<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/usb/misc/yurex.c, branch v6.8</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>usb: yurex: Fix inconsistent locking bug in yurex_read()</title>
<updated>2024-01-02T13:41:51+00:00</updated>
<author>
<name>Harshit Mogalapalli</name>
<email>harshit.m.mogalapalli@oracle.com</email>
</author>
<published>2023-12-19T06:36:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e7d3b9f28654dbfce7e09f8028210489adaf6a33'/>
<id>e7d3b9f28654dbfce7e09f8028210489adaf6a33</id>
<content type='text'>
Unlock before returning on the error path.

Fixes: 86b20af11e84 ("usb: yurex: Replace snprintf() with the safer scnprintf() variant")
Reported-by: Dan Carpenter &lt;error27@gmail.com&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Closes: https://lore.kernel.org/r/202312170252.3udgrIcP-lkp@intel.com/
Signed-off-by: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Link: https://lore.kernel.org/r/20231219063639.450994-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Unlock before returning on the error path.

Fixes: 86b20af11e84 ("usb: yurex: Replace snprintf() with the safer scnprintf() variant")
Reported-by: Dan Carpenter &lt;error27@gmail.com&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Closes: https://lore.kernel.org/r/202312170252.3udgrIcP-lkp@intel.com/
Signed-off-by: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Link: https://lore.kernel.org/r/20231219063639.450994-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: yurex: Replace snprintf() with the safer scnprintf() variant</title>
<updated>2023-12-15T12:55:30+00:00</updated>
<author>
<name>Lee Jones</name>
<email>lee@kernel.org</email>
</author>
<published>2023-12-13T16:42:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=86b20af11e84c26ae3fde4dcc4f490948e3f8035'/>
<id>86b20af11e84c26ae3fde4dcc4f490948e3f8035</id>
<content type='text'>
There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array.  However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it.  This misunderstanding has led to buffer-overruns
in the past.  It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases).  So let's
do that.

Whilst we're at it, let's define some magic numbers to increase
readability and ease of maintenance.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Cc: Tomoki Sekiyama &lt;tomoki.sekiyama@gmail.com&gt;
Signed-off-by: Lee Jones &lt;lee@kernel.org&gt;
Link: https://lore.kernel.org/r/20231213164246.1021885-9-lee@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array.  However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it.  This misunderstanding has led to buffer-overruns
in the past.  It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases).  So let's
do that.

Whilst we're at it, let's define some magic numbers to increase
readability and ease of maintenance.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Cc: Tomoki Sekiyama &lt;tomoki.sekiyama@gmail.com&gt;
Signed-off-by: Lee Jones &lt;lee@kernel.org&gt;
Link: https://lore.kernel.org/r/20231213164246.1021885-9-lee@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: yurex: fix control-URB timeout handling</title>
<updated>2020-12-28T14:47:06+00:00</updated>
<author>
<name>Johan Hovold</name>
<email>johan@kernel.org</email>
</author>
<published>2020-12-14T10:30:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=372c93131998c0622304bed118322d2a04489e63'/>
<id>372c93131998c0622304bed118322d2a04489e63</id>
<content type='text'>
Make sure to always cancel the control URB in write() so that it can be
reused after a timeout or spurious CMD_ACK.

Currently any further write requests after a timeout would fail after
triggering a WARN() in usb_submit_urb() when attempting to submit the
already active URB.

Reported-by: syzbot+e87ebe0f7913f71f2ea5@syzkaller.appspotmail.com
Fixes: 6bc235a2e24a ("USB: add driver for Meywa-Denki &amp; Kayac YUREX")
Cc: stable &lt;stable@vger.kernel.org&gt;     # 2.6.37
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Make sure to always cancel the control URB in write() so that it can be
reused after a timeout or spurious CMD_ACK.

Currently any further write requests after a timeout would fail after
triggering a WARN() in usb_submit_urb() when attempting to submit the
already active URB.

