linux-kernel - [PATCH] drivers/media/dvb-core: copy user arrays safely

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Message-ID: <20231102191633.52592-2-pstanner@redhat.com>
Date:   Thu,  2 Nov 2023 20:16:34 +0100
From:   Philipp Stanner <pstanner@...hat.com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Robert Schlabbach <robert_s@....net>,
        Takashi Iwai <tiwai@...e.de>, Hyunwoo Kim <imv4bel@...il.com>,
        Lin Ma <linma@....edu.cn>,
        Chen Zhongjin <chenzhongjin@...wei.com>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Philipp Stanner <pstanner@...hat.com>,
        Dave Airlie <airlied@...hat.com>
Subject: [PATCH] drivers/media/dvb-core: copy user arrays safely

At several positions in dvb_frontend.c, memdup_user() is utilized to
copy userspace arrays. This is done without overflow checks.

Use the new wrapper memdup_array_user() to copy the arrays more safely.

Suggested-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Philipp Stanner <pstanner@...hat.com>
---
 drivers/media/dvb-core/dvb_frontend.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 9293b058ab99..93d3378a0df4 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -2168,7 +2168,8 @@ static int dvb_frontend_handle_compat_ioctl(struct file *file, unsigned int cmd,
 		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
 			return -EINVAL;
 
-		tvp = memdup_user(compat_ptr(tvps->props), tvps->num * sizeof(*tvp));
+		tvp = memdup_array_user(compat_ptr(tvps->props),
+					tvps->num, sizeof(*tvp));
 		if (IS_ERR(tvp))
 			return PTR_ERR(tvp);
 
@@ -2199,7 +2200,8 @@ static int dvb_frontend_handle_compat_ioctl(struct file *file, unsigned int cmd,
 		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
 			return -EINVAL;
 
-		tvp = memdup_user(compat_ptr(tvps->props), tvps->num * sizeof(*tvp));
+		tvp = memdup_array_user(compat_ptr(tvps->props),
+					tvps->num, sizeof(*tvp));
 		if (IS_ERR(tvp))
 			return PTR_ERR(tvp);
 
@@ -2379,7 +2381,8 @@ static int dvb_get_property(struct dvb_frontend *fe, struct file *file,
 	if (!tvps->num || tvps->num > DTV_IOCTL_MAX_MSGS)
 		return -EINVAL;
 
-	tvp = memdup_user((void __user *)tvps->props, tvps->num * sizeof(*tvp));
+	tvp = memdup_array_user((void __user *)tvps->props,
+				tvps->num, sizeof(*tvp));
 	if (IS_ERR(tvp))
 		return PTR_ERR(tvp);
 
@@ -2457,7 +2460,8 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
 			return -EINVAL;
 
-		tvp = memdup_user((void __user *)tvps->props, tvps->num * sizeof(*tvp));
+		tvp = memdup_array_user((void __user *)tvps->props,
+					tvps->num, sizeof(*tvp));
 		if (IS_ERR(tvp))
 			return PTR_ERR(tvp);
 
-- 
2.41.0