[PATCH 3.4 19/35] firewire: net: fix use after free

Greg Kroah-Hartman
2014-03-21T00:14:05Z

From: Stefan Richter <stefanr@s5r6.in-berlin.de>

commit 8987583366ae9e03c306c2b7d73bdb952df1d08d upstream.

Commit 8408dc1c14c1 "firewire: net: use dev_printk API" introduced a
use-after-free in a failure path. fwnet_transmit_packet_failed(ptask)
may free ptask, then the dev_err() call dereferenced it. The fix is
straightforward; simply reorder the two calls.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/firewire/net.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -1014,8 +1014,6 @@ static void fwnet_write_complete(struct
if (rcode == RCODE_COMPLETE) {
fwnet_transmit_packet_done(ptask);
} else {
- fwnet_transmit_packet_failed(ptask);
-
if (printk_timed_ratelimit(&j, 1000) || rcode != last_rcode) {
dev_err(&ptask->dev->netdev->dev,
"fwnet_write_complete failed: %x (skipped %d)\n",
@@ -1023,8 +1021,10 @@ static void fwnet_write_complete(struct

errors_skipped = 0;
last_rcode = rcode;
- } else
+ } else {
errors_skipped++;
+ }
+ fwnet_transmit_packet_failed(ptask);
}
}