diff options
| author | Felix Fietkau <nbd@nbd.name> | 2024-09-26 10:53:14 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-10-02 17:21:47 -0700 |
| commit | 17bd3bd82f9f79f3feba15476c2b2c95a9b11ff8 (patch) | |
| tree | 2a519575f05f2c31718d0b4a93222d01d4934dd3 /net | |
| parent | 854e9bf5c524c836e3c65737b9ddc90e8b7622cc (diff) | |
net: gso: fix tcp fraglist segmentation after pull from frag_list
Detect tcp gso fraglist skbs with corrupted geometry (see below) and
pass these to skb_segment instead of skb_segment_list, as the first
can segment them correctly.
Valid SKB_GSO_FRAGLIST skbs
- consist of two or more segments
- the head_skb holds the protocol headers plus first gso_size
- one or more frag_list skbs hold exactly one segment
- all but the last must be gso_size
Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can
modify these skbs, breaking these invariants.
In extreme cases they pull all data into skb linear. For TCP, this
causes a NULL ptr deref in __tcpv4_gso_segment_list_csum at
tcp_hdr(seg->next).
Detect invalid geometry due to pull, by checking head_skb size.
Don't just drop, as this may blackhole a destination. Convert to be
able to pass to regular skb_segment.
Approach and description based on a patch by Willem de Bruijn.
Link: https://lore.kernel.org/netdev/20240428142913.18666-1-shiming.cheng@mediatek.com/
Link: https://lore.kernel.org/netdev/20240922150450.3873767-1-willemdebruijn.kernel@gmail.com/
Fixes: bee88cd5bd83 ("net: add support for segmenting TCP fraglist GSO packets")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240926085315.51524-1-nbd@nbd.name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_offload.c | 10 | ||||
| -rw-r--r-- | net/ipv6/tcpv6_offload.c | 10 |
2 files changed, 16 insertions, 4 deletions
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index e4ad3311e148..2308665b51c5 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -101,8 +101,14 @@ static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb, if (!pskb_may_pull(skb, sizeof(struct tcphdr))) return ERR_PTR(-EINVAL); - if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) - return __tcp4_gso_segment_list(skb, features); + if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) { + struct tcphdr *th = tcp_hdr(skb); + + if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) + return __tcp4_gso_segment_list(skb, features); + + skb->ip_summed = CHECKSUM_NONE; + } if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) { const struct iphdr *iph = ip_hdr(skb); diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c index 23971903e66d..a45bf17cb2a1 100644 --- a/net/ipv6/tcpv6_offload.c +++ b/net/ipv6/tcpv6_offload.c @@ -159,8 +159,14 @@ static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb, if (!pskb_may_pull(skb, sizeof(*th))) return ERR_PTR(-EINVAL); - if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) - return __tcp6_gso_segment_list(skb, features); + if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) { + struct tcphdr *th = tcp_hdr(skb); + + if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) + return __tcp6_gso_segment_list(skb, features); + + skb->ip_summed = CHECKSUM_NONE; + } if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) { const struct ipv6hdr *ipv6h = ipv6_hdr(skb); |