Thread (16 messages) flat view 16 messages, 5 authors, 2018-08-08
STALE2928d

[PATCH 4.4 12/12] jfs: Fix inconsistency between memory allocation and ea_buf->max_size

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2018-08-07 18:56:15
Also in: lkml

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Shankara Pailoor <redacted>

commit 92d34134193e5b129dc24f8d79cb9196626e8d7a upstream.

The code is assuming the buffer is max_size length, but we weren't
allocating enough space for it.

Signed-off-by: Shankara Pailoor <redacted>
Signed-off-by: Dave Kleikamp <redacted>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/jfs/xattr.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -493,15 +493,17 @@ static int ea_get(struct inode *inode, s
 	if (size > PSIZE) {
 		/*
 		 * To keep the rest of the code simple.  Allocate a
-		 * contiguous buffer to work with
+		 * contiguous buffer to work with. Make the buffer large
+		 * enough to make use of the whole extent.
 		 */
-		ea_buf->xattr = kmalloc(size, GFP_KERNEL);
+		ea_buf->max_size = (size + sb->s_blocksize - 1) &
+		    ~(sb->s_blocksize - 1);
+
+		ea_buf->xattr = kmalloc(ea_buf->max_size, GFP_KERNEL);
 		if (ea_buf->xattr == NULL)
 			return -ENOMEM;
 
 		ea_buf->flag = EA_MALLOC;
-		ea_buf->max_size = (size + sb->s_blocksize - 1) &
-		    ~(sb->s_blocksize - 1);
 
 		if (ea_size == 0)
 			return 0;
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