tipc: Fix use-after-free of kernel socket in cleanup_bearer(). #128

dvdgomez · 2025-02-13T01:28:39Z

jira VULN-8673
cve CVE-2024-56642
commit-author Kuniyuki Iwashima [email protected]
commit 6a2fa13

Commit that this fixes: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=26abe14379f8
Our matching commit no diff seen: 26abe14379f8

syzkaller reported a use-after-free of UDP kernel socket in cleanup_bearer() without repro. [0][1]

When bearer_disable() calls tipc_udp_disable(), cleanup of the UDP kernel socket is deferred by work calling cleanup_bearer().

tipc_net_stop() waits for such works to finish by checking tipc_net(net)->wq_count.  However, the work decrements the count too early before releasing the kernel socket, unblocking cleanup_net() and resulting in use-after-free.

Let's move the decrement after releasing the socket in cleanup_bearer().

[0]:
ref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at
     sk_alloc+0x438/0x608
     inet_create+0x4c8/0xcb0
     __sock_create+0x350/0x6b8
     sock_create_kern+0x58/0x78
     udp_sock_create4+0x68/0x398
     udp_sock_create+0x88/0xc8
     tipc_udp_enable+0x5e8/0x848
     __tipc_nl_bearer_enable+0x84c/0xed8
     tipc_nl_bearer_enable+0x38/0x60
     genl_family_rcv_msg_doit+0x170/0x248
     genl_rcv_msg+0x400/0x5b0
     netlink_rcv_skb+0x1dc/0x398
     genl_rcv+0x44/0x68
     netlink_unicast+0x678/0x8b0
     netlink_sendmsg+0x5e4/0x898
     ____sys_sendmsg+0x500/0x830

[1]:
BUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline] BUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979
 udp_hashslot include/net/udp.h:85 [inline]
 udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979
 sk_common_release+0xaf/0x3f0 net/core/sock.c:3820
 inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437
 inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489
 __sock_release net/socket.c:658 [inline]
 sock_release+0xa0/0x210 net/socket.c:686
 cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310
 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391
 kthread+0x531/0x6b0 kernel/kthread.c:389
 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_free_hook mm/slub.c:2269 [inline]
 slab_free mm/slub.c:4580 [inline]
 kmem_cache_free+0x207/0xc40 mm/slub.c:4682
 net_free net/core/net_namespace.c:454 [inline]
 cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310
 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391
 kthread+0x531/0x6b0 kernel/kthread.c:389
 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244

CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Workqueue: events cleanup_bearer

Fixes: 26abe14379f8 ("net: Modify sk_alloc to not reference count the netns of kernel sockets.")
	Reported-by: syzkaller <[email protected]>
	Signed-off-by: Kuniyuki Iwashima <[email protected]>
Link: https://patch.msgid.link/[email protected]
	Signed-off-by: Paolo Abeni <[email protected]>

(cherry picked from commit 6a2fa13312e51a621f652d522d7e2df7066330b6)
	Signed-off-by: David Gomez <[email protected]>

Build log:

