Description

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

net: ip_tunnel: make sure to pull inner header in ip_tunnel_rcv()

Apply the same fix than ones found in :

8d975c15c0cd ("ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()")
1ca1ba465e55 ("geneve: make sure to pull inner header in geneve_rx()")

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.

syzbot reported:
BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
BUG: KMSAN: uninit-value in IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
BUG: KMSAN: uninit-value in ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
__INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
__ipgre_rcv+0x9bc/0xbc0 net/ipv4/ip_gre.c:389
ipgre_rcv net/ipv4/ip_gre.c:411 [inline]
gre_rcv+0x423/0x19f0 net/ipv4/ip_gre.c:447
gre_rcv+0x2a4/0x390 net/ipv4/gre_demux.c:163
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]
...

Classification

CVE ID: CVE-2024-26882

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (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/ec6bb01e02cbd47781dd90775b631a1dc4bd9d2b
https://git.kernel.org/stable/c/77fd5294ea09b21f6772ac954a121b87323cec80
https://git.kernel.org/stable/c/5c03387021cfa3336b97e0dcba38029917a8af2a
https://git.kernel.org/stable/c/60044ab84836359534bd7153b92e9c1584140e4a
https://git.kernel.org/stable/c/c4c857723b37c20651300b3de4ff25059848b4b0
https://git.kernel.org/stable/c/f6723d8dbfdc10c784a56748f86a9a3cd410dbd5
https://git.kernel.org/stable/c/ca914f1cdee8a85799942c9b0ce5015bbd6844e1
https://git.kernel.org/stable/c/b0ec2abf98267f14d032102551581c833b0659d3

Timeline