Reported-by: syzbot+e87ebe0f7913f71f2ea5@syzkaller.appspotmail.com
Fixes: 6bc235a2e24a ("USB: add driver for Meywa-Denki &amp; Kayac YUREX")
Cc: stable &lt;stable@vger.kernel.org&gt;     # 2.6.37
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: Fix fall-through warnings for Clang</title>
<updated>2020-11-23T16:46:01+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavoars@kernel.org</email>
</author>
<published>2020-11-20T18:40:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=93c747ed00c1c74316645f7761f0cdb3f3d3952d'/>
<id>93c747ed00c1c74316645f7761f0cdb3f3d3952d</id>
<content type='text'>
In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break/return/fallthrough
statements instead of letting the code fall through to the next
case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/a76da7ca5b4f41c13d27b298accb8222d0b04e61.1605896060.git.gustavoars@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break/return/fallthrough
statements instead of letting the code fall through to the next
case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/a76da7ca5b4f41c13d27b298accb8222d0b04e61.1605896060.git.gustavoars@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge 5.9-rc3 into usb-next</title>
<updated>2020-08-31T05:11:45+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2020-08-31T05:11:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5fedf0d295d3ef69fd85fdee4cb68fd3756b54c2'/>
<id>5fedf0d295d3ef69fd85fdee4cb68fd3756b54c2</id>
<content type='text'>
We want the USB fixes in here as well.

Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We want the USB fixes in here as well.

Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: yurex: remove needless check before usb_free_coherent()</title>
<updated>2020-08-18T10:12:58+00:00</updated>
<author>
<name>Xu Wang</name>
<email>vulab@iscas.ac.cn</email>
</author>
<published>2020-08-10T02:08:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4d671957d45346decb1a9d488921cf90c19e0d0f'/>
<id>4d671957d45346decb1a9d488921cf90c19e0d0f</id>
<content type='text'>
usb_free_coherent() is safe with NULL addr and this check is
not required.

Signed-off-by: Xu Wang &lt;vulab@iscas.ac.cn&gt;
Link: https://lore.kernel.org/r/20200810020802.9082-1-vulab@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
usb_free_coherent() is safe with NULL addr and this check is
not required.

Signed-off-by: Xu Wang &lt;vulab@iscas.ac.cn&gt;
Link: https://lore.kernel.org/r/20200810020802.9082-1-vulab@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: yurex: Fix bad gfp argument</title>
<updated>2020-08-18T09:48:57+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2020-08-10T18:29:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f176ede3a3bde5b398a6777a7f9ff091baa2d3ff'/>
<id>f176ede3a3bde5b398a6777a7f9ff091baa2d3ff</id>
<content type='text'>
The syzbot fuzzer identified a bug in the yurex driver: It passes
GFP_KERNEL as a memory-allocation flag to usb_submit_urb() at a time
when its state is TASK_INTERRUPTIBLE, not TASK_RUNNING:

do not call blocking ops when !TASK_RUNNING; state=1 set at [&lt;00000000370c7c68&gt;] prepare_to_wait+0xb1/0x2a0 kernel/sched/wait.c:247
WARNING: CPU: 1 PID: 340 at kernel/sched/core.c:7253 __might_sleep+0x135/0x190
kernel/sched/core.c:7253
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 340 Comm: syz-executor677 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xf6/0x16e lib/dump_stack.c:118
 panic+0x2aa/0x6e1 kernel/panic.c:231
 __warn.cold+0x20/0x50 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x41/0x80 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:__might_sleep+0x135/0x190 kernel/sched/core.c:7253
Code: 65 48 8b 1c 25 40 ef 01 00 48 8d 7b 10 48 89 fe 48 c1 ee 03 80 3c 06 00 75
2b 48 8b 73 10 48 c7 c7 e0 9e 06 86 e8 ed 12 f6 ff &lt;0f&gt; 0b e9 46 ff ff ff e8 1f
b2 4b 00 e9 29 ff ff ff e8 15 b2 4b 00
RSP: 0018:ffff8881cdb77a28 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881c6458000 RCX: 0000000000000000
RDX: ffff8881c6458000 RSI: ffffffff8129ec93 RDI: ffffed1039b6ef37
RBP: ffffffff86fdade2 R08: 0000000000000001 R09: ffff8881db32f54f
R10: 0000000000000000 R11: 0000000030343354 R12: 00000000000001f2
R13: 0000000000000000 R14: 0000000000000068 R15: ffffffff83c1b1aa
 slab_pre_alloc_hook.constprop.0+0xea/0x200 mm/slab.h:498
 slab_alloc_node mm/slub.c:2816 [inline]
 slab_alloc mm/slub.c:2900 [inline]
 kmem_cache_alloc_trace+0x46/0x220 mm/slub.c:2917
 kmalloc include/linux/slab.h:554 [inline]
 dummy_urb_enqueue+0x7a/0x880 drivers/usb/gadget/udc/dummy_hcd.c:1251
 usb_hcd_submit_urb+0x2b2/0x22d0 drivers/usb/core/hcd.c:1547
 usb_submit_urb+0xb4e/0x13e0 drivers/usb/core/urb.c:570
 yurex_write+0x3ea/0x820 drivers/usb/misc/yurex.c:495

This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL.

