| Message ID | 20240913170615.3670897-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 9c778fe48d20ef362047e3376dee56d77f8500d4 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() | expand |
On Fri, Sep 13, 2024 at 05:06:15PM +0000, Eric Dumazet wrote: > syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending > garbage on the four reserved tcp bits (th->res1) > > Use skb_put_zero() to clear the whole TCP header, > as done in nf_reject_ip_tcphdr_put() ... > Fixes: c8d7b98bec43 ("netfilter: move nf_send_resetX() code to nf_reject_ipvX modules") > Reported-by: syzbot <syzkaller@googlegroups.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org>
On Fri, Sep 13, 2024 at 05:06:15PM +0000, Eric Dumazet wrote: > syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending > garbage on the four reserved tcp bits (th->res1) > > Use skb_put_zero() to clear the whole TCP header, > as done in nf_reject_ip_tcphdr_put() Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org> Thanks.
Hello: This patch was applied to netdev/net.git (main) by Paolo Abeni <pabeni@redhat.com>: On Fri, 13 Sep 2024 17:06:15 +0000 you wrote: > syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending > garbage on the four reserved tcp bits (th->res1) > > Use skb_put_zero() to clear the whole TCP header, > as done in nf_reject_ip_tcphdr_put() > > BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 > nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 > nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 > nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 > expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] > nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 > nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 > nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] > nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 > nf_hook include/linux/netfilter.h:269 [inline] > NF_HOOK include/linux/netfilter.h:312 [inline] > ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 > __netif_receive_skb_one_core net/core/dev.c:5661 [inline] > __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 > process_backlog+0x4ad/0xa50 net/core/dev.c:6108 > __napi_poll+0xe7/0x980 net/core/dev.c:6772 > napi_poll net/core/dev.c:6841 [inline] > net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 > handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 > __do_softirq+0x14/0x1a kernel/softirq.c:588 > do_softirq+0x9a/0x100 kernel/softirq.c:455 > __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:382 > local_bh_enable include/linux/bottom_half.h:33 [inline] > rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline] > __dev_queue_xmit+0x2692/0x5610 net/core/dev.c:4450 > dev_queue_xmit include/linux/netdevice.h:3105 [inline] > neigh_resolve_output+0x9ca/0xae0 net/core/neighbour.c:1565 > neigh_output include/net/neighbour.h:542 [inline] > ip6_finish_output2+0x2347/0x2ba0 net/ipv6/ip6_output.c:141 > __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] > ip6_finish_output+0xbb8/0x14b0 net/ipv6/ip6_output.c:226 > NF_HOOK_COND include/linux/netfilter.h:303 [inline] > ip6_output+0x356/0x620 net/ipv6/ip6_output.c:247 > dst_output include/net/dst.h:450 [inline] > NF_HOOK include/linux/netfilter.h:314 [inline] > ip6_xmit+0x1ba6/0x25d0 net/ipv6/ip6_output.c:366 > inet6_csk_xmit+0x442/0x530 net/ipv6/inet6_connection_sock.c:135 > __tcp_transmit_skb+0x3b07/0x4880 net/ipv4/tcp_output.c:1466 > tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] > tcp_connect+0x35b6/0x7130 net/ipv4/tcp_output.c:4143 > tcp_v6_connect+0x1bcc/0x1e40 net/ipv6/tcp_ipv6.c:333 > __inet_stream_connect+0x2ef/0x1730 net/ipv4/af_inet.c:679 > inet_stream_connect+0x6a/0xd0 net/ipv4/af_inet.c:750 > __sys_connect_file net/socket.c:2061 [inline] > __sys_connect+0x606/0x690 net/socket.c:2078 > __do_sys_connect net/socket.c:2088 [inline] > __se_sys_connect net/socket.c:2085 [inline] > __x64_sys_connect+0x91/0xe0 net/socket.c:2085 > x64_sys_call+0x27a5/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:43 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > [...] Here is the summary with links: - [net] netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() https://git.kernel.org/netdev/net/c/9c778fe48d20 You are awesome, thank you!
diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c index dedee264b8f6c8e5155074c6788c53fdf228ca3c..b9457473c176df7a797ae9d4dabd36bcfffaa2fd 100644 --- a/net/ipv6/netfilter/nf_reject_ipv6.c +++ b/net/ipv6/netfilter/nf_reject_ipv6.c @@ -223,33 +223,23 @@ void nf_reject_ip6_tcphdr_put(struct sk_buff *nskb, const struct tcphdr *oth, unsigned int otcplen) { struct tcphdr *tcph; - int needs_ack; skb_reset_transport_header(nskb); - tcph = skb_put(nskb, sizeof(struct tcphdr)); + tcph = skb_put_zero(nskb, sizeof(struct tcphdr)); /* Truncate to length (no data) */ tcph->doff = sizeof(struct tcphdr)/4; tcph->source = oth->dest; tcph->dest = oth->source; if (oth->ack) { - needs_ack = 0; tcph->seq = oth->ack_seq; - tcph->ack_seq = 0; } else { - needs_ack = 1; tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin + otcplen - (oth->doff<<2)); - tcph->seq = 0; + tcph->ack = 1; } - /* Reset flags */ - ((u_int8_t *)tcph)[13] = 0; tcph->rst = 1; - tcph->ack = needs_ack; - tcph->window = 0; - tcph->urg_ptr = 0; - tcph->check = 0; /* Adjust TCP checksum */ tcph->check = csum_ipv6_magic(&ipv6_hdr(nskb)->saddr,
syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending garbage on the four reserved tcp bits (th->res1) Use skb_put_zero() to clear the whole TCP header, as done in nf_reject_ip_tcphdr_put() BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 process_backlog+0x4ad/0xa50 net/core/dev.c:6108 __napi_poll+0xe7/0x980 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 __do_softirq+0x14/0x1a kernel/softirq.c:588 do_softirq+0x9a/0x100 kernel/softirq.c:455 __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline] __dev_queue_xmit+0x2692/0x5610 net/core/dev.c:4450 dev_queue_xmit include/linux/netdevice.h:3105 [inline] neigh_resolve_output+0x9ca/0xae0 net/core/neighbour.c:1565 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x2347/0x2ba0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0xbb8/0x14b0 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x356/0x620 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:450 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] ip6_xmit+0x1ba6/0x25d0 net/ipv6/ip6_output.c:366 inet6_csk_xmit+0x442/0x530 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x3b07/0x4880 net/ipv4/tcp_output.c:1466 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] tcp_connect+0x35b6/0x7130 net/ipv4/tcp_output.c:4143 tcp_v6_connect+0x1bcc/0x1e40 net/ipv6/tcp_ipv6.c:333 __inet_stream_connect+0x2ef/0x1730 net/ipv4/af_inet.c:679 inet_stream_connect+0x6a/0xd0 net/ipv4/af_inet.c:750 __sys_connect_file net/socket.c:2061 [inline] __sys_connect+0x606/0x690 net/socket.c:2078 __do_sys_connect net/socket.c:2088 [inline] __se_sys_connect net/socket.c:2085 [inline] __x64_sys_connect+0x91/0xe0 net/socket.c:2085 x64_sys_call+0x27a5/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:43 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: nf_reject_ip6_tcphdr_put+0x60c/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:249 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 process_backlog+0x4ad/0xa50 net/core/dev.c:6108 __napi_poll+0xe7/0x980 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 __do_softirq+0x14/0x1a kernel/softirq.c:588 Uninit was stored to memory at: nf_reject_ip6_tcphdr_put+0x2ca/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:231 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 process_backlog+0x4ad/0xa50 net/core/dev.c:6108 __napi_poll+0xe7/0x980 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 __do_softirq+0x14/0x1a kernel/softirq.c:588 Uninit was created at: slab_post_alloc_hook mm/slub.c:3998 [inline] slab_alloc_node mm/slub.c:4041 [inline] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4084 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:583 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:674 alloc_skb include/linux/skbuff.h:1320 [inline] nf_send_reset6+0x98d/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:327 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775 process_backlog+0x4ad/0xa50 net/core/dev.c:6108 __napi_poll+0xe7/0x980 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963 handle_softirqs+0x1ce/0x800 kernel/softirq.c:554 __do_softirq+0x14/0x1a kernel/softirq.c:588 Fixes: c8d7b98bec43 ("netfilter: move nf_send_resetX() code to nf_reject_ipvX modules") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/ipv6/netfilter/nf_reject_ipv6.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-)