Ksawlii/kernel_samsung_a53x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

BACKPORT: gso: fix udp gso fraglist segmentation after pull from frag_list

Browse source 
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)
This commit is contained in:
Willem de Bruijn 2024-10-01 13:17:46 -04:00 • committed by Ksawlii
parent 33a4759f21
commit e1d2f5465e
1 changed files with 21 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
net/ipv4/udp_offload.c
View file

@ -7,6 +7,7 @@
*/
#include <linux/skbuff.h>
#include <net/ip6_checksum.h>
#include <net/udp.h>
#include <net/protocol.h>
#include <net/inet_common.h>
@ -269,8 +270,26 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
__sum16 check;
__be16 newlen;
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
/* Detect modified geometry and pass those to skb_segment. */
if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
/* Setup csum, as fraglist skips this in udp4_gro_receive. */
gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
gso_skb->csum_offset = offsetof(struct udphdr, check);
gso_skb->ip_summed = CHECKSUM_PARTIAL;
uh = udp_hdr(gso_skb);
if (is_ipv6)
uh->check = ~udp_v6_check(gso_skb->len,
&ipv6_hdr(gso_skb)->saddr,
&ipv6_hdr(gso_skb)->daddr, 0);
else
uh->check = ~udp_v4_check(gso_skb->len,
ip_hdr(gso_skb)->saddr,
ip_hdr(gso_skb)->daddr, 0);
}
mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)