CVE-2024-44934: net: bridge: mcast: wait for previous gc cycles when removing port
First published: Mon Aug 26 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: wait for previous gc cycles when removing port syzbot hit a use-after-free[1] which is caused because the bridge doesn't make sure that all previous garbage has been collected when removing a port. What happens is: CPU 1 CPU 2 start gc cycle remove port acquire gc lock first wait for lock call br_multicasg_gc() directly acquire lock now but free port the port can be freed while grp timers still running Make sure all previous gc cycles have finished by using flush_work before freeing the port. [1] BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699 CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=5.10<5.15.165 | |
| Linux Linux kernel | >=5.16<6.1.105 | |
| Linux Linux kernel | >=6.2<6.6.46 | |
| Linux Linux kernel | >=6.7<6.10.5 | |
| Linux Linux kernel | =6.11-rc1 | |
| Linux Linux kernel | =6.11-rc2 | |
| debian/linux | <=5.10.223-1<=5.10.226-1 | 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
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Reference Links
- https://git.kernel.org/stable/c/0d8b26e10e680c01522d7cc14abe04c3265a928f
- https://git.kernel.org/stable/c/1e16828020c674b3be85f52685e8b80f9008f50f
- https://git.kernel.org/stable/c/92c4ee25208d0f35dafc3213cdf355fbe449e078
- https://git.kernel.org/stable/c/b2f794b168cf560682ff976b255aa6d29d14a658
- https://git.kernel.org/stable/c/e3145ca904fa8dbfd1a5bf0187905bc117b0efce
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-44934
- https://nvd.nist.gov/vuln/detail/CVE-2024-44934
- https://launchpad.net/bugs/cve/CVE-2024-44934
- https://security-tracker.debian.org/tracker/CVE-2024-44934
- https://ubuntu.com/security/CVE-2024-44934
- https://git.kernel.org/linus/92c4ee25208d0f35dafc3213cdf355fbe449e078
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