much was copied (including the terminal NUL).
*/ */
long keyctl_get_security(key_serial_t keyid, long keyctl_get_security(key_serial_t keyid,
char __user *buffer, char __user *buffer,
@ -1205,10 +1293,16 @@ long keyctl_get_security(key_serial_t keyid,
} }
/* /*
* attempt to install the calling process's session keyring on the process's * Attempt to install the calling process's session keyring on the process's
* parent process * parent process.
* - the keyring must exist and must grant us LINK permission *
* - implements keyctl(KEYCTL_SESSION_TO_PARENT) * The keyring must exist and must grant the caller LINK permission, and the
* parent process must be single-threaded and must have the same effective
* ownership as this process and mustn't be SUID/SGID.
*
* The keyring will be emplaced on the parent when it next resumes userspace.
*
* If successful, 0 will be returned.
*/ */
long keyctl_session_to_parent(void) long keyctl_session_to_parent(void)
{ {
@ -1312,7 +1406,7 @@ error_keyring:
} }
/* /*
* the key control system call * The key control system call
*/ */
SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5) unsigned long, arg4, unsigned long, arg5)

231
security/keys/keyring.c
View File

@ -26,13 +26,13 @@
rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem)))
/* /*
* when plumbing the depths of the key tree, this sets a hard limit set on how * When plumbing the depths of the key tree, this sets a hard limit
* deep we're willing to go * set on how deep we're willing to go.
*/ */
#define KEYRING_SEARCH_MAX_DEPTH 6 #define KEYRING_SEARCH_MAX_DEPTH 6
/* /*
* we keep all named keyrings in a hash to speed looking them up * We keep all named keyrings in a hash to speed looking them up.
*/ */
#define KEYRING_NAME_HASH_SIZE (1 << 5) #define KEYRING_NAME_HASH_SIZE (1 << 5)
@ -50,7 +50,9 @@ static inline unsigned keyring_hash(const char *desc)
} }
/* /*
* the keyring type definition * The keyring key type definition. Keyrings are simply keys of this type and
* can be treated as ordinary keys in addition to having their own special
* operations.
*/ */
static int keyring_instantiate(struct key *keyring, static int keyring_instantiate(struct key *keyring,
const void *data, size_t datalen); const void *data, size_t datalen);
@ -71,18 +73,17 @@ struct key_type key_type_keyring = {
.describe = keyring_describe, .describe = keyring_describe,
.read = keyring_read, .read = keyring_read,
}; };
EXPORT_SYMBOL(key_type_keyring); EXPORT_SYMBOL(key_type_keyring);
/* /*
* semaphore to serialise link/link calls to prevent two link calls in parallel * Semaphore to serialise link/link calls to prevent two link calls in parallel
* introducing a cycle * introducing a cycle.
*/ */
static DECLARE_RWSEM(keyring_serialise_link_sem); static DECLARE_RWSEM(keyring_serialise_link_sem);
/* /*
* publish the name of a keyring so that it can be found by name (if it has * Publish the name of a keyring so that it can be found by name (if it has
* one) * one).
*/ */
static void keyring_publish_name(struct key *keyring) static void keyring_publish_name(struct key *keyring)
{ {
@ -104,8 +105,9 @@ static void keyring_publish_name(struct key *keyring)
} }
/* /*
* initialise a keyring * Initialise a keyring.
* - we object if we were given any data *
* Returns 0 on success, -EINVAL if given any data.
*/ */
static int keyring_instantiate(struct key *keyring, static int keyring_instantiate(struct key *keyring,
const void *data, size_t datalen) const void *data, size_t datalen)
@ -123,7 +125,7 @@ static int keyring_instantiate(struct key *keyring,
} }
/* /*
* match keyrings on their name * Match keyrings on their name
*/ */
static int keyring_match(const struct key *keyring, const void *description) static int keyring_match(const struct key *keyring, const void *description)
{ {
@ -132,7 +134,8 @@ static int keyring_match(const struct key *keyring, const void *description)
} }
/* /*
* dispose of the data dangling from the corpse of a keyring * Clean up a keyring when it is destroyed. Unpublish its name if it had one
* and dispose of its data.
*/ */
static void keyring_destroy(struct key *keyring) static void keyring_destroy(struct key *keyring)
{ {
@ -160,7 +163,7 @@ static void keyring_destroy(struct key *keyring)
} }
/* /*
* describe the keyring * Describe a keyring for /proc.
*/ */
static void keyring_describe(const struct key *keyring, struct seq_file *m) static void keyring_describe(const struct key *keyring, struct seq_file *m)
{ {
@ -181,8 +184,9 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m)
} }
/* /*
* read a list of key IDs from the keyring's contents * Read a list of key IDs from the keyring's contents in binary form
* - the keyring's semaphore is read-locked *
* The keyring's semaphore is read-locked by the caller.
*/ */
static long keyring_read(const struct key *keyring, static long keyring_read(const struct key *keyring,
char __user *buffer, size_t buflen) char __user *buffer, size_t buflen)
@ -233,7 +237,7 @@ error:
} }
/* /*
* allocate a keyring and link into the destination keyring * Allocate a keyring and link into the destination keyring.
