CVE-2024-50035

Description

From CVE.org

In the Linux kernel, the following vulnerability has been resolved: ppp: fix ppp_async_encode() illegal access syzbot reported an issue in ppp_async_encode() [1] In this case, pppoe_sendmsg() is called with a zero size. Then ppp_async_encode() is called with an empty skb. BUG: KMSAN: uninit-value in ppp_async_encode drivers/net/ppp/ppp_async.c:545 [inline] BUG: KMSAN: uninit-value in ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675 ppp_async_encode drivers/net/ppp/ppp_async.c:545 [inline] ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675 ppp_async_send+0x130/0x1b0 drivers/net/ppp/ppp_async.c:634 ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2280 [inline] ppp_input+0x1f1/0xe60 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113 __release_sock+0x1da/0x330 net/core/sock.c:3072 release_sock+0x6b/0x250 net/core/sock.c:3626 pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4092 [inline] slab_alloc_node mm/slub.c:4135 [inline] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4187 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1322 [inline] sock_wmalloc+0xfe/0x1a0 net/core/sock.c:2732 pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 5411 Comm: syz.1.14 Not tainted 6.12.0-rc1-syzkaller-00165-g360c1f1f24c6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score7.17.1N/A
Attack VectorLocalLocalN/A
Attack ComplexityLowLowN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactNoneNoneN/A
Availability ImpactHighHighN/A

Vector

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

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

Understanding the Weakness (CWE)

CWE-908

Confidentiality

Technical Impact: Read Memory; Read Application Data

When reusing a resource such as memory or a program variable, the original contents of that resource may not be cleared before it is sent to an untrusted party.

Availability

Technical Impact: DoS: Crash, Exit, or Restart

The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend.

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