[PATCH 4.14 21/21] jfs: Fix inconsistency between memory allocation and ea_buf->max_size

Greg Kroah-Hartman
2018-08-07T18:54:16Z

From: Shankara Pailoor <shankarapailoor@gmail.com>

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 <shankarapailoor@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
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
@@ -491,15 +491,17 @@ 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;