Now that /proc/keys is used by libkeyutils to look up a key by type and
description, we should make it unconditional and remove
CONFIG_DEBUG_PROC_KEYS.
Reported-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
When a key is being garbage collected, it's key->user would get put before
the ->destroy() callback is called, where the key is removed from it's
respective tracking structures.
This leaves a key hanging in a semi-invalid state which leaves a window open
for a different task to try an access key->user. An example is
find_keyring_by_name() which would dereference key->user for a key that is
in the process of being garbage collected (where key->user was freed but
->destroy() wasn't called yet - so it's still present in the linked list).
This would cause either a panic, or corrupt memory.
Fixes CVE-2014-9529.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
We already checked if "desc" was NULL at the beginning of the function
and we've dereferenced it so this causes a static checker warning.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
When loading encrypted-keys module, if the last check of
aes_get_sizes() in init_encrypted() fails, the driver just returns an
error without unregistering its key type. This results in the stale
entry in the list. In addition to memory leaks, this leads to a kernel
crash when registering a new key type later.
This patch fixes the problem by swapping the calls of aes_get_sizes()
and register_key_type(), and releasing resources properly at the error
paths.
Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Since the keyring facility can be viewed as a cache (at least in some
applications), the local expiration time on the key should probably be viewed
as a 'needs updating after this time' property rather than an absolute 'anyone
now wanting to use this object is out of luck' property.
Since request_key() is the main interface for the usage of keys, this should
update or replace an expired key rather than issuing EKEYEXPIRED if the local
expiration has been reached (ie. it should refresh the cache).
For absolute conditions where refreshing the cache probably doesn't help, the
key can be negatively instantiated using KEYCTL_REJECT_KEY with EKEYEXPIRED
given as the error to issue. This will still cause request_key() to return
EKEYEXPIRED as that was explicitly set.
In the future, if the key type has an update op available, we might want to
upcall with the expired key and allow the upcall to update it. We would pass
a different operation name (the first column in /etc/request-key.conf) to the
request-key program.
request_key() returning EKEYEXPIRED is causing an NFS problem which Chuck
Lever describes thusly:
After about 10 minutes, my NFSv4 functional tests fail because the
ownership of the test files goes to "-2". Looking at /proc/keys
shows that the id_resolv keys that map to my test user ID have
expired. The ownership problem persists until the expired keys are
purged from the keyring, and fresh keys are obtained.
I bisected the problem to 3.13 commit b2a4df200d ("KEYS: Expand
the capacity of a keyring"). This commit inadvertantly changes the
API contract of the internal function keyring_search_aux().
The root cause appears to be that b2a4df200d made "no state check"
the default behavior. "No state check" means the keyring search
iterator function skips checking the key's expiry timeout, and
returns expired keys. request_key_and_link() depends on getting
an -EAGAIN result code to know when to perform an upcall to refresh
an expired key.
This patch can be tested directly by:
keyctl request2 user debug:fred a @s
keyctl timeout %user:debug:fred 3
sleep 4
keyctl request2 user debug:fred a @s
Without the patch, the last command gives error EKEYEXPIRED, but with the
command it gives a new key.
Reported-by: Carl Hetherington <cth@carlh.net>
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Simplify KEYRING_SEARCH_{NO,DO}_STATE_CHECK flags to be two variations of the
same flag. They are effectively mutually exclusive and one or the other
should be provided, but not both.
Keyring cycle detection and key possession determination are the only things
that set NO_STATE_CHECK, except that neither flag really does anything there
because neither purpose makes use of the keyring_search_iterator() function,
but rather provides their own.
For cycle detection we definitely want to check inside of expired keyrings,
just so that we don't create a cycle we can't get rid of. Revoked keyrings
are cleared at revocation time and can't then be reused, so shouldn't be a
problem either way.
For possession determination, we *might* want to validate each keyring before
searching it: do you possess a key that's hidden behind an expired or just
plain inaccessible keyring? Currently, the answer is yes. Note that you
cannot, however, possess a key behind a revoked keyring because they are
cleared on revocation.
keyring_search() sets DO_STATE_CHECK, which is correct.
request_key_and_link() currently doesn't specify whether to check the key
state or not - but it should set DO_STATE_CHECK.
key_get_instantiation_authkey() also currently doesn't specify whether to
check the key state or not - but it probably should also set DO_STATE_CHECK.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
When a key description argument is imported into the kernel from userspace, as
happens in add_key(), request_key(), KEYCTL_JOIN_SESSION_KEYRING,
KEYCTL_SEARCH, the description is copied into a buffer up to PAGE_SIZE in size.
PAGE_SIZE, however, is a variable quantity, depending on the arch. Fix this at
4096 instead (ie. 4095 plus a NUL termination) and define a constant
(KEY_MAX_DESC_SIZE) to this end.
When reading the description back with KEYCTL_DESCRIBE, a PAGE_SIZE internal
buffer is allocated into which the information and description will be
rendered. This means that the description will get truncated if an extremely
long description it has to be crammed into the buffer with the stringified
information. There is no particular need to copy the description into the
buffer, so just copy it directly to userspace in a separate operation.
Reported-by: Christian Kastner <debian@kvr.at>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Christian Kastner <debian@kvr.at>
Pull security subsystem updates from James Morris.
Mostly ima, selinux, smack and key handling updates.
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (65 commits)
integrity: do zero padding of the key id
KEYS: output last portion of fingerprint in /proc/keys
KEYS: strip 'id:' from ca_keyid
KEYS: use swapped SKID for performing partial matching
KEYS: Restore partial ID matching functionality for asymmetric keys
X.509: If available, use the raw subjKeyId to form the key description
KEYS: handle error code encoded in pointer
selinux: normalize audit log formatting
selinux: cleanup error reporting in selinux_nlmsg_perm()
KEYS: Check hex2bin()'s return when generating an asymmetric key ID
ima: detect violations for mmaped files
ima: fix race condition on ima_rdwr_violation_check and process_measurement
ima: added ima_policy_flag variable
ima: return an error code from ima_add_boot_aggregate()
ima: provide 'ima_appraise=log' kernel option
ima: move keyring initialization to ima_init()
PKCS#7: Handle PKCS#7 messages that contain no X.509 certs
PKCS#7: Better handling of unsupported crypto
KEYS: Overhaul key identification when searching for asymmetric keys
KEYS: Implement binary asymmetric key ID handling
...
Make the key matching functions pointed to by key_match_data::cmp return bool
rather than int.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
A previous patch added a ->match_preparse() method to the key type. This is
allowed to override the function called by the iteration algorithm.
Therefore, we can just set a default that simply checks for an exact match of
the key description with the original criterion data and allow match_preparse
to override it as needed.
The key_type::match op is then redundant and can be removed, as can the
user_match() function.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Remove key_type::def_lookup_type as it's no longer used. The information now
defaults to KEYRING_SEARCH_LOOKUP_DIRECT but may be overridden by
type->match_preparse().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Preparse the match data. This provides several advantages:
(1) The preparser can reject invalid criteria up front.
