Nayna pointed out that the "keyrings=" option in an IMA policy rule should only be accepted when CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled: https://lore.kernel.org/linux-integrity/336cc947-1f70-0286-6506-6df3d1d23a1d@xxxxxxxxxxxxxxxxxx/ While fixing this, the compiler warned me about the potential for the ima_keyrings pointer to be NULL despite it being used, without a check for NULL, as the destination address for the strcpy() in ima_match_keyring(). It also became apparent that there was not adequate locking around the use of the pre-allocated buffer that ima_keyrings points to. The kernel keyring has a lock (.sem member of struct key) that ensures only one key can be added to a given keyring at a time but there's no protection against adding multiple keys to different keyrings at the same time. The first patch in this series fixes both ima_keyrings related issues by parsing the list of keyrings in a KEY_CHECK rule at policy load time rather than deferring the parsing to policy check time. Once that fix is in place, the second patch can enforce that CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS must be enabled in order to use "func=KEY_CHECK" or "keyrings=" options in IMA policy. The new "keyrings=" value handling is done in a generic manner that can be reused by other options in the future. This seems to make sense as "appraise_type=" has similar style (though it doesn't need to be fully parsed at this time) and using "|" as an alternation delimiter is becoming the norm in IMA policy. This series is based on commit 311aa6aafea4 ("ima: move APPRAISE_BOOTPARAM dependency on ARCH_POLICY to runtime") in next-integrity. Tyler Tyler Hicks (2): ima: Pre-parse the list of keyrings in a KEY_CHECK rule ima: Fail rule parsing when asymmetric key measurement isn't supportable security/integrity/ima/ima_policy.c | 142 +++++++++++++++++++--------- 1 file changed, 96 insertions(+), 46 deletions(-) -- 2.25.1
