1. 10 Sep, 2024 6 commits
    • Jakub Kicinski's avatar
      Merge branch 'af_unix-correct-manage_oob-when-oob-follows-a-consumed-oob' · 228fa9b1
      Jakub Kicinski authored
      Kuniyuki Iwashima says:
      
      ====================
      af_unix: Correct manage_oob() when OOB follows a consumed OOB.
      
      Recently syzkaller reported UAF of OOB skb.
      
      The bug was introduced by commit 93c99f21 ("af_unix: Don't stop
      recv(MSG_DONTWAIT) if consumed OOB skb is at the head.") but uncovered
      by another recent commit 8594d9b8 ("af_unix: Don't call skb_get()
      for OOB skb.").
      
      [0]: https://lore.kernel.org/netdev/00000000000083b05a06214c9ddc@google.com/
      ====================
      
      Link: https://patch.msgid.link/20240905193240.17565-1-kuniyu@amazon.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      228fa9b1
    • Kuniyuki Iwashima's avatar
      af_unix: Don't return OOB skb in manage_oob(). · 5aa57d9f
      Kuniyuki Iwashima authored
      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 8594d9b8 ("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-gfbdaffe4 #0
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
      Call Trace:
       <TASK>
       __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
       </TASK>
      
      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: 93c99f21 ("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=8811381d455e3e9ec788Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
      Link: https://patch.msgid.link/20240905193240.17565-5-kuniyu@amazon.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      5aa57d9f
    • Kuniyuki Iwashima's avatar
      af_unix: Move spin_lock() in manage_oob(). · a0264a9f
      Kuniyuki Iwashima authored
      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: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
      Link: https://patch.msgid.link/20240905193240.17565-4-kuniyu@amazon.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      a0264a9f
    • Kuniyuki Iwashima's avatar
      af_unix: Rename unlinked_skb in manage_oob(). · beb2c5f1
      Kuniyuki Iwashima authored
      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: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
      Link: https://patch.msgid.link/20240905193240.17565-3-kuniyu@amazon.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      beb2c5f1
    • Kuniyuki Iwashima's avatar
      af_unix: Remove single nest in manage_oob(). · 579770dd
      Kuniyuki Iwashima authored
      This is a prep for the later fix.
      
      No functional change intended.
      Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
      Link: https://patch.msgid.link/20240905193240.17565-2-kuniyu@amazon.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      579770dd
    • Jakub Kicinski's avatar
      Merge tag 'linux-can-next-for-6.12-20240909' of... · e4225a8c
      Jakub Kicinski authored
      Merge tag 'linux-can-next-for-6.12-20240909' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next
      
      Marc Kleine-Budde says:
      
      ====================
      pull-request: can-next 2024-09-09
      
      The first patch is by Rob Herring and simplifies the DT parsing in the
      cc770 driver.
      
      The next 2 patches both target the rockchip_canfd driver added in the
      last pull request to net-next. The first one is by Nathan Chancellor
      and fixes the return type of rkcanfd_start_xmit(), the second one is
      by me and fixes a 64 bit division on 32 bit platforms in
      rkcanfd_timestamp_init().
      
      * tag 'linux-can-next-for-6.12-20240909' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next:
        can: rockchip_canfd: rkcanfd_timestamp_init(): fix 64 bit division on 32 bit platforms
        can: rockchip_canfd: fix return type of rkcanfd_start_xmit()
        net: can: cc770: Simplify parsing DT properties
      ====================
      
      Link: https://patch.msgid.link/20240909063657.2287493-1-mkl@pengutronix.deSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      e4225a8c
  2. 09 Sep, 2024 34 commits