(2) The preparser can convert the criteria to binary data if necessary (the
asymmetric key type really wants to do binary comparison of the key IDs).
(3) The preparser can set the type of search to be performed. This means
that it's not then a one-off setting in the key type.
(4) The preparser can set an appropriate comparator function.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reinstate the generation of EPERM for a key type name beginning with a '.' in
a userspace call. Types whose name begins with a '.' are internal only.
The test was removed by:
commit a4e3b8d79a
Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
Date: Thu May 22 14:02:23 2014 -0400
Subject: KEYS: special dot prefixed keyring name bug fix
I think we want to keep the restriction on type name so that userspace can't
add keys of a special internal type.
Note that removal of the test causes several of the tests in the keyutils
testsuite to fail.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Now that NFS client uses the kernel key ring facility to store the NFSv4
id/gid mappings, the defaults for root_maxkeys and root_maxbytes need to be
substantially increased.
These values have been soak tested:
https://bugzilla.redhat.com/show_bug.cgi?id=1033708#c73
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull security subsystem updates from James Morris:
"In this release:
- PKCS#7 parser for the key management subsystem from David Howells
- appoint Kees Cook as seccomp maintainer
- bugfixes and general maintenance across the subsystem"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (94 commits)
X.509: Need to export x509_request_asymmetric_key()
netlabel: shorter names for the NetLabel catmap funcs/structs
netlabel: fix the catmap walking functions
netlabel: fix the horribly broken catmap functions
netlabel: fix a problem when setting bits below the previously lowest bit
PKCS#7: X.509 certificate issuer and subject are mandatory fields in the ASN.1
tpm: simplify code by using %*phN specifier
tpm: Provide a generic means to override the chip returned timeouts
tpm: missing tpm_chip_put in tpm_get_random()
tpm: Properly clean sysfs entries in error path
tpm: Add missing tpm_do_selftest to ST33 I2C driver
PKCS#7: Use x509_request_asymmetric_key()
Revert "selinux: fix the default socket labeling in sock_graft()"
X.509: x509_request_asymmetric_keys() doesn't need string length arguments
PKCS#7: fix sparse non static symbol warning
KEYS: revert encrypted key change
ima: add support for measuring and appraising firmware
firmware_class: perform new LSM checks
security: introduce kernel_fw_from_file hook
PKCS#7: Missing inclusion of linux/err.h
...
Commit fc7c70e "KEYS: struct key_preparsed_payload should have two
payload pointers" erroneously modified encrypted-keys. This patch
reverts the change to that file.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Provide key preparsing for the request_key_auth key type so that we can make
preparsing mandatory. This does nothing as this type can only be set up
internally to the kernel.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Provide key preparsing in the keyring so that we can make preparsing
mandatory. For keyrings, however, only an empty payload is permitted.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Make use of key preparsing in the big key type so that quota size determination
can take place prior to keyring locking when a key is being added.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Make use of key preparsing in user-defined and logon keys so that quota size
determination can take place prior to keyring locking when a key is being
added.
Also the idmapper key types need to change to match as they use the
user-defined key type routines.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Call the ->free_preparse() key type op even after ->preparse() returns an
error as it does cleaning up type stuff.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Allow a key type's preparsing routine to set the expiry time for a key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
struct key_preparsed_payload should have two payload pointers to correspond
with those in struct key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Provide a generic instantiation function for key types that use the preparse
hook. This makes it easier to prereserve key quota before keyrings get locked
to retain the new key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Special kernel keys, such as those used to hold DNS results for AFS, CIFS and
NFS and those used to hold idmapper results for NFS, used to be
'invalidateable' with key_revoke(). However, since the default permissions for
keys were reduced:
Commit: 96b5c8fea6
KEYS: Reduce initial permissions on keys
it has become impossible to do this.
Add a key flag (KEY_FLAG_ROOT_CAN_INVAL) that will permit a key to be
invalidated by root. This should not be used for system keyrings as the
garbage collector will try and remove any invalidate key. For system keyrings,
KEY_FLAG_ROOT_CAN_CLEAR can be used instead.
After this, from userspace, keyctl_invalidate() and "keyctl invalidate" can be
used by any possessor of CAP_SYS_ADMIN (typically root) to invalidate DNS and
idmapper keys. Invalidated keys are immediately garbage collected and will be
immediately rerequested if needed again.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Steve Dickson <steved@redhat.com>
Dot prefixed keyring names are supposed to be reserved for the
kernel, but add_key() calls key_get_type_from_user(), which
incorrectly verifies the 'type' field, not the 'description' field.
This patch verifies the 'description' field isn't dot prefixed,
when creating a new keyring, and removes the dot prefix test in
key_get_type_from_user().
Changelog v6:
- whitespace and other cleanup
Changelog v5:
- Only prevent userspace from creating a dot prefixed keyring, not
regular keys - Dmitry
Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().
So:
Rename wait_on_bit and wait_on_bit_lock to
wait_on_bit_action and wait_on_bit_lock_action
to make it explicit that they need an action function.
Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
which are *not* given an action function but implicitly use
a standard one.
The decision to error-out if a signal is pending is now made
based on the 'mode' argument rather than being encoded in the action
function.
All instances of the old wait_on_bit and wait_on_bit_lock which
can use the new version have been changed accordingly and their
action functions have been discarded.
wait_on_bit{_lock} does not return any specific error code in the
event of a signal so the caller must check for non-zero and
interpolate their own error code as appropriate.
The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"
The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.
A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack. So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).
Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS. CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull security layer updates from Serge Hallyn:
"This is a merge of James Morris' security-next tree from 3.14 to
yesterday's master, plus four patches from Paul Moore which are in
linux-next, plus one patch from Mimi"
* 'serge-next-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-security:
ima: audit log files opened with O_DIRECT flag
selinux: conditionally reschedule in hashtab_insert while loading selinux policy
selinux: conditionally reschedule in mls_convert_context while loading selinux policy
selinux: reject setexeccon() on MNT_NOSUID applications with -EACCES
selinux: Report permissive mode in avc: denied messages.
Warning in scanf string typing
Smack: Label cgroup files for systemd
Smack: Verify read access on file open - v3
security: Convert use of typedef ctl_table to struct ctl_table
Smack: bidirectional UDS connect check
Smack: Correctly remove SMACK64TRANSMUTE attribute
SMACK: Fix handling value==NULL in post setxattr
bugfix patch for SMACK
Smack: adds smackfs/ptrace interface
Smack: unify all ptrace accesses in the smack
Smack: fix the subject/object order in smack_ptrace_traceme()
Minor improvement of 'smack_sb_kern_mount'
smack: fix key permission verification
KEYS: Move the flags representing required permission to linux/key.h
This typedef is unnecessary and should just be removed.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull security subsystem updates from James Morris:
"Apart from reordering the SELinux mmap code to ensure DAC is called
before MAC, these are minor maintenance updates"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
selinux: correctly label /proc inodes in use before the policy is loaded
selinux: put the mmap() DAC controls before the MAC controls
selinux: fix the output of ./scripts/get_maintainer.pl for SELinux
evm: enable key retention service automatically
ima: skip memory allocation for empty files
evm: EVM does not use MD5
ima: return d_name.name if d_path fails
integrity: fix checkpatch errors
ima: fix erroneous removal of security.ima xattr
security: integrity: Use a more current logging style
MAINTAINERS: email updates and other misc. changes
ima: reduce memory usage when a template containing the n field is used
ima: restore the original behavior for sending data with ima template
Integrity: Pass commname via get_task_comm()
fs: move i_readcount
ima: use static const char array definitions
security: have cap_dentry_init_security return error
ima: new helper: file_inode(file)
kernel: Mark function as static in kernel/seccomp.c
capability: Use current logging styles
...
