// For flags

CVE-2024-26857

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

Severity Score

5.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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:449 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_rcv+0x46f/0x760 net/ipv4/ip_input.c:569
__netif_receive_skb_one_core net/core/dev.c:5534 [inline]
__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5648
process_backlog+0x480/0x8b0 net/core/dev.c:5976
__napi_poll+0xe3/0x980 net/core/dev.c:6576
napi_poll net/core/dev.c:6645 [inline]
net_rx_action+0x8b8/0x1870 net/core/dev.c:6778
__do_softirq+0x1b7/0x7c5 kernel/softirq.c:553
do_softirq+0x9a/0xf0 kernel/softirq.c:454
__local_bh_enable_ip+0x9b/0xa0 kernel/softirq.c:381
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:820 [inline]
__dev_queue_xmit+0x2768/0x51c0 net/core/dev.c:4378
dev_queue_xmit include/linux/netdevice.h:3171 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3081 [inline]
packet_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook mm/slub.c:3819 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmem_cache_alloc_node+0x5cb/0xbc0 mm/slub.c:3903
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
__alloc_skb+0x352/0x790 net/core/skbuff.c:651
alloc_skb include/linux/skbuff.h:1296 [inline]
alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6394
sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2783
packet_alloc_skb net/packet/af_packet.c:2930 [inline]
packet_snd net/packet/af_packet.c:3024 [inline]
packet_sendmsg+0x70c2/0x9f10 net/packet/af_packet.c:3113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: geneve: asegúrese de extraer el encabezado interno en geneve_rx() syzbot desencadenó un error en geneve_rx() [1] El problema es similar al que solucioné en la confirmación 8d975c15c0cd ("ip6_tunnel: asegúrese de extraer el encabezado interno en __ip6_tnl_rcv()"). Tenemos que guardar skb->network_header en una variable temporal para poder volver a calcular el puntero network_header después de una llamada a pskb_inet_may_pull(). pskb_inet_may_pull() se asegura de que los encabezados necesarios estén en skb->head. [1] ERROR: KMSAN: valor uninit en IP_ECN_decapsulate include/net/inet_ecn.h:302 [en línea] ERROR: KMSAN: valor uninit en geneve_rx drivers/net/geneve.c:279 [en línea] ERROR: KMSAN: uninit -valor en geneve_udp_encap_recv+0x36f9/0x3c10 drivers/net/geneve.c:391 IP_ECN_decapsulate include/net/inet_ecn.h:302 [en línea] geneve_rx drivers/net/geneve.c:279 [en línea] 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 [en línea] ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:461 [en línea] ip_rcv_finish net/ipv4/ ip_input.c:449 [en línea] NF_HOOK include/linux/netfilter.h:314 [en línea] ip_rcv+0x46f/0x760 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core net/core/dev.c:5534 [en línea] __netif_receive_skb+ 0x1a6/0x5a0 net/core/dev.c:5648 Process_backlog+0x480/0x8b0 net/core/dev.c:5976 __napi_poll+0xe3/0x980 net/core/dev.c:6576 napi_poll net/core/dev.c:6645 [en línea] net_rx_action+0x8b8/0x1870 net/core/dev.c:6778 __do_softirq+0x1b7/0x7c5 kernel/softirq.c:553 do_softirq+0x9a/0xf0 kernel/softirq.c:454 __local_bh_enable_ip+0x9b/0xa0 kernel/softirq. c:381 local_bh_enable include/linux/bottom_half.h:33 [en línea] rcu_read_unlock_bh include/linux/rcupdate.h:820 [en línea] __dev_queue_xmit+0x2768/0x51c0 net/core/dev.c:4378 dev_queue_xmit include/linux/netdevice. h:3171 [en línea] paquete_xmit+0x9c/0x6b0 net/packet/af_packet.c:276 paquete_snd net/packet/af_packet.c:3081 [en línea] paquete_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/ socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea] __sys_sendto+0x735/0xa10 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [en línea] __se_sys_sendto net/socket.c:2199 [en línea] __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x63 / 0x6b Uninit se creó en: slab_post_alloc_hook mm/slub.c:3819 [en línea] slab_alloc_node mm/slub.c:3860 [en línea] kmem_cache_alloc_node+0x5cb/0xbc0 mm/slub.c:3903 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff .c:560 __alloc_skb+0x352/0x790 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1296 [en línea] alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6394 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2783 paquete_alloc_skb net/packet/af_packet.c:2930 [en línea] paquete_snd net/packet/af_packet.c:3024 [en línea] paquete_sendmsg+0x70c2/0x9f10 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea] __sys_sendto+0x735/0xa10 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [en línea] __se_sys_sendto net/socket.c :2199 [en línea] __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe + 0x63/0x6b

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-02-19 CVE Reserved
  • 2024-04-17 CVE Published
  • 2024-04-18 EPSS Updated
  • 2024-12-19 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-20: Improper Input Validation
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 4.19.310
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 4.19.310"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 5.4.272
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 5.4.272"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 5.10.213
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 5.10.213"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 5.15.152
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 5.15.152"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 6.1.82
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.1.82"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 6.6.22
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.6.22"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 6.7.10
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.7.10"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.2 < 6.8
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.8"
en
Affected