Description

In the Linux kernel, the following vulnerability has been resolved:

geneve: make sure to pull inner header in geneve_rx()

syzbot triggered a bug in geneve_rx() [1]

Issue is similar to the one I fixed in commit 8d975c15c0cd
("ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()")

We have to save skb->network_header in a temporary variable
in order to be able to recompute the network_header pointer
after a pskb_inet_may_pull() call.

pskb_inet_may_pull() makes sure the needed headers are in skb->head.

[1]
BUG: KMSAN: uninit-value in IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
BUG: KMSAN: uninit-value in geneve_rx drivers/net/geneve.c:279 [inline]
BUG: KMSAN: uninit-value in geneve_udp_encap_recv+0x36f9/0x3c10 drivers/net/geneve.c:391
IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
geneve_rx drivers/net/geneve.c:279 [inline]
geneve_udp_encap_recv+0x36f9/0x3c10 drivers/net/geneve.c:391
udp_queue_rcv_one_skb+0x1d39/0x1f20 net/ipv4/udp.c:2108
udp_queue_rcv_skb+0x6ae/0x6e0 net/ipv4/udp.c:2186
udp_unicast_rcv_skb+0x184/0x4b0 net/ipv4/udp.c:2346
__udp4_lib_rcv+0x1c6b/0x3010 net/ipv4/udp.c:2422
udp_rcv+0x7d/0xa0 net/ipv4/udp.c:2604
ip_protocol_deliver_rcu+0x264/0x1300 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x2b8/0x440 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:461 [inline]
ip_rcv_finish net/ipv4/ip_input.c...

Classification

CVE ID: CVE-2024-26857

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/e431c3227864b5646601c97f5f898d99472f2914
https://git.kernel.org/stable/c/59d2a4076983303f324557a114cfd5c32e1f6b29
https://git.kernel.org/stable/c/c7137900691f5692fe3de54566ea7b30bb35d66c
https://git.kernel.org/stable/c/e77e0b0f2a11735c64b105edaee54d6344faca8a
https://git.kernel.org/stable/c/c0b22568a9d8384fd000cc49acb8f74bde40d1b5
https://git.kernel.org/stable/c/0ece581d2a66e8e488c0d3b3e7b5760dbbfdbdd5
https://git.kernel.org/stable/c/048e16dee1fc609c1c85072ccd70bfd4b5fef6ca
https://git.kernel.org/stable/c/1ca1ba465e55b9460e4e75dec9fff31e708fec74

Timeline