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Patch "ima: accept previously set IMA_NEW_FILE" has been added to the 3.18-stable tree

PATCH [email protected] 1 participant 1 message May 22, 2017

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This is a note to let you know that I've just added the patch titled

ima: accept previously set IMA_NEW_FILE

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ima-accept-previously-set-ima_new_file.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 1ac202e978e18f045006d75bd549612620c6ec3a Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Daniel=20Gl=C3=B6ckner?= <[email protected]>
Date: Fri, 24 Feb 2017 15:05:14 +0100
Subject: ima: accept previously set IMA_NEW_FILE
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Daniel Glöckner <[email protected]>

commit 1ac202e978e18f045006d75bd549612620c6ec3a upstream.

Modifying the attributes of a file makes ima_inode_post_setattr reset the IMA cache flags. So if the file, which has just been created, is opened a second time before the first file descriptor is closed, verification fails since the security.ima xattr has not been written yet. We therefore have to look at the IMA_NEW_FILE even if the file already existed.

With this patch there should no longer be an error when cat tries to open testfile:

$ rm -f testfile
$ ( echo test >&3 ; touch testfile ; cat testfile ) 3>testfile

A file being new is no reason to accept that it is missing a digital signature demanded by the policy.

---
 security/integrity/ima/ima_appraise.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
security/integrity/ima/ima_appraise.c +3 -2
@@ -203,10 +203,11 @@ int ima_appraise_measurement(int func, s
 
 		cause = "missing-hash";
 		status = INTEGRITY_NOLABEL;
-		if (opened & FILE_CREATED) {
+		if (opened & FILE_CREATED)
 			iint->flags |= IMA_NEW_FILE;
+		if ((iint->flags & IMA_NEW_FILE) &&
+		    !(iint->flags & IMA_DIGSIG_REQUIRED))
 			status = INTEGRITY_PASS;
-		}
 		goto out;
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/ima-accept-previously-set-ima_new_file.patch