On Sun, Apr 24, 2022 at 12:00:12PM +0200, Michael Straube wrote:
> Hi,
>
> It looks like
> commit 0afaa121813e ("staging: r8188eu: use in-kernel ieee channel")
> intoduced a. See KASAN output below.
>
> That commit replaced the use of struct rtw_ieee80211_channel with struct
> ieee80211_channel.
>
> There are several calls to memcpy that used sizeof(struct
> rtw_ieee80211_channel)
> and now use sizeof(struct ieee80211_channel) but the sizes of these two
> structures are not equal.
>
Oh no. When does this issue get triggered?
> regards,
> Michael
>
> dmesg:
>
> ==================================================================
> [ 422.214237] BUG: KASAN: slab-out-of-bounds in rtw_cmd_thread+0x1e8/0x430
> [r8188eu]
> [ 422.214277] Write of size 3600 at addr ffff8881e149d200 by task
> RTW_CMD_THREAD/2563
>
> [ 422.214289] CPU: 11 PID: 2563 Comm: RTW_CMD_THREAD Tainted: G C OE
> 5.18.0-rc2-staging+ #47 94e3ca73bebf5b7fec506721475e4fff2a023bb9
> [ 422.214301] Hardware name: Gigabyte Technology Co., Ltd. B550M S2H/B550M
> S2H, BIOS F15a 02/16/2022
> [ 422.214309] Call Trace:
> [ 422.214313] <TASK>
> [ 422.214317] dump_stack_lvl+0x45/0x5b
> [ 422.214327] print_report.cold+0x5e/0x5dc
> [ 422.214335] ? kasan_set_track+0x21/0x30
> [ 422.214342] ? kasan_set_free_info+0x20/0x40
> [ 422.214349] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> 91924fe1575bf49b9b37985ffde2c585d847446d]
> [ 422.214386] kasan_report+0xab/0x120
> [ 422.214394] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> 91924fe1575bf49b9b37985ffde2c585d847446d]
> [ 422.214430] kasan_check_range+0xf6/0x1d0
> [ 422.214436] memcpy+0x39/0x60
> [ 422.214442] rtw_cmd_thread+0x1e8/0x430 [r8188eu
> 91924fe1575bf49b9b37985ffde2c585d847446d]
> [ 422.214479] ? rtw_setassocsta_cmdrsp_callback+0xd0/0xd0 [r8188eu
> 91924fe1575bf49b9b37985ffde2c585d847446d]
> [ 422.214516] kthread+0x15d/0x190
> [ 422.214523] ? kthread_complete_and_exit+0x20/0x20
> [ 422.214531] ret_from_fork+0x22/0x30
> [ 422.214540] </TASK>
Sorry, I am not familiar with KASAN. How should I interpret this output?
I see the paragraph above has references to rtw_cmd_thread. I assume
that is its way of indicating that rtw_cmd_thread is the cause of the
problem, but the one below refers to other functions. I'm not sure where
I should start looking. I would start looking at `rtw_sitesurvey_cmd` and
`rtw_scan_ch_decision`, which call the memcpy on the
rtw_ieee80211_channel structure, but they are not on the call trace.
>
> [ 422.214546] Allocated by task 2522:
> [ 422.214551] kasan_save_stack+0x1e/0x40
> [ 422.214555] __kasan_kmalloc+0xa9/0xe0
> [ 422.214559] rtw_init_cmd_priv+0xd6/0x1b0 [r8188eu]
> [ 422.214589] rtw_init_drv_sw+0x21/0x370 [r8188eu]
> [ 422.214619] rtw_drv_init+0x3a6/0x4f0 [r8188eu]
> [ 422.214649] usb_probe_interface+0x155/0x340 [usbcore]
> [ 422.214705] really_probe.part.0+0x11f/0x320
> [ 422.214709] __driver_probe_device+0xe0/0x180
> [ 422.214712] driver_probe_device+0x4d/0x170
> [ 422.214715] __driver_attach+0x110/0x250
> [ 422.214718] bus_for_each_dev+0xe7/0x140
> [ 422.214721] bus_add_driver+0x25a/0x2b0
> [ 422.214723] driver_register+0x10f/0x190
> [ 422.214726] usb_register_driver+0x10e/0x1e0 [usbcore]
> [ 422.214780] do_one_initcall+0x8a/0x2a0
> [ 422.214784] do_init_module+0xe4/0x3b0
> [ 422.214787] load_module+0x41c4/0x4650
> [ 422.214789] __do_sys_finit_module+0x111/0x190
> [ 422.214791] do_syscall_64+0x5c/0x80
> [ 422.214795] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> [ 422.214802] Last potentially related work creation:
> [ 422.214807] kasan_save_stack+0x1e/0x40
> [ 422.214810] __kasan_record_aux_stack+0xb1/0xc0
> [ 422.214813] call_rcu+0xb5/0xfc0
> [ 422.214817] netlink_release+0x791/0xa40
> [ 422.214820] __sock_release+0x72/0x120
> [ 422.214824] sock_close+0x11/0x20
> [ 422.214828] __fput+0x10c/0x400
> [ 422.214831] task_work_run+0x8b/0xc0
