[PATCH v2] cw1200: Don't leak memory if krealloc failes

From: Johannes Thumshirn
Date: Fri Sep 30 2016 - 08:39:33 EST


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 <jthumshirn@xxxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
drivers/net/wireless/st/cw1200/wsm.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

Changes from v1:
* Do the correct check for a failed re-allocation (Johannes Berg)

diff --git a/drivers/net/wireless/st/cw1200/wsm.c b/drivers/net/wireless/st/cw1200/wsm.c
index 680d60e..ffb245e 100644
--- a/drivers/net/wireless/st/cw1200/wsm.c
+++ b/drivers/net/wireless/st/cw1200/wsm.c
@@ -1807,16 +1807,18 @@ static int wsm_buf_reserve(struct wsm_buf *buf, size_t extra_size)
{
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;
}
--
1.8.5.6