Pull s390 compat wrapper rework from Heiko Carstens:
"S390 compat system call wrapper simplification work.
The intention of this work is to get rid of all hand written assembly
compat system call wrappers on s390, which perform proper sign or zero
extension, or pointer conversion of compat system call parameters.
Instead all of this should be done with C code eg by using Al's
COMPAT_SYSCALL_DEFINEx() macro.
Therefore all common code and s390 specific compat system calls have
been converted to the COMPAT_SYSCALL_DEFINEx() macro.
In order to generate correct code all compat system calls may only
have eg compat_ulong_t parameters, but no unsigned long parameters.
Those patches which change parameter types from unsigned long to
compat_ulong_t parameters are separate in this series, but shouldn't
cause any harm.
The only compat system calls which intentionally have 64 bit
parameters (preadv64 and pwritev64) in support of the x86/32 ABI
haven't been changed, but are now only available if an architecture
defines __ARCH_WANT_COMPAT_SYS_PREADV64/PWRITEV64.
System calls which do not have a compat variant but still need proper
zero extension on s390, like eg "long sys_brk(unsigned long brk)" will
get a proper wrapper function with the new s390 specific
COMPAT_SYSCALL_WRAPx() macro:
COMPAT_SYSCALL_WRAP1(brk, unsigned long, brk);
which generates the following code (simplified):
asmlinkage long sys_brk(unsigned long brk);
asmlinkage long compat_sys_brk(long brk)
{
return sys_brk((u32)brk);
}
Given that the C file which contains all the COMPAT_SYSCALL_WRAP lines
includes both linux/syscall.h and linux/compat.h, it will generate
build errors, if the declaration of sys_brk() doesn't match, or if
there exists a non-matching compat_sys_brk() declaration.
In addition this will intentionally result in a link error if
somewhere else a compat_sys_brk() function exists, which probably
should have been used instead. Two more BUILD_BUG_ONs make sure the
size and type of each compat syscall parameter can be handled
correctly with the s390 specific macros.
I converted the compat system calls step by step to verify the
generated code is correct and matches the previous code. In fact it
did not always match, however that was always a bug in the hand
written asm code.
In result we get less code, less bugs, and much more sanity checking"
* 'compat' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (44 commits)
s390/compat: add copyright statement
compat: include linux/unistd.h within linux/compat.h
s390/compat: get rid of compat wrapper assembly code
s390/compat: build error for large compat syscall args
mm/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
kexec/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
net/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
ipc/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
fs/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
ipc/compat: convert to COMPAT_SYSCALL_DEFINE
fs/compat: convert to COMPAT_SYSCALL_DEFINE
security/compat: convert to COMPAT_SYSCALL_DEFINE
mm/compat: convert to COMPAT_SYSCALL_DEFINE
net/compat: convert to COMPAT_SYSCALL_DEFINE
kernel/compat: convert to COMPAT_SYSCALL_DEFINE
fs/compat: optional preadv64/pwrite64 compat system calls
ipc/compat_sys_msgrcv: change msgtyp type from long to compat_long_t
s390/compat: partial parameter conversion within syscall wrappers
s390/compat: automatic zero, sign and pointer conversion of syscalls
s390/compat: add sync_file_range and fallocate compat syscalls
...
Move the flags representing required permission to linux/key.h as the perm
parameter of security_key_permission() is in terms of them - and not the
permissions mask flags used in key->perm.
Whilst we're at it:
(1) Rename them to be KEY_NEED_xxx rather than KEY_xxx to avoid collisions
with symbols in uapi/linux/input.h.
(2) Don't use key_perm_t for a mask of required permissions, but rather limit
it to the permissions mask attached to the key and arguments related
directly to that.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
This fixes CVE-2014-0102.
The following command sequence produces an oops:
keyctl new_session
i=`keyctl newring _ses @s`
keyctl link @s $i
The problem is that search_nested_keyrings() sees two keyrings that have
matching type and description, so keyring_compare_object() returns true.
s_n_k() then passes the key to the iterator function -
keyring_detect_cycle_iterator() - which *should* check to see whether this is
the keyring of interest, not just one with the same name.
Because assoc_array_find() will return one and only one match, I assumed that
the iterator function would only see an exact match or never be called - but
the iterator isn't only called from assoc_array_find()...
The oops looks something like this:
kernel BUG at /data/fs/linux-2.6-fscache/security/keys/keyring.c:1003!
invalid opcode: 0000 [#1] SMP
...
RIP: keyring_detect_cycle_iterator+0xe/0x1f
...
Call Trace:
search_nested_keyrings+0x76/0x2aa
__key_link_check_live_key+0x50/0x5f
key_link+0x4e/0x85
keyctl_keyring_link+0x60/0x81
SyS_keyctl+0x65/0xe4
tracesys+0xdd/0xe2
The fix is to make keyring_detect_cycle_iterator() check that the key it
has is the key it was actually looking for rather than calling BUG_ON().
A testcase has been included in the keyutils testsuite for this:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=891f3365d07f1996778ade0e3428f01878a1790b
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert all compat system call functions where all parameter types
have a size of four or less than four bytes, or are pointer types
to COMPAT_SYSCALL_DEFINE.
The implicit casts within COMPAT_SYSCALL_DEFINE will perform proper
zero and sign extension to 64 bit of all parameters if needed.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
The usage of strict_strto*() is not preferred, because
strict_strto*() is obsolete. Thus, kstrto*() should be
used.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
We have a problem where the big_key key storage implementation uses a
shmem backed inode to hold the key contents. Because of this detail of
implementation LSM checks are being done between processes trying to
read the keys and the tmpfs backed inode. The LSM checks are already
being handled on the key interface level and should not be enforced at
the inode level (since the inode is an implementation detail, not a
part of the security model)
This patch implements a new function shmem_kernel_file_setup() which
returns the equivalent to shmem_file_setup() only the underlying inode
has S_PRIVATE set. This means that all LSM checks for the inode in
question are skipped. It should only be used for kernel internal
operations where the inode is not exposed to userspace without proper
LSM checking. It is possible that some other users of
shmem_file_setup() should use the new interface, but this has not been
explored.