> [ 422.214834] do_exit+0x5a4/0x10e0
> [ 422.214837] do_group_exit+0x58/0x100
> [ 422.214840] __x64_sys_exit_group+0x28/0x30
> [ 422.214843] do_syscall_64+0x5c/0x80
> [ 422.214846] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> [ 422.214852] The buggy address belongs to the object at ffff8881e149d000
> which belongs to the cache kmalloc-2k of size 2048
> [ 422.214862] The buggy address is located 512 bytes inside of
> 2048-byte region [ffff8881e149d000, ffff8881e149d800)
>
> [ 422.214874] The buggy address belongs to the physical page:
> [ 422.214879] page:000000003f187866 refcount:1 mapcount:0
> mapping:0000000000000000 index:0x0 pfn:0x1e1498
> [ 422.214883] head:000000003f187866 order:3 compound_mapcount:0
> compound_pincount:0
> [ 422.214885] flags:
> 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
> [ 422.214891] raw: 0017ffffc0010200 ffffea0004f1ca00 dead000000000002
> ffff888100042f00
> [ 422.214894] raw: 0000000000000000 0000000000080008 00000001ffffffff
> 0000000000000000
> [ 422.214896] page dumped because: kasan: bad access detected
>
> [ 422.214900] Memory state around the buggy address:
> [ 422.214905] ffff8881e149d500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00 00
> [ 422.214914] ffff8881e149d580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00 00
> [ 422.214921] >ffff8881e149d600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> fc fc
> [ 422.214927] ^
> [ 422.214932] ffff8881e149d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> fc fc
> [ 422.214939] ffff8881e149d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> fc fc
> [ 422.214946]
> ==================================================================
Hi Solomon,
On 4/24/22 15:11, Solomon Tan wrote:
> On Sun, Apr 24, 2022 at 12:00:12PM +0200, Michael Straube wrote:
>> Hi,
>>
>> It looks like
>> commit 0afaa121813e ("staging: r8188eu: use in-kernel ieee channel")
>> intoduced a. See KASAN output below.
>>
>> That commit replaced the use of struct rtw_ieee80211_channel with struct
>> ieee80211_channel.
>>
>> There are several calls to memcpy that used sizeof(struct
>> rtw_ieee80211_channel)
>> and now use sizeof(struct ieee80211_channel) but the sizes of these two
>> structures are not equal.
>>
>
> Oh no. When does this issue get triggered?
>
>> regards,
>> Michael
>>
>> dmesg:
>>
>> ==================================================================
>> [ 422.214237] BUG: KASAN: slab-out-of-bounds in rtw_cmd_thread+0x1e8/0x430
>> [r8188eu]
>> [ 422.214277] Write of size 3600 at addr ffff8881e149d200 by task
>> RTW_CMD_THREAD/2563
>>
>> [ 422.214289] CPU: 11 PID: 2563 Comm: RTW_CMD_THREAD Tainted: G C OE
>> 5.18.0-rc2-staging+ #47 94e3ca73bebf5b7fec506721475e4fff2a023bb9
>> [ 422.214301] Hardware name: Gigabyte Technology Co., Ltd. B550M S2H/B550M
>> S2H, BIOS F15a 02/16/2022
>> [ 422.214309] Call Trace:
>> [ 422.214313] <TASK>
>> [ 422.214317] dump_stack_lvl+0x45/0x5b
>> [ 422.214327] print_report.cold+0x5e/0x5dc
>> [ 422.214335] ? kasan_set_track+0x21/0x30
>> [ 422.214342] ? kasan_set_free_info+0x20/0x40
>> [ 422.214349] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
>> 91924fe1575bf49b9b37985ffde2c585d847446d]
>> [ 422.214386] kasan_report+0xab/0x120
>> [ 422.214394] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
>> 91924fe1575bf49b9b37985ffde2c585d847446d]
>> [ 422.214430] kasan_check_range+0xf6/0x1d0
>> [ 422.214436] memcpy+0x39/0x60
>> [ 422.214442] rtw_cmd_thread+0x1e8/0x430 [r8188eu
>> 91924fe1575bf49b9b37985ffde2c585d847446d]
>> [ 422.214479] ? rtw_setassocsta_cmdrsp_callback+0xd0/0xd0 [r8188eu
>> 91924fe1575bf49b9b37985ffde2c585d847446d]
>> [ 422.214516] kthread+0x15d/0x190
>> [ 422.214523] ? kthread_complete_and_exit+0x20/0x20
>> [ 422.214531] ret_from_fork+0x22/0x30
>> [ 422.214540] </TASK>
>
> Sorry, I am not familiar with KASAN. How should I interpret this output?
