Re: dell_smbios KASAN bug
From: Tom Zanussi
Date: Wed Mar 20 2019 - 15:30:26 EST
On Wed, 2019-03-20 at 15:13 -0400, Steven Rostedt wrote:
> On Wed, 20 Mar 2019 14:05:49 -0500
> Tom Zanussi <tzanussi@xxxxxxxxx> wrote:
>
> > On Wed, 2019-03-20 at 14:41 -0400, Steven Rostedt wrote:
> > > On Wed, 20 Mar 2019 13:29:20 -0500
> > > Tom Zanussi <tzanussi@xxxxxxxxx> wrote:
> > >
> > > > Hi,
> > > >
> > > > While looking into an unrelated problem, I hit this KASAN use-
> > > > after-
> > > > free warning, so thought I'd let you know.
> > > >
> > > > I have no idea how to fix it, but let me know if you need more
> > > > info.
> > > >
> > >
> > > Could you run with debug in the kernel command line, and see if
> > > you
> > > hit
> > > any failed messages from the dell_smbios_init() call?
> > >
> >
> > Not much, but this looks relevant:
> >
> > [ 26.783749] dell_smbios: No SMBIOS backends available (wmi: -19,
> > smm: -19)
> > [ 26.963648] dell_smbios: No dell-smbios drivers are loaded
> >
>
> And does this fix you problem?
>
> -- Steve
>
> diff --git a/drivers/platform/x86/dell-smbios-base.c
> b/drivers/platform/x86/dell-smbios-base.c
> index 9dc282ed5a9e..c3825c674522 100644
> --- a/drivers/platform/x86/dell-smbios-base.c
> +++ b/drivers/platform/x86/dell-smbios-base.c
> @@ -619,6 +619,7 @@ static int __init dell_smbios_init(void)
>
> fail_platform_driver:
> kfree(da_tokens);
> + da_num_tokens = 0;
> return ret;
> }
>
Unfortunately, no.
[ 26.125995] dell_smbios: No SMBIOS backends available (wmi: -19, smm: -19)
[ 26.232716] systemd-journald[407]: Successfully sent stream file descriptor to service manager.
[ 26.242860] dell_smbios: No dell-smbios drivers are loaded
[ 26.243142] ==================================================================
[ 26.243241] BUG: KASAN: use-after-free in dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243254] Read of size 2 at addr ffff8883bdf941a8 by task systemd-udevd/458
[ 26.243277] CPU: 1 PID: 458 Comm: systemd-udevd Not tainted 5.1.0-rc1+ #10
[ 26.243283] Hardware name: Dell Inc. XPS 13 9360/02PG84, BIOS 2.3.1 10/03/2017
[ 26.243288] Call Trace:
[ 26.243303] dump_stack+0x7c/0xbb
[ 26.243317] ? dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243327] print_address_description+0xc7/0x280
[ 26.243339] ? dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243350] ? dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243359] kasan_report+0x14e/0x192
[ 26.243379] ? dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243399] dell_smbios_find_token+0x2e/0x80 [dell_smbios]
[ 26.243421] kbd_led_init+0x2e7/0x473 [dell_laptop]
[ 26.243440] ? dmi_matched+0x2a/0x2a [dell_laptop]
[ 26.243451] ? get_device_parent.isra.28+0x2a0/0x2a0
[ 26.243466] ? lockdep_init_map+0x98/0x2c0
[ 26.243494] ? platform_device_add+0x1b5/0x3a0
[ 26.243525] dell_init+0x4ad/0xb63 [dell_laptop]
[ 26.243542] ? kbd_led_init+0x473/0x473 [dell_laptop]
[ 26.243563] ? ___slab_alloc+0x61f/0x700
[ 26.243572] ? ___slab_alloc+0x61f/0x700
[ 26.243594] ? preempt_count_sub+0x15/0x100
[ 26.243616] ? kbd_led_init+0x473/0x473 [dell_laptop]
[ 26.243626] do_one_initcall+0xbd/0x3fd
[ 26.243638] ? perf_trace_initcall_level+0x280/0x280
[ 26.243650] ? kasan_unpoison_shadow+0x30/0x40
[ 26.243662] ? __kasan_kmalloc.constprop.8+0xa0/0xd0
[ 26.243681] ? kmem_cache_alloc_trace+0x163/0x390
[ 26.243691] ? kasan_unpoison_shadow+0x30/0x40
[ 26.243716] do_init_module+0xe3/0x341
