linux.git/net/unix, branch master

af_unix: Don't return OOB skb in manage_oob().

2024-09-10T00:14:27+00:00

syzbot reported use-after-free in unix_stream_recv_urg(). [0]

The scenario is

  1. send(MSG_OOB)
  2. recv(MSG_OOB)
     -> The consumed OOB remains in recv queue
  3. send(MSG_OOB)
  4. recv()
     -> manage_oob() returns the next skb of the consumed OOB
     -> This is also OOB, but unix_sk(sk)->oob_skb is not cleared
  5. recv(MSG_OOB)
     -> unix_sk(sk)->oob_skb is used but already freed

The recent commit 8594d9b85c07 ("af_unix: Don't call skb_get() for OOB
skb.") uncovered the issue.

If the OOB skb is consumed and the next skb is peeked in manage_oob(),
we still need to check if the skb is OOB.

Let's do so by falling back to the following checks in manage_oob()
and add the test case in selftest.

Note that we need to add a similar check for SIOCATMARK.

[0]:
BUG: KASAN: slab-use-after-free in unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959
Read of size 4 at addr ffff8880326abcc4 by task syz-executor178/5235

CPU: 0 UID: 0 PID: 5235 Comm: syz-executor178 Not tainted 6.11.0-rc5-syzkaller-00742-gfbdaffe41adc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959
 unix_stream_recv_urg+0x1df/0x320 net/unix/af_unix.c:2640
 unix_stream_read_generic+0x2456/0x2520 net/unix/af_unix.c:2778
 unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg+0x22f/0x280 net/socket.c:1068
 ____sys_recvmsg+0x1db/0x470 net/socket.c:2816
 ___sys_recvmsg net/socket.c:2858 [inline]
 __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2888
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5360d6b4e9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff29b3a458 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007fff29b3a638 RCX: 00007f5360d6b4e9
RDX: 0000000000002001 RSI: 0000000020000640 RDI: 0000000000000003
RBP: 00007f5360dde610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff29b3a628 R14: 0000000000000001 R15: 0000000000000001
 

Allocated by task 5235:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3988 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4080
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667
 alloc_skb include/linux/skbuff.h:1320 [inline]
 alloc_skb_with_frags+0xc3/0x770 net/core/skbuff.c:6528
 sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2815
 sock_alloc_send_skb include/net/sock.h:1778 [inline]
 queue_oob+0x108/0x680 net/unix/af_unix.c:2198
 unix_stream_sendmsg+0xd24/0xf80 net/unix/af_unix.c:2351
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
 ___sys_sendmsg net/socket.c:2651 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5235:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2252 [inline]
 slab_free mm/slub.c:4473 [inline]
 kmem_cache_free+0x145/0x350 mm/slub.c:4548
 unix_stream_read_generic+0x1ef6/0x2520 net/unix/af_unix.c:2917
 unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg+0x22f/0x280 net/socket.c:1068
 __sys_recvfrom+0x256/0x3e0 net/socket.c:2255
 __do_sys_recvfrom net/socket.c:2273 [inline]
 __se_sys_recvfrom net/socket.c:2269 [inline]
 __x64_sys_recvfrom+0xde/0x100 net/socket.c:2269
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880326abc80
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 68 bytes inside of
 freed 240-byte region [ffff8880326abc80, ffff8880326abd70)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x326ab
ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xfdffffff(slab)
raw: 00fff00000000000 ffff88801eaee780 ffffea0000b7dc80 dead000000000003
raw: 0000000000000000 00000000800c000c 00000001fdffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4686, tgid 4686 (udevadm), ts 32357469485, free_ts 28829011109
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2321
 allocate_slab+0x5a/0x2f0 mm/slub.c:2484
 new_slab mm/slub.c:2537 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
 __slab_alloc+0x58/0xa0 mm/slub.c:3813
 __slab_alloc_node mm/slub.c:3866 [inline]
 slab_alloc_node mm/slub.c:4025 [inline]
 kmem_cache_alloc_node_noprof+0x1fe/0x320 mm/slub.c:4080
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667
 alloc_skb include/linux/skbuff.h:1320 [inline]
 alloc_uevent_skb+0x74/0x230 lib/kobject_uevent.c:289
 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
 kobject_uevent_net_broadcast+0x2fd/0x580 lib/kobject_uevent.c:410
 kobject_uevent_env+0x57d/0x8e0 lib/kobject_uevent.c:608
 kobject_synth_uevent+0x4ef/0xae0 lib/kobject_uevent.c:207
 uevent_store+0x4b/0x70 drivers/base/bus.c:633
 kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0xd22/0xea0 mm/page_alloc.c:2612
 kasan_depopulate_vmalloc_pte+0x74/0x90 mm/kasan/shadow.c:408
 apply_to_pte_range mm/memory.c:2797 [inline]
 apply_to_pmd_range mm/memory.c:2841 [inline]
 apply_to_pud_range mm/memory.c:2877 [inline]
 apply_to_p4d_range mm/memory.c:2913 [inline]
 __apply_to_page_range+0x8a8/0xe50 mm/memory.c:2947
 kasan_release_vmalloc+0x9a/0xb0 mm/kasan/shadow.c:525
 purge_vmap_node+0x3e3/0x770 mm/vmalloc.c:2208
 __purge_vmap_area_lazy+0x708/0xae0 mm/vmalloc.c:2290
 _vm_unmap_aliases+0x79d/0x840 mm/vmalloc.c:2885
 change_page_attr_set_clr+0x2fe/0xdb0 arch/x86/mm/pat/set_memory.c:1881
 change_page_attr_set arch/x86/mm/pat/set_memory.c:1922 [inline]
 set_memory_nx+0xf2/0x130 arch/x86/mm/pat/set_memory.c:2110
 free_init_pages arch/x86/mm/init.c:924 [inline]
 free_kernel_image_pages arch/x86/mm/init.c:943 [inline]
 free_initmem+0x79/0x110 arch/x86/mm/init.c:970
 kernel_init+0x31/0x2b0 init/main.c:1476
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff8880326abb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880326abc00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
>ffff8880326abc80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880326abd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
 ffff8880326abd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb

Fixes: 93c99f21db36 ("af_unix: Don't stop recv(MSG_DONTWAIT) if consumed OOB skb is at the head.")
Reported-by: syzbot+8811381d455e3e9ec788@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8811381d455e3e9ec788
Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240905193240.17565-5-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

af_unix: Move spin_lock() in manage_oob().

2024-09-10T00:14:26+00:00

When OOB skb has been already consumed, manage_oob() returns the next
skb if exists.  In such a case, we need to fall back to the else branch
below.

Then, we want to keep holding spin_lock(&sk->sk_receive_queue.lock).

Let's move it out of if-else branch and add lightweight check before
spin_lock() for major use cases without OOB skb.

Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240905193240.17565-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

af_unix: Rename unlinked_skb in manage_oob().

2024-09-10T00:14:26+00:00

When OOB skb has been already consumed, manage_oob() returns the next
skb if exists.  In such a case, we need to fall back to the else branch
below.

Then, we need to keep two skbs and free them later with consume_skb()
and kfree_skb().

Let's rename unlinked_skb accordingly.

Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240905193240.17565-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

af_unix: Remove single nest in manage_oob().

2024-09-10T00:14:26+00:00

This is a prep for the later fix.

No functional change intended.

Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240905193240.17565-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

af_unix: Don't call skb_get() for OOB skb.

2024-08-20T22:48:00+00:00

Since introduced, OOB skb holds an additional reference count with no
special reason and caused many issues.

Also, kfree_skb() and consume_skb() are used to decrement the count,
which is confusing.

Let's drop the unnecessary skb_get() in queue_oob() and corresponding
kfree_skb(), consume_skb(), and skb_unref().

Now unix_sk(sk)->oob_skb is just a pointer to skb in the receive queue,
so special handing is no longer needed in GC.

Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240816233921.57800-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

af_unix: Disable MSG_OOB handling for sockets in sockmap/sockhash

2024-07-17T20:49:00+00:00

AF_UNIX socket tracks the most recent OOB packet (in its receive queue)
with an `oob_skb` pointer. BPF redirecting does not account for that: when
an OOB packet is moved between sockets, `oob_skb` is left outdated. This
results in a single skb that may be accessed from two different sockets.

Take the easy way out: silently drop MSG_OOB data targeting any socket that
is in a sockmap or a sockhash. Note that such silent drop is akin to the
fate of redirected skb's scm_fp_list (SCM_RIGHTS, SCM_CREDENTIALS).

For symmetry, forbid MSG_OOB in unix_bpf_recvmsg().

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Suggested-by: Kuniyuki Iwashima 
Signed-off-by: Michal Luczaj 
Signed-off-by: Daniel Borkmann 
Tested-by: Jakub Sitnicki 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Jakub Sitnicki 
Link: https://lore.kernel.org/bpf/20240713200218.2140950-2-mhal@rbox.co

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-07-04T21:16:11+00:00

Cross-merge networking fixes after downstream PR.