*/ */
struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
const struct cred *cred, unsigned long flags, const struct cred *cred, unsigned long flags,
@ -258,16 +262,40 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
return keyring; return keyring;
} }
/* /**
* search the supplied keyring tree for a key that matches the criterion * keyring_search_aux - Search a keyring tree for a key matching some criteria
* - perform a breadth-then-depth search up to the prescribed limit * @keyring_ref: A pointer to the keyring with possession indicator.
* - we only find keys on which we have search permission * @cred: The credentials to use for permissions checks.
* - we use the supplied match function to see if the description (or other * @type: The type of key to search for.
* feature of interest) matches * @description: Parameter for @match.
* - we rely on RCU to prevent the keyring lists from disappearing on us * @match: Function to rule on whether or not a key is the one required.
* - we return -EAGAIN if we didn't find any matching key *
* - we return -ENOKEY if we only found negative matching keys * Search the supplied keyring tree for a key that matches the criteria given.
* - we propagate the possession attribute from the keyring ref to the key ref * The root keyring and any linked keyrings must grant Search permission to the
* caller to be searchable and keys can only be found if they too grant Search
* to the caller. The possession flag on the root keyring pointer controls use
* of the possessor bits in permissions checking of the entire tree. In
* addition, the LSM gets to forbid keyring searches and key matches.
*
* The search is performed as a breadth-then-depth search up to the prescribed
* limit (KEYRING_SEARCH_MAX_DEPTH).
*
* Keys are matched to the type provided and are then filtered by the match
* function, which is given the description to use in any way it sees fit. The
* match function may use any attributes of a key that it wishes to to
* determine the match. Normally the match function from the key type would be
* used.
*
* RCU is used to prevent the keyring key lists from disappearing without the
* need to take lots of locks.
*
* Returns a pointer to the found key and increments the key usage count if
* successful; -EAGAIN if no matching keys were found, or if expired or revoked
* keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
* specified keyring wasn't a keyring.
*
* In the case of a successful return, the possession attribute from
* @keyring_ref is propagated to the returned key reference.
*/ */
key_ref_t keyring_search_aux(key_ref_t keyring_ref, key_ref_t keyring_search_aux(key_ref_t keyring_ref,
const struct cred *cred, const struct cred *cred,
@ -431,13 +459,14 @@ error:
return key_ref; return key_ref;
} }
/* /**
* search the supplied keyring tree for a key that matches the criterion * keyring_search - Search the supplied keyring tree for a matching key
* - perform a breadth-then-depth search up to the prescribed limit * @keyring: The root of the keyring tree to be searched.
* - we only find keys on which we have search permission * @type: The type of keyring we want to find.
* - we readlock the keyrings as we search down the tree * @description: The name of the keyring we want to find.
* - we return -EAGAIN if we didn't find any matching key *
* - we return -ENOKEY if we only found negative matching keys * As keyring_search_aux() above, but using the current task's credentials and
* type's default matching function.
*/ */
key_ref_t keyring_search(key_ref_t keyring, key_ref_t keyring_search(key_ref_t keyring,
struct key_type *type, struct key_type *type,
@ -449,13 +478,22 @@ key_ref_t keyring_search(key_ref_t keyring,
return keyring_search_aux(keyring, current->cred, return keyring_search_aux(keyring, current->cred,
type, description, type->match); type, description, type->match);
} }
EXPORT_SYMBOL(keyring_search); EXPORT_SYMBOL(keyring_search);
/* /*
* search the given keyring only (no recursion) * Search the given keyring only (no recursion).
* - keyring must be locked by caller *
* - caller must guarantee that the keyring is a keyring * The caller must guarantee that the keyring is a keyring and that the
* permission is granted to search the keyring as no check is made here.
*
* RCU is used to make it unnecessary to lock the keyring key list here.
*
* Returns a pointer to the found key with usage count incremented if
* successful and returns -ENOKEY if not found. Revoked keys and keys not
* providing the requested permission are skipped over.
*
* If successful, the possession indicator is propagated from the keyring ref
* to the returned key reference.
*/ */
key_ref_t __keyring_search_one(key_ref_t keyring_ref, key_ref_t __keyring_search_one(key_ref_t keyring_ref,
const struct key_type *ktype, const struct key_type *ktype,
@ -498,9 +536,15 @@ found:
} }
/* /*
* find a keyring with the specified name * Find a keyring with the specified name.
* - all named keyrings are searched *
* - normally only finds keyrings with search permission for the current process * All named keyrings in the current user namespace are searched, provided they
* grant Search permission directly to the caller (unless this check is
* skipped). Keyrings whose usage points have reached zero or who have been
* revoked are skipped.
*
* Returns a pointer to the keyring with the keyring's refcount having being
* incremented on success. -ENOKEY is returned if a key could not be found.
*/ */
struct key *find_keyring_by_name(const char *name, bool skip_perm_check) struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
{ {
@ -551,10 +595,11 @@ out:
} }
/* /*
* see if a cycle will will be created by inserting acyclic tree B in acyclic * See if a cycle will will be created by inserting acyclic tree B in acyclic
* tree A at the topmost level (ie: as a direct child of A) * tree A at the topmost level (ie: as a direct child of A).
* - since we are adding B to A at the top level, checking for cycles should *
* just be a matter of seeing if node A is somewhere in tree B * Since we are adding B to A at the top level, checking for cycles should just
* be a matter of seeing if node A is somewhere in tree B.
