UBUNTU-CVE-2024-44934
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
02 / AFFECTED SOFTWARE
Affected packages
28 explicit affected versions
4 explicit affected versions
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37 explicit affected versions
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12 explicit affected versions
47 explicit affected versions
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14 explicit affected versions
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7 explicit affected versions
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35 explicit affected versions
14 explicit affected versions
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1 explicit affected versions
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13 explicit affected versions
9 explicit affected versions
29 explicit affected versions
13 explicit affected versions
58 explicit affected versions
8 explicit affected versions
9 explicit affected versions
56 explicit affected versions
18 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
1 explicit affected versions
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12 explicit affected versions
45 explicit affected versions
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10 explicit affected versions
26 explicit affected versions
16 explicit affected versions
1 explicit affected versions
7 explicit affected versions
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13 explicit affected versions
16 explicit affected versions
16 explicit affected versions
58 explicit affected versions
17 explicit affected versions
46 explicit affected versions
3 explicit affected versions
2 explicit affected versions
51 explicit affected versions
14 explicit affected versions
13 explicit affected versions
12 explicit affected versions
44 explicit affected versions
27 explicit affected versions
30 explicit affected versions
10 explicit affected versions
19 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
13 explicit affected versions
12 explicit affected versions
13 explicit affected versions
7 explicit affected versions
50 explicit affected versions
10 explicit affected versions
14 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
44 explicit affected versions
37 explicit affected versions
17 explicit affected versions
14 explicit affected versions
38 explicit affected versions
47 explicit affected versions
47 explicit affected versions
11 explicit affected versions
8 explicit affected versions
7 explicit affected versions
55 explicit affected versions
7 explicit affected versions
53 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
14 explicit affected versions
4 explicit affected versions
11 explicit affected versions
1 explicit affected versions
10 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/92c4ee25208d0f35dafc3213cdf355fbe449e078
- 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://ubuntu.com/security/CVE-2024-44934
- https://ubuntu.com/security/notices/USN-7100-1
- https://ubuntu.com/security/notices/USN-7100-2
- https://ubuntu.com/security/notices/USN-7123-1
- https://ubuntu.com/security/notices/USN-7144-1
- https://ubuntu.com/security/notices/USN-7154-1
- https://ubuntu.com/security/notices/USN-7154-2
- https://ubuntu.com/security/notices/USN-7155-1
- https://ubuntu.com/security/notices/USN-7156-1
- https://ubuntu.com/security/notices/USN-7194-1
- https://ubuntu.com/security/notices/USN-7196-1
- https://www.cve.org/CVERecord?id=CVE-2024-44934