From: Randy Dunlap <rdunlap@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: Randy Dunlap <rdunlap@infradead.org>,
syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com,
Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
linux-input@vger.kernel.org
Subject: [PATCH] HID: core: detect and skip invalid inputs to snto32()
Date: Wed, 16 Dec 2020 17:12:21 -0800 [thread overview]
Message-ID: <20201217011221.25678-1-rdunlap@infradead.org> (raw)
Prevent invalid (0, 0) inputs to hid-core's snto32() function.
Maybe it is just the dummy device here that is causing this, but
there are hundreds of calls to snto32(0, 0). Having n (bits count)
of 0 is causing the current UBSAN trap with a shift value of
0xffffffff (-1, or n - 1 in this function).
Either of the value to shift being 0 or the bits count being 0 can be
handled by just returning 0 to the caller, avoiding the following
complex shift + OR operations:
return value & (1 << (n - 1)) ? value | (~0U << n) : value;
Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
---
drivers/hid/hid-core.c | 3 +++
1 file changed, 3 insertions(+)
--- lnx-510.orig/drivers/hid/hid-core.c
+++ lnx-510/drivers/hid/hid-core.c
@@ -1307,6 +1307,9 @@ EXPORT_SYMBOL_GPL(hid_open_report);
static s32 snto32(__u32 value, unsigned n)
{
+ if (!value || !n)
+ return 0;
+
switch (n) {
case 8: return ((__s8)value);
case 16: return ((__s16)value);
next reply other threads:[~2020-12-17 1:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 1:12 Randy Dunlap [this message]
2021-01-08 13:52 ` [PATCH] HID: core: detect and skip invalid inputs to snto32() Jiri Kosina
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201217011221.25678-1-rdunlap@infradead.org \
--to=rdunlap@infradead.org \
--cc=benjamin.tissoires@redhat.com \
--cc=jikos@kernel.org \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).