*/ */
static int keyring_detect_cycle(struct key *A, struct key *B) static int keyring_detect_cycle(struct key *A, struct key *B)
{ {
@ -637,7 +682,7 @@ cycle_detected:
} }
/* /*
* dispose of a keyring list after the RCU grace period, freeing the unlinked * Dispose of a keyring list after the RCU grace period, freeing the unlinked
* key * key
*/ */
static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
@ -651,7 +696,7 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
} }
/* /*
* preallocate memory so that a key can be linked into to a keyring * Preallocate memory so that a key can be linked into to a keyring.
*/ */
int __key_link_begin(struct key *keyring, const struct key_type *type, int __key_link_begin(struct key *keyring, const struct key_type *type,
const char *description, const char *description,
@ -768,10 +813,10 @@ error_krsem:
} }
/* /*
* check already instantiated keys aren't going to be a problem * Check already instantiated keys aren't going to be a problem.
* - the caller must have called __key_link_begin() *
* - don't need to call this for keys that were created since __key_link_begin() * The caller must have called __key_link_begin(). Don't need to call this for
* was called * keys that were created since __key_link_begin() was called.
*/ */
int __key_link_check_live_key(struct key *keyring, struct key *key) int __key_link_check_live_key(struct key *keyring, struct key *key)
{ {
@ -783,9 +828,12 @@ int __key_link_check_live_key(struct key *keyring, struct key *key)
} }
/* /*
* link a key into to a keyring * Link a key into to a keyring.
* - must be called with __key_link_begin() having being called *
* - discard already extant link to matching key if there is one * Must be called with __key_link_begin() having being called. Discards any
* already extant link to matching key if there is one, so that each keyring
* holds at most one link to any given key of a particular type+description
* combination.
*/ */
void __key_link(struct key *keyring, struct key *key, void __key_link(struct key *keyring, struct key *key,
struct keyring_list **_prealloc) struct keyring_list **_prealloc)
@ -828,8 +876,9 @@ void __key_link(struct key *keyring, struct key *key,
} }
/* /*
* finish linking a key into to a keyring * Finish linking a key into to a keyring.
* - must be called with __key_link_begin() having being called *
* Must be called with __key_link_begin() having being called.
*/ */
void __key_link_end(struct key *keyring, struct key_type *type, void __key_link_end(struct key *keyring, struct key_type *type,
struct keyring_list *prealloc) struct keyring_list *prealloc)
@ -850,8 +899,25 @@ void __key_link_end(struct key *keyring, struct key_type *type,
up_write(&keyring->sem); up_write(&keyring->sem);
} }
/* /**
* link a key to a keyring * key_link - Link a key to a keyring
* @keyring: The keyring to make the link in.
* @key: The key to link to.
*
* Make a link in a keyring to a key, such that the keyring holds a reference
* on that key and the key can potentially be found by searching that keyring.
*
* This function will write-lock the keyring's semaphore and will consume some
* of the user's key data quota to hold the link.
*
* Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
* -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
* full, -EDQUOT if there is insufficient key data quota remaining to add
* another link or -ENOMEM if there's insufficient memory.
*
* It is assumed that the caller has checked that it is permitted for a link to
* be made (the keyring should have Write permission and the key Link
* permission).
*/ */
int key_link(struct key *keyring, struct key *key) int key_link(struct key *keyring, struct key *key)
{ {
@ -871,11 +937,24 @@ int key_link(struct key *keyring, struct key *key)
return ret; return ret;
} }
EXPORT_SYMBOL(key_link); EXPORT_SYMBOL(key_link);
/* /**
* unlink the first link to a key from a keyring * key_unlink - Unlink the first link to a key from a keyring.
* @keyring: The keyring to remove the link from.
* @key: The key the link is to.
*
* Remove a link from a keyring to a key.
*
* This function will write-lock the keyring's semaphore.
*
* Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
* the key isn't linked to by the keyring or -ENOMEM if there's insufficient
* memory.
*
* It is assumed that the caller has checked that it is permitted for a link to
* be removed (the keyring should have Write permission; no permissions are
* required on the key).
*/ */
int key_unlink(struct key *keyring, struct key *key) int key_unlink(struct key *keyring, struct key *key)
{ {
@ -944,12 +1023,11 @@ nomem:
up_write(&keyring->sem); up_write(&keyring->sem);
goto error; goto error;
} }
EXPORT_SYMBOL(key_unlink); EXPORT_SYMBOL(key_unlink);
/* /*
* dispose of a keyring list after the RCU grace period, releasing the keys it * Dispose of a keyring list after the RCU grace period, releasing the keys it
* links to * links to.
*/ */
static void keyring_clear_rcu_disposal(struct rcu_head *rcu) static void keyring_clear_rcu_disposal(struct rcu_head *rcu)
{ {
@ -964,9 +1042,13 @@ static void keyring_clear_rcu_disposal(struct rcu_head *rcu)
kfree(klist); kfree(klist);
} }
/* /**
* clear the specified process keyring * keyring_clear - Clear a keyring
* - implements keyctl(KEYCTL_CLEAR) * @keyring: The keyring to clear.
*
* Clear the contents of the specified keyring.