Reproducing this bug is a little bit difficult. The steps I used on
Fedora are:
(1) Turn off selinux enforcing:
setenforce 0
(2) Create a huge key
k=`dd if=/dev/zero bs=8192 count=1 | keyctl padd big_key test-key @s`
(3) Access the key in another context:
runcon system_u:system_r:httpd_t:s0-s0:c0.c1023 keyctl print $k >/dev/null
(4) Examine the audit logs:
ausearch -m AVC -i --subject httpd_t | audit2allow
If the last command's output includes a line that looks like:
allow httpd_t user_tmpfs_t:file { open read };
There was an inode check between httpd and the tmpfs filesystem. With
this patch no such denial will be seen. (NOTE! you should clear your
audit log if you have tested for this previously)
(Please return you box to enforcing)
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hugh Dickins <hughd@google.com>
cc: linux-mm@kvack.org
If a keyring contains more than 16 keyrings (the capacity of a single node in
the associative array) then those keyrings are split over multiple nodes
arranged as a tree.
If search_nested_keyrings() is called to search the keyring then it will
attempt to manually walk over just the 0 branch of the associative array tree
where all the keyring links are stored. This works provided the key is found
before the algorithm steps from one node containing keyrings to a child node
or if there are sufficiently few keyring links that the keyrings are all in
one node.
However, if the algorithm does need to step from a node to a child node, it
doesn't change the node pointer unless a shortcut also gets transited. This
means that the algorithm will keep scanning the same node over and over again
without terminating and without returning.
To fix this, move the internal-pointer-to-node translation from inside the
shortcut transit handler so that it applies it to node arrival as well.
This can be tested by:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done
for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done
for ((i=17; i<=20; i++)); do keyctl search $r user a$i; done
The searches should all complete successfully (or with an error for 17-20),
but instead one or more of them will hang.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
If sufficient keys (or keyrings) are added into a keyring such that a node in
the associative array's tree overflows (each node has a capacity N, currently
16) and such that all N+1 keys have the same index key segment for that level
of the tree (the level'th nibble of the index key), then assoc_array_insert()
calls ops->diff_objects() to indicate at which bit position the two index keys
vary.
However, __key_link_begin() passes a NULL object to assoc_array_insert() with
the intention of supplying the correct pointer later before we commit the
change. This means that keyring_diff_objects() is given a NULL pointer as one
of its arguments which it does not expect. This results in an oops like the
attached.
With the previous patch to fix the keyring hash function, this can be forced
much more easily by creating a keyring and only adding keyrings to it. Add any
other sort of key and a different insertion path is taken - all 16+1 objects
must want to cluster in the same node slot.
This can be tested by:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
This should work fine, but oopses when the 17th keyring is added.
Since ops->diff_objects() is always called with the first pointer pointing to
the object to be inserted (ie. the NULL pointer), we can fix the problem by
changing the to-be-inserted object pointer to point to the index key passed
into assoc_array_insert() instead.
Whilst we're at it, we also switch the arguments so that they are the same as
for ->compare_object().
BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
IP: [<ffffffff81191ee4>] hash_key_type_and_desc+0x18/0xb0
...
RIP: 0010:[<ffffffff81191ee4>] hash_key_type_and_desc+0x18/0xb0
...
Call Trace:
[<ffffffff81191f9d>] keyring_diff_objects+0x21/0xd2
[<ffffffff811f09ef>] assoc_array_insert+0x3b6/0x908
[<ffffffff811929a7>] __key_link_begin+0x78/0xe5
[<ffffffff81191a2e>] key_create_or_update+0x17d/0x36a
[<ffffffff81192e0a>] SyS_add_key+0x123/0x183
[<ffffffff81400ddb>] tracesys+0xdd/0xe2
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
The keyring hash function (used by the associative array) is supposed to clear
the bottommost nibble of the index key (where the hash value resides) for
keyrings and make sure it is non-zero for non-keyrings. This is done to make
keyrings cluster together on one branch of the tree separately to other keys.
Unfortunately, the wrong mask is used, so only the bottom two bits are
examined and cleared and not the whole bottom nibble. This means that keys
and keyrings can still be successfully searched for under most circumstances
as the hash is consistent in its miscalculation, but if a keyring's
associative array bottom node gets filled up then approx 75% of the keyrings
will not be put into the 0 branch.
The consequence of this is that a key in a keyring linked to by another
keyring, ie.
keyring A -> keyring B -> key
may not be found if the search starts at keyring A and then descends into
keyring B because search_nested_keyrings() only searches up the 0 branch (as it
"knows" all keyrings must be there and not elsewhere in the tree).
The fix is to use the right mask.
This can be tested with:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done
for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done
This creates a sandbox keyring, then creates 17 keyrings therein (labelled
ring0..ring16). This causes the root node of the sandbox's associative array
to overflow and for the tree to have extra nodes inserted.
Each keyring then is given a user key (labelled aN for ringN) for us to search
for.
We then search for the user keys we added, starting from the sandbox. If
working correctly, it should return the same ordered list of key IDs as
for...keyctl add... did. Without this patch, it reports ENOKEY "Required key
not available" for some of the keys. Just which keys get this depends as the
kernel pointer to the key type forms part of the hash function.
Reported-by: Nalin Dahyabhai <nalin@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
The second word of key->payload does not get initialised in key_alloc(), but
the big_key type is relying on it having been cleared. The problem comes when
big_key fails to instantiate a large key and doesn't then set the payload. The
big_key_destroy() op is called from the garbage collector and this assumes that
the dentry pointer stored in the second word will be NULL if instantiation did
not complete.
Therefore just pre-clear the entire struct key on allocation rather than trying
to be clever and only initialising to 0 only those bits that aren't otherwise
initialised.
The lack of initialisation can lead to a bug report like the following if
big_key failed to initialise its file:
general protection fault: 0000 [#1] SMP
Modules linked in: ...
CPU: 0 PID: 51 Comm: kworker/0:1 Not tainted 3.10.0-53.el7.x86_64 #1
Hardware name: Dell Inc. PowerEdge 1955/0HC513, BIOS 1.4.4 12/09/2008
Workqueue: events key_garbage_collector
task: ffff8801294f5680 ti: ffff8801296e2000 task.ti: ffff8801296e2000
RIP: 0010:[<ffffffff811b4a51>] dput+0x21/0x2d0
...
Call Trace:
[<ffffffff811a7b06>] path_put+0x16/0x30
[<ffffffff81235604>] big_key_destroy+0x44/0x60
[<ffffffff8122dc4b>] key_gc_unused_keys.constprop.2+0x5b/0xe0
[<ffffffff8122df2f>] key_garbage_collector+0x1df/0x3c0
[<ffffffff8107759b>] process_one_work+0x17b/0x460
[<ffffffff8107834b>] worker_thread+0x11b/0x400
[<ffffffff81078230>] ? rescuer_thread+0x3e0/0x3e0
[<ffffffff8107eb00>] kthread+0xc0/0xd0
[<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
[<ffffffff815c4bec>] ret_from_fork+0x7c/0xb0
[<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
Reported-by: Patrik Kis <pkis@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
Key pointers stored in the keyring are marked in bit 1 to indicate if they
point to a keyring. We need to strip off this bit before using the pointer
when iterating over the keyring for the purpose of looking for links to garbage
collect.