> I see the paragraph above has references to rtw_cmd_thread. I assume
> that is its way of indicating that rtw_cmd_thread is the cause of the
> problem, but the one below refers to other functions. I'm not sure where
> I should start looking. I would start looking at `rtw_sitesurvey_cmd` and
> `rtw_scan_ch_decision`, which call the memcpy on the
> rtw_ieee80211_channel structure, but they are not on the call trace.
>
drivers/staging/r8188eu/core/rtw_cmd.c:276: memcpy() call.
As Michael said the sizes of structures do not mach and the memcpy
writes below allocated buffer.
With regards,
Pavel Skripkin
On Sun, Apr 24, 2022 at 06:06:32PM +0300, Pavel Skripkin wrote:
> Hi Solomon,
>
> On 4/24/22 15:11, Solomon Tan wrote:
> > On Sun, Apr 24, 2022 at 12:00:12PM +0200, Michael Straube wrote:
> > > Hi,
> > >
> > > It looks like
> > > commit 0afaa121813e ("staging: r8188eu: use in-kernel ieee channel")
> > > intoduced a. See KASAN output below.
> > >
> > > That commit replaced the use of struct rtw_ieee80211_channel with struct
> > > ieee80211_channel.
> > >
> > > There are several calls to memcpy that used sizeof(struct
> > > rtw_ieee80211_channel)
> > > and now use sizeof(struct ieee80211_channel) but the sizes of these two
> > > structures are not equal.
> > >
> >
> > Oh no. When does this issue get triggered?
> >
> > > regards,
> > > Michael
> > >
> > > dmesg:
> > >
> > > ==================================================================
> > > [ 422.214237] BUG: KASAN: slab-out-of-bounds in rtw_cmd_thread+0x1e8/0x430
> > > [r8188eu]
> > > [ 422.214277] Write of size 3600 at addr ffff8881e149d200 by task
> > > RTW_CMD_THREAD/2563
> > >
> > > [ 422.214289] CPU: 11 PID: 2563 Comm: RTW_CMD_THREAD Tainted: G C OE
> > > 5.18.0-rc2-staging+ #47 94e3ca73bebf5b7fec506721475e4fff2a023bb9
> > > [ 422.214301] Hardware name: Gigabyte Technology Co., Ltd. B550M S2H/B550M
> > > S2H, BIOS F15a 02/16/2022
> > > [ 422.214309] Call Trace:
> > > [ 422.214313] <TASK>
> > > [ 422.214317] dump_stack_lvl+0x45/0x5b
> > > [ 422.214327] print_report.cold+0x5e/0x5dc
> > > [ 422.214335] ? kasan_set_track+0x21/0x30
> > > [ 422.214342] ? kasan_set_free_info+0x20/0x40
> > > [ 422.214349] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > [ 422.214386] kasan_report+0xab/0x120
> > > [ 422.214394] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > [ 422.214430] kasan_check_range+0xf6/0x1d0
> > > [ 422.214436] memcpy+0x39/0x60
> > > [ 422.214442] rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > [ 422.214479] ? rtw_setassocsta_cmdrsp_callback+0xd0/0xd0 [r8188eu
> > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > [ 422.214516] kthread+0x15d/0x190
> > > [ 422.214523] ? kthread_complete_and_exit+0x20/0x20
> > > [ 422.214531] ret_from_fork+0x22/0x30
> > > [ 422.214540] </TASK>
> >
> > Sorry, I am not familiar with KASAN. How should I interpret this output?
> > I see the paragraph above has references to rtw_cmd_thread. I assume
> > that is its way of indicating that rtw_cmd_thread is the cause of the
> > problem, but the one below refers to other functions. I'm not sure where
> > I should start looking. I would start looking at `rtw_sitesurvey_cmd` and
> > `rtw_scan_ch_decision`, which call the memcpy on the
> > rtw_ieee80211_channel structure, but they are not on the call trace.
> >
>
> drivers/staging/r8188eu/core/rtw_cmd.c:276: memcpy() call.
>
What git hash are you on? Is that the line:
memcpy(&psurveyPara->ch[i], &ch[i], sizeof(struct ieee80211_channel));
Are you sure that's the line which crashes? According to Smatch and my
simple grep that's dead code because "ch" is always NULL.
> As Michael said the sizes of structures do not mach and the memcpy writes
> below allocated buffer.
