From: Shigeru Yoshida syoshida@redhat.com
stable inclusion from stable-v6.6.2 commit 0b8906fb48b99e993d6e8a12539f618f4854dd26 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 34c4effacfc329aeca5635a69fd9e0f6c90b4101 ]
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@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c8ce1da0ac31abbadcd Signed-off-by: Shigeru Yoshida syoshida@redhat.com Reviewed-by: Stefano Garzarella sgarzare@redhat.com Link: https://lore.kernel.org/r/20231104150531.257952-1-syoshida@redhat.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- net/vmw_vsock/virtio_transport_common.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index eb1465d506ef..8bc272b6003b 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -68,6 +68,8 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info, hdr->dst_port = cpu_to_le32(dst_port); hdr->flags = cpu_to_le32(info->flags); hdr->len = cpu_to_le32(len); + hdr->buf_alloc = cpu_to_le32(0); + hdr->fwd_cnt = cpu_to_le32(0);
if (info->msg && len > 0) { payload = skb_put(skb, len);