This means that expirable keyrings aren't correctly expiring because the
checker is seeing their key pointer with 2 added to it.
Since the fix for this involves knowing about the internals of the keyring,
key_gc_keyring() is moved to keyring.c and merged into keyring_gc().
This can be tested by:
echo 2 >/proc/sys/kernel/keys/gc_delay
keyctl timeout `keyctl add keyring qwerty "" @s` 2
cat /proc/keys
sleep 5; cat /proc/keys
which should see a keyring called "qwerty" appear in the session keyring and
then disappear after it expires, and:
echo 2 >/proc/sys/kernel/keys/gc_delay
a=`keyctl get_persistent @s`
b=`keyctl add keyring 0 "" $a`
keyctl add user a a $b
keyctl timeout $b 2
cat /proc/keys
sleep 5; cat /proc/keys
which should see a keyring called "0" with a key called "a" in it appear in the
user's persistent keyring (which will be attached to the session keyring) and
then both the "0" keyring and the "a" key should disappear when the "0" keyring
expires.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Simo Sorce <simo@redhat.com>
In the big_key_instantiate() function we return 0 if kernel_write() returns us
an error rather than returning an error. This can potentially lead to
dentry_open() giving a BUG when called from big_key_read() with an unset
tmpfile path.
------------[ cut here ]------------
kernel BUG at fs/open.c:798!
...
RIP: 0010:[<ffffffff8119bbd1>] dentry_open+0xd1/0xe0
...
Call Trace:
[<ffffffff812350c5>] big_key_read+0x55/0x100
[<ffffffff81231084>] keyctl_read_key+0xb4/0xe0
[<ffffffff81231e58>] SyS_keyctl+0xf8/0x1d0
[<ffffffff815bb799>] system_call_fastpath+0x16/0x1b
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
If the UID is specified by userspace when calling the KEYCTL_GET_PERSISTENT
function and the process does not have the CAP_SETUID capability, then the
function will return -EPERM if the current process's uid, suid, euid and fsuid
all match the requested UID. This is incorrect.
Fix it such that when a non-privileged caller requests a persistent keyring by
a specific UID they can only request their own (ie. the specified UID matches
either then process's UID or the process's EUID).
This can be tested by logging in as the user and doing:
keyctl get_persistent @p
keyctl get_persistent @p `id -u`
keyctl get_persistent @p 0
The first two should successfully print the same key ID. The third should do
the same if called by UID 0 or indicate Operation Not Permitted otherwise.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Stephen Gallagher <sgallagh@redhat.com>
Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David Howells <dhowells@redhat.com>
If a key is displaced from a keyring by a matching one, then four more bytes
of quota are allocated to the keyring - despite the fact that the keyring does
not change in size.
Further, when a key is unlinked from a keyring, the four bytes of quota
allocated the link isn't recovered and returned to the user's pool.
The first can be tested by repeating:
keyctl add big_key a fred @s
cat /proc/key-users
(Don't put it in a shell loop otherwise the garbage collector won't have time
to clear the displaced keys, thus affecting the result).
This was causing the kerberos keyring to run out of room fairly quickly.
The second can be tested by:
cat /proc/key-users
a=`keyctl add user a a @s`
cat /proc/key-users
keyctl unlink $a
sleep 1 # Give RCU a chance to delete the key
cat /proc/key-users
assuming no system activity that otherwise adds/removes keys, the amount of
key data allocated should go up (say 40/20000 -> 47/20000) and then return to
the original value at the end.
Reported-by: Stephen Gallagher <sgallagh@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Having the big_keys functionality as a module is very marginally useful.
The userspace code that would use this functionality will get odd error
messages from the keys layer if the module isn't loaded. The code itself
is fairly small, so just have this as a boolean option and not a tristate.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
In order to create the integrity keyrings (eg. _evm, _ima), root's
uid and session keyrings need to be initialized early.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source
or had a cryptographic signature chain that led back to a trusted key the
kernel already possessed.
Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to
keys marked with KEY_FLAGS_TRUSTED.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Add support for per-user_namespace registers of persistent per-UID kerberos
caches held within the kernel.
This allows the kerberos cache to be retained beyond the life of all a user's
processes so that the user's cron jobs can work.
The kerberos cache is envisioned as a keyring/key tree looking something like:
struct user_namespace
\___ .krb_cache keyring - The register
\___ _krb.0 keyring - Root's Kerberos cache
\___ _krb.5000 keyring - User 5000's Kerberos cache
\___ _krb.5001 keyring - User 5001's Kerberos cache
\___ tkt785 big_key - A ccache blob
\___ tkt12345 big_key - Another ccache blob
Or possibly:
struct user_namespace
\___ .krb_cache keyring - The register
\___ _krb.0 keyring - Root's Kerberos cache
\___ _krb.5000 keyring - User 5000's Kerberos cache
\___ _krb.5001 keyring - User 5001's Kerberos cache
\___ tkt785 keyring - A ccache
\___ krbtgt/REDHAT.COM@REDHAT.COM big_key
\___ http/REDHAT.COM@REDHAT.COM user
\___ afs/REDHAT.COM@REDHAT.COM user
\___ nfs/REDHAT.COM@REDHAT.COM user
\___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key
\___ http/KERNEL.ORG@KERNEL.ORG big_key
What goes into a particular Kerberos cache is entirely up to userspace. Kernel
support is limited to giving you the Kerberos cache keyring that you want.
The user asks for their Kerberos cache by:
krb_cache = keyctl_get_krbcache(uid, dest_keyring);
The uid is -1 or the user's own UID for the user's own cache or the uid of some
other user's cache (requires CAP_SETUID). This permits rpc.gssd or whatever to
mess with the cache.
The cache returned is a keyring named "_krb.<uid>" that the possessor can read,
search, clear, invalidate, unlink from and add links to. Active LSMs get a
chance to rule on whether the caller is permitted to make a link.
Each uid's cache keyring is created when it first accessed and is given a
timeout that is extended each time this function is called so that the keyring
goes away after a while. The timeout is configurable by sysctl but defaults to
three days.
Each user_namespace struct gets a lazily-created keyring that serves as the
register. The cache keyrings are added to it. This means that standard key
search and garbage collection facilities are available.
The user_namespace struct's register goes away when it does and anything left
in it is then automatically gc'd.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Simo Sorce <simo@redhat.com>
cc: Serge E. Hallyn <serge.hallyn@ubuntu.com>
cc: Eric W. Biederman <ebiederm@xmission.com>
Implement a big key type that can save its contents to tmpfs and thus
swapspace when memory is tight. This is useful for Kerberos ticket caches.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Simo Sorce <simo@redhat.com>
Expand the capacity of a keyring to be able to hold a lot more keys by using
the previously added associative array implementation. Currently the maximum
capacity is:
(PAGE_SIZE - sizeof(header)) / sizeof(struct key *)
which, on a 64-bit system, is a little more 500. However, since this is being
used for the NFS uid mapper, we need more than that. The new implementation
gives us effectively unlimited capacity.