*
* Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
*/ */
int keyring_clear(struct key *keyring) int keyring_clear(struct key *keyring)
{ {
@ -999,12 +1081,12 @@ int keyring_clear(struct key *keyring)
return ret; return ret;
} }
EXPORT_SYMBOL(keyring_clear); EXPORT_SYMBOL(keyring_clear);
/* /*
* dispose of the links from a revoked keyring * Dispose of the links from a revoked keyring.
* - called with the key sem write-locked *
* This is called with the key sem write-locked.
*/ */
static void keyring_revoke(struct key *keyring) static void keyring_revoke(struct key *keyring)
{ {
@ -1022,7 +1104,7 @@ static void keyring_revoke(struct key *keyring)
} }
/* /*
* Determine whether a key is dead * Determine whether a key is dead.
*/ */
static bool key_is_dead(struct key *key, time_t limit) static bool key_is_dead(struct key *key, time_t limit)
{ {
@ -1031,7 +1113,12 @@ static bool key_is_dead(struct key *key, time_t limit)
} }
/* /*
* Collect garbage from the contents of a keyring * Collect garbage from the contents of a keyring, replacing the old list with
* a new one with the pointers all shuffled down.
*
* Dead keys are classed as oned that are flagged as being dead or are revoked,
* expired or negative keys that were revoked or expired before the specified
* limit.
*/ */
void keyring_gc(struct key *keyring, time_t limit) void keyring_gc(struct key *keyring, time_t limit)
{ {

25
security/keys/permission.c
View File

@ -1,4 +1,4 @@
/* permission.c: key permission determination /* Key permission checking
* *
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -15,15 +15,17 @@
/** /**
* key_task_permission - Check a key can be used * key_task_permission - Check a key can be used
* @key_ref: The key to check * @key_ref: The key to check.
* @cred: The credentials to use * @cred: The credentials to use.
* @perm: The permissions to check for * @perm: The permissions to check for.
* *
* Check to see whether permission is granted to use a key in the desired way, * Check to see whether permission is granted to use a key in the desired way,
* but permit the security modules to override. * but permit the security modules to override.
* *
* The caller must hold either a ref on cred or must hold the RCU readlock or a * The caller must hold either a ref on cred or must hold the RCU readlock.
* spinlock. *
* Returns 0 if successful, -EACCES if access is denied based on the
* permissions bits or the LSM check.
*/ */
int key_task_permission(const key_ref_t key_ref, const struct cred *cred, int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
key_perm_t perm) key_perm_t perm)
@ -79,11 +81,15 @@ use_these_perms:
/* let LSM be the final arbiter */ /* let LSM be the final arbiter */
return security_key_permission(key_ref, cred, perm); return security_key_permission(key_ref, cred, perm);
} }
EXPORT_SYMBOL(key_task_permission); EXPORT_SYMBOL(key_task_permission);
/* /**
* validate a key * key_validate - Validate a key.
* @key: The key to be validated.
*
* Check that a key is valid, returning 0 if the key is okay, -EKEYREVOKED if
* the key's type has been removed or if the key has been revoked or
* -EKEYEXPIRED if the key has expired.
*/ */
int key_validate(struct key *key) int key_validate(struct key *key)
{ {
@ -109,5 +115,4 @@ int key_validate(struct key *key)
error: error:
return ret; return ret;
} }
EXPORT_SYMBOL(key_validate); EXPORT_SYMBOL(key_validate);

10
security/keys/proc.c
View File

@ -1,4 +1,4 @@
/* proc.c: proc files for key database enumeration /* procfs files for key database enumeration
* *
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -61,7 +61,7 @@ static const struct file_operations proc_key_users_fops = {
}; };
/* /*
* declare the /proc files * Declare the /proc files.
*/ */
static int __init key_proc_init(void) static int __init key_proc_init(void)
{ {
@ -83,7 +83,8 @@ static int __init key_proc_init(void)
__initcall(key_proc_init); __initcall(key_proc_init);
/* /*
* implement "/proc/keys" to provides a list of the keys on the system * Implement "/proc/keys" to provide a list of the keys on the system that
* grant View permission to the caller.
*/ */
#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
@ -291,7 +292,8 @@ static struct rb_node *key_user_first(struct rb_root *r)
} }
/* /*
* implement "/proc/key-users" to provides a list of the key users * Implement "/proc/key-users" to provides a list of the key users and their
* quotas.
*/ */
static int proc_key_users_open(struct inode *inode, struct file *file) static int proc_key_users_open(struct inode *inode, struct file *file)
{ {

112
security/keys/process_keys.c
View File

@ -1,4 +1,4 @@
/* Management of a process's keyrings /* Manage a process's keyrings
* *
* Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -21,13 +21,13 @@
#include <asm/uaccess.h> #include <asm/uaccess.h>
#include "internal.h" #include "internal.h"
/* session keyring create vs join semaphore */ /* Session keyring create vs join semaphore */
static DEFINE_MUTEX(key_session_mutex); static DEFINE_MUTEX(key_session_mutex);
/* user keyring creation semaphore */ /* User keyring creation semaphore */
static DEFINE_MUTEX(key_user_keyring_mutex); static DEFINE_MUTEX(key_user_keyring_mutex);
/* the root user's tracking struct */ /* The root user's tracking struct */
struct key_user root_key_user = { struct key_user root_key_user = {
.usage = ATOMIC_INIT(3), .usage = ATOMIC_INIT(3),
.cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
@ -39,7 +39,7 @@ struct key_user root_key_user = {
}; };
/* /*
* install user and user session keyrings for a particular UID * Install the user and user session keyrings for the current process's UID.