Reported-and-tested-by: syzbot+c2c3302f9c601a4b1be2@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200810182954.GB307778@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The syzbot fuzzer identified a bug in the yurex driver: It passes
GFP_KERNEL as a memory-allocation flag to usb_submit_urb() at a time
when its state is TASK_INTERRUPTIBLE, not TASK_RUNNING:

do not call blocking ops when !TASK_RUNNING; state=1 set at [&lt;00000000370c7c68&gt;] prepare_to_wait+0xb1/0x2a0 kernel/sched/wait.c:247
WARNING: CPU: 1 PID: 340 at kernel/sched/core.c:7253 __might_sleep+0x135/0x190
kernel/sched/core.c:7253
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 340 Comm: syz-executor677 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xf6/0x16e lib/dump_stack.c:118
 panic+0x2aa/0x6e1 kernel/panic.c:231
 __warn.cold+0x20/0x50 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x41/0x80 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:__might_sleep+0x135/0x190 kernel/sched/core.c:7253
Code: 65 48 8b 1c 25 40 ef 01 00 48 8d 7b 10 48 89 fe 48 c1 ee 03 80 3c 06 00 75
2b 48 8b 73 10 48 c7 c7 e0 9e 06 86 e8 ed 12 f6 ff &lt;0f&gt; 0b e9 46 ff ff ff e8 1f
b2 4b 00 e9 29 ff ff ff e8 15 b2 4b 00
RSP: 0018:ffff8881cdb77a28 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881c6458000 RCX: 0000000000000000
RDX: ffff8881c6458000 RSI: ffffffff8129ec93 RDI: ffffed1039b6ef37
RBP: ffffffff86fdade2 R08: 0000000000000001 R09: ffff8881db32f54f
R10: 0000000000000000 R11: 0000000030343354 R12: 00000000000001f2
R13: 0000000000000000 R14: 0000000000000068 R15: ffffffff83c1b1aa
 slab_pre_alloc_hook.constprop.0+0xea/0x200 mm/slab.h:498
 slab_alloc_node mm/slub.c:2816 [inline]
 slab_alloc mm/slub.c:2900 [inline]
 kmem_cache_alloc_trace+0x46/0x220 mm/slub.c:2917
 kmalloc include/linux/slab.h:554 [inline]
 dummy_urb_enqueue+0x7a/0x880 drivers/usb/gadget/udc/dummy_hcd.c:1251
 usb_hcd_submit_urb+0x2b2/0x22d0 drivers/usb/core/hcd.c:1547
 usb_submit_urb+0xb4e/0x13e0 drivers/usb/core/urb.c:570
 yurex_write+0x3ea/0x820 drivers/usb/misc/yurex.c:495

This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL.

Reported-and-tested-by: syzbot+c2c3302f9c601a4b1be2@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200810182954.GB307778@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: Use fallthrough pseudo-keyword</title>
<updated>2020-07-10T06:55:17+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavoars@kernel.org</email>
</author>
<published>2020-07-07T19:56:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0d9b6d49fe39bd397f1d5913b1bfb8c4fdef0255'/>
<id>0d9b6d49fe39bd397f1d5913b1bfb8c4fdef0255</id>
<content type='text'>
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/20200707195607.GA4198@embeddedor
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/20200707195607.GA4198@embeddedor
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: yurex: fix NULL-derefs on disconnect</title>
<updated>2019-10-10T12:24:06+00:00</updated>
<author>
<name>Johan Hovold</name>
<email>johan@kernel.org</email>
</author>
<published>2019-10-09T15:38:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=aafb00a977cf7d81821f7c9d12e04c558c22dc3c'/>
<id>aafb00a977cf7d81821f7c9d12e04c558c22dc3c</id>
<content type='text'>
The driver was using its struct usb_interface pointer as an inverted
disconnected flag, but was setting it to NULL without making sure all
code paths that used it were done with it.

