Detect 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 UDP, this
causes a NULL ptr deref in __udpv4_gso_segment_list_csum at
udp_hdr(seg->next)->dest.
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.
Link: https://lore.kernel.org/netdev/20240428142913.18666-1-shiming.cheng@mediatek.com/
Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20241001171752.107580-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Bug: 373245346
Bug: 333849117
Change-Id: I5a317e002f149cf9d399dce9bf87cd649a24da19
(cherry picked from commit a1e40ac5b5e9077fe1f7ae0eb88034db0f9ae1ab)
Signed-off-by: Lena Wang <lena.wang@mediatek.corp-partner.google.com>
(cherry picked from commit 42c2d1ea7c1bf984372f0ca1711d91165cbb87a6)
(cherry picked from commit 7376b8e51c4ddaa8e36b2b33d6ac3392135183b1)
e1d2f5465e