With some alterations, the keyutils testsuite runs successfully to completion
after this patch is applied. The alterations are because (a) keyrings that
are simply added to no longer appear ordered and (b) some of the errors have
changed a bit.
Signed-off-by: David Howells <dhowells@redhat.com>
Drop the permissions argument from __keyring_search_one() as the only caller
passes 0 here - which causes all checks to be skipped.
Signed-off-by: David Howells <dhowells@redhat.com>
Define a __key_get() wrapper to use rather than atomic_inc() on the key usage
count as this makes it easier to hook in refcount error debugging.
Signed-off-by: David Howells <dhowells@redhat.com>
Search for auth-key by name rather than by target key ID as, in a future
patch, we'll by searching directly by index key in preference to iteration
over all keys.
Signed-off-by: David Howells <dhowells@redhat.com>
Search functions pass around a bunch of arguments, each of which gets copied
with each call. Introduce a search context structure to hold these.
Whilst we're at it, create a search flag that indicates whether the search
should be directly to the description or whether it should iterate through all
keys looking for a non-description match.
This will be useful when keyrings use a generic data struct with generic
routines to manage their content as the search terms can just be passed
through to the iterator callback function.
Also, for future use, the data to be supplied to the match function is
separated from the description pointer in the search context. This makes it
clear which is being supplied.
Signed-off-by: David Howells <dhowells@redhat.com>
Consolidate the concept of an 'index key' for accessing keys. The index key
is the search term needed to find a key directly - basically the key type and
the key description. We can add to that the description length.
This will be useful when turning a keyring into an associative array rather
than just a pointer block.
Signed-off-by: David Howells <dhowells@redhat.com>
Skip key state checks (invalidation, revocation and expiration) when checking
for possession. Without this, keys that have been marked invalid, revoked
keys and expired keys are not given a possession attribute - which means the
possessor is not granted any possession permits and cannot do anything with
them unless they also have one a user, group or other permit.
This causes failures in the keyutils test suite's revocation and expiration
tests now that commit 96b5c8fea6 reduced the
initial permissions granted to a key.
The failures are due to accesses to revoked and expired keys being given
EACCES instead of EKEYREVOKED or EKEYEXPIRED.
Signed-off-by: David Howells <dhowells@redhat.com>
Use call_usermodehelper_setup() + call_usermodehelper_exec() instead of
calling call_usermodehelper_fns(). In case there's an OOM in this last
function the cleanup function may not be called - in this case we would
miss a call to key_put().
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().
This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:
Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().
I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.
While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.
And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes CVE-2013-1792.
There is a race in install_user_keyrings() that can cause a NULL pointer
dereference when called concurrently for the same user if the uid and
uid-session keyrings are not yet created. It might be possible for an
unprivileged user to trigger this by calling keyctl() from userspace in
parallel immediately after logging in.
Assume that we have two threads both executing lookup_user_key(), both
looking for KEY_SPEC_USER_SESSION_KEYRING.
THREAD A THREAD B
=============================== ===============================
==>call install_user_keyrings();
if (!cred->user->session_keyring)
==>call install_user_keyrings()
...
user->uid_keyring = uid_keyring;
if (user->uid_keyring)
return 0;
<==
key = cred->user->session_keyring [== NULL]
user->session_keyring = session_keyring;
atomic_inc(&key->usage); [oops]
At the point thread A dereferences cred->user->session_keyring, thread B
hasn't updated user->session_keyring yet, but thread A assumes it is
populated because install_user_keyrings() returned ok.
The race window is really small but can be exploited if, for example,
thread B is interrupted or preempted after initializing uid_keyring, but
before doing setting session_keyring.
This couldn't be reproduced on a stock kernel. However, after placing
systemtap probe on 'user->session_keyring = session_keyring;' that
introduced some delay, the kernel could be crashed reliably.
Fix this by checking both pointers before deciding whether to return.
Alternatively, the test could be done away with entirely as it is checked
inside the mutex - but since the mutex is global, that may not be the best
way.
Signed-off-by: David Howells <dhowells@redhat.com>
Reported-by: Mateusz Guzik <mguzik@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
A patch to fix some unreachable code in search_my_process_keyrings() got
applied twice by two different routes upstream as commits e67eab39be
and b010520ab3 (both "fix unreachable code").
Unfortunately, the second application removed something it shouldn't
have and this wasn't detected by GIT. This is due to the patch not
having sufficient lines of context to distinguish the two places of
application.
The effect of this is relatively minor: inside the kernel, the keyring
search routines may search multiple keyrings and then prioritise the
errors if no keys or negative keys are found in any of them. With the
extra deletion, the presence of a negative key in the thread keyring
(causing ENOKEY) is incorrectly overridden by an error searching the
process keyring.
So revert the second application of the patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We set ret to NULL then test it. Remove the bogus test
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull security subsystem updates from James Morris:
"A quiet cycle for the security subsystem with just a few maintenance
updates."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: create a sysfs mount point for smackfs
Smack: use select not depends in Kconfig
Yama: remove locking from delete path
Yama: add RCU to drop read locking
drivers/char/tpm: remove tasklet and cleanup
KEYS: Use keyring_alloc() to create special keyrings
KEYS: Reduce initial permissions on keys
KEYS: Make the session and process keyrings per-thread
seccomp: Make syscall skipping and nr changes more consistent
key: Fix resource leak
keys: Fix unreachable code
KEYS: Add payload preparsing opportunity prior to key instantiate or update
Pull module signing support from Rusty Russell:
"module signing is the highlight, but it's an all-over David Howells frenzy..."
Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.
* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
X.509: Fix indefinite length element skip error handling
X.509: Convert some printk calls to pr_devel
asymmetric keys: fix printk format warning
MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
MODSIGN: Make mrproper should remove generated files.
MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
MODSIGN: Use the same digest for the autogen key sig as for the module sig
MODSIGN: Sign modules during the build process
MODSIGN: Provide a script for generating a key ID from an X.509 cert
MODSIGN: Implement module signature checking
MODSIGN: Provide module signing public keys to the kernel
MODSIGN: Automatically generate module signing keys if missing
MODSIGN: Provide Kconfig options
MODSIGN: Provide gitignore and make clean rules for extra files
MODSIGN: Add FIPS policy
module: signature checking hook
X.509: Add a crypto key parser for binary (DER) X.509 certificates
MPILIB: Provide a function to read raw data into an MPI
X.509: Add an ASN.1 decoder
X.509: Add simple ASN.1 grammar compiler
...
Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called. This is done with the
provision of two new key type operations:
int (*preparse)(struct key_preparsed_payload *prep);
void (*free_preparse)(struct key_preparsed_payload *prep);
If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases). The second operation is called to clean up if the first
was called.
preparse() is given the opportunity to fill in the following structure:
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};
Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.
The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.
The preparser may also propose a description for the key by attaching it as a
string to the description field. This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function. This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.
This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.
