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| author | THOBY Simon <Simon.THOBY@viveris.fr> | 2021-08-22 08:55:26 +0000 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.ibm.com> | 2021-08-23 18:22:00 -0400 |
| commit | cb181da161963eddc9de0000de6ab2c7942be219 (patch) | |
| tree | cf41ca44b1e7b216b75f9ffdc0c13fe776d144e6 /security/integrity | |
| parent | d07eeeb8745973389e1d772b3b654f5860441589 (diff) | |
| download | lwn-cb181da161963eddc9de0000de6ab2c7942be219.tar.gz lwn-cb181da161963eddc9de0000de6ab2c7942be219.zip | |
IMA: reject unknown hash algorithms in ima_get_hash_algo
The new function validate_hash_algo() assumed that ima_get_hash_algo()
always return a valid 'enum hash_algo', but it returned the
user-supplied value present in the digital signature without
any bounds checks.
Update ima_get_hash_algo() to always return a valid hash algorithm,
defaulting on 'ima_hash_algo' when the user-supplied value inside
the xattr is invalid.
Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reported-by: syzbot+e8bafe7b82c739eaf153@syzkaller.appspotmail.com
Fixes: 50f742dd9147 ("IMA: block writes of the security.ima xattr with unsupported algorithms")
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security/integrity')
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 8f1eb7ef041e..dbba51583e7c 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -185,7 +185,8 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value, switch (xattr_value->type) { case EVM_IMA_XATTR_DIGSIG: sig = (typeof(sig))xattr_value; - if (sig->version != 2 || xattr_len <= sizeof(*sig)) + if (sig->version != 2 || xattr_len <= sizeof(*sig) + || sig->hash_algo >= HASH_ALGO__LAST) return ima_hash_algo; return sig->hash_algo; break; |