IM
IronMonkey Threat Research

CVE-2024-36927 MEDIUM

Published: 2024-05-30 | Last Modified: 2026-07-14 | Status: Modified

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix uninit-value access in __ip_make_skb() KMSAN reported uninit-value access in __ip_make_skb() [1]. __ip_make_skb() tests HDRINCL to know if the skb has icmphdr. However, HDRINCL can cause a race condition. If calling setsockopt(2) with IP_HDRINCL changes HDRINCL while __ip_make_skb() is running, the function will access icmphdr in the skb even if it is not included. This causes the issue reported by KMSAN. Check FLOWI_FLAG_KNOWN_NH on fl4->flowi4_flags instead of testing HDRINCL on the socket. Also, fl4->fl4_icmp_type and fl4->fl4_icmp_code are not initialized. These are union in struct flowi4 and are implicitly initialized by flowi4_init_output(), but we should not rely on specific union layout. Initialize these explicitly in raw_sendmsg(). [1] BUG: KMSAN: uninit-value in __ip_make_skb+0x2b74/0x2d20 net/ipv4/ip_output.c:1481 __ip_make_skb+0x2b74/0x2d20 net/ipv4/ip_output.c:1481 ip_finish_skb include/net/ip.h:243 [inline] ip_push_pending_frames+0x4c/0x5c0 net/ipv4/ip_output.c:1508 raw_sendmsg+0x2381/0x2690 net/ipv4/raw.c:654 inet_sendmsg+0x27b/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x274/0x3c0 net/socket.c:745 __sys_sendto+0x62c/0x7b0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x130/0x200 net/socket.c:2199 do_syscall_64+0xd8/0x1f0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 Uninit was created at: slab_post_alloc_hook mm/slub.c:3804 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc_node+0x5f6/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35a/0x7c0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1318 [inline] __ip_append_data+0x49ab/0x68c0 net/ipv4/ip_output.c:1128 ip_append_data+0x1e7/0x260 net/ipv4/ip_output.c:1365 raw_sendmsg+0x22b1/0x2690 net/ipv4/raw.c:648 inet_sendmsg+0x27b/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x274/0x3c0 net/socket.c:745 __sys_sendto+0x62c/0x7b0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0x130/0x200 net/socket.c:2199 do_syscall_64+0xd8/0x1f0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 CPU: 1 PID: 15709 Comm: syz-executor.7 Not tainted 6.8.0-11567-gb3603fcb79b1 #25 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014

Additional Descriptions (1)

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: ipv4: corrigió el acceso de valor uninit en __ip_make_skb() KMSAN informó el acceso de valor uninit en __ip_make_skb() [1]. __ip_make_skb() prueba HDRINCL para saber si el skb tiene icmphdr. Sin embargo, HDRINCL puede provocar una condición de ejecución. Si llamar a setsockopt(2) con IP_HDRINCL cambia HDRINCL mientras se ejecuta __ip_make_skb(), la función accederá a icmphdr en el skb incluso si no está incluido. Esto provoca el problema informado por KMSAN. Verifique FLOWI_FLAG_KNOWN_NH en fl4->flowi4_flags en lugar de probar HDRINCL en el socket. Además, fl4->fl4_icmp_type y fl4->fl4_icmp_code no están inicializados. Estas son una unión en la estructura flowi4 y se inicializan implícitamente mediante flowi4_init_output(), pero no debemos confiar en un diseño de unión específico. Inicialícelos explícitamente en raw_sendmsg(). [1] ERROR: KMSAN: valor uninit en __ip_make_skb+0x2b74/0x2d20 net/ipv4/ip_output.c:1481 __ip_make_skb+0x2b74/0x2d20 net/ipv4/ip_output.c:1481 ip_finish_skb include/net/ip.h:243 [ inline] ip_push_pending_frames+0x4c/0x5c0 net/ipv4/ip_output.c:1508 raw_sendmsg+0x2381/0x2690 net/ipv4/raw.c:654 inet_sendmsg+0x27b/0x2a0 net/ipv4/af_inet.c:851 net/socket.c : 730 [en línea] __sock_sendmsg+0x274/0x3c0 net/Socket.c: 745 __sys_sendto+0x62c/0x7b0 net/Socket.c: 2191 __do_sys_sendto net/socket.c: 2203 [en línea] __se_sys_sendto net/sows. ] __x64_sys_sendto+0x130/0x200 net/socket.c:2199 do_syscall_64+0xd8/0x1f0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x6d/0x75 Uninit se creó en: slab_post_alloc_hook mm/slub.c :3804 [en línea] slab_alloc_node mm/slub.c:3845 [en línea] kmem_cache_alloc_node+0x5f6/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35a/0x7c0 net/core/skbuff.c: 668 alloc_skb include/linux/skbuff.h:1318 [en línea] __ip_append_data+0x49ab/0x68c0 net/ipv4/ip_output.c:1128 ip_append_data+0x1e7/0x260 net/ipv4/ip_output.c:1365 raw_sendmsg+0x22b1/0x2690 net /ipv4 /raw.c:648 inet_sendmsg+0x27b/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg+0x274/0x3c0 net/socket.c:745 __sys_sendto+0x62c/0x7b0 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+0x130/0x200 net/socket.c:2199 do_syscall_64+0xd8/0x1f0 arch/x86/ent ry/ common.c:83 Entry_SYSCALL_64_after_hwframe+0x6d/0x75 CPU: 1 PID: 15709 Comm: syz-executor.7 Not tainted 6.8.0-11567-gb3603fcb79b1 #25 Nombre de hardware: PC estándar QEMU (i440FX + PIIX, 1996), BIOS 1.16 .3-1.fc39 01/04/2014

CVSS Metrics

Base Score: 4.7 (MEDIUM)

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack VectorLOCAL
Attack ComplexityHIGH
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactNONE
Integrity ImpactNONE
Availability ImpactHIGH

Source: [email protected]

Type: Primary

Exploitability Score: 1.0

Impact Score: 3.6

Weaknesses

Source Type Description
[email protected] Primary
en CWE-362
en CWE-908

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x702ba7b34d00> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bcbd3b8c0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bcbd39f40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bcbd39000> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702ba7b36a40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702ba6ab6ec0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bcbd38a40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702b8344db80> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bcbd3b600> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702ba7b34080> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702bcbd3b9c0> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702bcbd3b2c0> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702b53f50bc0> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702bdd9a0940> Operating System
linux linux_kernel 6.9 <built-in method update of dict object at 0x702bdd9a03c0> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc3:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc4:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc5:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.9:rc6:*:*:*:*:*:*

References

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