diff options
author | THOBY Simon <Simon.THOBY@viveris.fr> | 2021-08-16 08:11:01 +0000 |
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committer | Mimi Zohar <zohar@linux.ibm.com> | 2021-08-16 17:35:35 -0400 |
commit | 8ecd39cb61d9e302716d73be329c4d4822c24931 (patch) | |
tree | aa22f9b920ee39cf366404b4f7468c5b8860a176 /mm/mmap.c | |
parent | 4f2946aa0c45c78b4f4ef101bab9694e38c68db0 (diff) |
IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithms
SETXATTR_CHECK policy rules assume that any algorithm listed in the
'appraise_algos' flag must be accepted when performing setxattr() on
the security.ima xattr. However nothing checks that they are
available in the current kernel. A userland application could hash
a file with a digest that the kernel wouldn't be able to verify.
However, if SETXATTR_CHECK is not in use, the kernel already forbids
that xattr write.
Verify that algorithms listed in appraise_algos are available to the
current kernel and reject the policy update otherwise. This will fix
the inconsistency between SETXATTR_CHECK and non-SETXATTR_CHECK
behaviors.
That filtering is only performed in ima_parse_appraise_algos() when
updating policies so that we do not have to pay the price of
allocating a hash object every time validate_hash_algo() is called
in ima_inode_setxattr().
Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'mm/mmap.c')
0 files changed, 0 insertions, 0 deletions