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authorTHOBY Simon <Simon.THOBY@viveris.fr>2021-08-16 08:11:01 +0000
committerMimi Zohar <zohar@linux.ibm.com>2021-08-16 17:35:35 -0400
commit8ecd39cb61d9e302716d73be329c4d4822c24931 (patch)
treeaa22f9b920ee39cf366404b4f7468c5b8860a176 /mm/mmap.c
parent4f2946aa0c45c78b4f4ef101bab9694e38c68db0 (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