INSTALL /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/virtio/virtio_snd.ko
  STRIP   /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/virtio/virtio_snd.ko
  SIGN    /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/virtio/virtio_snd.ko
  INSTALL /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/x86/snd-hdmi-lpe-audio.ko
  STRIP   /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/x86/snd-hdmi-lpe-audio.ko
  SIGN    /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/x86/snd-hdmi-lpe-audio.ko
  INSTALL /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/xen/snd_xen_front.ko
  STRIP   /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/xen/snd_xen_front.ko
  SIGN    /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/sound/xen/snd_xen_front.ko
  INSTALL /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/virt/lib/irqbypass.ko
  STRIP   /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/virt/lib/irqbypass.ko
  SIGN    /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+/kernel/virt/lib/irqbypass.ko
  DEPMOD  /lib/modules/5.14.0-dgomez_ciqlts9_2_VULN-8673+
[TIMER]{MODULES}: 34s
Making Install
sh ./arch/x86/boot/install.sh \
	5.14.0-dgomez_ciqlts9_2_VULN-8673+ arch/x86/boot/bzImage \
	System.map "/boot"
[TIMER]{INSTALL}: 25s
Checking kABI
Checking kABI
kABI check passed
Setting Default Kernel to /boot/vmlinuz-5.14.0-dgomez_ciqlts9_2_VULN-8673+ and Index to 1
The default is /boot/loader/entries/a3b1671384d649058a39eef081d89d44-5.14.0-dgomez_ciqlts9_2_VULN-8673+.conf with index 1 and kernel /boot/vmlinuz-5.14.0-dgomez_ciqlts9_2_VULN-8673+
The default is /boot/loader/entries/a3b1671384d649058a39eef081d89d44-5.14.0-dgomez_ciqlts9_2_VULN-8673+.conf with index 1 and kernel /boot/vmlinuz-5.14.0-dgomez_ciqlts9_2_VULN-8673+
Generating grub configuration file ...
Adding boot menu entry for UEFI Firmware Settings ...
done
Hopefully Grub2.0 took everything ... rebooting after time metrices
[TIMER]{MRPROPER}: 7s
[TIMER]{BUILD}: 2083s
[TIMER]{MODULES}: 34s
[TIMER]{INSTALL}: 25s
[TIMER]{TOTAL} 2153s
Rebooting in 10 seconds

kernel self tests:
kernel-selftest_before.log
kernel-selftest_after.log

[dgomez@r92 kernel-src-tree]$ grep '^ok' kernel-selftest_before.log | wc -l
247
[dgomez@r92 kernel-src-tree]$ grep '^ok' kernel-selftest_after.log | wc -l
246
[dgomez@r92 kernel-src-tree]$ grep 'not ok' kernel-selftest_before.log | wc -l
39
[dgomez@r92 kernel-src-tree]$ grep 'not ok' kernel-selftest_after.log | wc -l
40

jira VULN-8673 cve CVE-2024-56642 commit-author Kuniyuki Iwashima <[email protected]> commit 6a2fa13 syzkaller reported a use-after-free of UDP kernel socket in cleanup_bearer() without repro. [0][1] When bearer_disable() calls tipc_udp_disable(), cleanup of the UDP kernel socket is deferred by work calling cleanup_bearer(). tipc_net_stop() waits for such works to finish by checking tipc_net(net)->wq_count. However, the work decrements the count too early before releasing the kernel socket, unblocking cleanup_net() and resulting in use-after-free. Let's move the decrement after releasing the socket in cleanup_bearer(). [0]: ref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at sk_alloc+0x438/0x608 inet_create+0x4c8/0xcb0 __sock_create+0x350/0x6b8 sock_create_kern+0x58/0x78 udp_sock_create4+0x68/0x398 udp_sock_create+0x88/0xc8 tipc_udp_enable+0x5e8/0x848 __tipc_nl_bearer_enable+0x84c/0xed8 tipc_nl_bearer_enable+0x38/0x60 genl_family_rcv_msg_doit+0x170/0x248 genl_rcv_msg+0x400/0x5b0 netlink_rcv_skb+0x1dc/0x398 genl_rcv+0x44/0x68 netlink_unicast+0x678/0x8b0 netlink_sendmsg+0x5e4/0x898 ____sys_sendmsg+0x500/0x830 [1]: BUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline] BUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 udp_hashslot include/net/udp.h:85 [inline] udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 sk_common_release+0xaf/0x3f0 net/core/sock.c:3820 inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437 inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489 __sock_release net/socket.c:658 [inline] sock_release+0xa0/0x210 net/socket.c:686 cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244 Uninit was created at: slab_free_hook mm/slub.c:2269 [inline] slab_free mm/slub.c:4580 [inline] kmem_cache_free+0x207/0xc40 mm/slub.c:4682 net_free net/core/net_namespace.c:454 [inline] cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244 CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: events cleanup_bearer Fixes: 26abe14 ("net: Modify sk_alloc to not reference count the netns of kernel sockets.") Reported-by: syzkaller <[email protected]> Signed-off-by: Kuniyuki Iwashima <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Paolo Abeni <[email protected]> (cherry picked from commit 6a2fa13) Signed-off-by: David Gomez <[email protected]>

bmastbergen

🥌

gvrose8192

LGTM - Thanks!

