If a socket has a netlabel in place then don't let setsockopt() alter
the socket's IPv6 hop-by-hop option. This is in the same spirit as
the existing check for IPv4.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
CALIPSO is a hop-by-hop IPv6 option. A lot of this patch is based on
the equivalent CISPO code. The main difference is due to manipulating
the options in the hop-by-hop header.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This is to allow the CALIPSO labelling engine to use these.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The functionality is equivalent to ipv6_renew_options() except
that the newopt pointer is in kernel, not user, memory
The kernel memory implementation will be used by the CALIPSO network
labelling engine, which needs to be able to set IPv6 hop-by-hop
options.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Remove a specified DOI through the NLBL_CALIPSO_C_REMOVE command.
It requires the attribute:
NLBL_CALIPSO_A_DOI.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This extends the NLBL_MGMT_C_ADD and NLBL_MGMT_C_ADDDEF commands
to accept CALIPSO protocol DOIs.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Enumerate the DOI list through the NLBL_CALIPSO_C_LISTALL command.
It takes no attributes.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Query a specified DOI through the NLBL_CALIPSO_C_LIST command.
It requires the attribute:
NLBL_CALIPSO_A_DOI.
The reply will contain:
NLBL_CALIPSO_A_MTYPE
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
CALIPSO is a packet labelling protocol for IPv6 which is very similar
to CIPSO. It is specified in RFC 5570. Much of the code is based on
the current CIPSO code.
This adds support for adding passthrough-type CALIPSO DOIs through the
NLBL_CALIPSO_C_ADD command. It requires attributes:
NLBL_CALIPSO_A_TYPE which must be CALIPSO_MAP_PASS.
NLBL_CALIPSO_A_DOI.
In passthrough mode the CALIPSO engine will map MLS secattr levels
and categories directly to the packet label.
At this stage, the major difference between this and the CIPSO
code is that IPv6 may be compiled as a module. To allow for
this the CALIPSO functions are registered at module init time.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The reason is to allow different labelling protocols for
different address families with the same domain.
This requires the addition of an address family attribute
in the netlink communication protocol. It is used in several
messages:
NLBL_MGMT_C_ADD and NLBL_MGMT_C_ADDDEF take it as an optional
attribute for the unlabelled protocol. It may be one of AF_INET,
AF_INET6 or AF_UNSPEC (to specify both address families). If it
is missing, it defaults to AF_UNSPEC.
NLBL_MGMT_C_LISTALL and NLBL_MGMT_C_LISTDEF return it as part of
the enumeration of each item. Addtionally, it may be sent to
LISTDEF to specify which address family to return.
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This fixes sparse errors of the form:
incompatible types in comparison expression (different address spaces)
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
avc_cache_threshold is of type unsigned int. Do not use a signed
new_value in sscanf(page, "%u", &new_value).
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
[PM: subject prefix fix, description cleanup]
Signed-off-by: Paul Moore <paul@paul-moore.com>
In cases where the category bitmap is sparse enough that gaps exist
between netlbl_lsm_catmap structs, callers to netlbl_catmap_getlong()
could find themselves prematurely ending their search through the
category bitmap. Further, the methods used to calculate the 'idx'
and 'off' values were incorrect for bitmaps this large. This patch
changes the netlbl_catmap_getlong() behavior so that it always skips
over gaps and calculates the index and offset values correctly.
Signed-off-by: Paul Moore <paul@paul-moore.com>
The existing ebitmap_netlbl_import() code didn't correctly handle the
case where the ebitmap_node was not aligned/sized to a power of two,
this patch fixes this (on x86_64 ebitmap_node contains six bitmaps
making a range of 0..383).
Signed-off-by: Paul Moore <paul@paul-moore.com>
Much like we had to do for AF_BLUETOOTH and AF_ALG, make sure we
properly clone the parent socket's LSM attributes to newly created
child sockets.
Signed-off-by: Paul Moore <paul@paul-moore.com>
It seems risky to always rely on the caller to ensure the socket's
address family is correct before passing it to the NetLabel kAPI,
especially since we see at least one LSM which didn't. Add address
family checks to the *_delattr() functions to help prevent future
problems.
