CVE-2024-40905: ipv6: fix possible race in __fib6_drop_pcpu_from()
First published: Fri Jul 12 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix possible race in __fib6_drop_pcpu_from() syzbot found a race in __fib6_drop_pcpu_from() [1] If compiler reads more than once (*ppcpu_rt), second read could read NULL, if another cpu clears the value in rt6_get_pcpu_route(). Add a READ_ONCE() to prevent this race. Also add rcu_read_lock()/rcu_read_unlock() because we rely on RCU protection while dereferencing pcpu_rt. [1] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097] CPU: 0 PID: 7543 Comm: kworker/u8:17 Not tainted 6.10.0-rc1-syzkaller-00013-g2bfcfd584ff5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Workqueue: netns cleanup_net RIP: 0010:__fib6_drop_pcpu_from.part.0+0x10a/0x370 net/ipv6/ip6_fib.c:984 Code: f8 48 c1 e8 03 80 3c 28 00 0f 85 16 02 00 00 4d 8b 3f 4d 85 ff 74 31 e8 74 a7 fa f7 49 8d bf 90 00 00 00 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 1e 02 00 00 49 8b 87 90 00 00 00 48 8b 0c 24 48 RSP: 0018:ffffc900040df070 EFLAGS: 00010206 RAX: 0000000000000012 RBX: 0000000000000001 RCX: ffffffff89932e16 RDX: ffff888049dd1e00 RSI: ffffffff89932d7c RDI: 0000000000000091 RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000007 R10: 0000000000000001 R11: 0000000000000006 R12: ffff88807fa080b8 R13: fffffbfff1a9a07d R14: ffffed100ff41022 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32c26000 CR3: 000000005d56e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __fib6_drop_pcpu_from net/ipv6/ip6_fib.c:966 [inline] fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1027 [inline] fib6_purge_rt+0x7f2/0x9f0 net/ipv6/ip6_fib.c:1038 fib6_del_route net/ipv6/ip6_fib.c:1998 [inline] fib6_del+0xa70/0x17b0 net/ipv6/ip6_fib.c:2043 fib6_clean_node+0x426/0x5b0 net/ipv6/ip6_fib.c:2205 fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2127 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2175 fib6_clean_tree+0xd7/0x120 net/ipv6/ip6_fib.c:2255 __fib6_clean_all+0x100/0x2d0 net/ipv6/ip6_fib.c:2271 rt6_sync_down_dev net/ipv6/route.c:4906 [inline] rt6_disable_ip+0x7ed/0xa00 net/ipv6/route.c:4911 addrconf_ifdown.isra.0+0x117/0x1b40 net/ipv6/addrconf.c:3855 addrconf_notify+0x223/0x19e0 net/ipv6/addrconf.c:3778 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1992 call_netdevice_notifiers_extack net/core/dev.c:2030 [inline] call_netdevice_notifiers net/core/dev.c:2044 [inline] dev_close_many+0x333/0x6a0 net/core/dev.c:1585 unregister_netdevice_many_notify+0x46d/0x19f0 net/core/dev.c:11193 unregister_netdevice_many net/core/dev.c:11276 [inline] default_device_exit_batch+0x85b/0xae0 net/core/dev.c:11759 ops_exit_list+0x128/0x180 net/core/net_namespace.c:178 cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:640 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=4.2<5.4.279 | |
| Linux Linux kernel | >=5.5<5.10.221 | |
| Linux Linux kernel | >=5.11<5.15.162 | |
| Linux Linux kernel | >=5.16<6.1.95 | |
| Linux Linux kernel | >=6.2<6.6.35 | |
| Linux Linux kernel | >=6.7<6.9.6 | |
| Linux Linux kernel | =6.10-rc1 | |
| Linux Linux kernel | =6.10-rc2 | |
| redhat/kernel | <5.4.279 | 5.4.279 |
| redhat/kernel | <5.10.221 | 5.10.221 |
| redhat/kernel | <5.15.162 | 5.15.162 |
| redhat/kernel | <6.1.95 | 6.1.95 |
| redhat/kernel | <6.6.35 | 6.6.35 |
| redhat/kernel | <6.9.6 | 6.9.6 |
| redhat/kernel | <6.10 | 6.10 |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.11.10-1 6.12.5-1 |
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Reference Links
- https://git.kernel.org/stable/c/09e5a5a80e205922151136069e440477d6816914
- https://git.kernel.org/stable/c/2498960dac9b6fc49b6d1574f7cd1a4872744adf
- https://git.kernel.org/stable/c/7e796c3fefa8b17b30e7252886ae8cffacd2b9ef
- https://git.kernel.org/stable/c/a0bc020592b54a8f3fa2b7f244b6e39e526c2e12
- https://git.kernel.org/stable/c/b01e1c030770ff3b4fe37fc7cc6bca03f594133f
- https://git.kernel.org/stable/c/c693698787660c97950bc1f93a8dd19d8307153d
- https://git.kernel.org/stable/c/c90af1cced2f669a7b2304584be4ada495eaa0e5
- https://access.redhat.com/errata/RHSA-2024:5928
- https://bugzilla.redhat.com/show_bug.cgi?id=2297489
- https://git.kernel.org/linus/b01e1c030770ff3b4fe37fc7cc6bca03f594133f
- https://security-tracker.debian.org/tracker/CVE-2024-40905
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-40905
- https://nvd.nist.gov/vuln/detail/CVE-2024-40905
- https://launchpad.net/bugs/cve/CVE-2024-40905
- https://ubuntu.com/security/CVE-2024-40905
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