diff options
| author | Willem de Bruijn <willemb@google.com> | 2024-05-23 10:13:45 -0400 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-05-27 16:46:59 -0700 |
| commit | be008726d0ac338a6bb19c2da2853e3e2112b055 (patch) | |
| tree | 5bd9fb7e267f7363f01e17937ee43aa6e3ea3c2e | |
| parent | 7b05ab85e28f615e70520d24c075249b4512044e (diff) | |
net: gro: initialize network_offset in network layer
Syzkaller was able to trigger
kernel BUG at net/core/gro.c:424 !
RIP: 0010:gro_pull_from_frag0 net/core/gro.c:424 [inline]
RIP: 0010:gro_try_pull_from_frag0 net/core/gro.c:446 [inline]
RIP: 0010:dev_gro_receive+0x242f/0x24b0 net/core/gro.c:571
Due to using an incorrect NAPI_GRO_CB(skb)->network_offset.
The referenced commit sets this offset to 0 in skb_gro_reset_offset.
That matches the expected case in dev_gro_receive:
pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
ipv6_gro_receive, inet_gro_receive,
&gro_list->list, skb);
But syzkaller injected an skb with protocol ETH_P_TEB into an ip6gre
device (by writing the IP6GRE encapsulated version to a TAP device).
The result was a first call to eth_gro_receive, and thus an extra
ETH_HLEN in network_offset that should not be there. First issue hit
is when computing offset from network header in ipv6_gro_pull_exthdrs.
Initialize both offsets in the network layer gro_receive.
This pairs with all reads in gro_receive, which use
skb_gro_receive_network_offset().
Fixes: 186b1ea73ad8 ("net: gro: use cb instead of skb->network_header")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
CC: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240523141434.1752483-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/af_inet.c | 2 | ||||
| -rw-r--r-- | net/ipv6/ip6_offload.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index e03ba4a21c39..b24d74616637 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1532,7 +1532,7 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) } NAPI_GRO_CB(skb)->flush |= flush; - NAPI_GRO_CB(skb)->inner_network_offset = off; + NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off; /* Note : No need to call skb_gro_postpull_rcsum() here, * as we already checked checksum over ipv4 header was 0 diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index bd5aff97d8b1..9822163428b0 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -236,7 +236,7 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, if (unlikely(!iph)) goto out; - NAPI_GRO_CB(skb)->inner_network_offset = off; + NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off; flush += ntohs(iph->payload_len) != skb->len - hlen; |