* [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
@ 2024-01-05 17:03 Eric Dumazet
2024-01-05 19:45 ` Willem de Bruijn
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Eric Dumazet @ 2024-01-05 17:03 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Willem de Bruijn, netdev, eric.dumazet, Eric Dumazet,
syzbot
syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.
Reading frag_off can only be done if we pulled enough bytes
to skb->head. Currently we might access garbage.
[1]
BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__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]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
dst_output include/net/dst.h:451 [inline]
ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 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+0x5c9/0x970 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:1027
kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
__pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655
pskb_may_pull_reason include/linux/skbuff.h:2673 [inline]
pskb_may_pull include/linux/skbuff.h:2681 [inline]
ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0 net/ipv6/ip6_tunnel.c:408
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__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]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
dst_output include/net/dst.h:451 [inline]
ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
CPU: 0 PID: 7345 Comm: syz-executor.3 Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Fixes: fbfa743a9d2a ("ipv6: fix ip6_tnl_parse_tlv_enc_lim()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
---
net/ipv6/ip6_tunnel.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 5e80e517f071013410349d1fd93afc00a394e284..46c19bd4899011d53b4feb84e25013c01ddce701 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -399,7 +399,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)raw;
unsigned int nhoff = raw - skb->data;
unsigned int off = nhoff + sizeof(*ipv6h);
- u8 next, nexthdr = ipv6h->nexthdr;
+ u8 nexthdr = ipv6h->nexthdr;
while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
struct ipv6_opt_hdr *hdr;
@@ -410,25 +410,25 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
hdr = (struct ipv6_opt_hdr *)(skb->data + off);
if (nexthdr == NEXTHDR_FRAGMENT) {
- struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
- if (frag_hdr->frag_off)
- break;
optlen = 8;
} else if (nexthdr == NEXTHDR_AUTH) {
optlen = ipv6_authlen(hdr);
} else {
optlen = ipv6_optlen(hdr);
}
- /* cache hdr->nexthdr, since pskb_may_pull() might
- * invalidate hdr
- */
- next = hdr->nexthdr;
- if (nexthdr == NEXTHDR_DEST) {
- u16 i = 2;
- /* Remember : hdr is no longer valid at this point. */
- if (!pskb_may_pull(skb, off + optlen))
+ if (!pskb_may_pull(skb, off + optlen))
+ break;
+
+ hdr = (struct ipv6_opt_hdr *)(skb->data + off);
+ if (nexthdr == NEXTHDR_FRAGMENT) {
+ struct frag_hdr *frag_hdr = (struct frag_hdr *)hdr;
+
+ if (frag_hdr->frag_off)
break;
+ }
+ if (nexthdr == NEXTHDR_DEST) {
+ u16 i = 2;
while (1) {
struct ipv6_tlv_tnl_enc_lim *tel;
@@ -449,7 +449,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
i++;
}
}
- nexthdr = next;
+ nexthdr = hdr->nexthdr;
off += optlen;
}
return 0;
--
2.43.0.472.g3155946c3a-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
2024-01-05 17:03 [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim() Eric Dumazet
@ 2024-01-05 19:45 ` Willem de Bruijn
2024-01-06 16:10 ` David Ahern
2024-01-07 15:30 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: Willem de Bruijn @ 2024-01-05 19:45 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Willem de Bruijn, netdev, eric.dumazet, Eric Dumazet,
syzbot
Eric Dumazet wrote:
> syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.
>
> Reading frag_off can only be done if we pulled enough bytes
> to skb->head. Currently we might access garbage.
>
> [1]
> BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
> ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
> __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]
> neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
> neigh_output include/net/neighbour.h:542 [inline]
> ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
> ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
> dst_output include/net/dst.h:451 [inline]
> ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
> ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
> ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
> rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
> rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
> inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 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+0x5c9/0x970 mm/slub.c:3517
> __do_kmalloc_node mm/slab_common.c:1006 [inline]
> __kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:1027
> kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
> pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
> __pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655
> pskb_may_pull_reason include/linux/skbuff.h:2673 [inline]
> pskb_may_pull include/linux/skbuff.h:2681 [inline]
> ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0 net/ipv6/ip6_tunnel.c:408
> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
> ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
> __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]
> neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
> neigh_output include/net/neighbour.h:542 [inline]
> ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
> ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
> dst_output include/net/dst.h:451 [inline]
> ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
> ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
> ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
> rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
> rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
> inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> CPU: 0 PID: 7345 Comm: syz-executor.3 Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
>
> Fixes: fbfa743a9d2a ("ipv6: fix ip6_tnl_parse_tlv_enc_lim()")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Willem de Bruijn <willemb@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
> ---
> net/ipv6/ip6_tunnel.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
> index 5e80e517f071013410349d1fd93afc00a394e284..46c19bd4899011d53b4feb84e25013c01ddce701 100644
> --- a/net/ipv6/ip6_tunnel.c
> +++ b/net/ipv6/ip6_tunnel.c
> @@ -399,7 +399,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
> const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)raw;
> unsigned int nhoff = raw - skb->data;
> unsigned int off = nhoff + sizeof(*ipv6h);
> - u8 next, nexthdr = ipv6h->nexthdr;
> + u8 nexthdr = ipv6h->nexthdr;
>
> while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
> struct ipv6_opt_hdr *hdr;
> @@ -410,25 +410,25 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
>
> hdr = (struct ipv6_opt_hdr *)(skb->data + off);
> if (nexthdr == NEXTHDR_FRAGMENT) {
> - struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
> - if (frag_hdr->frag_off)
> - break;
> optlen = 8;
Eventually this could be sizeof(struct frag_hdr). Not necessarily for
this fix.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
2024-01-05 17:03 [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim() Eric Dumazet
2024-01-05 19:45 ` Willem de Bruijn
@ 2024-01-06 16:10 ` David Ahern
2024-01-08 9:36 ` Eric Dumazet
2024-01-07 15:30 ` patchwork-bot+netdevbpf
2 siblings, 1 reply; 5+ messages in thread
From: David Ahern @ 2024-01-06 16:10 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Willem de Bruijn, netdev, eric.dumazet, syzbot
On 1/5/24 10:03 AM, Eric Dumazet wrote:
> syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.