I feel a bit bad for not spotting this in review because I was looking
for that kind of bug. I still don't immediately spot where the bug is.
regards,
dan carpenter
On Mon, Apr 25, 2022 at 06:41:38PM +0300, Dan Carpenter wrote:
> On Sun, Apr 24, 2022 at 06:06:32PM +0300, Pavel Skripkin wrote:
> > Hi Solomon,
> >
> > On 4/24/22 15:11, Solomon Tan wrote:
> > > On Sun, Apr 24, 2022 at 12:00:12PM +0200, Michael Straube wrote:
> > > > Hi,
> > > >
> > > > It looks like
> > > > commit 0afaa121813e ("staging: r8188eu: use in-kernel ieee channel")
> > > > intoduced a. See KASAN output below.
> > > >
> > > > That commit replaced the use of struct rtw_ieee80211_channel with struct
> > > > ieee80211_channel.
> > > >
> > > > There are several calls to memcpy that used sizeof(struct
> > > > rtw_ieee80211_channel)
> > > > and now use sizeof(struct ieee80211_channel) but the sizes of these two
> > > > structures are not equal.
> > > >
> > >
> > > Oh no. When does this issue get triggered?
> > >
> > > > regards,
> > > > Michael
> > > >
> > > > dmesg:
> > > >
> > > > ==================================================================
> > > > [ 422.214237] BUG: KASAN: slab-out-of-bounds in rtw_cmd_thread+0x1e8/0x430
> > > > [r8188eu]
> > > > [ 422.214277] Write of size 3600 at addr ffff8881e149d200 by task
> > > > RTW_CMD_THREAD/2563
> > > >
> > > > [ 422.214289] CPU: 11 PID: 2563 Comm: RTW_CMD_THREAD Tainted: G C OE
> > > > 5.18.0-rc2-staging+ #47 94e3ca73bebf5b7fec506721475e4fff2a023bb9
> > > > [ 422.214301] Hardware name: Gigabyte Technology Co., Ltd. B550M S2H/B550M
> > > > S2H, BIOS F15a 02/16/2022
> > > > [ 422.214309] Call Trace:
> > > > [ 422.214313] <TASK>
> > > > [ 422.214317] dump_stack_lvl+0x45/0x5b
> > > > [ 422.214327] print_report.cold+0x5e/0x5dc
> > > > [ 422.214335] ? kasan_set_track+0x21/0x30
> > > > [ 422.214342] ? kasan_set_free_info+0x20/0x40
> > > > [ 422.214349] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > > [ 422.214386] kasan_report+0xab/0x120
> > > > [ 422.214394] ? rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > > [ 422.214430] kasan_check_range+0xf6/0x1d0
> > > > [ 422.214436] memcpy+0x39/0x60
> > > > [ 422.214442] rtw_cmd_thread+0x1e8/0x430 [r8188eu
> > > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > > [ 422.214479] ? rtw_setassocsta_cmdrsp_callback+0xd0/0xd0 [r8188eu
> > > > 91924fe1575bf49b9b37985ffde2c585d847446d]
> > > > [ 422.214516] kthread+0x15d/0x190
> > > > [ 422.214523] ? kthread_complete_and_exit+0x20/0x20
> > > > [ 422.214531] ret_from_fork+0x22/0x30
> > > > [ 422.214540] </TASK>
> > >
> > > Sorry, I am not familiar with KASAN. How should I interpret this output?
> > > I see the paragraph above has references to rtw_cmd_thread. I assume
> > > that is its way of indicating that rtw_cmd_thread is the cause of the
> > > problem, but the one below refers to other functions. I'm not sure where
> > > I should start looking. I would start looking at `rtw_sitesurvey_cmd` and
> > > `rtw_scan_ch_decision`, which call the memcpy on the
> > > rtw_ieee80211_channel structure, but they are not on the call trace.
> > >
> >
> > drivers/staging/r8188eu/core/rtw_cmd.c:276: memcpy() call.
> >
>
> What git hash are you on? Is that the line:
>
> memcpy(&psurveyPara->ch[i], &ch[i], sizeof(struct ieee80211_channel));
>
> Are you sure that's the line which crashes? According to Smatch and my
> simple grep that's dead code because "ch" is always NULL.
>
I don't think Pavel is referring to that line as it belongs to the
`rtw_sitesurvey_cmd` function. That func didnt appear in the dmesg output.
Rather I think Pavel refers to line 267, which is
`memcpy(pcmdbuf, pcmd->parmbuf, pcmd->cmdsz);` from function
`rtw_cmd_thread`. Changing rtw_ieee80211_channel to ieee80211_channel
must have messed up that line somewhere but I just can't figure out what
or why.
> > As Michael said the sizes of structures do not mach and the memcpy writes
> > below allocated buffer.
>
> I feel a bit bad for not spotting this in review because I was looking
> for that kind of bug. I still don't immediately spot where the bug is.
Sorry I put you in this position, Dan.
>
> regards,
> dan carpenter