ima: process_measurement() needlessly takes inode_lock() on MAY_READ
[ Upstream commit 30d68cb0c37ebe2dc63aa1d46a28b9163e61caa2 ] 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 <fred@cloudflare.com> Acked-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
committed by
Greg Kroah-Hartman
parent
91ba964a75
commit
722a6972de
@@ -235,7 +235,9 @@ static int process_measurement(struct file *file, const struct cred *cred,
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&allowed_algos);
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violation_check = ((func == FILE_CHECK || func == MMAP_CHECK ||
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func == MMAP_CHECK_REQPROT) &&
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(ima_policy_flag & IMA_MEASURE));
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(ima_policy_flag & IMA_MEASURE) &&
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((action & IMA_MEASURE) ||
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(file->f_mode & FMODE_WRITE)));
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if (!action && !violation_check)
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return 0;
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