CVE-2024-36902 ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()

2024-05-3015:29:04

Linux

github.com

linux kernel

vulnerability

ipv6

fib6_rules

null dereference

crash

syzbot

ip6_dst_idev()

general protection fault

google compute engine

kasan

smp

pti

bios

fib_rules_lookup

ip6_route_output_flags_noref

sctp_transport_route

sctp_connect

syscall

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

5.1%

JSON

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

ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()

syzbot is able to trigger the following crash [1],
caused by unsafe ip6_dst_idev() use.

Indeed ip6_dst_idev() can return NULL, and must always be checked.

[1]

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
FS: 00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317
fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108
ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649
ip6_route_output include/net/ip6_route.h:93 [inline]
ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120
ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250
sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326
sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455
sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662
sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099
__sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197
sctp_connect net/sctp/socket.c:4819 [inline]
sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
__sys_connect_file net/socket.c:2048 [inline]
__sys_connect+0x2df/0x310 net/socket.c:2065
__do_sys_connect net/socket.c:2075 [inline]
__se_sys_connect net/socket.c:2072 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2072
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/fib6_rules.c"
    ],
    "versions": [
      {
        "version": "5e5f3f0f8013",
        "lessThan": "4a5a573387da",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "ddec23f206a9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "674c951ab8a2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "35297fc68de3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "7e3242c139c3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "8745a8d74ba1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "1876881c9a49",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5e5f3f0f8013",
        "lessThan": "d101291b2681",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/fib6_rules.c"
    ],
    "versions": [
      {
        "version": "2.6.26",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "2.6.26",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.314",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.276",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.217",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.159",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.91",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.31",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.10",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]