From: Frederick Lawler Date: Thu, 27 Mar 2025 16:09:11 +0000 (-0500) Subject: ima: process_measurement() needlessly takes inode_lock() on MAY_READ X-Git-Tag: v6.15-rc4~36^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=30d68cb0c37ebe2dc63aa1d46a28b9163e61caa2;p=thirdparty%2Flinux.git ima: process_measurement() needlessly takes inode_lock() on MAY_READ On IMA policy update, if a measure rule exists in the policy, IMA_MEASURE is set for ima_policy_flags which makes the violation_check variable always true. Coupled with a no-action on MAY_READ for a FILE_CHECK call, we're always taking the inode_lock(). This becomes a performance problem for extremely heavy read-only workloads. Therefore, prevent this only in the case there's no action to be taken. Signed-off-by: Frederick Lawler Acked-by: Roberto Sassu Signed-off-by: Mimi Zohar --- diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f3e7ac513db3f..f99ab1a3b0f09 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -245,7 +245,9 @@ static int process_measurement(struct file *file, const struct cred *cred, &allowed_algos); violation_check = ((func == FILE_CHECK || func == MMAP_CHECK || func == MMAP_CHECK_REQPROT) && - (ima_policy_flag & IMA_MEASURE)); + (ima_policy_flag & IMA_MEASURE) && + ((action & IMA_MEASURE) || + (file->f_mode & FMODE_WRITE))); if (!action && !violation_check) return 0;