Stefano Garzarella
2023-Nov-06 08:42 UTC
[PATCH net v2] virtio/vsock: Fix uninit-value in virtio_transport_recv_pkt()
On Sun, Nov 05, 2023 at 12:05:31AM +0900, Shigeru Yoshida wrote:>KMSAN reported the following uninit-value access issue: > >====================================================>BUG: KMSAN: uninit-value in virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421 > virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421 > vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 > process_one_work kernel/workqueue.c:2630 [inline] > process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 > worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 > kthread+0x3cc/0x520 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:304 > >Uninit was stored to memory at: > virtio_transport_space_update net/vmw_vsock/virtio_transport_common.c:1274 [inline] > virtio_transport_recv_pkt+0x1ee8/0x26a0 net/vmw_vsock/virtio_transport_common.c:1415 > vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 > process_one_work kernel/workqueue.c:2630 [inline] > process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 > worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 > kthread+0x3cc/0x520 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:304 > >Uninit was created at: > slab_post_alloc_hook+0x105/0xad0 mm/slab.h:767 > slab_alloc_node mm/slub.c:3478 [inline] > kmem_cache_alloc_node+0x5a2/0xaf0 mm/slub.c:3523 > kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:559 > __alloc_skb+0x2fd/0x770 net/core/skbuff.c:650 > alloc_skb include/linux/skbuff.h:1286 [inline] > virtio_vsock_alloc_skb include/linux/virtio_vsock.h:66 [inline] > virtio_transport_alloc_skb+0x90/0x11e0 net/vmw_vsock/virtio_transport_common.c:58 > virtio_transport_reset_no_sock net/vmw_vsock/virtio_transport_common.c:957 [inline] > virtio_transport_recv_pkt+0x1279/0x26a0 net/vmw_vsock/virtio_transport_common.c:1387 > vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 > process_one_work kernel/workqueue.c:2630 [inline] > process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 > worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 > kthread+0x3cc/0x520 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:304 > >CPU: 1 PID: 10664 Comm: kworker/1:5 Not tainted 6.6.0-rc3-00146-g9f3ebbef746f #3 >Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 >Workqueue: vsock-loopback vsock_loopback_work >====================================================> >The following simple reproducer can cause the issue described above: > >int main(void) >{ > int sock; > struct sockaddr_vm addr = { > .svm_family = AF_VSOCK, > .svm_cid = VMADDR_CID_ANY, > .svm_port = 1234, > }; > > sock = socket(AF_VSOCK, SOCK_STREAM, 0); > connect(sock, (struct sockaddr *)&addr, sizeof(addr)); > return 0; >} > >This issue occurs because the `buf_alloc` and `fwd_cnt` fields of the >`struct virtio_vsock_hdr` are not initialized when a new skb is allocated >in `virtio_transport_init_hdr()`. This patch resolves the issue by >initializing these fields during allocation. > >Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") >Reported-and-tested-by: syzbot+0c8ce1da0ac31abbadcd at syzkaller.appspotmail.com >Closes: https://syzkaller.appspot.com/bug?extid=0c8ce1da0ac31abbadcd >Signed-off-by: Shigeru Yoshida <syoshida at redhat.com> >--- >v1->v2: >- Rebase on the latest net tree >https://lore.kernel.org/all/20231026150154.3536433-1-syoshida at redhat.com/ >--- > net/vmw_vsock/virtio_transport_common.c | 2 ++ > 1 file changed, 2 insertions(+)The patch remained the same, so you could bring back my R-b ;-) In any case: Reviewed-by: Stefano Garzarella <sgarzare at redhat.com> Thanks, Stefano> >diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >index e22c81435ef7..dc65dd4d26df 100644 >--- a/net/vmw_vsock/virtio_transport_common.c >+++ b/net/vmw_vsock/virtio_transport_common.c >@@ -130,6 +130,8 @@ static void virtio_transport_init_hdr(struct sk_buff *skb, > hdr->dst_port = cpu_to_le32(dst_port); > hdr->flags = cpu_to_le32(info->flags); > hdr->len = cpu_to_le32(payload_len); >+ hdr->buf_alloc = cpu_to_le32(0); >+ hdr->fwd_cnt = cpu_to_le32(0); > } > > static void virtio_transport_copy_nonlinear_skb(const struct sk_buff *skb, >-- >2.41.0 >