[PATCH 4.4 69/86] cw1200: Dont leak memory if krealloc failes

[Greg Kroah-Hartman]

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

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

From: Johannes Thumshirn <jthumsh...@suse.de>

commit 9afdd6128c39f42398041bb2e017d8df0dcebcd1 upstream.

The call to krealloc() in wsm_buf_reserve() directly assigns the newly
returned memory to buf->begin. This is all fine except when krealloc()
failes we loose the ability to free the old memory pointed to by
buf->begin. If we just create a temporary variable to assign memory to
and assign the memory to it we can mitigate the memory leak.

Signed-off-by: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Johannes Berg <johan...@sipsolutions.net>
Signed-off-by: Kalle Valo <kv...@codeaurora.org>
Signed-off-by: Amit Pundir <amit.pun...@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/net/wireless/cw1200/wsm.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

--- a/drivers/net/wireless/cw1200/wsm.c
+++ b/drivers/net/wireless/cw1200/wsm.c
@@ -1805,16 +1805,18 @@ static int wsm_buf_reserve(struct wsm_bu
 {
        size_t pos = buf->data - buf->begin;
        size_t size = pos + extra_size;
+       u8 *tmp;
 
        size = round_up(size, FWLOAD_BLOCK_SIZE);
 
-       buf->begin = krealloc(buf->begin, size, GFP_KERNEL | GFP_DMA);
-       if (buf->begin) {
-               buf->data = &buf->begin[pos];
-               buf->end = &buf->begin[size];
-               return 0;
-       } else {
-               buf->end = buf->data = buf->begin;
+       tmp = krealloc(buf->begin, size, GFP_KERNEL | GFP_DMA);
+       if (!tmp) {
+               wsm_buf_deinit(buf);
                return -ENOMEM;
        }
+
+       buf->begin = tmp;
+       buf->data = &buf->begin[pos];
+       buf->end = &buf->begin[size];
+       return 0;
 }