*/ */
int install_user_keyrings(void) int install_user_keyrings(void)
{ {
@ -121,7 +121,8 @@ error:
} }
/* /*
* install a fresh thread keyring directly to new credentials * Install a fresh thread keyring directly to new credentials. This keyring is
* allowed to overrun the quota.
*/ */
int install_thread_keyring_to_cred(struct cred *new) int install_thread_keyring_to_cred(struct cred *new)
{ {
@ -137,7 +138,7 @@ int install_thread_keyring_to_cred(struct cred *new)
} }
/* /*
* install a fresh thread keyring, discarding the old one * Install a fresh thread keyring, discarding the old one.
*/ */
static int install_thread_keyring(void) static int install_thread_keyring(void)
{ {
@ -160,9 +161,10 @@ static int install_thread_keyring(void)
} }
/* /*
* install a process keyring directly to a credentials struct * Install a process keyring directly to a credentials struct.
* - returns -EEXIST if there was already a process keyring, 0 if one installed, *
* and other -ve on any other error * Returns -EEXIST if there was already a process keyring, 0 if one installed,
* and other value on any other error
*/ */
int install_process_keyring_to_cred(struct cred *new) int install_process_keyring_to_cred(struct cred *new)
{ {
@ -191,8 +193,11 @@ int install_process_keyring_to_cred(struct cred *new)
} }
/* /*
* make sure a process keyring is installed * Make sure a process keyring is installed for the current process. The
* - we * existing process keyring is not replaced.
*
* Returns 0 if there is a process keyring by the end of this function, some
* error otherwise.
*/ */
static int install_process_keyring(void) static int install_process_keyring(void)
{ {
@ -213,7 +218,7 @@ static int install_process_keyring(void)
} }
/* /*
* install a session keyring directly to a credentials struct * Install a session keyring directly to a credentials struct.
*/ */
int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
{ {
@ -253,8 +258,8 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
} }
/* /*
* install a session keyring, discarding the old one * Install a session keyring, discarding the old one. If a keyring is not
* - if a keyring is not supplied, an empty one is invented * supplied, an empty one is invented.
*/ */
static int install_session_keyring(struct key *keyring) static int install_session_keyring(struct key *keyring)
{ {
@ -275,7 +280,7 @@ static int install_session_keyring(struct key *keyring)
} }
/* /*
* the filesystem user ID changed * Handle the fsuid changing.
*/ */
void key_fsuid_changed(struct task_struct *tsk) void key_fsuid_changed(struct task_struct *tsk)
{ {
@ -289,7 +294,7 @@ void key_fsuid_changed(struct task_struct *tsk)
} }
/* /*
* the filesystem group ID changed * Handle the fsgid changing.
*/ */
void key_fsgid_changed(struct task_struct *tsk) void key_fsgid_changed(struct task_struct *tsk)
{ {
@ -303,11 +308,25 @@ void key_fsgid_changed(struct task_struct *tsk)
} }
/* /*
* search only my process keyrings for the first matching key * Search the process keyrings attached to the supplied cred for the first
* - we use the supplied match function to see if the description (or other * matching key.
* feature of interest) matches *
* - we return -EAGAIN if we didn't find any matching key * The search criteria are the type and the match function. The description is
* - we return -ENOKEY if we found only negative matching keys * given to the match function as a parameter, but doesn't otherwise influence
* the search. Typically the match function will compare the description
* parameter to the key's description.
*
* This can only search keyrings that grant Search permission to the supplied
* credentials. Keyrings linked to searched keyrings will also be searched if
* they grant Search permission too. Keys can only be found if they grant
* Search permission to the credentials.
*
* Returns a pointer to the key with the key usage count incremented if
* successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
* matched negative keys.
*
* In the case of a successful return, the possession attribute is set on the
* returned key reference.
*/ */
key_ref_t search_my_process_keyrings(struct key_type *type, key_ref_t search_my_process_keyrings(struct key_type *type,
const void *description, const void *description,
@ -423,11 +442,12 @@ found:
} }
/* /*
* search the process keyrings for the first matching key * Search the process keyrings attached to the supplied cred for the first
* - we use the supplied match function to see if the description (or other * matching key in the manner of search_my_process_keyrings(), but also search
* feature of interest) matches * the keys attached to the assumed authorisation key using its credentials if
* - we return -EAGAIN if we didn't find any matching key * one is available.
* - we return -ENOKEY if we found only negative matching keys *
* Return same as search_my_process_keyrings().
*/ */
key_ref_t search_process_keyrings(struct key_type *type, key_ref_t search_process_keyrings(struct key_type *type,
const void *description, const void *description,
@ -485,7 +505,7 @@ found:
} }
/* /*
* see if the key we're looking at is the target key * See if the key we're looking at is the target key.
