linux-media.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Sean Young <sean@mess.org>
To: syzbot <syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com>
Cc: andreyknvl@google.com, hans.verkuil@cisco.com,
	keescook@chromium.org, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
	mchehab@kernel.org, syzkaller-bugs@googlegroups.com
Subject: [PATCH] media: technisat-usb2: break out of loop at end of buffer
Date: Wed, 3 Jul 2019 15:52:39 +0100	[thread overview]
Message-ID: <20190703145239.ridwf2jegipnoxfz@gofer.mess.org> (raw)
In-Reply-To: <000000000000089d7f058683115e@google.com>

Ensure we do not access the buffer beyond the end if no 0xff byte
is encountered.

Reported-by: syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com
Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/usb/dvb-usb/technisat-usb2.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/technisat-usb2.c b/drivers/media/usb/dvb-usb/technisat-usb2.c
index c659e18b358b..676d233d46d5 100644
--- a/drivers/media/usb/dvb-usb/technisat-usb2.c
+++ b/drivers/media/usb/dvb-usb/technisat-usb2.c
@@ -608,10 +608,9 @@ static int technisat_usb2_frontend_attach(struct dvb_usb_adapter *a)
 static int technisat_usb2_get_ir(struct dvb_usb_device *d)
 {
 	struct technisat_usb2_state *state = d->priv;
-	u8 *buf = state->buf;
-	u8 *b;
-	int ret;
 	struct ir_raw_event ev;
+	u8 *buf = state->buf;
+	int i, ret;
 
 	buf[0] = GET_IR_DATA_VENDOR_REQUEST;
 	buf[1] = 0x08;
@@ -647,26 +646,25 @@ static int technisat_usb2_get_ir(struct dvb_usb_device *d)
 		return 0; /* no key pressed */
 
 	/* decoding */
-	b = buf+1;
 
 #if 0
 	deb_rc("RC: %d ", ret);
-	debug_dump(b, ret, deb_rc);
+	debug_dump(buf + 1, ret, deb_rc);
 #endif
 
 	ev.pulse = 0;
-	while (1) {
-		ev.pulse = !ev.pulse;
-		ev.duration = (*b * FIRMWARE_CLOCK_DIVISOR * FIRMWARE_CLOCK_TICK) / 1000;
-		ir_raw_event_store(d->rc_dev, &ev);
-
-		b++;
-		if (*b == 0xff) {
+	for (i = 1; i < ARRAY_SIZE(state->buf); i++) {
+		if (buf[i] == 0xff) {
 			ev.pulse = 0;
 			ev.duration = 888888*2;
 			ir_raw_event_store(d->rc_dev, &ev);
 			break;
 		}
+
+		ev.pulse = !ev.pulse;
+		ev.duration = (buf[i] * FIRMWARE_CLOCK_DIVISOR *
+			       FIRMWARE_CLOCK_TICK) / 1000;
+		ir_raw_event_store(d->rc_dev, &ev);
 	}
 
 	ir_raw_event_handle(d->rc_dev);
-- 
2.21.0


  parent reply	other threads:[~2019-07-03 14:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-14 20:06 KASAN: slab-out-of-bounds Read in technisat_usb2_rc_query syzbot
2019-07-02 14:02 ` [PATCH] media: usb: technisat-usb2: fix buffer overflow Phong Tran
2019-07-02 14:23   ` Alexander Potapenko
2019-07-02 16:03   ` Kees Cook
2019-07-03  2:14   ` [PATCH V2] " Phong Tran
2019-07-03  2:26     ` Kees Cook
2019-07-03 14:52 ` Sean Young [this message]
2019-07-03 16:54   ` [PATCH] media: technisat-usb2: break out of loop at end of buffer Kees Cook

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=20190703145239.ridwf2jegipnoxfz@gofer.mess.org \
    --to=sean@mess.org \
    --cc=andreyknvl@google.com \
    --cc=hans.verkuil@cisco.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=mchehab@kernel.org \
    --cc=syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --subject='Re: [PATCH] media: technisat-usb2: break out of loop at end of buffer' \
    /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

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).