CVE-2024-44934

Summary

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

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe12cec65b5546f19217e26aafb8add6e2fadca18 < 1e16828020c674b3be85f52685e8b80f9008f50faffected
LinuxLinuxe12cec65b5546f19217e26aafb8add6e2fadca18 < 0d8b26e10e680c01522d7cc14abe04c3265a928faffected
LinuxLinuxe12cec65b5546f19217e26aafb8add6e2fadca18 < e3145ca904fa8dbfd1a5bf0187905bc117b0efceaffected
LinuxLinuxe12cec65b5546f19217e26aafb8add6e2fadca18 < b2f794b168cf560682ff976b255aa6d29d14a658affected
LinuxLinuxe12cec65b5546f19217e26aafb8add6e2fadca18 < 92c4ee25208d0f35dafc3213cdf355fbe449e078affected
LinuxLinux5.10affected
LinuxLinux0 < 5.10unaffected
LinuxLinux5.15.165 <= 5.15.*unaffected
LinuxLinux6.1.105 <= 6.1.*unaffected
LinuxLinux6.6.46 <= 6.6.*unaffected
LinuxLinux6.10.5 <= 6.10.*unaffected
LinuxLinux6.11 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References