*/ */
int lookup_user_key_possessed(const struct key *key, const void *target) int lookup_user_key_possessed(const struct key *key, const void *target)
{ {
@ -493,9 +513,22 @@ int lookup_user_key_possessed(const struct key *key, const void *target)
} }
/* /*
* lookup a key given a key ID from userspace with a given permissions mask * Look up a key ID given us by userspace with a given permissions mask to get
* - don't create special keyrings unless so requested * the key it refers to.
* - partially constructed keys aren't found unless requested *
* Flags can be passed to request that special keyrings be created if referred
* to directly, to permit partially constructed keys to be found and to skip
* validity and permission checks on the found key.
*
* Returns a pointer to the key with an incremented usage count if successful;
* -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
* to a key or the best found key was a negative key; -EKEYREVOKED or
* -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
* found key doesn't grant the requested permit or the LSM denied access to it;
* or -ENOMEM if a special keyring couldn't be created.
*
* In the case of a successful return, the possession attribute is set on the
* returned key reference.
*/ */
key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
key_perm_t perm) key_perm_t perm)
@ -703,10 +736,15 @@ reget_creds:
} }
/* /*
* join the named keyring as the session keyring if possible, or attempt to * Join the named keyring as the session keyring if possible else attempt to
* create a new one of that name if not * create a new one of that name and join that.
* - if the name is NULL, an empty anonymous keyring is installed instead *
* - named session keyring joining is done with a semaphore held * If the name is NULL, an empty anonymous keyring will be installed as the
* session keyring.
*
* Named session keyrings are joined with a semaphore held to prevent the
* keyrings from going away whilst the attempt is made to going them and also
* to prevent a race in creating compatible session keyrings.
*/ */
long join_session_keyring(const char *name) long join_session_keyring(const char *name)
{ {
@ -778,8 +816,8 @@ error:
} }
/* /*
* Replace a process's session keyring when that process resumes userspace on * Replace a process's session keyring on behalf of one of its children when
* behalf of one of its children * the target process is about to resume userspace execution.
*/ */
void key_replace_session_keyring(void) void key_replace_session_keyring(void)
{ {

164
security/keys/request_key.c
View File

@ -39,8 +39,14 @@ static int key_wait_bit_intr(void *flags)
return signal_pending(current) ? -ERESTARTSYS : 0; return signal_pending(current) ? -ERESTARTSYS : 0;
} }
/* /**
* call to complete the construction of a key * complete_request_key - Complete the construction of a key.
* @cons: The key construction record.
* @error: The success or failute of the construction.
*
* Complete the attempt to construct a key. The key will be negated
* if an error is indicated. The authorisation key will be revoked
* unconditionally.
*/ */
void complete_request_key(struct key_construction *cons, int error) void complete_request_key(struct key_construction *cons, int error)
{ {
@ -58,23 +64,33 @@ void complete_request_key(struct key_construction *cons, int error)
} }
EXPORT_SYMBOL(complete_request_key); EXPORT_SYMBOL(complete_request_key);
/*
* Initialise a usermode helper that is going to have a specific session
* keyring.
*
* This is called in context of freshly forked kthread before kernel_execve(),
* so we can simply install the desired session_keyring at this point.
*/
static int umh_keys_init(struct subprocess_info *info) static int umh_keys_init(struct subprocess_info *info)
{ {
struct cred *cred = (struct cred*)current_cred(); struct cred *cred = (struct cred*)current_cred();
struct key *keyring = info->data; struct key *keyring = info->data;
/*
* This is called in context of freshly forked kthread before
* kernel_execve(), we can just change our ->session_keyring.
*/
return install_session_keyring_to_cred(cred, keyring); return install_session_keyring_to_cred(cred, keyring);
} }
/*
* Clean up a usermode helper with session keyring.
*/
static void umh_keys_cleanup(struct subprocess_info *info) static void umh_keys_cleanup(struct subprocess_info *info)
{ {
struct key *keyring = info->data; struct key *keyring = info->data;
key_put(keyring); key_put(keyring);
} }
/*
* Call a usermode helper with a specific session keyring.
*/
static int call_usermodehelper_keys(char *path, char **argv, char **envp, static int call_usermodehelper_keys(char *path, char **argv, char **envp,
struct key *session_keyring, enum umh_wait wait) struct key *session_keyring, enum umh_wait wait)
{ {
@ -91,7 +107,7 @@ static int call_usermodehelper_keys(char *path, char **argv, char **envp,
} }
/* /*
* request userspace finish the construction of a key * Request userspace finish the construction of a key
* - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>" * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
*/ */
static int call_sbin_request_key(struct key_construction *cons, static int call_sbin_request_key(struct key_construction *cons,
@ -198,8 +214,9 @@ error_alloc:
} }
/* /*
* call out to userspace for key construction * Call out to userspace for key construction.
* - we ignore program failure and go on key status instead *
* Program failure is ignored in favour of key status.
*/ */
static int construct_key(struct key *key, const void *callout_info, static int construct_key(struct key *key, const void *callout_info,
size_t callout_len, void *aux, size_t callout_len, void *aux,
@ -246,9 +263,10 @@ static int construct_key(struct key *key, const void *callout_info,
} }
/* /*
* get the appropriate destination keyring for the request * Get the appropriate destination keyring for the request.
* - we return whatever keyring we select with an extra reference upon it which *
* the caller must release * The keyring selected is returned with an extra reference upon it which the
* caller must release.
