Inject fault while probing mtty.ko, if kstrdup() fails in
kobject_set_name_varg() in dev_set_name(), the strchr()
in kobject_add() of device_add() will cause null-ptr-deref below.
So check the err of dev_set_name().
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 9430 Comm: modprobe Tainted: G W 6.5.0-g32bf43e4efdb #50
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:strchr+0x17/0xa0
Code: 48 89 34 24 e8 fa 59 ad fd 48 8b 34 24 eb 9a 0f 1f 40 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 fa 53 48 c1 ea 03 48 83 ec 10 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 51 0f b6 07 89
RSP: 0018:ffff8881095e76a0 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: ffffffffa0274710 RCX: 1ffffffff404e8e2
RDX: 0000000000000000 RSI: 0000000000000025 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88810021eb28 R09: ffff888103f13bd8
R10: ffffed1021cdf94a R11: ffff88810e6fca53 R12: ffff8881095e7748
R13: 0000000000000cc0 R14: ffff888103f13bd8 R15: ffffffffa0274710
FS: 00007f5dfa57c540(0000) GS:ffff88811a080000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd59a4ecf8 CR3: 00000001065bb004 CR4: 0000000000170ee0
Call Trace:
<TASK>
? __die_body+0x1b/0x60
? die_addr+0x43/0x70
? exc_general_protection+0x121/0x210
? asm_exc_general_protection+0x22/0x30
? strchr+0x17/0xa0
kvasprintf_const+0x1c/0x120
kobject_set_name_vargs+0x41/0x110
? kobject_add_internal+0x860/0x860
? kasan_unpoison+0x23/0x50
kobject_add+0xec/0x1f0
? _raw_spin_unlock_irqrestore+0x42/0x80
? kobject_add_internal+0x860/0x860
? mutex_unlock+0x80/0xd0
? kobject_put+0x5c/0x310
? get_device_parent.isra.0+0x1a2/0x430
? kobject_put+0x5c/0x310
device_add+0x2ca/0x1440
? __fw_devlink_link_to_suppliers+0x180/0x180
? __hrtimer_init+0x38/0x200
? pm_runtime_init+0x2df/0x3d0
mtty_dev_init+0x12b/0x1000 [mtty]
? 0xffffffffa02a8000
do_one_initcall+0x87/0x2e0
? efi_enabled.constprop.0+0x50/0x50
? _raw_spin_unlock_irqrestore+0x42/0x80
? __kmem_cache_alloc_node+0x342/0x550
? do_init_module+0x4b/0x750
? kasan_unpoison+0x23/0x50
do_init_module+0x24d/0x750
load_module+0x4e60/0x68d0
? module_frob_arch_sections+0x20/0x20
? update_cfs_group+0x10c/0x2a0
? __wake_up_common+0x10b/0x5d0
? kernel_read_file+0x3ca/0x510
? __x64_sys_fsconfig+0x650/0x650
? __schedule+0xa0b/0x2a60
? init_module_from_file+0xd2/0x130
init_module_from_file+0xd2/0x130
? __ia32_sys_init_module+0xa0/0xa0
? _raw_spin_lock_irqsave+0xe0/0xe0
? ptrace_stop+0x487/0x790
idempotent_init_module+0x32d/0x6a0
? init_module_from_file+0x130/0x130
? __fget_light+0x57/0x500
__x64_sys_finit_module+0xbb/0x130
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f5df9f1b839
Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffd59a51dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
RAX: ffffffffffffffda RBX: 0000557c13e2de40 RCX: 00007f5df9f1b839
RDX: 0000000000000000 RSI: 0000557c12e1bc2e RDI: 0000000000000003
RBP: 0000557c12e1bc2e R08: 0000000000000000 R09: 0000557c13e2de40
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 0000557c13e2df90 R14: 0000000000040000 R15: 0000557c13e2de40
</TASK>
Modules linked in: mtty(+) mdev vfio_iommu_type1 vfio [last unloaded: mtty]
Dumping ftrace buffer:
(ftrace buffer empty)
---[ end trace 0000000000000000 ]---
RIP: 0010:strchr+0x17/0xa0
Code: 48 89 34 24 e8 fa 59 ad fd 48 8b 34 24 eb 9a 0f 1f 40 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 fa 53 48 c1 ea 03 48 83 ec 10 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 51 0f b6 07 89
RSP: 0018:ffff8881095e76a0 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: ffffffffa0274710 RCX: 1ffffffff404e8e2
RDX: 0000000000000000 RSI: 0000000000000025 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88810021eb28 R09: ffff888103f13bd8
R10: ffffed1021cdf94a R11: ffff88810e6fca53 R12: ffff8881095e7748
R13: 0000000000000cc0 R14: ffff888103f13bd8 R15: ffffffffa0274710
FS: 00007f5dfa57c540(0000) GS:ffff88811a080000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd59a4ecf8 CR3: 00000001065bb004 CR4: 0000000000170ee0
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 1 seconds..
Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.")
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
samples/vfio-mdev/mtty.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 5af00387c519..2e403099e3e5 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1330,7 +1330,9 @@ static int __init mtty_dev_init(void)
mtty_dev.dev.class = mtty_dev.vd_class;
mtty_dev.dev.release = mtty_device_release;
- dev_set_name(&mtty_dev.dev, "%s", MTTY_NAME);
+ ret = dev_set_name(&mtty_dev.dev, "%s", MTTY_NAME);
+ if (ret)
+ goto err_put;
ret = device_register(&mtty_dev.dev);
if (ret)
--
2.34.1
