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Date: Thu,  4 Apr 2024 12:36:02 +0000
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Message-ID: <20240404123602.2369488-1-edumazet@google.com>
Subject: [PATCH net] Bluetooth: validate setsockopt( BT_PKT_STATUS /
 BT_DEFER_SETUP) user input
From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, 
	Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, 
	Eric Dumazet <edumazet@google.com>, syzbot <syzkaller@googlegroups.com>, 
	Marcel Holtmann <marcel@holtmann.org>, Johan Hedberg <johan.hedberg@gmail.com>, 
	Luiz Augusto von Dentz <luiz.dentz@gmail.com>, linux-bluetooth@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

syzbot reported sco_sock_setsockopt() is copying data without
checking user input length.

 BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
 BUG: KASAN: slab-out-of-bounds in copy_from_sockptr include/linux/sockptr.h:55 [inline]
 BUG: KASAN: slab-out-of-bounds in sco_sock_setsockopt+0xc0b/0xf90 net/bluetooth/sco.c:893
Read of size 4 at addr ffff88805f7b15a3 by task syz-executor.5/12578

CPU: 1 PID: 12578 Comm: syz-executor.5 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
  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
  copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
  copy_from_sockptr include/linux/sockptr.h:55 [inline]
  sco_sock_setsockopt+0xc0b/0xf90 net/bluetooth/sco.c:893
  do_sock_setsockopt+0x3b1/0x720 net/socket.c:2311
  __sys_setsockopt+0x1ae/0x250 net/socket.c:2334
  __do_sys_setsockopt net/socket.c:2343 [inline]
  __se_sys_setsockopt net/socket.c:2340 [inline]
  __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340
 do_syscall_64+0xfd/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f3c2487dde9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3c256b40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f3c249abf80 RCX: 00007f3c2487dde9
RDX: 0000000000000010 RSI: 0000000000000112 RDI: 0000000000000008
RBP: 00007f3c248ca47a R08: 0000000000000002 R09: 0000000000000000
R10: 0000000020000080 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000004d R14: 00007f3c249abf80 R15: 00007fff5dcf4978
 </TASK>

Allocated by task 12578:
  kasan_save_stack mm/kasan/common.c:47 [inline]
  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
  poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
  __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
  kasan_kmalloc include/linux/kasan.h:211 [inline]
  __do_kmalloc_node mm/slub.c:3966 [inline]
  __kmalloc+0x233/0x4a0 mm/slub.c:3979
  kmalloc include/linux/slab.h:632 [inline]
  __cgroup_bpf_run_filter_setsockopt+0xd2f/0x1040 kernel/bpf/cgroup.c:1869
  do_sock_setsockopt+0x6b4/0x720 net/socket.c:2293
  __sys_setsockopt+0x1ae/0x250 net/socket.c:2334
  __do_sys_setsockopt net/socket.c:2343 [inline]
  __se_sys_setsockopt net/socket.c:2340 [inline]
  __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340
 do_syscall_64+0xfd/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

The buggy address belongs to the object at ffff88805f7b15a0
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 1 bytes to the right of
 allocated 2-byte region [ffff88805f7b15a0, ffff88805f7b15a2)

