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([2a09:bac5:8152:1b37::2b6:1]) by smtp.gmail.com with ESMTPSA id ca18e2360f4ac-85e2bc273a1sm219975639f.18.2025.03.25.08.59.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Mar 2025 08:59:47 -0700 (PDT) From: Frederick Lawler To: Mimi Zohar , Dmitry Kasatkin , Roberto Sassu Cc: Eric Snowberg , James Morris , "Serge E. Hallyn" , linux-ima-devel@lists.sourceforge.net, linux-ima-user@lists.sourceforge.net, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-team@cloudflare.com, Frederick Lawler Subject: [PATCH] ima: process_measurement() needlessly takes inode_lock() on MAY_READ Date: Tue, 25 Mar 2025 10:58:59 -0500 Message-ID: <20250325155934.4120184-1-fred@cloudflare.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 --- security/integrity/ima/ima_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2aebb7984437..78921e69ee14 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -181,7 +181,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size, action = ima_get_action(inode, mask, func, &pcr); violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) && (ima_policy_flag & IMA_MEASURE)); - if (!action && !violation_check) + if (!action && (mask == MAY_READ || !violation_check)) return 0; must_appraise = action & IMA_APPRAISE;