b43: rfkill use after free

PATCH NAK Eric Paris 2 participants 2 messages Jan 13, 2008 Networking drivers (wireless)

Share & tools

Eric Paris

author

2008-01-13 21:21 UTC #0 lore raw

PATCH 1/1 b43: rfkill use after free

inside b43_rfkill_exit() we call rfkill_unregister() which puts the last reference and frees the rfkill struct. Then just 3 lines later the code explicitly calls rfkill_free() on the struct we already freed. This showed up as slub corruption (what should have been 6b was showing up as 6a) since the rfkill_free had dec'ed the are that should have been the use counter.

stop using the already freed rfkill struct.

=============================================================================
BUG kmalloc-1024 (Not tainted): Poison overwritten
-----------------------------------------------------------------------------

INFO: 0xf40b89e8-0xf40b89e8. First byte 0x6a instead of 0x6b
INFO: Allocated in rfkill_allocate+0x1b/0x8b [rfkill] age=231032011 cpu=0 pid=2403
INFO: Freed in rfkill_release+0xd/0x19 [rfkill] age=366 cpu=0 pid=2403
INFO: Slab 0xc1b62840 used=6 fp=0xf40b8860 flags=0x400040c3
INFO: Object 0xf40b8860 @offset=2144 fp=0x00000000

Signed-off-by Eric Paris <[email protected]>

---

 drivers/net/wireless/b43/rfkill.c |    1 -
 1 file changed, 1 deletion(-)

drivers/net/wireless/b43/rfkill.c +0 -1

index 98cf70c..a19be53 100644
@@ -195,6 +195,5 @@ void b43_rfkill_exit(struct b43_wldev *dev)
 	rfkill_unregister(rfk->rfkill);
 	input_free_polled_device(rfk->poll_dev);
 	rfk->poll_dev = NULL;
-	rfkill_free(rfk->rfkill);
 	rfk->rfkill = NULL;
 }

Michael Buesch

NAK

2008-01-13 21:29 UTC #1 lore raw

Quoted 35 lines · On Sunday 13 January 2008 22:20:52 Eric Paris wrote:

inside b43_rfkill_exit() we call rfkill_unregister() which puts the last reference and frees the rfkill struct. Then just 3 lines later the code explicitly calls rfkill_free() on the struct we already freed. This showed up as slub corruption (what should have been 6b was showing up as 6a) since the rfkill_free had dec'ed the are that should have been the use counter.
stop using the already freed rfkill struct.
=============================================================================
BUG kmalloc-1024 (Not tainted): Poison overwritten
-----------------------------------------------------------------------------
INFO: 0xf40b89e8-0xf40b89e8. First byte 0x6a instead of 0x6b
INFO: Allocated in rfkill_allocate+0x1b/0x8b [rfkill] age=231032011 cpu=0 pid=2403
INFO: Freed in rfkill_release+0xd/0x19 [rfkill] age=366 cpu=0 pid=2403
INFO: Slab 0xc1b62840 used=6 fp=0xf40b8860 flags=0x400040c3
INFO: Object 0xf40b8860 @offset=2144 fp=0x00000000
Signed-off-by Eric Paris <[email protected]>
---
 drivers/net/wireless/b43/rfkill.c |    1 -
 1 file changed, 1 deletion(-)
drivers/net/wireless/b43/rfkill.c +0 -0
index 98cf70c..a19be53 100644

drivers/net/wireless/b43/rfkill.c void b43_rfkill_exit(struct b43_wldev *dev) · line 199

Quoted 6 lines

drivers/net/wireless/b43/rfkill.c +0 -1

@@ -195,6 +195,5 @@ void b43_rfkill_exit(struct b43_wldev *dev)
 	rfkill_unregister(rfk->rfkill);
 	input_free_polled_device(rfk->poll_dev);
 	rfk->poll_dev = NULL;
-	rfkill_free(rfk->rfkill);
 	rfk->rfkill = NULL;
 }

NACK.
Better patch available from Stefano.

Signature · 1 line

Greetings Michael.