>
> Reading frag_off can only be done if we pulled enough bytes
> to skb->head. Currently we might access garbage.
>
> [1]
> BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
> ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
> __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]
> neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
> neigh_output include/net/neighbour.h:542 [inline]
> ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
> ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
> dst_output include/net/dst.h:451 [inline]
> ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
> ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
> ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
> rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
> rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
> inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 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+0x5c9/0x970 mm/slub.c:3517
> __do_kmalloc_node mm/slab_common.c:1006 [inline]
> __kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:1027
> kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
> pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
> __pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655
> pskb_may_pull_reason include/linux/skbuff.h:2673 [inline]
> pskb_may_pull include/linux/skbuff.h:2681 [inline]
> ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0 net/ipv6/ip6_tunnel.c:408
> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
> ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
> __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]
> neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
> neigh_output include/net/neighbour.h:542 [inline]
> ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
> ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
> dst_output include/net/dst.h:451 [inline]
> ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
> ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
> ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
> rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
> rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
> inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> CPU: 0 PID: 7345 Comm: syz-executor.3 Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
>
> Fixes: fbfa743a9d2a ("ipv6: fix ip6_tnl_parse_tlv_enc_lim()")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Willem de Bruijn <willemb@google.com>
> ---
> net/ipv6/ip6_tunnel.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
> index 5e80e517f071013410349d1fd93afc00a394e284..46c19bd4899011d53b4feb84e25013c01ddce701 100644
> --- a/net/ipv6/ip6_tunnel.c
> +++ b/net/ipv6/ip6_tunnel.c
> @@ -399,7 +399,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
> const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)raw;
> unsigned int nhoff = raw - skb->data;
> unsigned int off = nhoff + sizeof(*ipv6h);
> - u8 next, nexthdr = ipv6h->nexthdr;
> + u8 nexthdr = ipv6h->nexthdr;
>
> while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
> struct ipv6_opt_hdr *hdr;
> @@ -410,25 +410,25 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
>
> hdr = (struct ipv6_opt_hdr *)(skb->data + off);
> if (nexthdr == NEXTHDR_FRAGMENT) {
> - struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
> - if (frag_hdr->frag_off)
> - break;
> optlen = 8;
> } else if (nexthdr == NEXTHDR_AUTH) {
> optlen = ipv6_authlen(hdr);
> } else {
> optlen = ipv6_optlen(hdr);
> }
> - /* cache hdr->nexthdr, since pskb_may_pull() might
> - * invalidate hdr
> - */
> - next = hdr->nexthdr;
> - if (nexthdr == NEXTHDR_DEST) {
> - u16 i = 2;
>
> - /* Remember : hdr is no longer valid at this point. */
> - if (!pskb_may_pull(skb, off + optlen))
you dropped the comment above the may_pull which is helpful for reviewers.
Reviewed-by: David Ahern <dsahern@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
2024-01-05 17:03 [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim() Eric Dumazet
2024-01-05 19:45 ` Willem de Bruijn
2024-01-06 16:10 ` David Ahern
@ 2024-01-07 15:30 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-01-07 15:30 UTC (permalink / raw)
To: Eric Dumazet
Cc: davem, kuba, pabeni, dsahern, willemb, netdev, eric.dumazet,
syzkaller
Hello:
This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:
On Fri, 5 Jan 2024 17:03:13 +0000 you wrote:
> syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.
>
> Reading frag_off can only be done if we pulled enough bytes
> to skb->head. Currently we might access garbage.
>
> [1]
> BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
> ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
> __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]
> neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
> neigh_output include/net/neighbour.h:542 [inline]
> ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
> ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
> dst_output include/net/dst.h:451 [inline]
> ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
> ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
> ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
> rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
> rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
> inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> [...]
Here is the summary with links:
- [net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
https://git.kernel.org/netdev/net/c/d375b98e0248
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
2024-01-06 16:10 ` David Ahern
@ 2024-01-08 9:36 ` Eric Dumazet
0 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2024-01-08 9:36 UTC (permalink / raw)
To: David Ahern
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Willem de Bruijn,
netdev, eric.dumazet, syzbot
On Sat, Jan 6, 2024 at 5:10 PM David Ahern <dsahern@kernel.org> wrote:
> you dropped the comment above the may_pull which is helpful for reviewers.
>
Yes, this is because I reload "hdr = (struct ipv6_opt_hdr *)(skb->data
+ off);" right after the pskb_may_pull(),
so there is no more stale pointer.
Thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-01-08 9:36 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2024-01-05 17:03 [PATCH net] ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim() Eric Dumazet
2024-01-05 19:45 ` Willem de Bruijn
2024-01-06 16:10 ` David Ahern
2024-01-08 9:36 ` Eric Dumazet
2024-01-07 15:30 ` patchwork-bot+netdevbpf
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