The instantiate() and update() operations are then modified to look like this:
int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
int (*update)(struct key *key, struct key_preparsed_payload *prep);
and the new payload data is passed in *prep, whether or not it was preparsed.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Pull security subsystem updates from James Morris:
"Highlights:
- Integrity: add local fs integrity verification to detect offline
attacks
- Integrity: add digital signature verification
- Simple stacking of Yama with other LSMs (per LSS discussions)
- IBM vTPM support on ppc64
- Add new driver for Infineon I2C TIS TPM
- Smack: add rule revocation for subject labels"
Fixed conflicts with the user namespace support in kernel/auditsc.c and
security/integrity/ima/ima_policy.c.
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (39 commits)
Documentation: Update git repository URL for Smack userland tools
ima: change flags container data type
Smack: setprocattr memory leak fix
Smack: implement revoking all rules for a subject label
Smack: remove task_wait() hook.
ima: audit log hashes
ima: generic IMA action flag handling
ima: rename ima_must_appraise_or_measure
audit: export audit_log_task_info
tpm: fix tpm_acpi sparse warning on different address spaces
samples/seccomp: fix 31 bit build on s390
ima: digital signature verification support
ima: add support for different security.ima data types
ima: add ima_inode_setxattr/removexattr function and calls
ima: add inode_post_setattr call
ima: replace iint spinblock with rwlock/read_lock
ima: allocating iint improvements
ima: add appraise action keywords and default rules
ima: integrity appraisal extension
vfs: move ima_file_free before releasing the file
...
Use keyring_alloc() to create special keyrings now that it has a permissions
parameter rather than using key_alloc() + key_instantiate_and_link().
Also document and export keyring_alloc() so that modules can use it too.
Signed-off-by: David Howells <dhowells@redhat.com>
Reduce the initial permissions on new keys to grant the possessor everything,
view permission only to the user (so the keys can be seen in /proc/keys) and
nothing else.
This gives the creator a chance to adjust the permissions mask before other
processes can access the new key or create a link to it.
To aid with this, keyring_alloc() now takes a permission argument rather than
setting the permissions itself.
The following permissions are now set:
(1) The user and user-session keyrings grant the user that owns them full
permissions and grant a possessor everything bar SETATTR.
(2) The process and thread keyrings grant the possessor full permissions but
only grant the user VIEW. This permits the user to see them in
/proc/keys, but not to do anything with them.
(3) Anonymous session keyrings grant the possessor full permissions, but only
grant the user VIEW and READ. This means that the user can see them in
/proc/keys and can list them, but nothing else. Possibly READ shouldn't
be provided either.
(4) Named session keyrings grant everything an anonymous session keyring does,
plus they grant the user LINK permission. The whole point of named
session keyrings is that others can also subscribe to them. Possibly this
should be a separate permission to LINK.
(5) The temporary session keyring created by call_sbin_request_key() gets the
same permissions as an anonymous session keyring.
(6) Keys created by add_key() get VIEW, SEARCH, LINK and SETATTR for the
possessor, plus READ and/or WRITE if the key type supports them. The used
only gets VIEW now.
(7) Keys created by request_key() now get the same as those created by
add_key().
Reported-by: Lennart Poettering <lennart@poettering.net>
Reported-by: Stef Walter <stefw@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Make the session keyring per-thread rather than per-process, but still
inherited from the parent thread to solve a problem with PAM and gdm.
The problem is that join_session_keyring() will reject attempts to change the
session keyring of a multithreaded program but gdm is now multithreaded before
it gets to the point of starting PAM and running pam_keyinit to create the
session keyring. See:
https://bugs.freedesktop.org/show_bug.cgi?id=49211
The reason that join_session_keyring() will only change the session keyring
under a single-threaded environment is that it's hard to alter the other
thread's credentials to effect the change in a multi-threaded program. The
problems are such as:
(1) How to prevent two threads both running join_session_keyring() from
racing.
(2) Another thread's credentials may not be modified directly by this process.
(3) The number of threads is uncertain whilst we're not holding the
appropriate spinlock, making preallocation slightly tricky.
(4) We could use TIF_NOTIFY_RESUME and key_replace_session_keyring() to get
another thread to replace its keyring, but that means preallocating for
each thread.
A reasonable way around this is to make the session keyring per-thread rather
than per-process and just document that if you want a common session keyring,
you must get it before you spawn any threads - which is the current situation
anyway.
Whilst we're at it, we can the process keyring behave in the same way. This
means we can clean up some of the ickyness in the creds code.
Basically, after this patch, the session, process and thread keyrings are about
inheritance rules only and not about sharing changes of keyring.
Reported-by: Mantas M. <grawity@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ray Strode <rstrode@redhat.com>
Pull user namespace changes from Eric Biederman:
"This is a mostly modest set of changes to enable basic user namespace
support. This allows the code to code to compile with user namespaces
enabled and removes the assumption there is only the initial user
namespace. Everything is converted except for the most complex of the
filesystems: autofs4, 9p, afs, ceph, cifs, coda, fuse, gfs2, ncpfs,
nfs, ocfs2 and xfs as those patches need a bit more review.
The strategy is to push kuid_t and kgid_t values are far down into
subsystems and filesystems as reasonable. Leaving the make_kuid and
from_kuid operations to happen at the edge of userspace, as the values
come off the disk, and as the values come in from the network.
Letting compile type incompatible compile errors (present when user
namespaces are enabled) guide me to find the issues.
The most tricky areas have been the places where we had an implicit
union of uid and gid values and were storing them in an unsigned int.
Those places were converted into explicit unions. I made certain to
handle those places with simple trivial patches.
Out of that work I discovered we have generic interfaces for storing
quota by projid. I had never heard of the project identifiers before.
Adding full user namespace support for project identifiers accounts
for most of the code size growth in my git tree.
Ultimately there will be work to relax privlige checks from
"capable(FOO)" to "ns_capable(user_ns, FOO)" where it is safe allowing
root in a user names to do those things that today we only forbid to
non-root users because it will confuse suid root applications.
While I was pushing kuid_t and kgid_t changes deep into the audit code
I made a few other cleanups. I capitalized on the fact we process
netlink messages in the context of the message sender. I removed
usage of NETLINK_CRED, and started directly using current->tty.
Some of these patches have also made it into maintainer trees, with no
problems from identical code from different trees showing up in
linux-next.
After reading through all of this code I feel like I might be able to
win a game of kernel trivial pursuit."
Fix up some fairly trivial conflicts in netfilter uid/git logging code.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (107 commits)
userns: Convert the ufs filesystem to use kuid/kgid where appropriate
userns: Convert the udf filesystem to use kuid/kgid where appropriate
userns: Convert ubifs to use kuid/kgid
userns: Convert squashfs to use kuid/kgid where appropriate
userns: Convert reiserfs to use kuid and kgid where appropriate
userns: Convert jfs to use kuid/kgid where appropriate
userns: Convert jffs2 to use kuid and kgid where appropriate
userns: Convert hpfs to use kuid and kgid where appropriate
userns: Convert btrfs to use kuid/kgid where appropriate
userns: Convert bfs to use kuid/kgid where appropriate
userns: Convert affs to use kuid/kgid wherwe appropriate
userns: On alpha modify linux_to_osf_stat to use convert from kuids and kgids
userns: On ia64 deal with current_uid and current_gid being kuid and kgid
userns: On ppc convert current_uid from a kuid before printing.
userns: Convert s390 getting uid and gid system calls to use kuid and kgid
userns: Convert s390 hypfs to use kuid and kgid where appropriate
userns: Convert binder ipc to use kuids
userns: Teach security_path_chown to take kuids and kgids
userns: Add user namespace support to IMA
userns: Convert EVM to deal with kuids and kgids in it's hmac computation
...
