commit b151d6b00bbb798c58f2f21305e7d43fa763f34f
author Dmitry Kasatkin <d.kasatkin@samsung.com> Fri Jun 27 18:04:27 2014 +0300
committer Mimi Zohar <zohar@linux.vnet.ibm.com> Mon Sep 08 17:38:57 2014 -0400
tree 3a10265d73d01f900860aa9e7e1faa5c4eab4f4d
parent 1f1009791b2e81f106d4809007720495ba3ed90c

ima: provide flag to identify new empty files

On ima_file_free(), newly created empty files are not labeled with
an initial security.ima value, because the iversion did not change.
Commit dff6efc "fs: fix iversion handling" introduced a change in
iversion behavior.  To verify this change use the shell command:

  $ (exec >foo)
  $ getfattr -h -e hex -d -m security foo

This patch defines the IMA_NEW_FILE flag.  The flag is initially
set, when IMA detects that a new file is created, and subsequently
checked on the ima_file_free() hook to set the initial security.ima
value.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>  3.14+

security/integrity/ima/ima_appraise.c

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 86bfd5c..a4605d6 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -202,8 +202,11 @@
 			goto out;
 
 		cause = "missing-hash";
-		status =
-		    (inode->i_size == 0) ? INTEGRITY_PASS : INTEGRITY_NOLABEL;
+		status = INTEGRITY_NOLABEL;
+		if (inode->i_size == 0) {
+			iint->flags |= IMA_NEW_FILE;
+			status = INTEGRITY_PASS;
+		}
 		goto out;
 	}
 

security/integrity/ima/ima_main.c

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2917f98..0a2298f 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -124,11 +124,13 @@
 		return;
 
 	mutex_lock(&inode->i_mutex);
-	if (atomic_read(&inode->i_writecount) == 1 &&
-	    iint->version != inode->i_version) {
-		iint->flags &= ~IMA_DONE_MASK;
-		if (iint->flags & IMA_APPRAISE)
-			ima_update_xattr(iint, file);
+	if (atomic_read(&inode->i_writecount) == 1) {
+		if ((iint->version != inode->i_version) ||
+		    (iint->flags & IMA_NEW_FILE)) {
+			iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
+			if (iint->flags & IMA_APPRAISE)
+				ima_update_xattr(iint, file);
+		}
 	}
 	mutex_unlock(&inode->i_mutex);
 }

security/integrity/integrity.h

diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 19b8e31..904e68a 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -31,6 +31,7 @@
 #define IMA_DIGSIG		0x01000000
 #define IMA_DIGSIG_REQUIRED	0x02000000
 #define IMA_PERMIT_DIRECTIO	0x04000000
+#define IMA_NEW_FILE		0x08000000
 
 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
 				 IMA_APPRAISE_SUBMASK)