PlaidCat

In the future for the PR title can you put the target lts / kernel source in the []
Examples:

[lts8.6]
[FIPS-legacy-8.6]
[FIPS-8-553]
[SIG-CLOUD-rX]

JIRA: https://issues.redhat.com/browse/RHEL-78201 Conflicts: Context change from already backported commit adfdd9c ("selftests/bpf: Introduce __caps_unpriv annotation for tests") commit 4fec4c2 Author: Kumar Kartikeya Dwivedi <[email protected]> Date: Tue Dec 3 19:04:00 2024 -0800 selftests/bpf: Add IRQ save/restore tests Include tests that check for rejection in erroneous cases, like unbalanced IRQ-disabled counts, within and across subprogs, invalid IRQ flag state or input to kfuncs, behavior upon overwriting IRQ saved state on stack, interaction with sleepable kfuncs/helpers, global functions, and out of order restore. Include some success scenarios as well to demonstrate usage. #128/1 irq/irq_save_bad_arg:OK #128/2 irq/irq_restore_bad_arg:OK #128/3 irq/irq_restore_missing_2:OK #128/4 irq/irq_restore_missing_3:OK #128/5 irq/irq_restore_missing_3_minus_2:OK #128/6 irq/irq_restore_missing_1_subprog:OK #128/7 irq/irq_restore_missing_2_subprog:OK #128/8 irq/irq_restore_missing_3_subprog:OK #128/9 irq/irq_restore_missing_3_minus_2_subprog:OK #128/10 irq/irq_balance:OK #128/11 irq/irq_balance_n:OK #128/12 irq/irq_balance_subprog:OK #128/13 irq/irq_global_subprog:OK #128/14 irq/irq_restore_ooo:OK #128/15 irq/irq_restore_ooo_3:OK #128/16 irq/irq_restore_3_subprog:OK #128/17 irq/irq_restore_4_subprog:OK #128/18 irq/irq_restore_ooo_3_subprog:OK #128/19 irq/irq_restore_invalid:OK #128/20 irq/irq_save_invalid:OK #128/21 irq/irq_restore_iter:OK #128/22 irq/irq_save_iter:OK #128/23 irq/irq_flag_overwrite:OK #128/24 irq/irq_flag_overwrite_partial:OK #128/25 irq/irq_ooo_refs_array:OK #128/26 irq/irq_sleepable_helper:OK #128/27 irq/irq_sleepable_kfunc:OK #128 irq:OK Summary: 1/27 PASSED, 0 SKIPPED, 0 FAILED Acked-by: Eduard Zingerman <[email protected]> Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Jerome Marchand <[email protected]>

In a filesystem with a block size larger than 4KB, the hole length calculation for a non-extent inode in ext4_ind_map_blocks() can easily exceed INT_MAX. Then it could return a zero length hole and trigger the following waring and infinite in the iomap infrastructure. ------------[ cut here ]------------ WARNING: CPU: 3 PID: 434101 at fs/iomap/iter.c:34 iomap_iter_done+0x148/0x190 CPU: 3 UID: 0 PID: 434101 Comm: fsstress Not tainted 6.16.0-rc7+ #128 PREEMPT(voluntary) Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : iomap_iter_done+0x148/0x190 lr : iomap_iter+0x174/0x230 sp : ffff8000880af740 x29: ffff8000880af740 x28: ffff0000db8e6840 x27: 0000000000000000 x26: 0000000000000000 x25: ffff8000880af830 x24: 0000004000000000 x23: 0000000000000002 x22: 000001bfdbfa8000 x21: ffffa6a41c002e48 x20: 0000000000000001 x19: ffff8000880af808 x18: 0000000000000000 x17: 0000000000000000 x16: ffffa6a495ee6cd0 x15: 0000000000000000 x14: 00000000000003d4 x13: 00000000fa83b2da x12: 0000b236fc95f18c x11: ffffa6a4978b9c08 x10: 0000000000001da0 x9 : ffffa6a41c1a2a44 x8 : ffff8000880af5c8 x7 : 0000000001000000 x6 : 0000000000000000 x5 : 0000000000000004 x4 : 000001bfdbfa8000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000004004030000 x0 : 0000000000000000 Call trace: iomap_iter_done+0x148/0x190 (P) iomap_iter+0x174/0x230 iomap_fiemap+0x154/0x1d8 ext4_fiemap+0x110/0x140 [ext4] do_vfs_ioctl+0x4b8/0xbc0 __arm64_sys_ioctl+0x8c/0x120 invoke_syscall+0x6c/0x100 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x38/0x120 el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x198/0x1a0 ---[ end trace 0000000000000000 ]--- Cc: [email protected] Fixes: facab4d ("ext4: return hole from ext4_map_blocks()") Reported-by: Qu Wenruo <[email protected]> Closes: https://lore.kernel.org/linux-ext4/[email protected]/ Tested-by: Qu Wenruo <[email protected]> Signed-off-by: Zhang Yi <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Theodore Ts'o <[email protected]>

