[PATCH v14 00/23] LSM: Module stacking for AppArmor

Fri Jan 24 21:04:37 UTC 2020

On 1/23/20 7:22 PM, Casey Schaufler wrote:
> This patchset provides the changes required for
> the AppArmor security module to stack safely with any other.
> 
> v14: Rebase to 5.5-rc5
>       Incorporate feedback from v13
>       - Use an array of audit rules (patch 0002)
>       - Significant change, removed Acks (patch 0002)
>       - Remove unneeded include (patch 0013)
>       - Use context.len correctly (patch 0015)
>       - Reorder code to be more sensible (patch 0016)
>       - Drop SO_PEERCONTEXT as it's not needed yet (patch 0023)

I don't know for sure if this is your bug, but it happens every time I 
boot with your patches applied and not at all on stock v5.5-rc5 so here 
it is.  Will try to bisect as time permits but not until next week. 
Trigger seems to be loading the tun driver.

[   67.726834] tun: Universal TUN/TAP device driver, 1.6
[   67.736657] 
==================================================================
[   67.741335] BUG: KASAN: slab-out-of-bounds in sock_init_data+0x14a/0x5a0
[   67.745037] Read of size 4 at addr ffff88870afe8928 by task libvirtd/1238

[   67.751861] CPU: 4 PID: 1238 Comm: libvirtd Tainted: G 
T 5.5.0-rc5+ #54
[   67.756250] Call Trace:
[   67.759510]  dump_stack+0xb8/0x110
[   67.761604]  print_address_description.constprop.0+0x1f/0x280
[   67.763768]  __kasan_report.cold+0x75/0x8f
[   67.765895]  ? sock_init_data+0x14a/0x5a0
[   67.768282]  kasan_report+0xe/0x20
[   67.770397]  sock_init_data+0x14a/0x5a0
[   67.772511]  tun_chr_open+0x1de/0x280 [tun]
[   67.774644]  misc_open+0x1cb/0x210
[   67.776820]  chrdev_open+0x15b/0x350
[   67.778917]  ? cdev_put.part.0+0x30/0x30
[   67.781030]  do_dentry_open+0x2cb/0x800
[   67.783135]  ? cdev_put.part.0+0x30/0x30
[   67.785225]  ? devcgroup_check_permission+0x11a/0x260
[   67.787321]  ? __x64_sys_fchdir+0xf0/0xf0
[   67.789418]  ? security_inode_permission+0x5b/0x70
[   67.791513]  path_openat+0x858/0x14a0
[   67.793589]  ? path_mountpoint+0x5e0/0x5e0
[   67.795719]  ? mark_lock+0xb8/0xb00
[   67.797786]  do_filp_open+0x11e/0x1b0
[   67.799840]  ? may_open_dev+0x60/0x60
[   67.801871]  ? match_held_lock+0x1b/0x240
[   67.803968]  ? lock_downgrade+0x360/0x360
[   67.805997]  ? do_raw_spin_lock+0x119/0x1d0
[   67.808041]  ? rwlock_bug.part.0+0x60/0x60
[   67.810099]  ? do_raw_spin_unlock+0xa3/0x130
[   67.812244]  ? _raw_spin_unlock+0x1f/0x30
[   67.814287]  ? __alloc_fd+0x143/0x2f0
[   67.816324]  do_sys_open+0x1f0/0x2d0
[   67.818358]  ? filp_open+0x50/0x50
[   67.820404]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   67.822447]  ? lockdep_hardirqs_off+0xbe/0x100
[   67.824473]  ? mark_held_locks+0x24/0x90
[   67.826484]  do_syscall_64+0x74/0xd0
[   67.828480]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   67.830478] RIP: 0033:0x7f1a2cce6074
[   67.832495] Code: 24 20 eb 8f 66 90 44 89 54 24 0c e8 86 f4 ff ff 44 
8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 
05 <48> 3d 00 f0 ff ff 77 32 44 89 c7 89 44 24 0c e8 b8 f4 ff ff 8b 44
[   67.834760] RSP: 002b:00007f19e4af46d0 EFLAGS: 00000293 ORIG_RAX: 
0000000000000101
[   67.837032] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 
00007f1a2cce6074
[   67.839318] RDX: 0000000000000002 RSI: 00007f1a2d0bfb67 RDI: 
00000000ffffff9c
[   67.841598] RBP: 00007f1a2d0bfb67 R08: 0000000000000000 R09: 
00007f19e4af4914
[   67.843941] R10: 0000000000000000 R11: 0000000000000293 R12: 
0000000000000002
[   67.846283] R13: 000000000000000d R14: 00007f19e4af4920 R15: 
00007f1a2d0bfb67

[   67.850936] Allocated by task 1238:
[   67.853241]  save_stack+0x1b/0x80
[   67.855533]  __kasan_kmalloc.constprop.0+0xc2/0xd0
[   67.857935]  sk_prot_alloc+0x115/0x170
[   67.860235]  sk_alloc+0x2f/0xa10
[   67.862541]  tun_chr_open+0x4d/0x280 [tun]
[   67.864894]  misc_open+0x1cb/0x210
[   67.867164]  chrdev_open+0x15b/0x350
[   67.869448]  do_dentry_open+0x2cb/0x800
[   67.871768]  path_openat+0x858/0x14a0
[   67.874041]  do_filp_open+0x11e/0x1b0
[   67.876328]  do_sys_open+0x1f0/0x2d0
[   67.878592]  do_syscall_64+0x74/0xd0
[   67.880899]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

[   67.885431] Freed by task 726:
[   67.887689]  save_stack+0x1b/0x80
[   67.889967]  __kasan_slab_free+0x12c/0x170
[   67.892197]  kfree+0xff/0x430
[   67.894444]  uevent_show+0x176/0x1b0
[   67.896709]  dev_attr_show+0x37/0x70
[   67.898940]  sysfs_kf_seq_show+0x119/0x210
[   67.901159]  seq_read+0x29d/0x720
[   67.903367]  vfs_read+0xf9/0x1f0
[   67.905538]  ksys_read+0xc9/0x160
[   67.907736]  do_syscall_64+0x74/0xd0
[   67.909889]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

[   67.914100] The buggy address belongs to the object at ffff88870afe8000
                 which belongs to the cache kmalloc-4k of size 4096
[   67.918357] The buggy address is located 2344 bytes inside of
                 4096-byte region [ffff88870afe8000, ffff88870afe9000)
[   67.922562] The buggy address belongs to the page:
[   67.924725] page:ffffea001c2bfa00 refcount:1 mapcount:0 
mapping:ffff88881f00de00 index:0x0 compound_mapcount: 0
[   67.926926] raw: 0017ffe000010200 ffffea001c167a00 0000000200000002 
ffff88881f00de00
[   67.929144] raw: 0000000000000000 0000000080040004 00000001ffffffff 
0000000000000000
[   67.931362] page dumped because: kasan: bad access detected

[   67.936192] Memory state around the buggy address:
[   67.938438]  ffff88870afe8800: 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00
[   67.941078]  ffff88870afe8880: fc fc fc fc fc fc fc fc fc fc fc fc fc 
fc fc fc
[   67.943393] >ffff88870afe8900: fc fc fc fc fc fc fc fc fc fc fc fc fc 
fc fc fc
[   67.945709]                                   ^
[   67.948000]  ffff88870afe8980: fc fc fc fc fc fc fc fc fc fc fc fc fc 
fc fc fc
[   67.950311]  ffff88870afe8a00: fc fc fc fc fc fc fc fc fc fc fc fc fc 
fc fc fc
[   67.952629] 
==================================================================