Before commit ef61eb43ada6 ("USB: yurex: Fix protection fault after
device removal") this included the interrupt-in completion handler, but
there are further accesses in dev_err and dev_dbg statements in
yurex_write() and the driver-data destructor (sic!).

Fix this by unconditionally stopping also the control URB at disconnect
and by using a dedicated disconnected flag.

Note that we need to take a reference to the struct usb_interface to
avoid a use-after-free in the destructor whenever the device was
disconnected while the character device was still open.

Fixes: aadd6472d904 ("USB: yurex.c: remove dbg() usage")
Fixes: 45714104b9e8 ("USB: yurex.c: remove err() usage")
Cc: stable &lt;stable@vger.kernel.org&gt;     # 3.5: ef61eb43ada6
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Link: https://lore.kernel.org/r/20191009153848.8664-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The driver was using its struct usb_interface pointer as an inverted
disconnected flag, but was setting it to NULL without making sure all
code paths that used it were done with it.

Before commit ef61eb43ada6 ("USB: yurex: Fix protection fault after
device removal") this included the interrupt-in completion handler, but
there are further accesses in dev_err and dev_dbg statements in
yurex_write() and the driver-data destructor (sic!).

Fix this by unconditionally stopping also the control URB at disconnect
and by using a dedicated disconnected flag.

Note that we need to take a reference to the struct usb_interface to
avoid a use-after-free in the destructor whenever the device was
disconnected while the character device was still open.

Fixes: aadd6472d904 ("USB: yurex.c: remove dbg() usage")
Fixes: 45714104b9e8 ("USB: yurex.c: remove err() usage")
Cc: stable &lt;stable@vger.kernel.org&gt;     # 3.5: ef61eb43ada6
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Link: https://lore.kernel.org/r/20191009153848.8664-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: yurex: Don't retry on unexpected errors</title>
<updated>2019-10-04T09:02:59+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2019-09-17T16:47:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=32a0721c6620b77504916dac0cea8ad497c4878a'/>
<id>32a0721c6620b77504916dac0cea8ad497c4878a</id>
<content type='text'>
According to Greg KH, it has been generally agreed that when a USB
driver encounters an unknown error (or one it can't handle directly),
it should just give up instead of going into a potentially infinite
retry loop.

The three codes -EPROTO, -EILSEQ, and -ETIME fall into this category.
They can be caused by bus errors such as packet loss or corruption,
attempting to communicate with a disconnected device, or by malicious
firmware.  Nowadays the extent of packet loss or corruption is
negligible, so it should be safe for a driver to give up whenever one
of these errors occurs.

Although the yurex driver handles -EILSEQ errors in this way, it
doesn't do the same for -EPROTO (as discovered by the syzbot fuzzer)
or other unrecognized errors.  This patch adjusts the driver so that
it doesn't log an error message for -EPROTO or -ETIME, and it doesn't
retry after any errors.

Reported-and-tested-by: syzbot+b24d736f18a1541ad550@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Tomoki Sekiyama &lt;tomoki.sekiyama@gmail.com&gt;
CC: &lt;stable@vger.kernel.org&gt;

Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1909171245410.1590-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
According to Greg KH, it has been generally agreed that when a USB
driver encounters an unknown error (or one it can't handle directly),
it should just give up instead of going into a potentially infinite
retry loop.

The three codes -EPROTO, -EILSEQ, and -ETIME fall into this category.
They can be caused by bus errors such as packet loss or corruption,
attempting to communicate with a disconnected device, or by malicious
firmware.  Nowadays the extent of packet loss or corruption is
negligible, so it should be safe for a driver to give up whenever one
of these errors occurs.

Although the yurex driver handles -EILSEQ errors in this way, it
doesn't do the same for -EPROTO (as discovered by the syzbot fuzzer)
or other unrecognized errors.  This patch adjusts the driver so that
it doesn't log an error message for -EPROTO or -ETIME, and it doesn't
retry after any errors.

Reported-and-tested-by: syzbot+b24d736f18a1541ad550@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Tomoki Sekiyama &lt;tomoki.sekiyama@gmail.com&gt;
CC: &lt;stable@vger.kernel.org&gt;

Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1909171245410.1590-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
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