diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2023-05-24 16:29:34 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-05-25 21:03:23 -0700 |
| commit | 822b5a1c17df7e338b9f05d1cfe5764e37c7f74f (patch) | |
| tree | ee9511f808bd9dd20dab29cc0018b6a9a3b3ce4c /net/packet | |
| parent | 081e8df6819997eae236f75dd52f0c147c4be939 (diff) | |
af_packet: Fix data-races of pkt_sk(sk)->num.
syzkaller found a data race of pkt_sk(sk)->num.
The value is changed under lock_sock() and po->bind_lock, so we
need READ_ONCE() to access pkt_sk(sk)->num without these locks in
packet_bind_spkt(), packet_bind(), and sk_diag_fill().
Note that WRITE_ONCE() is already added by commit c7d2ef5dd4b0
("net/packet: annotate accesses to po->bind").
BUG: KCSAN: data-race in packet_bind / packet_do_bind
write (marked) to 0xffff88802ffd1cee of 2 bytes by task 7322 on cpu 0:
packet_do_bind+0x446/0x640 net/packet/af_packet.c:3236
packet_bind+0x99/0xe0 net/packet/af_packet.c:3321
__sys_bind+0x19b/0x1e0 net/socket.c:1803
__do_sys_bind net/socket.c:1814 [inline]
__se_sys_bind net/socket.c:1812 [inline]
__x64_sys_bind+0x40/0x50 net/socket.c:1812
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x72/0xdc
read to 0xffff88802ffd1cee of 2 bytes by task 7318 on cpu 1:
packet_bind+0xbf/0xe0 net/packet/af_packet.c:3322
__sys_bind+0x19b/0x1e0 net/socket.c:1803
__do_sys_bind net/socket.c:1814 [inline]
__se_sys_bind net/socket.c:1812 [inline]
__x64_sys_bind+0x40/0x50 net/socket.c:1812
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x72/0xdc
value changed: 0x0300 -> 0x0000
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7318 Comm: syz-executor.4 Not tainted 6.3.0-13380-g7fddb5b5300c #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Fixes: 96ec6327144e ("packet: Diag core and basic socket info dumping")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230524232934.50950-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 4 | ||||
| -rw-r--r-- | net/packet/diag.c | 2 |
2 files changed, 3 insertions, 3 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 94c6a1ffa459..a1f9a0e9f3c8 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3299,7 +3299,7 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr, memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data_min)); name[sizeof(uaddr->sa_data_min)] = 0; - return packet_do_bind(sk, name, 0, pkt_sk(sk)->num); + return packet_do_bind(sk, name, 0, READ_ONCE(pkt_sk(sk)->num)); } static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) @@ -3317,7 +3317,7 @@ static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len return -EINVAL; return packet_do_bind(sk, NULL, sll->sll_ifindex, - sll->sll_protocol ? : pkt_sk(sk)->num); + sll->sll_protocol ? : READ_ONCE(pkt_sk(sk)->num)); } static struct proto packet_proto = { diff --git a/net/packet/diag.c b/net/packet/diag.c index d0c4eda4cdc6..f6b200cb3c06 100644 --- a/net/packet/diag.c +++ b/net/packet/diag.c @@ -143,7 +143,7 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, rp = nlmsg_data(nlh); rp->pdiag_family = AF_PACKET; rp->pdiag_type = sk->sk_type; - rp->pdiag_num = ntohs(po->num); + rp->pdiag_num = ntohs(READ_ONCE(po->num)); rp->pdiag_ino = sk_ino; sock_diag_save_cookie(sk, rp->pdiag_cookie); |