2022-08-01 21:15:01

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: [PATCH] Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm regression

From: Luiz Augusto von Dentz <[email protected]>

The patch d0be8347c623: "Bluetooth: L2CAP: Fix use-after-free caused
by l2cap_chan_put" from Jul 21, 2022, leads to the following Smatch
static checker warning:

net/bluetooth/l2cap_core.c:1977 l2cap_global_chan_by_psm()
error: we previously assumed 'c' could be null (see line 1996)

Fixes: d0be8347c623: "Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put"
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
net/bluetooth/l2cap_core.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 52668662ae8d..f18d0c72713f 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1969,11 +1969,11 @@ static struct l2cap_chan *l2cap_global_chan_by_psm(int state, __le16 psm,
bdaddr_t *dst,
u8 link_type)
- struct l2cap_chan *c, *c1 = NULL;
+ struct l2cap_chan *c, *tmp, *c1 = NULL;


- list_for_each_entry(c, &chan_list, global_l) {
+ list_for_each_entry_safe(c, tmp, &chan_list, global_l) {
if (state && c->state != state)

@@ -1992,11 +1992,10 @@ static struct l2cap_chan *l2cap_global_chan_by_psm(int state, __le16 psm,
dst_match = !bacmp(&c->dst, dst);
if (src_match && dst_match) {
c = l2cap_chan_hold_unless_zero(c);
- if (!c)
- continue;
- read_unlock(&chan_list_lock);
- return c;
+ if (c) {
+ read_unlock(&chan_list_lock);
+ return c;
+ }

/* Closest match */

2022-08-01 21:49:41

by bluez.test.bot

[permalink] [raw]
Subject: RE: Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm regression

This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----
error: patch failed: net/bluetooth/l2cap_core.c:1992
error: net/bluetooth/l2cap_core.c: patch does not apply
hint: Use 'git am --show-current-patch' to see the failed patch

Please resolve the issue and submit the patches again.

Linux Bluetooth

2022-08-01 22:27:55

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm regression

Hi Luiz,

I love your patch! Perhaps something to improve:

[auto build test WARNING on bluetooth-next/master]
[also build test WARNING on bluetooth/master linus/master v5.19 next-20220728]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in

url: https://github.com/intel-lab-lkp/linux/commits/Luiz-Augusto-von-Dentz/Bluetooth-L2CAP-Fix-l2cap_global_chan_by_psm-regression/20220802-050647
base: https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
config: parisc-randconfig-r024-20220801 (https://download.01.org/0day-ci/archive/20220802/[email protected]/config)
compiler: hppa-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/075988314335917c0e43d00f6a3a8ef68963b3de
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Luiz-Augusto-von-Dentz/Bluetooth-L2CAP-Fix-l2cap_global_chan_by_psm-regression/20220802-050647
git checkout 075988314335917c0e43d00f6a3a8ef68963b3de
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=parisc SHELL=/bin/bash net/bluetooth/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

In file included from net/bluetooth/l2cap_core.c:37:
In function 'bacmp',
inlined from 'l2cap_global_chan_by_psm' at net/bluetooth/l2cap_core.c:2003:15:
>> include/net/bluetooth/bluetooth.h:347:16: warning: 'memcmp' specified bound 6 exceeds source size 0 [-Wstringop-overread]
347 | return memcmp(ba1, ba2, sizeof(bdaddr_t));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

vim +/memcmp +347 include/net/bluetooth/bluetooth.h

^1da177e4c3f41 Linus Torvalds 2005-04-16 343
^1da177e4c3f41 Linus Torvalds 2005-04-16 344 /* Copy, swap, convert BD Address */
f53c20e93612f7 David Herrmann 2013-04-06 345 static inline int bacmp(const bdaddr_t *ba1, const bdaddr_t *ba2)
^1da177e4c3f41 Linus Torvalds 2005-04-16 346 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 @347 return memcmp(ba1, ba2, sizeof(bdaddr_t));
^1da177e4c3f41 Linus Torvalds 2005-04-16 348 }
f53c20e93612f7 David Herrmann 2013-04-06 349 static inline void bacpy(bdaddr_t *dst, const bdaddr_t *src)
^1da177e4c3f41 Linus Torvalds 2005-04-16 350 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 351 memcpy(dst, src, sizeof(bdaddr_t));
^1da177e4c3f41 Linus Torvalds 2005-04-16 352 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 353

0-DAY CI Kernel Test Service