Begin forwarded message:
Date: Fri, 28 Apr 2023 10:22:28 +0000
From: [email protected]
To: [email protected]
Subject: [Bug 217383] New: Bluetooth: L2CAP: possible data race in __sco_sock_close()
https://bugzilla.kernel.org/show_bug.cgi?id=217383
Bug ID: 217383
Summary: Bluetooth: L2CAP: possible data race in
__sco_sock_close()
Product: Networking
Version: 2.5
Hardware: All
OS: Linux
Status: NEW
Severity: normal
Priority: P3
Component: Other
Assignee: [email protected]
Reporter: [email protected]
Regression: No
Our static analysis tool finds a possible data race in the l2cap protocol
in Linux 6.3.0-rc7:
In most calling contexts, the variable sk->sk_socket is accessed
with holding the lock sk->sk_callback_lock. Here is an example:
l2cap_sock_accept() --> Line 346 in net/bluetooth/l2cap_sock.c
bt_accept_dequeue() --> Line 368 in net/bluetooth/l2cap_sock.c
sock_graft() --> Line 240 in net/bluetooth/af_bluetooth.c
write_lock_bh(&sk->sk_callback_lock); --> Line 2081 in
include/net/sock.h (Lock sk->sk_callback_lock)
sk_set_socket() --> Line 2084 in include/net/sock.h
sk->sk_socket = sock; --> Line 2054 in include/net/sock.h
(Access sk->sk_socket)
However, in the following calling context:
sco_sock_shutdown() --> Line 1227 in net/bluetooth/sco.c
__sco_sock_close() --> Line 1243 in net/bluetooth/sco.c
BT_DBG(..., sk->sk_socket); --> Line 431 in net/bluetooth/sco.c
(Access sk->sk_socket)
the variable sk->sk_socket is accessed without holding the lock
sk->sk_callback_lock, and thus a data race may occur.
Reported-by: BassCheck <[email protected]>
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From: Stephen Hemminger <[email protected]>
Date: Fri, 28 Apr 2023 08:52:39 -0700
> Begin forwarded message:
>
> Date: Fri, 28 Apr 2023 10:22:28 +0000
> From: [email protected]
> To: [email protected]
> Subject: [Bug 217383] New: Bluetooth: L2CAP: possible data race in __sco_sock_close()
>
>
> https://bugzilla.kernel.org/show_bug.cgi?id=217383
>
> Bug ID: 217383
> Summary: Bluetooth: L2CAP: possible data race in
> __sco_sock_close()
> Product: Networking
> Version: 2.5
> Hardware: All
> OS: Linux
> Status: NEW
> Severity: normal
> Priority: P3
> Component: Other
> Assignee: [email protected]
> Reporter: [email protected]
> Regression: No
>
> Our static analysis tool finds a possible data race in the l2cap protocol
> in Linux 6.3.0-rc7:
>
> In most calling contexts, the variable sk->sk_socket is accessed
> with holding the lock sk->sk_callback_lock. Here is an example:
>
> l2cap_sock_accept() --> Line 346 in net/bluetooth/l2cap_sock.c
> bt_accept_dequeue() --> Line 368 in net/bluetooth/l2cap_sock.c
> sock_graft() --> Line 240 in net/bluetooth/af_bluetooth.c
> write_lock_bh(&sk->sk_callback_lock); --> Line 2081 in
> include/net/sock.h (Lock sk->sk_callback_lock)
> sk_set_socket() --> Line 2084 in include/net/sock.h
> sk->sk_socket = sock; --> Line 2054 in include/net/sock.h
> (Access sk->sk_socket)
>
> However, in the following calling context:
>
> sco_sock_shutdown() --> Line 1227 in net/bluetooth/sco.c
> __sco_sock_close() --> Line 1243 in net/bluetooth/sco.c
> BT_DBG(..., sk->sk_socket); --> Line 431 in net/bluetooth/sco.c
> (Access sk->sk_socket)
Those two sockets have different proto, BTPROTO_L2CAP and BTPROTO_SCO.
Also, we cannot shutdown() for not-yet-accepted socket, and both
l2cap_sock_accept() and sco_sock_shutdown() take lock_sock().
>
> the variable sk->sk_socket is accessed without holding the lock
> sk->sk_callback_lock, and thus a data race may occur.
>
> Reported-by: BassCheck <[email protected]>
>
> --
> You may reply to this email to add a comment.
>
> You are receiving this mail because:
> You are the assignee for the bug.