In the Linux kernel, the following vulnerability has been resolved:
af_unix: Fix task hung while purging oob_skb in GC.
syzbot reported a task hung; at the same time, GC was looping infinitely in list_for_each_entry_safe() for OOB skb. [0]
syzbot demonstrated that the list_for_each_entry_safe() was not actually safe in this case.
A single skb could have references for multiple sockets. If we free such a skb in the list_for_each_entry_safe(), the current and next sockets could be unlinked in a single iteration.
unix_notinflight() uses list_del_init() to unlink the socket, so the prefetched next socket forms a loop itself and list_for_each_entry_safe() never stops.
Here, we must use while() and make sure we always fetch the first socket.
[0]: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5065 Comm: syz-executor236 Not tainted 6.8.0-rc3-syzkaller-00136-g1f719a2f3fa6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:207 Code: cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 14 25 40 c2 03 00 <65> 8b 05 b4 7c 78 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 RSP: 0018:ffffc900033efa58 EFLAGS: 00000283 RAX: ffff88807b077800 RBX: ffff88807b077800 RCX: 1ffffffff27b1189 RDX: ffff88802a5a3b80 RSI: ffffffff8968488d RDI: ffff88807b077f70 RBP: ffffc900033efbb0 R08: 0000000000000001 R09: fffffbfff27a900c R10: ffffffff93d48067 R11: ffffffff8ae000eb R12: ffff88807b077800 R13: dffffc0000000000 R14: ffff88807b077e40 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564f4fc1e3a8 CR3: 000000000d57a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <TASK> unix_gc+0x563/0x13b0 net/unix/garbage.c:319 unix_release_sock+0xa93/0xf80 net/unix/af_unix.c:683 unix_release+0x91/0xf0 net/unix/af_unix.c:1064 __sock_release+0xb0/0x270 net/socket.c:659 sock_close+0x1c/0x30 net/socket.c:1421 __fput+0x270/0xb80 fs/file_table.c:376 task_work_run+0x14f/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa8a/0x2ad0 kernel/exit.c:871 do_group_exit+0xd4/0x2a0 kernel/exit.c:1020 __do_sys_exit_group kernel/exit.c:1031 [inline] __se_sys_exit_group kernel/exit.c:1029 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1029 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f9d6cbdac09 Code: Unable to access opcode bytes at 0x7f9d6cbdabdf. RSP: 002b:00007fff5952feb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9d6cbdac09 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007f9d6cc552b0 R08: ffffffffffffffb8 R09: 0000000000000006 R10: 0000000000000006 R11: 0000000000000246 R12: 00007f9d6cc552b0 R13: 0000000000000000 R14: 00007f9d6cc55d00 R15: 00007f9d6cbabe70 </TASK>
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade bpftoolUpgrade perfUpgrade kernel-modules-extra-commonUpgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade bpftool-debuginfoUpgrade kernel-modules-extraUpgrade perf-debuginfoUpgrade kernel-livepatch-6.1.82-99.168Upgrade kernel-debuginfoUpgrade kernel-headersUpgrade kernel-libbpfUpgrade kernel-tools-debuginfoUpgrade python3-perfUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-libbpf-staticUpgrade kernelUpgrade kernel-develUpgrade kernel-tools-develUpgrade python3-perf-debuginfoUpgrade kernel-libbpf-devel | Feb 17, 2025 | Apr 4, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | Apr 4, 2024 |
| Suse | — | Upgrade dtb-apmUpgrade dtb-appleUpgrade ocfs2-kmp-azureUpgrade dtb-freescaleUpgrade kselftests-kmp-rtUpgrade gfs2-kmp-defaultUpgrade kernel-azure-extraUpgrade kernel-rt_debug-develUpgrade kernel-docsUpgrade kernel-debugUpgrade kernel-rt-livepatch-develUpgrade dtb-broadcomUpgrade reiserfs-kmp-64kbUpgrade dtb-marvellUpgrade kernel-rt_debug-vdsoUpgrade kernel-kvmsmall-livepatch-develUpgrade dtb-hisiliconUpgrade kernel-64kbUpgrade kernel-source-rtUpgrade kernel-azure-optionalUpgrade kernel-azure-vdsoUpgrade kernel-rt_debug-livepatch-develUpgrade kernel-develUpgrade ocfs2-kmp-64kbUpgrade kernel-64kb-livepatch-develUpgrade reiserfs-kmp-rtUpgrade dtb-renesasUpgrade kernel-64kb-extraUpgrade dlm-kmp-defaultUpgrade ocfs2-kmp-defaultUpgrade cluster-md-kmp-azureUpgrade kernel-debug-develUpgrade ocfs2-kmp-rtUpgrade kernel-default-livepatch-develUpgrade reiserfs-kmp-defaultUpgrade kernel-default-baseUpgrade kernel-source-azureUpgrade kernel-kvmsmall-develUpgrade kernel-default-develUpgrade kernel-rt_debugUpgrade dtb-amdUpgrade kernel-64kb-optionalUpgrade gfs2-kmp-64kbUpgrade kernel-zfcpdumpUpgrade kernel-docs-htmlUpgrade kernel-obs-qaUpgrade kernel-syms-rtUpgrade kernel-64kb-develUpgrade kernel-kvmsmall-vdsoUpgrade dtb-lgUpgrade dtb-socionextUpgrade kernel-default-livepatchUpgrade kernel-symsUpgrade dlm-kmp-azureUpgrade dtb-allwinnerUpgrade dtb-amazonUpgrade gfs2-kmp-rtUpgrade kernel-macrosUpgrade kernel-default-vdsoUpgrade kselftests-kmp-defaultUpgrade cluster-md-kmp-64kbUpgrade kernel-azure-livepatch-develUpgrade dtb-xilinxUpgrade kselftests-kmp-64kbUpgrade kernel-rt-develUpgrade kernel-debug-livepatch-develUpgrade dtb-caviumUpgrade dlm-kmp-rtUpgrade dtb-armUpgrade cluster-md-kmp-defaultUpgrade kernel-source-vanillaUpgrade kernel-devel-azureUpgrade kernel-azureUpgrade gfs2-kmp-azureUpgrade dtb-exynosUpgrade dlm-kmp-64kbUpgrade dtb-sprdUpgrade kernel-default-optionalUpgrade dtb-alteraUpgrade kernel-rt-extraUpgrade kernel-obs-buildUpgrade kernel-rtUpgrade kernel-syms-azureUpgrade kernel-azure-develUpgrade dtb-rockchipUpgrade reiserfs-kmp-azureUpgrade kernel-sourceUpgrade kernel-default-base-rebuildUpgrade cluster-md-kmp-rtUpgrade dtb-nvidiaUpgrade kernel-rt-vdsoUpgrade dtb-qcomUpgrade kernel-devel-rtUpgrade kselftests-kmp-azureUpgrade dtb-mediatekUpgrade kernel-defaultUpgrade kernel-default-extraUpgrade dtb-amlogicUpgrade kernel-kvmsmallUpgrade kernel-debug-vdsoUpgrade kernel-rt-optional | Jul 23, 2024 | Apr 4, 2024 |
| Ubuntu | — | Upgrade linux-raspi-realtime | Feb 11, 2025 | Apr 4, 2024 |
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