*/ */
static void construct_get_dest_keyring(struct key **_dest_keyring) static void construct_get_dest_keyring(struct key **_dest_keyring)
{ {
@ -321,9 +339,11 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
} }
/* /*
* allocate a new key in under-construction state and attempt to link it in to * Allocate a new key in under-construction state and attempt to link it in to
* the requested place * the requested keyring.
* - may return a key that's already under construction instead *
* May return a key that's already under construction instead if there was a
* race between two thread calling request_key().
*/ */
static int construct_alloc_key(struct key_type *type, static int construct_alloc_key(struct key_type *type,
const char *description, const char *description,
@ -414,7 +434,7 @@ alloc_failed:
} }
/* /*
* commence key construction * Commence key construction.
*/ */
static struct key *construct_key_and_link(struct key_type *type, static struct key *construct_key_and_link(struct key_type *type,
const char *description, const char *description,
@ -465,12 +485,32 @@ construction_failed:
return ERR_PTR(ret); return ERR_PTR(ret);
} }
/* /**
* request a key * request_key_and_link - Request a key and cache it in a keyring.
* - search the process's keyrings * @type: The type of key we want.
* - check the list of keys being created or updated * @description: The searchable description of the key.
* - call out to userspace for a key if supplementary info was provided * @callout_info: The data to pass to the instantiation upcall (or NULL).
* - cache the key in an appropriate keyring * @callout_len: The length of callout_info.
* @aux: Auxiliary data for the upcall.
* @dest_keyring: Where to cache the key.
* @flags: Flags to key_alloc().
*
* A key matching the specified criteria is searched for in the process's
* keyrings and returned with its usage count incremented if found. Otherwise,
* if callout_info is not NULL, a key will be allocated and some service
* (probably in userspace) will be asked to instantiate it.
*
* If successfully found or created, the key will be linked to the destination
* keyring if one is provided.
*
* Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
* or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
* found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
* if insufficient key quota was available to create a new key; or -ENOMEM if
* insufficient memory was available.
*
* If the returned key was created, then it may still be under construction,
* and wait_for_key_construction() should be used to wait for that to complete.
*/ */
struct key *request_key_and_link(struct key_type *type, struct key *request_key_and_link(struct key_type *type,
const char *description, const char *description,
@ -524,8 +564,16 @@ error:
return key; return key;
} }
/* /**
* wait for construction of a key to complete * wait_for_key_construction - Wait for construction of a key to complete
* @key: The key being waited for.
* @intr: Whether to wait interruptibly.
*
* Wait for a key to finish being constructed.
*
* Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
* if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
* revoked or expired.
*/ */
int wait_for_key_construction(struct key *key, bool intr) int wait_for_key_construction(struct key *key, bool intr)
{ {
@ -542,12 +590,19 @@ int wait_for_key_construction(struct key *key, bool intr)
} }
EXPORT_SYMBOL(wait_for_key_construction); EXPORT_SYMBOL(wait_for_key_construction);
/* /**
* request a key * request_key - Request a key and wait for construction
* - search the process's keyrings * @type: Type of key.
* - check the list of keys being created or updated * @description: The searchable description of the key.
* - call out to userspace for a key if supplementary info was provided * @callout_info: The data to pass to the instantiation upcall (or NULL).
* - waits uninterruptible for creation to complete *
* As for request_key_and_link() except that it does not add the returned key
* to a keyring if found, new keys are always allocated in the user's quota,
* the callout_info must be a NUL-terminated string and no auxiliary data can
* be passed.
*
* Furthermore, it then works as wait_for_key_construction() to wait for the
* completion of keys undergoing construction with a non-interruptible wait.
*/ */
struct key *request_key(struct key_type *type, struct key *request_key(struct key_type *type,
const char *description, const char *description,
@ -572,12 +627,19 @@ struct key *request_key(struct key_type *type,
} }
EXPORT_SYMBOL(request_key); EXPORT_SYMBOL(request_key);
/* /**
* request a key with auxiliary data for the upcaller * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
* - search the process's keyrings * @type: The type of key we want.
* - check the list of keys being created or updated * @description: The searchable description of the key.
* - call out to userspace for a key if supplementary info was provided * @callout_info: The data to pass to the instantiation upcall (or NULL).
* - waits uninterruptible for creation to complete * @callout_len: The length of callout_info.
* @aux: Auxiliary data for the upcall.
*
* As for request_key_and_link() except that it does not add the returned key
* to a keyring if found and new keys are always allocated in the user's quota.
*
* Furthermore, it then works as wait_for_key_construction() to wait for the
* completion of keys undergoing construction with a non-interruptible wait.
*/ */
struct key *request_key_with_auxdata(struct key_type *type, struct key *request_key_with_auxdata(struct key_type *type,
const char *description, const char *description,
@ -602,10 +664,18 @@ struct key *request_key_with_auxdata(struct key_type *type,
EXPORT_SYMBOL(request_key_with_auxdata); EXPORT_SYMBOL(request_key_with_auxdata);
/* /*
* request a key (allow async construction) * request_key_async - Request a key (allow async construction)
* - search the process's keyrings * @type: Type of key.
* - check the list of keys being created or updated * @description: The searchable description of the key.
* - call out to userspace for a key if supplementary info was provided * @callout_info: The data to pass to the instantiation upcall (or NULL).
