From: Tyler Hicks tyhicks@linux.microsoft.com
[ Upstream commit 5f3e92657bbfb63ad3109433d843c89996114b03 ]
Verifying that a file hash is not blacklisted is currently only supported for files with appended signatures (modsig). In the future, this might change.
For now, the "appraise_flag" option is only appropriate for appraise actions and its "blacklist" value is only appropriate when CONFIG_IMA_APPRAISE_MODSIG is enabled and "appraise_flag=blacklist" is only appropriate when "appraise_type=imasig|modsig" is also present. Make this clear at policy load so that IMA policy authors don't assume that other uses of "appraise_flag=blacklist" are supported.
Fixes: 273df864cf74 ("ima: Check against blacklisted hashes for files with modsig") Signed-off-by: Tyler Hicks tyhicks@linux.microsoft.com Reivewed-by: Nayna Jain nayna@linux.ibm.com Tested-by: Nayna Jain nayna@linux.ibm.com Signed-off-by: Mimi Zohar zohar@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/integrity/ima/ima_policy.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 3e3e568c81309..a59bf2f5b2d4f 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -1035,6 +1035,11 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) return false; }
+ /* Ensure that combinations of flags are compatible with each other */ + if (entry->flags & IMA_CHECK_BLACKLIST && + !(entry->flags & IMA_MODSIG_ALLOWED)) + return false; + return true; }
@@ -1371,9 +1376,17 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) result = -EINVAL; break; case Opt_appraise_flag: + if (entry->action != APPRAISE) { + result = -EINVAL; + break; + } + ima_log_string(ab, "appraise_flag", args[0].from); - if (strstr(args[0].from, "blacklist")) + if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) && + strstr(args[0].from, "blacklist")) entry->flags |= IMA_CHECK_BLACKLIST; + else + result = -EINVAL; break; case Opt_permit_directio: entry->flags |= IMA_PERMIT_DIRECTIO;