Pull workqueue changes from Tejun Heo:
"This is workqueue updates for v3.7-rc1. A lot of activities this
round including considerable API and behavior cleanups.
* delayed_work combines a timer and a work item. The handling of the
timer part has always been a bit clunky leading to confusing
cancelation API with weird corner-case behaviors. delayed_work is
updated to use new IRQ safe timer and cancelation now works as
expected.
* Another deficiency of delayed_work was lack of the counterpart of
mod_timer() which led to cancel+queue combinations or open-coded
timer+work usages. mod_delayed_work[_on]() are added.
These two delayed_work changes make delayed_work provide interface
and behave like timer which is executed with process context.
* A work item could be executed concurrently on multiple CPUs, which
is rather unintuitive and made flush_work() behavior confusing and
half-broken under certain circumstances. This problem doesn't
exist for non-reentrant workqueues. While non-reentrancy check
isn't free, the overhead is incurred only when a work item bounces
across different CPUs and even in simulated pathological scenario
the overhead isn't too high.
All workqueues are made non-reentrant. This removes the
distinction between flush_[delayed_]work() and
flush_[delayed_]_work_sync(). The former is now as strong as the
latter and the specified work item is guaranteed to have finished
execution of any previous queueing on return.
* In addition to the various bug fixes, Lai redid and simplified CPU
hotplug handling significantly.
* Joonsoo introduced system_highpri_wq and used it during CPU
hotplug.
There are two merge commits - one to pull in IRQ safe timer from
tip/timers/core and the other to pull in CPU hotplug fixes from
wq/for-3.6-fixes as Lai's hotplug restructuring depended on them."
Fixed a number of trivial conflicts, but the more interesting conflicts
were silent ones where the deprecated interfaces had been used by new
code in the merge window, and thus didn't cause any real data conflicts.
Tejun pointed out a few of them, I fixed a couple more.
* 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits)
workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending()
workqueue: use cwq_set_max_active() helper for workqueue_set_max_active()
workqueue: introduce cwq_set_max_active() helper for thaw_workqueues()
workqueue: remove @delayed from cwq_dec_nr_in_flight()
workqueue: fix possible stall on try_to_grab_pending() of a delayed work item
workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
workqueue: use __cpuinit instead of __devinit for cpu callbacks
workqueue: rename manager_mutex to assoc_mutex
workqueue: WORKER_REBIND is no longer necessary for idle rebinding
workqueue: WORKER_REBIND is no longer necessary for busy rebinding
workqueue: reimplement idle worker rebinding
workqueue: deprecate __cancel_delayed_work()
workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()
workqueue: use mod_delayed_work() instead of __cancel + queue
workqueue: use irqsafe timer for delayed_work
workqueue: clean up delayed_work initializers and add missing one
workqueue: make deferrable delayed_work initializer names consistent
workqueue: cosmetic whitespace updates for macro definitions
workqueue: deprecate system_nrt[_freezable]_wq
workqueue: deprecate flush[_delayed]_work_sync()
...
On an error iov may still have been reallocated and need freeing
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
We set ret to NULL then test it. Remove the bogus test
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
- Replace key_user ->user_ns equality checks with kuid_has_mapping checks.
- Use from_kuid to generate key descriptions
- Use kuid_t and kgid_t and the associated helpers instead of uid_t and gid_t
- Avoid potential problems with file descriptor passing by displaying
keys in the user namespace of the opener of key status proc files.
Cc: linux-security-module@vger.kernel.org
Cc: keyrings@linux-nfs.org
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This reverts commit d35abdb288.
task_lock() was added to ensure exit_mm() and thus exit_task_work() is
not possible before task_work_add().
This is wrong, task_lock() must not be nested with write_lock(tasklist).
And this is no longer needed, task_work_add() now fails if it is called
after exit_task_work().
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120826191214.GA4231@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called. This is done with the
provision of two new key type operations:
int (*preparse)(struct key_preparsed_payload *prep);
void (*free_preparse)(struct key_preparsed_payload *prep);
If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases). The second operation is called to clean up if the first
was called.
preparse() is given the opportunity to fill in the following structure:
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};
Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.
The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.
The preparser may also propose a description for the key by attaching it as a
string to the description field. This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function. This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.
This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.
The instantiate() and update() operations are then modified to look like this:
int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
int (*update)(struct key *key, struct key_preparsed_payload *prep);
and the new payload data is passed in *prep, whether or not it was preparsed.
Signed-off-by: David Howells <dhowells@redhat.com>
Move the tpm_get_random api from the trusted keys code into the TPM
device driver itself so that other callers can make use of it. Also,
change the api slightly so that the number of bytes read is returned in
the call, since the TPM command can potentially return fewer bytes than
requested.
Acked-by: David Safford <safford@linux.vnet.ibm.com>
Reviewed-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
system_nrt[_freezable]_wq are now spurious. Mark them deprecated and
convert all users to system[_freezable]_wq.
If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant, so there's no reason to use system_nrt[_freezable]_wq.
Please use system[_freezable]_wq instead.
This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-By: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Pull security subsystem updates from James Morris:
"Nothing groundbreaking for this kernel, just cleanups and fixes, and a
couple of Smack enhancements."
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (21 commits)
Smack: Maintainer Record
Smack: don't show empty rules when /smack/load or /smack/load2 is read
Smack: user access check bounds
Smack: onlycap limits on CAP_MAC_ADMIN
Smack: fix smack_new_inode bogosities
ima: audit is compiled only when enabled
ima: ima_initialized is set only if successful
ima: add policy for pseudo fs
ima: remove unused cleanup functions
ima: free securityfs violations file
ima: use full pathnames in measurement list
security: Fix nommu build.
samples: seccomp: add .gitignore for untracked executables
tpm: check the chip reference before using it
TPM: fix memleak when register hardware fails
TPM: chip disabled state erronously being reported as error
MAINTAINERS: TPM maintainers' contacts update
Merge branches 'next-queue' and 'next' into next
Remove unused code from MPI library
Revert "crypto: GnuPG based MPI lib - additional sources (part 4)"
...
task_work and rcu_head are identical now; merge them (calling the result
struct callback_head, rcu_head #define'd to it), kill separate allocation
in security/keys since we can just use cred->rcu now.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
get rid of the only user of ->data; this is _not_ the final variant - in the
end we'll have task_work and rcu_head identical and just use cred->rcu,
at which point the separate allocation will be gone completely.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
David Howells