On Mon, 2023-09-18 at 19:55 +0800, Jinjie Ruan wrote:
> Inject fault while probing mdpy.ko, if kstrdup() of create_dir()
> fails in
> kobject_add_internal() in kobject_init_and_add() in mdev_type_add()
> in parent_create_sysfs_files(), it will return 0 and probe
> successfully.
> And when rmmod mdpy.ko, the mdpy_dev_exit() will call
> mdev_unregister_parent(), the mdev_type_remove() may traverse
> uninitialized
> parent->types[i] in parent_remove_sysfs_files(), and it will cause
> below null-ptr-deref.
>
> If mdev_type_add() fails, return the error code and kset_unregister()
> to fix the issue.
>
> general protection fault, probably for non-canonical address
> 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000010-
> 0x0000000000000017]
> CPU: 2 PID: 10215 Comm: rmmod Tainted: G W N 6.6.0-
> rc2+ #20
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1
> 04/01/2014
> RIP: 0010:__kobject_del+0x62/0x1c0
> Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00
> 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80>
> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8
> RSP: 0018:ffff88810695fd30 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffffffffa0270268 RCX: 0000000000000000
> RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000010
> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10233a4ef1
> R10: ffff888119d2778b R11: 0000000063666572 R12: 0000000000000000
> R13: fffffbfff404e2d4 R14: dffffc0000000000 R15: ffffffffa0271660
> FS: 00007fbc81981540(0000) GS:ffff888119d00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fc14a142dc0 CR3: 0000000110a62003 CR4: 0000000000770ee0
> DR0: ffffffff8fb0bce8 DR1: ffffffff8fb0bce9 DR2: ffffffff8fb0bcea
> DR3: ffffffff8fb0bceb DR6: 00000000fffe0ff0 DR7: 0000000000000600
> PKRU: 55555554
> Call Trace:
> <TASK>
> ? die_addr+0x3d/0xa0
> ? exc_general_protection+0x144/0x220
> ? asm_exc_general_protection+0x22/0x30
> ? __kobject_del+0x62/0x1c0
> kobject_del+0x32/0x50
> parent_remove_sysfs_files+0xd6/0x170 [mdev]
> mdev_unregister_parent+0xfb/0x190 [mdev]
> ? mdev_register_parent+0x270/0x270 [mdev]
> ? find_module_all+0x9d/0xe0
> mdpy_dev_exit+0x17/0x63 [mdpy]
> __do_sys_delete_module.constprop.0+0x2fa/0x4b0
> ? module_flags+0x300/0x300
> ? __fput+0x4e7/0xa00
> do_syscall_64+0x35/0x80
> entry_SYSCALL_64_after_hwframe+0x46/0xb0
> RIP: 0033:0x7fbc813221b7
> Code: 73 01 c3 48 8b 0d d1 8c 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66
> 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48>
> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 8c 2c 00 f7 d8 64 89 01 48
> RSP: 002b:00007ffe780e0648 EFLAGS: 00000206 ORIG_RAX:
> 00000000000000b0
> RAX: ffffffffffffffda RBX: 00007ffe780e06a8 RCX: 00007fbc813221b7
> RDX: 000000000000000a RSI: 0000000000000800 RDI: 000055e214df9b58
> RBP: 000055e214df9af0 R08: 00007ffe780df5c1 R09: 0000000000000000
> R10: 00007fbc8139ecc0 R11: 0000000000000206 R12: 00007ffe780e0870
> R13: 00007ffe780e0ed0 R14: 000055e214df9260 R15: 000055e214df9af0
> </TASK>
> Modules linked in: mdpy(-) mdev vfio_iommu_type1 vfio [last
> unloaded: mdpy]
> Dumping ftrace buffer:
> (ftrace buffer empty)
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:__kobject_del+0x62/0x1c0
> Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00
> 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80>
> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8
> RSP: 0018:ffff88810695fd30 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffffffffa0270268 RCX: 0000000000000000
> RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000010
> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10233a4ef1
> R10: ffff888119d2778b R11: 0000000063666572 R12: 0000000000000000
> R13: fffffbfff404e2d4 R14: dffffc0000000000 R15: ffffffffa0271660
> FS: 00007fbc81981540(0000) GS:ffff888119d00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fc14a142dc0 CR3: 0000000110a62003 CR4: 0000000000770ee0
> DR0: ffffffff8fb0bce8 DR1: ffffffff8fb0bce9 DR2: ffffffff8fb0bcea
> DR3: ffffffff8fb0bceb DR6: 00000000fffe0ff0 DR7: 0000000000000600
> PKRU: 55555554
> Kernel panic - not syncing: Fatal exception
> Dumping ftrace buffer:
> (ftrace buffer empty)
> Kernel Offset: disabled
> Rebooting in 1 seconds..
>
> Fixes: da44c340c4fe ("vfio/mdev: simplify mdev_type handling")
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> ---
> drivers/vfio/mdev/mdev_sysfs.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by: Eric Farman <farman@xxxxxxxxxxxxx>