Cc: <stable@vger.kernel.org>
Reported-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The current bounds checking of both source and target types
requires allowing any domain that has access to the child
domain to also have the same permissions to the parent, which
is undesirable. Drop the target bounds checking.
KaiGai Kohei originally removed all use of target bounds in
commit 7d52a155e3 ("selinux: remove dead code in
type_attribute_bounds_av()") but this was reverted in
commit 2ae3ba3938 ("selinux: libsepol: remove dead code in
check_avtab_hierarchy_callback()") because it would have
required explicitly allowing the parent any permissions
to the child that the child is allowed to itself.
This change in contrast retains the logic for the case where both
source and target types are bounded, thereby allowing access
if the parent of the source is allowed the corresponding
permissions to the parent of the target. Further, this change
reworks the logic such that we only perform a single computation
for each case and there is no ambiguity as to how to resolve
a bounds violation.
Under the new logic, if the source type and target types are both
bounded, then the parent of the source type must be allowed the same
permissions to the parent of the target type. If only the source
type is bounded, then the parent of the source type must be allowed
the same permissions to the target type.
Examples of the new logic and comparisons with the old logic:
1. If we have:
typebounds A B;
then:
allow B self:process <permissions>;
will satisfy the bounds constraint iff:
allow A self:process <permissions>;
is also allowed in policy.
Under the old logic, the allow rule on B satisfies the
bounds constraint if any of the following three are allowed:
allow A B:process <permissions>; or
allow B A:process <permissions>; or
allow A self:process <permissions>;
However, either of the first two ultimately require the third to
satisfy the bounds constraint under the old logic, and therefore
this degenerates to the same result (but is more efficient - we only
need to perform one compute_av call).
2. If we have:
typebounds A B;
typebounds A_exec B_exec;
then:
allow B B_exec:file <permissions>;
will satisfy the bounds constraint iff:
allow A A_exec:file <permissions>;
is also allowed in policy.
This is essentially the same as #1; it is merely included as
an example of dealing with object types related to a bounded domain
in a manner that satisfies the bounds relationship. Note that
this approach is preferable to leaving B_exec unbounded and having:
allow A B_exec:file <permissions>;
in policy because that would allow B's entrypoints to be used to
enter A. Similarly for _tmp or other related types.
3. If we have:
typebounds A B;
and an unbounded type T, then:
allow B T:file <permissions>;
will satisfy the bounds constraint iff:
allow A T:file <permissions>;
is allowed in policy.
The old logic would have been identical for this example.
4. If we have:
typebounds A B;
and an unbounded domain D, then:
allow D B:unix_stream_socket <permissions>;
is not subject to any bounds constraints under the new logic
because D is not bounded. This is desirable so that we can
allow a domain to e.g. connectto a child domain without having
to allow it to do the same to its parent.
The old logic would have required:
allow D A:unix_stream_socket <permissions>;
to also be allowed in policy.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: re-wrapped description to appease checkpatch.pl]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Instead of being enabled by default when SECURITY_LOADPIN is selected,
provide an additional (default off) config to determine the boot time
behavior. As before, the "loadpin.enabled=0/1" kernel parameter remains
available.
Suggested-by: James Morris <jmorris@namei.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Drop accidentally repeated word in comment.
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Here's a set of patches that changes how certificates/keys are determined
to be trusted. That's currently a two-step process:
(1) Up until recently, when an X.509 certificate was parsed - no matter
the source - it was judged against the keys in .system_keyring,
assuming those keys to be trusted if they have KEY_FLAG_TRUSTED set
upon them.
This has just been changed such that any key in the .ima_mok keyring,
if configured, may also be used to judge the trustworthiness of a new
certificate, whether or not the .ima_mok keyring is meant to be
consulted for whatever process is being undertaken.
If a certificate is determined to be trustworthy, KEY_FLAG_TRUSTED
will be set upon a key it is loaded into (if it is loaded into one),
no matter what the key is going to be loaded for.
(2) If an X.509 certificate is loaded into a key, then that key - if
KEY_FLAG_TRUSTED gets set upon it - can be linked into any keyring
with KEY_FLAG_TRUSTED_ONLY set upon it. This was meant to be the
system keyring only, but has been extended to various IMA keyrings.
A user can at will link any key marked KEY_FLAG_TRUSTED into any
keyring marked KEY_FLAG_TRUSTED_ONLY if the relevant permissions masks
permit it.
