[PATCH 6.1 114/185] nbd: always initialize struct msghdr completely
6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
commit 78fbb92af27d0982634116c7a31065f24d092826 upstream.
syzbot complains that msg->msg_get_inq value can be uninitialized [1]
struct msghdr got many new fields recently, we should always make
sure their values is zero by default.
[1]
BUG: KMSAN: uninit-value in tcp_recvmsg+0x686/0xac0 net/ipv4/tcp.c:2571
tcp_recvmsg+0x686/0xac0 net/ipv4/tcp.c:2571
inet_recvmsg+0x131/0x580 net/ipv4/af_inet.c:879
sock_recvmsg_nosec net/socket.c:1044 [inline]
sock_recvmsg+0x12b/0x1e0 net/socket.c:1066
__sock_xmit+0x236/0x5c0 drivers/block/nbd.c:538
nbd_read_reply drivers/block/nbd.c:732 [inline]
recv_work+0x262/0x3100 drivers/block/nbd.c:863
process_one_work kernel/workqueue.c:2627 [inline]
process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2700
worker_thread+0xf45/0x1490 kernel/workqueue.c:2781
kthread+0x3ed/0x540 kernel/kthread.c:388
ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
Local variable msg created at:
__sock_xmit+0x4c/0x5c0 drivers/block/nbd.c:513
nbd_read_reply drivers/block/nbd.c:732 [inline]
recv_work+0x262/0x3100 drivers/block/nbd.c:863
CPU: 1 PID: 7465 Comm: kworker/u5:1 Not tainted 6.7.0-rc7-syzkaller-00041-gf016f7547aee #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: nbd5-recv recv_work
Fixes: f94fd25cb0aa ("tcp: pass back data left in socket after receive")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: stable@vger.kernel.org
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: nbd@other.debian.org
Reviewed-by: Simon Horman <horms@kernel.org>
Link: [🔎] 20240112132657.647112-1-edumazet@google.com">https://lore.kernel.org/r/[🔎] 20240112132657.647112-1-edumazet@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/nbd.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -494,7 +494,7 @@ static int __sock_xmit(struct nbd_device
struct iov_iter *iter, int msg_flags, int *sent)
{
int result;
- struct msghdr msg;
+ struct msghdr msg = { };
unsigned int noreclaim_flag;
if (unlikely(!sock)) {
@@ -509,10 +509,6 @@ static int __sock_xmit(struct nbd_device
noreclaim_flag = memalloc_noreclaim_save();
do {
sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
- msg.msg_name = NULL;
- msg.msg_namelen = 0;
- msg.msg_control = NULL;
- msg.msg_controllen = 0;
msg.msg_flags = msg_flags | MSG_NOSIGNAL;
if (send)
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