commit 02c7f72 upstream. In a filesystem with a block size larger than 4KB, the hole length calculation for a non-extent inode in ext4_ind_map_blocks() can easily exceed INT_MAX. Then it could return a zero length hole and trigger the following waring and infinite in the iomap infrastructure. ------------[ cut here ]------------ WARNING: CPU: 3 PID: 434101 at fs/iomap/iter.c:34 iomap_iter_done+0x148/0x190 CPU: 3 UID: 0 PID: 434101 Comm: fsstress Not tainted 6.16.0-rc7+ #128 PREEMPT(voluntary) Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : iomap_iter_done+0x148/0x190 lr : iomap_iter+0x174/0x230 sp : ffff8000880af740 x29: ffff8000880af740 x28: ffff0000db8e6840 x27: 0000000000000000 x26: 0000000000000000 x25: ffff8000880af830 x24: 0000004000000000 x23: 0000000000000002 x22: 000001bfdbfa8000 x21: ffffa6a41c002e48 x20: 0000000000000001 x19: ffff8000880af808 x18: 0000000000000000 x17: 0000000000000000 x16: ffffa6a495ee6cd0 x15: 0000000000000000 x14: 00000000000003d4 x13: 00000000fa83b2da x12: 0000b236fc95f18c x11: ffffa6a4978b9c08 x10: 0000000000001da0 x9 : ffffa6a41c1a2a44 x8 : ffff8000880af5c8 x7 : 0000000001000000 x6 : 0000000000000000 x5 : 0000000000000004 x4 : 000001bfdbfa8000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000004004030000 x0 : 0000000000000000 Call trace: iomap_iter_done+0x148/0x190 (P) iomap_iter+0x174/0x230 iomap_fiemap+0x154/0x1d8 ext4_fiemap+0x110/0x140 [ext4] do_vfs_ioctl+0x4b8/0xbc0 __arm64_sys_ioctl+0x8c/0x120 invoke_syscall+0x6c/0x100 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x38/0x120 el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x198/0x1a0 ---[ end trace 0000000000000000 ]--- Cc: [email protected] Fixes: facab4d ("ext4: return hole from ext4_map_blocks()") Reported-by: Qu Wenruo <[email protected]> Closes: https://lore.kernel.org/linux-ext4/[email protected]/ Tested-by: Qu Wenruo <[email protected]> Signed-off-by: Zhang Yi <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Theodore Ts'o <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

dvdgomez requested review from PlaidCat, bmastbergen and gvrose8192 February 13, 2025 01:28

dvdgomez self-assigned this Feb 13, 2025

bmastbergen approved these changes Feb 13, 2025

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gvrose8192 approved these changes Feb 13, 2025

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dvdgomez marked this pull request as ready for review February 13, 2025 17:51

PlaidCat approved these changes Feb 13, 2025

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dvdgomez merged commit 9331e3b into ciqlts9_2 Feb 13, 2025
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dvdgomez deleted the dgomez_ciqlts9_2/VULN-8673 branch February 13, 2025 18:14

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tipc: Fix use-after-free of kernel socket in cleanup_bearer(). #128

tipc: Fix use-after-free of kernel socket in cleanup_bearer(). #128

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tipc: Fix use-after-free of kernel socket in cleanup_bearer(). #128

tipc: Fix use-after-free of kernel socket in cleanup_bearer(). #128

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