* @callout_len: The length of callout_info.
*
* As for request_key_and_link() except that it does not add the returned key
* to a keyring if found, new keys are always allocated in the user's quota and
* no auxiliary data can be passed.
*
* The caller should call wait_for_key_construction() to wait for the
* completion of the returned key if it is still undergoing construction.
*/ */
struct key *request_key_async(struct key_type *type, struct key *request_key_async(struct key_type *type,
const char *description, const char *description,
@ -620,9 +690,17 @@ EXPORT_SYMBOL(request_key_async);
/* /*
* request a key with auxiliary data for the upcaller (allow async construction) * request a key with auxiliary data for the upcaller (allow async construction)
* - search the process's keyrings * @type: Type of key.
* - check the list of keys being created or updated * @description: The searchable description of the key.
* - call out to userspace for a key if supplementary info was provided * @callout_info: The data to pass to the instantiation upcall (or NULL).
* @callout_len: The length of callout_info.
* @aux: Auxiliary data for the upcall.
*
* As for request_key_and_link() except that it does not add the returned key
* to a keyring if found and new keys are always allocated in the user's quota.
*
* The caller should call wait_for_key_construction() to wait for the
* completion of the returned key if it is still undergoing construction.
*/ */
struct key *request_key_async_with_auxdata(struct key_type *type, struct key *request_key_async_with_auxdata(struct key_type *type,
const char *description, const char *description,

30
security/keys/request_key_auth.c
View File

@ -1,4 +1,4 @@
/* request_key_auth.c: request key authorisation controlling key def /* Request key authorisation token key definition.
* *
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com) * Written by David Howells (dhowells@redhat.com)
@ -26,7 +26,7 @@ static void request_key_auth_destroy(struct key *);
static long request_key_auth_read(const struct key *, char __user *, size_t); static long request_key_auth_read(const struct key *, char __user *, size_t);
/* /*
* the request-key authorisation key type definition * The request-key authorisation key type definition.
*/ */
struct key_type key_type_request_key_auth = { struct key_type key_type_request_key_auth = {
.name = ".request_key_auth", .name = ".request_key_auth",
@ -39,7 +39,7 @@ struct key_type key_type_request_key_auth = {
}; };
/* /*
* instantiate a request-key authorisation key * Instantiate a request-key authorisation key.
*/ */
static int request_key_auth_instantiate(struct key *key, static int request_key_auth_instantiate(struct key *key,
const void *data, const void *data,
@ -50,7 +50,7 @@ static int request_key_auth_instantiate(struct key *key,
} }
/* /*
* reading a request-key authorisation key retrieves the callout information * Describe an authorisation token.
*/ */
static void request_key_auth_describe(const struct key *key, static void request_key_auth_describe(const struct key *key,
struct seq_file *m) struct seq_file *m)
@ -63,7 +63,7 @@ static void request_key_auth_describe(const struct key *key,
} }
/* /*
* read the callout_info data * Read the callout_info data (retrieves the callout information).
* - the key's semaphore is read-locked * - the key's semaphore is read-locked
*/ */
static long request_key_auth_read(const struct key *key, static long request_key_auth_read(const struct key *key,
@ -89,8 +89,9 @@ static long request_key_auth_read(const struct key *key,
} }
/* /*
* handle revocation of an authorisation token key * Handle revocation of an authorisation token key.
* - called with the key sem write-locked *
* Called with the key sem write-locked.
*/ */
static void request_key_auth_revoke(struct key *key) static void request_key_auth_revoke(struct key *key)
{ {
@ -105,7 +106,7 @@ static void request_key_auth_revoke(struct key *key)
} }
/* /*
* destroy an instantiation authorisation token key * Destroy an instantiation authorisation token key.
*/ */
static void request_key_auth_destroy(struct key *key) static void request_key_auth_destroy(struct key *key)
{ {
@ -125,8 +126,8 @@ static void request_key_auth_destroy(struct key *key)
} }
/* /*
* create an authorisation token for /sbin/request-key or whoever to gain * Create an authorisation token for /sbin/request-key or whoever to gain
* access to the caller's security data * access to the caller's security data.
*/ */
struct key *request_key_auth_new(struct key *target, const void *callout_info, struct key *request_key_auth_new(struct key *target, const void *callout_info,
size_t callout_len, struct key *dest_keyring) size_t callout_len, struct key *dest_keyring)
@ -220,7 +221,7 @@ error_alloc:
} }
/* /*
* see if an authorisation key is associated with a particular key * See if an authorisation key is associated with a particular key.
*/ */
static int key_get_instantiation_authkey_match(const struct key *key, static int key_get_instantiation_authkey_match(const struct key *key,
const void *_id) const void *_id)
@ -232,11 +233,8 @@ static int key_get_instantiation_authkey_match(const struct key *key,
} }
/* /*
* get the authorisation key for instantiation of a specific key if attached to * Search the current process's keyrings for the authorisation key for
* the current process's keyrings * instantiation of a key.
* - this key is inserted into a keyring and that is set as /sbin/request-key's
* session keyring
* - a target_id of zero specifies any valid token
*/ */
struct key *key_get_instantiation_authkey(key_serial_t target_id) struct key *key_get_instantiation_authkey(key_serial_t target_id)
{ {