From: Shigeru Yoshida syoshida@redhat.com
[ Upstream commit ddbec99f58571301679addbc022256970ca3eac6 ]
KMSAN reported the following uninit-value access issue [1]:
===================================================== BUG: KMSAN: uninit-value in hsr_get_node+0xa2e/0xa40 net/hsr/hsr_framereg.c:246 hsr_get_node+0xa2e/0xa40 net/hsr/hsr_framereg.c:246 fill_frame_info net/hsr/hsr_forward.c:577 [inline] hsr_forward_skb+0xe12/0x30e0 net/hsr/hsr_forward.c:615 hsr_dev_xmit+0x1a1/0x270 net/hsr/hsr_device.c:223 __netdev_start_xmit include/linux/netdevice.h:4940 [inline] netdev_start_xmit include/linux/netdevice.h:4954 [inline] xmit_one net/core/dev.c:3548 [inline] dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3564 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349 dev_queue_xmit include/linux/netdevice.h:3134 [inline] packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3087 [inline] packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x735/0xa10 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560 __alloc_skb+0x318/0x740 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1286 [inline] alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2787 packet_alloc_skb net/packet/af_packet.c:2936 [inline] packet_snd net/packet/af_packet.c:3030 [inline] packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x735/0xa10 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b
CPU: 1 PID: 5033 Comm: syz-executor334 Not tainted 6.7.0-syzkaller-00562-g9f8413c4a66f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 =====================================================
If the packet type ID field in the Ethernet header is either ETH_P_PRP or ETH_P_HSR, but it is not followed by an HSR tag, hsr_get_skb_sequence_nr() reads an invalid value as a sequence number. This causes the above issue.
This patch fixes the issue by returning NULL if the Ethernet header is not followed by an HSR tag.
Fixes: f266a683a480 ("net/hsr: Better frame dispatch") Reported-and-tested-by: syzbot+2ef3a8ce8e91b5a50098@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2ef3a8ce8e91b5a50098 [1] Signed-off-by: Shigeru Yoshida syoshida@redhat.com Link: https://lore.kernel.org/r/20240312152719.724530-1-syoshida@redhat.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/hsr/hsr_framereg.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c index 87fc86aade5c9..fc9fb3e5ae3e2 100644 --- a/net/hsr/hsr_framereg.c +++ b/net/hsr/hsr_framereg.c @@ -237,6 +237,10 @@ struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db, */ if (ethhdr->h_proto == htons(ETH_P_PRP) || ethhdr->h_proto == htons(ETH_P_HSR)) { + /* Check if skb contains hsr_ethhdr */ + if (skb->mac_len < sizeof(struct hsr_ethhdr)) + return NULL; + /* Use the existing sequence_nr from the tag as starting point * for filtering duplicate frames. */