Conflicts:

drivers/net/phy/aquantia/aquantia.h
  219343755eae ("net: phy: aquantia: add missing include guards")
  61578f679378 ("net: phy: aquantia: add support for PHY LEDs")

drivers/net/ethernet/wangxun/libwx/wx_hw.c
  bd07a9817846 ("net: txgbe: remove separate irq request for MSI and INTx")
  b501d261a5b3 ("net: txgbe: add FDIR ATR support")
https://lore.kernel.org/all/20240703112936.483c1975@canb.auug.org.au/

include/linux/mlx5/mlx5_ifc.h
  048a403648fc ("net/mlx5: IFC updates for changing max EQs")
  99be56171fa9 ("net/mlx5e: SHAMPO, Re-enable HW-GRO")
https://lore.kernel.org/all/20240701133951.6926b2e3@canb.auug.org.au/

Adjacent changes:

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
  4130c67cd123 ("wifi: iwlwifi: mvm: check vif for NULL/ERR_PTR before dereference")
  3f3126515fbe ("wifi: iwlwifi: mvm: add mvm-specific guard")

include/net/mac80211.h
  816c6bec09ed ("wifi: mac80211: fix BSS_CHANGED_UNSOL_BCAST_PROBE_RESP")
  5a009b42e041 ("wifi: mac80211: track changes in AP's TPE")

Signed-off-by: Jakub Kicinski

af_unix: Fix uninit-value in __unix_walk_scc()

2024-07-04T02:36:22+00:00

KMSAN reported uninit-value access in __unix_walk_scc() [1].

In the list_for_each_entry_reverse() loop, when the vertex's index
equals it's scc_index, the loop uses the variable vertex as a
temporary variable that points to a vertex in scc. And when the loop
is finished, the variable vertex points to the list head, in this case
scc, which is a local variable on the stack (more precisely, it's not
even scc and might underflow the call stack of __unix_walk_scc():
container_of(&scc, struct unix_vertex, scc_entry)).

However, the variable vertex is used under the label prev_vertex. So
if the edge_stack is not empty and the function jumps to the
prev_vertex label, the function will access invalid data on the
stack. This causes the uninit-value access issue.

Fix this by introducing a new temporary variable for the loop.

[1]
BUG: KMSAN: uninit-value in __unix_walk_scc net/unix/garbage.c:478 [inline]
BUG: KMSAN: uninit-value in unix_walk_scc net/unix/garbage.c:526 [inline]
BUG: KMSAN: uninit-value in __unix_gc+0x2589/0x3c20 net/unix/garbage.c:584
 __unix_walk_scc net/unix/garbage.c:478 [inline]
 unix_walk_scc net/unix/garbage.c:526 [inline]
 __unix_gc+0x2589/0x3c20 net/unix/garbage.c:584
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xade/0x1bf0 kernel/workqueue.c:3312
 worker_thread+0xeb6/0x15b0 kernel/workqueue.c:3393
 kthread+0x3c4/0x530 kernel/kthread.c:389
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 unix_walk_scc net/unix/garbage.c:526 [inline]
 __unix_gc+0x2adf/0x3c20 net/unix/garbage.c:584
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xade/0x1bf0 kernel/workqueue.c:3312
 worker_thread+0xeb6/0x15b0 kernel/workqueue.c:3393
 kthread+0x3c4/0x530 kernel/kthread.c:389
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Local variable entries created at:
 ref_tracker_free+0x48/0xf30 lib/ref_tracker.c:222
 netdev_tracker_free include/linux/netdevice.h:4058 [inline]
 netdev_put include/linux/netdevice.h:4075 [inline]
 dev_put include/linux/netdevice.h:4101 [inline]
 update_gid_event_work_handler+0xaa/0x1b0 drivers/infiniband/core/roce_gid_mgmt.c:813

CPU: 1 PID: 12763 Comm: kworker/u8:31 Not tainted 6.10.0-rc4-00217-g35bb670d65fc #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
Workqueue: events_unbound __unix_gc

Fixes: 3484f063172d ("af_unix: Detect Strongly Connected Components.")
Reported-by: syzkaller 
Signed-off-by: Shigeru Yoshida 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20240702160428.10153-1-syoshida@redhat.com
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-06-27T19:14:11+00:00

Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:
  e3f02f32a050 ("ionic: fix kernel panic due to multi-buffer handling")
  d9c04209990b ("ionic: Mark error paths in the data path as unlikely")

Signed-off-by: Jakub Kicinski

af_unix: Fix wrong ioctl(SIOCATMARK) when consumed OOB skb is at the head.

2024-06-27T10:05:01+00:00

Even if OOB data is recv()ed, ioctl(SIOCATMARK) must return 1 when the
OOB skb is at the head of the receive queue and no new OOB data is queued.

Without fix:

  #  RUN           msg_oob.no_peek.oob ...
  # msg_oob.c:305:oob:Expected answ[0] (0) == oob_head (1)
  # oob: Test terminated by assertion
  #          FAIL  msg_oob.no_peek.oob
  not ok 2 msg_oob.no_peek.oob

With fix:

  #  RUN           msg_oob.no_peek.oob ...
  #            OK  msg_oob.no_peek.oob
  ok 2 msg_oob.no_peek.oob

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: Paolo Abeni