Patch "ima: relax requiring a file signature for new files with zero length" has been added to the 4.15-stable tree

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

ima: relax requiring a file signature for new files with zero length

to the 4.15-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-relax-requiring-a-file-signature-for-new-files-with-zero-length.patch
and it can be found in the queue-4.15 subdirectory.

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

From: Mimi Zohar <[email protected]>
Date: Wed, 8 Nov 2017 07:38:28 -0500
Subject: ima: relax requiring a file signature for new files with zero length

From: Mimi Zohar <[email protected]>

[ Upstream commit b7e27bc1d42e8e0cc58b602b529c25cd0071b336 ]

Custom policies can require file signatures based on LSM labels. These files are normally created and only afterwards labeled, requiring them to be signed.

Instead of requiring file signatures based on LSM labels, entire filesystems could require file signatures. In this case, we need the ability of writing new files without requiring file signatures.

The definition of a "new" file was originally defined as any file with a length of zero. Subsequent patches redefined a "new" file to be based on the FILE_CREATE open flag. By combining the open flag with a file size of zero, this patch relaxes the file signature requirement.

---
 security/integrity/ima/ima_appraise.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -223,7 +223,8 @@ int ima_appraise_measurement(enum ima_ho
 		if (opened & FILE_CREATED)
 			iint->flags |= IMA_NEW_FILE;
 		if ((iint->flags & IMA_NEW_FILE) &&
-		    !(iint->flags & IMA_DIGSIG_REQUIRED))
+		    (!(iint->flags & IMA_DIGSIG_REQUIRED) ||
+		     (inode->i_size == 0)))
 			status = INTEGRITY_PASS;
 		goto out;
 	}

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

queue-4.15/ima-relax-requiring-a-file-signature-for-new-files-with-zero-length.patch