The buggy address belongs to the physical page:
page:ffffea00017dec40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5f7b1
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888014c41280 ffffea0000a26d80 dead000000000002
raw: 0000000000000000 0000000080800080 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5091, tgid 5091 (syz-executor.3), ts 75758857522, free_ts 75730585588
  set_page_owner include/linux/page_owner.h:31 [inline]
  post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
  prep_new_page mm/page_alloc.c:1540 [inline]
  get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
  __alloc_pages+0x256/0x680 mm/page_alloc.c:4569
  __alloc_pages_node include/linux/gfp.h:238 [inline]
  alloc_pages_node include/linux/gfp.h:261 [inline]
  alloc_slab_page+0x5f/0x160 mm/slub.c:2175
  allocate_slab mm/slub.c:2338 [inline]
  new_slab+0x84/0x2f0 mm/slub.c:2391
  ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
  __slab_alloc mm/slub.c:3610 [inline]
  __slab_alloc_node mm/slub.c:3663 [inline]
  slab_alloc_node mm/slub.c:3835 [inline]
  __do_kmalloc_node mm/slub.c:3965 [inline]
  __kmalloc_node_track_caller+0x2d6/0x4e0 mm/slub.c:3986
  kstrdup+0x3a/0x80 mm/util.c:62
  __kernfs_new_node+0x9d/0x880 fs/kernfs/dir.c:611
  kernfs_new_node+0x13a/0x240 fs/kernfs/dir.c:691
  kernfs_create_dir_ns+0x43/0x120 fs/kernfs/dir.c:1052
  sysfs_create_dir_ns+0x189/0x3a0 fs/sysfs/dir.c:59
  create_dir lib/kobject.c:73 [inline]
  kobject_add_internal+0x435/0x8d0 lib/kobject.c:240
  kobject_add_varg lib/kobject.c:374 [inline]
  kobject_init_and_add+0x124/0x190 lib/kobject.c:457
  netdev_queue_add_kobject net/core/net-sysfs.c:1786 [inline]
  netdev_queue_update_kobjects+0x1ee/0x5f0 net/core/net-sysfs.c:1838
  register_queue_kobjects net/core/net-sysfs.c:1900 [inline]
  netdev_register_kobject+0x265/0x320 net/core/net-sysfs.c:2140
page last free pid 5103 tgid 5103 stack trace:
  reset_page_owner include/linux/page_owner.h:24 [inline]
  free_pages_prepare mm/page_alloc.c:1140 [inline]
  free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2346
  free_unref_page_list+0x5a3/0x850 mm/page_alloc.c:2532
  release_pages+0x2744/0x2a80 mm/swap.c:1042
  tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
  tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
  tlb_flush_mmu+0x34d/0x4e0 mm/mmu_gather.c:300
  tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:392
  exit_mmap+0x4b6/0xd40 mm/mmap.c:3300
  __mmput+0x115/0x3c0 kernel/fork.c:1345
  exit_mm+0x220/0x310 kernel/exit.c:569
  do_exit+0x99e/0x27e0 kernel/exit.c:865
  do_group_exit+0x207/0x2c0 kernel/exit.c:1027
  __do_sys_exit_group kernel/exit.c:1038 [inline]
  __se_sys_exit_group kernel/exit.c:1036 [inline]
  __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
 do_syscall_64+0xfd/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Memory state around the buggy address:
 ffff88805f7b1480: 05 fc fc fc 05 fc fc fc fa fc fc fc 05 fc fc fc
 ffff88805f7b1500: 05 fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc
>ffff88805f7b1580: 04 fc fc fc 02 fc fc fc fa fc fc fc 05 fc fc fc
                               ^
 ffff88805f7b1600: fa fc fc fc 05 fc fc fc fa fc fc fc 05 fc fc fc
 ffff88805f7b1680: 05 fc fc fc 05 fc fc fc 00 fc fc fc fa fc fc fc

Fixes: 00398e1d5183 ("Bluetooth: Add support for BT_PKT_STATUS CMSG data for SCO connections")
Fixes: b96e9c671b05 ("Bluetooth: Add BT_DEFER_SETUP option to sco socket")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> (supporter:BLUETOOTH SUBSYSTEM)
Cc: linux-bluetooth@vger.kernel.org
---
 net/bluetooth/sco.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 43daf965a01e4ac5c9329150080b00dcd63c7e1c..9d013f01865fd2509f28eac3bceadf682f0a5edb 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -843,6 +843,10 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
+		if (optlen < sizeof(u32)) {
+			err = -EINVAL;
+			break;
+		}
 		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
 			err = -EFAULT;
 			break;
@@ -890,6 +894,10 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case BT_PKT_STATUS:
+		if (optlen < sizeof(u32)) {
+			err = -EINVAL;
+			break;
+		}
 		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
 			err = -EFAULT;
 			break;
-- 
2.44.0.478.gd926399ef9-goog