[ 26.243736] load_module+0x2fc5/0x3ad0
[ 26.243824] ? layout_and_allocate+0x1170/0x1170
[ 26.243837] ? vfs_read+0xd4/0x1b0
[ 26.243855] ? kernel_read+0x74/0xa0
[ 26.243877] ? kernel_read_file+0x148/0x320
[ 26.243917] ? seccomp_notify_release+0x110/0x110
[ 26.243958] ? __do_sys_finit_module+0x192/0x1c0
[ 26.243964] __do_sys_finit_module+0x192/0x1c0
[ 26.243975] ? __ia32_sys_init_module+0x40/0x40
[ 26.244000] ? syscall_trace_enter+0x184/0x5e0
[ 26.244046] ? mark_held_locks+0x1a/0x90
[ 26.244068] do_syscall_64+0x72/0x220
[ 26.244083] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 26.244091] RIP: 0033:0x7f7ceda3aa49
[ 26.244100] 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 0f b4 2c 00 f7 d8 64 89 01 48
[ 26.244105] RSP: 002b:00007ffe6ca1cbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 26.244114] RAX: ffffffffffffffda RBX: 00005635100838f0 RCX: 00007f7ceda3aa49
[ 26.244121] RDX: 0000000000000000 RSI: 00007f7ced7261c5 RDI: 0000000000000010
[ 26.244127] RBP: 00007f7ced7261c5 R08: 0000000000000000 R09: 00005635100838f0
[ 26.244133] R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000000
[ 26.244139] R13: 0000563510089e90 R14: 0000000000020000 R15: 00005635100838f0
[ 26.244193] Allocated by task 458:
[ 26.244206] __kasan_kmalloc.constprop.8+0xa0/0xd0
[ 26.244214] krealloc+0xa0/0xc0
[ 26.244220] 0xffffffffc0d60075
[ 26.244228] dmi_decode_table+0xf6/0x140
[ 26.244235] dmi_walk+0x46/0x70
[ 26.244241] 0xffffffffc0d60109
[ 26.244248] do_one_initcall+0xbd/0x3fd
[ 26.244255] do_init_module+0xe3/0x341
[ 26.244261] load_module+0x2fc5/0x3ad0
[ 26.244269] __do_sys_finit_module+0x192/0x1c0
[ 26.244276] do_syscall_64+0x72/0x220
[ 26.244283] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 26.244297] Freed by task 458:
[ 26.244309] __kasan_slab_free+0x111/0x150
[ 26.244316] kfree+0xf5/0x350
[ 26.244323] 0xffffffffc0d601d4
[ 26.244330] do_one_initcall+0xbd/0x3fd
[ 26.244337] do_init_module+0xe3/0x341
[ 26.244344] load_module+0x2fc5/0x3ad0
[ 26.244352] __do_sys_finit_module+0x192/0x1c0
[ 26.244358] do_syscall_64+0x72/0x220
[ 26.244366] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 26.244381] The buggy address belongs to the object at ffff8883bdf941a8
which belongs to the cache kmalloc-2k of size 2048
[ 26.244393] The buggy address is located 0 bytes inside of
2048-byte region [ffff8883bdf941a8, ffff8883bdf949a8)
[ 26.244402] The buggy address belongs to the page:
[ 26.244413] page:ffffea000ef7e400 count:1 mapcount:0 mapping:ffff88841c0113c0 index:0xffff8883bdf90968 compound_mapcount: 0
[ 26.244423] flags: 0x17ffffc0010200(slab|head)
[ 26.244433] raw: 0017ffffc0010200 ffffea000eff8208 ffff88841c003200 ffff88841c0113c0
[ 26.244442] raw: ffff8883bdf90968 00000000000d0009 00000001ffffffff 0000000000000000
[ 26.244447] page dumped because: kasan: bad access detected
[ 26.244460] Memory state around the buggy address:
[ 26.244472] ffff8883bdf94080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 26.244483] ffff8883bdf94100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 26.244494] >ffff8883bdf94180: fc fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb
[ 26.244504] ^
[ 26.244515] ffff8883bdf94200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 26.244526] ffff8883bdf94280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 26.244535] ==================================================================