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From: Hans Petter Selasky <hps@selasky.org>
To: linux-media@vger.kernel.org
Subject: [PATCH] Make sure we parse really received data.
Date: Wed, 22 Dec 2021 11:46:55 +0100	[thread overview]
Message-ID: <06c00e24-cdad-8776-9fc1-2c0f3db5af9a@selasky.org> (raw)

Hi,

USB control requests may return less data than we ask for.
Found using valgrind and webcamd on FreeBSD.

==15522== Conditional jump or move depends on uninitialised value(s)
==15522==    at 0x662EF4: uvc_fixup_video_ctrl (uvc_video.c:135)
==15522==    by 0x662EF4: uvc_get_video_ctrl (uvc_video.c:297)
==15522==    by 0x6640B0: uvc_video_init (uvc_video.c:2078)
==15522==    by 0x65E79D: uvc_register_video (uvc_driver.c:2258)
==15522==    by 0x65E79D: uvc_register_terms (uvc_driver.c:2300)
==15522==    by 0x65E79D: uvc_register_chains (uvc_driver.c:2321)
==15522==    by 0x65E79D: uvc_probe (uvc_driver.c:2463)
==15522==    by 0x3C8F46: usb_linux_probe_p (linux_usb.c:449)
==15522==    by 0x75B4B2: main (webcamd.c:1021)
==15522==  Uninitialised value was created by a heap allocation
==15522==    at 0x4853844: malloc (in 
/usr/local/libexec/valgrind/vgpreload_memcheck-amd64-freebsd.so)
==15522==    by 0x3BC8A4: kmalloc (linux_func.c:1807)
==15522==    by 0x662C8C: uvc_get_video_ctrl (uvc_video.c:229)
==15522==    by 0x6640B0: uvc_video_init (uvc_video.c:2078)
==15522==    by 0x65E79D: uvc_register_video (uvc_driver.c:2258)
==15522==    by 0x65E79D: uvc_register_terms (uvc_driver.c:2300)
==15522==    by 0x65E79D: uvc_register_chains (uvc_driver.c:2321)
==15522==    by 0x65E79D: uvc_probe (uvc_driver.c:2463)
==15522==    by 0x3C8F46: usb_linux_probe_p (linux_usb.c:449)
==15522==    by 0x75B4B2: main (webcamd.c:1021)

Signed-off-by: Hans Petter Selasky <hps@selasky.org>
---
  drivers/media/usb/uvc/uvc_video.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c 
b/drivers/media/usb/uvc/uvc_video.c
index 9f37eaf28ce7..6233703f9a50 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -258,7 +258,11 @@ static int uvc_get_video_ctrl(struct uvc_streaming 
*stream,
  			query == UVC_GET_DEF)
  		return -EIO;

-	data = kmalloc(size, GFP_KERNEL);
+	/*
+	 * Make sure we parse really received data
+	 * by allocating a zeroed buffer.
+	 */
+	data = kzalloc(size, GFP_KERNEL);
  	if (data == NULL)
  		return -ENOMEM;

-- 
2.34.1

             reply	other threads:[~2021-12-22 10:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-22 10:46 Hans Petter Selasky [this message]
2021-12-23 19:09 ` [PATCH] Make sure we parse really received data Ricardo Ribalda
2021-12-31  9:59   ` Hans Petter Selasky
2022-01-03 15:18     ` Ricardo Ribalda
2022-01-03 16:03       ` Hans Petter Selasky

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