linux-kernel - [PATCH] ima: fix mprotect checking

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Date:   Thu, 11 Jun 2020 07:19:23 -0400
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     linux-integrity@...r.kernel.org
Cc:     Mimi Zohar <zohar@...ux.ibm.com>,
        Xing Zhengjun <zhengjun.xing@...ux.intel.com>,
        Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
        LKML <linux-kernel@...r.kernel.org>, lkp@...ts.01.org
Subject: [PATCH] ima: fix mprotect checking

Make sure IMA is enabled before checking mprotect change.  Addresses
report of a 3.7% regression of boot-time.dhcp.

Fixes: 8eb613c0b8f1 ("ima: verify mprotect change is consistent with mmap policy")
Reported-by: kernel test robot <rong.a.chen@...el.com>
Signed-off-by: Mimi Zohar <zohar@...ux.ibm.com>
---
 security/integrity/ima/ima_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 800fb3bba418..c1583d98c5e5 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -419,7 +419,8 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	int pcr;
 
 	/* Is mprotect making an mmap'ed file executable? */
-	if (!vma->vm_file || !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
+	if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
+	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
 	security_task_getsecid(current, &secid);
-- 
2.7.5