These patches change that:
(1) Trust becomes a matter of consulting the ring of trusted keys supplied
when the trust is evaluated only.
(2) Every keyring can be supplied with its own manager function to
restrict what may be added to that keyring. This is called whenever a
key is to be linked into the keyring to guard against a key being
created in one keyring and then linked across.
This function is supplied with the keyring and the key type and
payload[*] of the key being linked in for use in its evaluation. It
is permitted to use other data also, such as the contents of other
keyrings such as the system keyrings.
[*] The type and payload are supplied instead of a key because as an
optimisation this function may be called whilst creating a key and
so may reject the proposed key between preparse and allocation.
(3) A default manager function is provided that permits keys to be
restricted to only asymmetric keys that are vouched for by the
contents of the system keyring.
A second manager function is provided that just rejects with EPERM.
(4) A key allocation flag, KEY_ALLOC_BYPASS_RESTRICTION, is made available
so that the kernel can initialise keyrings with keys that form the
root of the trust relationship.
(5) KEY_FLAG_TRUSTED and KEY_FLAG_TRUSTED_ONLY are removed, along with
key_preparsed_payload::trusted.
This change also makes it possible in future for userspace to create a private
set of trusted keys and then to have it sealed by setting a manager function
where the private set is wholly independent of the kernel's trust
relationships.
Further changes in the set involve extracting certain IMA special keyrings
and making them generally global:
(*) .system_keyring is renamed to .builtin_trusted_keys and remains read
only. It carries only keys built in to the kernel. It may be where
UEFI keys should be loaded - though that could better be the new
secondary keyring (see below) or a separate UEFI keyring.
(*) An optional secondary system keyring (called .secondary_trusted_keys)
is added to replace the IMA MOK keyring.
(*) Keys can be added to the secondary keyring by root if the keys can
be vouched for by either ring of system keys.
(*) Module signing and kexec only use .builtin_trusted_keys and do not use
the new secondary keyring.
(*) Config option SYSTEM_TRUSTED_KEYS now depends on ASYMMETRIC_KEY_TYPE as
that's the only type currently permitted on the system keyrings.
(*) A new config option, IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY,
is provided to allow keys to be added to IMA keyrings, subject to the
restriction that such keys are validly signed by a key already in the
system keyrings.
If this option is enabled, but secondary keyrings aren't, additions to
the IMA keyrings will be restricted to signatures verifiable by keys in
the builtin system keyring only.
Signed-off-by: David Howells <dhowells@redhat.com>
Commit 3034a14 "ima: pass 'opened' flag to identify newly created files"
stopped identifying empty files as new files. However new empty files
can be created using the mknodat syscall. On systems with IMA-appraisal
enabled, these empty files are not labeled with security.ima extended
attributes properly, preventing them from subsequently being opened in
order to write the file data contents. This patch defines a new hook
named ima_post_path_mknod() to mark these empty files, created using
mknodat, as new in order to allow the file data contents to be written.
In addition, files with security.ima xattrs containing a file signature
are considered "immutable" and can not be modified. The file contents
need to be written, before signing the file. This patch relaxes this
requirement for new files, allowing the file signature to be written
before the file contents.
Changelog:
- defer identifying files with signatures stored as security.ima
(based on Dmitry Rozhkov's comments)
- removing tests (eg. dentry, dentry->d_inode, inode->i_size == 0)
(based on Al's review)
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Al Viro <<viro@zeniv.linux.org.uk>
Tested-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Changing file metadata (eg. uid, guid) could result in having to
re-appraise a file's integrity, but does not change the "new file"
status nor the security.ima xattr. The IMA_PERMIT_DIRECTIO and
IMA_DIGSIG_REQUIRED flags are policy rule specific. This patch
only resets these flags, not the IMA_NEW_FILE or IMA_DIGSIG flags.
With this patch, changing the file timestamp will not remove the
file signature on new files.
Reported-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Tested-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
This patch is based on top of the "vfs: support for a common kernel file
loader" patch set. In general when the kernel is reading a file into
memory it does not want anything else writing to it.
The kernel currently only forbids write access to a file being executed.
This patch extends this locking to files being read by the kernel.
