Bluetooth: L2CAP: handle NULL sock pointer in l2cap_sock_alloc

Commit Message

Fedor Pchelkin Dec. 17, 2024, 9:19 p.m. UTC

A NULL sock pointer is passed into l2cap_sock_alloc() when it is called
from l2cap_sock_new_connection_cb() and the error handling paths should
also be aware of it.

Seemingly a more elegant solution would be to swap bt_sock_alloc() and
l2cap_chan_create() calls since they are not interdependent to that moment
but then l2cap_chan_create() adds the soon to be deallocated and still
dummy-initialized channel to the global list accessible by many L2CAP
paths. The channel would be removed from the list in short period of time
but be a bit more straight-forward here and just check for NULL instead of
changing the order of function calls.

Found by Linux Verification Center (linuxtesting.org) with SVACE static
analysis tool.

Fixes: 7c4f78cdb8e7 ("Bluetooth: L2CAP: do not leave dangling sk pointer on error in l2cap_sock_create()")
Cc: [e-mail]
Signed-off-by: Fedor Pchelkin <[e-mail]>
---
 net/bluetooth/l2cap_sock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

[e-mail] Dec. 17, 2024, 9:54 p.m. UTC | #1

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=918835

---Test result---

Test Summary:
CheckPatch                    PENDING   0.25 seconds
GitLint                       PENDING   0.21 seconds
SubjectPrefix                 PASS      0.13 seconds
BuildKernel                   PASS      25.34 seconds
CheckAllWarning               PASS      27.79 seconds
CheckSparse                   PASS      31.50 seconds
BuildKernel32                 PASS      25.09 seconds
TestRunnerSetup               PASS      443.75 seconds
TestRunner_l2cap-tester       PASS      22.67 seconds
TestRunner_iso-tester         PASS      36.70 seconds
TestRunner_bnep-tester        PASS      4.95 seconds
TestRunner_mgmt-tester        FAIL      121.07 seconds
TestRunner_rfcomm-tester      PASS      7.69 seconds
TestRunner_sco-tester         PASS      11.44 seconds
TestRunner_ioctl-tester       PASS      8.20 seconds
TestRunner_mesh-tester        FAIL      6.61 seconds
TestRunner_smp-tester         PASS      7.08 seconds
TestRunner_userchan-tester    PASS      5.19 seconds
IncrementalBuild              PENDING   0.83 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 490, Passed: 485 (99.0%), Failed: 1, Not Run: 4

Failed Test Cases
LL Privacy - Start Discovery 1 (Disable RL)          Failed       0.173 seconds
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
Total: 10, Passed: 9 (90.0%), Failed: 1, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 2                               Failed       0.116 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Kuniyuki Iwashima Dec. 21, 2024, 8:17 a.m. UTC | #2

From: Fedor Pchelkin <[e-mail]>
Date: Wed, 18 Dec 2024 00:19:59 +0300
> A NULL sock pointer is passed into l2cap_sock_alloc() when it is called
> from l2cap_sock_new_connection_cb() and the error handling paths should
> also be aware of it.
> 
> Seemingly a more elegant solution would be to swap bt_sock_alloc() and
> l2cap_chan_create() calls since they are not interdependent to that moment
> but then l2cap_chan_create() adds the soon to be deallocated and still
> dummy-initialized channel to the global list accessible by many L2CAP
> paths. The channel would be removed from the list in short period of time
> but be a bit more straight-forward here and just check for NULL instead of
> changing the order of function calls.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE static
> analysis tool.
> 
> Fixes: 7c4f78cdb8e7 ("Bluetooth: L2CAP: do not leave dangling sk pointer on error in l2cap_sock_create()")
> Cc: [e-mail]
> Signed-off-by: Fedor Pchelkin <[e-mail]>

Reviewed-by: Kuniyuki Iwashima <[e-mail]>


> ---
>  net/bluetooth/l2cap_sock.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 3d2553dcdb1b..49f97d4138ea 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -1888,7 +1888,8 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
>  	chan = l2cap_chan_create();
>  	if (!chan) {
>  		sk_free(sk);
> -		sock->sk = NULL;
> +		if (sock)
> +			sock->sk = NULL;
>  		return NULL;
>  	}
>  
> -- 
> 2.39.5

Patch

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 3d2553dcdb1b..49f97d4138ea 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1888,7 +1888,8 @@  static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
 	chan = l2cap_chan_create();
 	if (!chan) {
 		sk_free(sk);
-		sock->sk = NULL;
+		if (sock)
+			sock->sk = NULL;
 		return NULL;
 	}