Changelog:
- moved function to kernel_read_file() - Mimi
- updated patch description - Mimi
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
When I was fixing up const recommendations from checkpatch.pl, I went
overboard. This fixes the warning (during a W=1 build):
include/linux/fs.h:2627:74: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
static inline const char * const kernel_read_file_id_str(enum kernel_read_file_id id)
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
The execstack check was only being applied on the main
process stack. Thread stacks allocated via mmap were
only subject to the execmem permission check. Augment
the check to apply to the current thread stack as well.
Note that this does NOT prevent making a different thread's
stack executable.
Suggested-by: Nick Kralevich <nnk@google.com>
Acked-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Distinguish capability checks against a target associated
with the init user namespace versus capability checks against
a target associated with a non-init user namespace by defining
and using separate security classes for the latter.
This is needed to support e.g. Chrome usage of user namespaces
for the Chrome sandbox without needing to allow Chrome to also
exercise capabilities on targets in the init user namespace.
Suggested-by: Dan Walsh <dwalsh@redhat.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This LSM enforces that kernel-loaded files (modules, firmware, etc)
must all come from the same filesystem, with the expectation that
such a filesystem is backed by a read-only device such as dm-verity
or CDROM. This allows systems that have a verified and/or unchangeable
filesystem to enforce module and firmware loading restrictions without
needing to sign the files individually.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
A string representation of the kernel_read_file_id enumeration is
needed for displaying messages (eg. pr_info, auditing) that can be
used by multiple LSMs and the integrity subsystem. To simplify
keeping the list of strings up to date with the enumeration, this
patch defines two new preprocessing macros named __fid_enumify and
__fid_stringify to create the enumeration and an array of strings.
kernel_read_file_id_str() returns a string based on the enumeration.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
[kees: removed removal of my old version, constified pointer values]
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Use a common error reporting function for Yama violation reports, and give
more detail into the process command lines.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Allocate a NULL-terminated file path with special characters escaped,
safe for logging.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Provide an escaped (but readable: no inter-argument NULLs) commandline
safe for logging.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Handle allocating and escaping a string safe for logging.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
There is no point in trying to revalidate an inode's security label if
the security server is not yet initialized.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Since looking up an inode's label can result in revalidation, delay
the lookup as long as possible to limit the performance impact.
Signed-off-by: Paul Moore <paul@paul-moore.com>
There is no point in attempting to revalidate an inode's security
label when we are in the process of setting it.
Reported-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
security_get_bool_value(int bool) argument "bool" conflicts with
in-kernel macros such as BUILD_BUG(). This patch changes this to
index which isn't a type.
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: selinux@tycho.nsa.gov
Cc: Eric Paris <eparis@redhat.com>
Cc: Paul Moore <pmoore@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
[PM: wrapped description for checkpatch.pl, use "selinux:..." as subj]
Signed-off-by: Paul Moore <paul@paul-moore.com>
These commits do the following:
(1) Retain a signature in an asymmetric-type key and associate with it the
identifiers that will match a key that can be used to verify it.
(2) Differentiate an X.509 cert that cannot be used versus one that cannot
be verified due to unavailable crypto. This is noted in the
structures involved.
(3) Determination of the self-signedness of an X.509 cert is improved to
include checks on the subject/issuer names and the key
algorithm/signature algorithm types.
(4) Self-signed X.509 certificates are consistency checked early on if the
appropriate crypto is available.
Signed-off-by: David Howells <dhowells@redhat.com>
This adds userspace access to Diffie-Hellman computations through a
new keyctl() syscall command to calculate shared secrets or public
keys using input parameters stored in the keyring.
Input key ids are provided in a struct due to the current 5-arg limit
for the keyctl syscall. Only user keys are supported in order to avoid
exposing the content of logon or encrypted keys.
The output is written to the provided buffer, based on the assumption
that the values are only needed in userspace.
Future support for other types of key derivation would involve a new
command, like KEYCTL_ECDH_COMPUTE.
Once Diffie-Hellman support is included in the crypto API, this code
can be converted to use the crypto API to take advantage of possible
hardware acceleration and reduce redundant code.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Solved TODO task: big keys saved to shmem file are now stored encrypted.
The encryption key is randomly generated and saved to payload[big_key_data].
Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
The payload preparsing routine for user keys makes a copy of the payload
provided by the caller and stashes it in the key_preparsed_payload struct for
->instantiate() or ->update() to use. However, ->update() takes another copy
of this to attach to the keyring. ->update() should be using this directly
and clearing the pointer in the preparse data.
Signed-off-by: David Howells <dhowells@redhat.com>
Commit d43de6c780 ("akcipher: Move the RSA DER encoding check to
the crypto layer") removed the Kconfig option PUBLIC_KEY_ALGO_RSA,
but forgot to remove a 'select' to this option in the definition of
INTEGRITY_ASYMMETRIC_KEYS.
Let's remove the select, as it's ineffective now.
Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Add a config option (IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY)
that, when enabled, allows keys to be added to the IMA keyrings by
userspace - with the restriction that each must be signed by a key in the
system trusted keyrings.
EPERM will be returned if this option is disabled, ENOKEY will be returned if
no authoritative key can be found and EKEYREJECTED will be returned if the
signature doesn't match. Other errors such as ENOPKG may also be returned.
If this new option is enabled, the builtin system keyring is searched, as is
the secondary system keyring if that is also enabled. Intermediate keys
between the builtin system keyring and the key being added can be added to
the secondary keyring (which replaces .ima_mok) to form a trust chain -
provided they are also validly signed by a key in one of the trusted keyrings.
The .ima_mok keyring is then removed and the IMA blacklist keyring gets its
own config option (IMA_BLACKLIST_KEYRING).
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Add a secondary system keyring that can be added to by root whilst the
system is running - provided the key being added is vouched for by a key
built into the kernel or already added to the secondary keyring.
Rename .system_keyring to .builtin_trusted_keys to distinguish it more
obviously from the new keyring (called .secondary_trusted_keys).
The new keyring needs to be enabled with CONFIG_SECONDARY_TRUSTED_KEYRING.
If the secondary keyring is enabled, a link is created from that to
.builtin_trusted_keys so that the the latter will automatically be searched
too if the secondary keyring is searched.
Signed-off-by: David Howells <dhowells@redhat.com>
Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer
meaningful. Also we can drop the trusted flag from the preparse structure.
Given this, we no longer need to pass the key flags through to
restrict_link().
Further, we can now get rid of keyring_restrict_trusted_only() also.
Signed-off-by: David Howells <dhowells@redhat.com>
Move the point at which a key is determined to be trustworthy to
__key_link() so that we use the contents of the keyring being linked in to
to determine whether the key being linked in is trusted or not.
What is 'trusted' then becomes a matter of what's in the keyring.
Currently, the test is done when the key is parsed, but given that at that
point we can only sensibly refer to the contents of the system trusted
keyring, we can only use that as the basis for working out the
trustworthiness of a new key.
With this change, a trusted keyring is a set of keys that once the
trusted-only flag is set cannot be added to except by verification through
one of the contained keys.
Further, adding a key into a trusted keyring, whilst it might grant
trustworthiness in the context of that keyring, does not automatically
grant trustworthiness in the context of a second keyring to which it could
be secondarily linked.
To accomplish this, the authentication data associated with the key source
must now be retained. For an X.509 cert, this means the contents of the
AuthorityKeyIdentifier and the signature data.
If system keyrings are disabled then restrict_link_by_builtin_trusted()
resolves to restrict_link_reject(). The integrity digital signature code
still works correctly with this as it was previously using
KEY_FLAG_TRUSTED_ONLY, which doesn't permit anything to be added if there
is no system keyring against which trust can be determined.
Signed-off-by: David Howells <dhowells@redhat.com>
Make the system trusted keyring depend on the asymmetric key type as
there's not a lot of point having it if you can't then load asymmetric keys
onto it.
This requires the ASYMMETRIC_KEY_TYPE to be made a bool, not a tristate, as
the Kconfig language doesn't then correctly force ASYMMETRIC_KEY_TYPE to
'y' rather than 'm' if SYSTEM_TRUSTED_KEYRING is 'y'.
Making SYSTEM_TRUSTED_KEYRING *select* ASYMMETRIC_KEY_TYPE instead doesn't
work as the Kconfig interpreter then wrongly complains about dependency
loops.
Signed-off-by: David Howells <dhowells@redhat.com>
Huw Davies