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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>,
	kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
	Sean Paul <sean@poorly.run>
Subject: [PATCH v2] drm: return -EFAULT if copy_to_user() fails
Date: Tue, 18 Jun 2019 13:18:43 +0000	[thread overview]
Message-ID: <20190618131843.GA29463@mwanda> (raw)
In-Reply-To: <20190618125623.GA24896@mwanda>

The copy_from_user() function returns the number of bytes remaining
to be copied but we want to return a negative error code.  Otherwise
the callers treat it as a successful copy.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: The first version was missing a chunk

 drivers/gpu/drm/drm_bufs.c  | 5 ++++-
 drivers/gpu/drm/drm_ioc32.c | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 68dacf8422c6..8ce9d73fab4f 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -1351,7 +1351,10 @@ static int copy_one_buf(void *data, int count, struct drm_buf_entry *from)
 				 .size = from->buf_size,
 				 .low_mark = from->low_mark,
 				 .high_mark = from->high_mark};
-	return copy_to_user(to, &v, offsetof(struct drm_buf_desc, flags));
+
+	if (copy_to_user(to, &v, offsetof(struct drm_buf_desc, flags)))
+		return -EFAULT;
+	return 0;
 }
 
 int drm_legacy_infobufs(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c
index 586aa28024c5..a16b6dc2fa47 100644
--- a/drivers/gpu/drm/drm_ioc32.c
+++ b/drivers/gpu/drm/drm_ioc32.c
@@ -378,7 +378,10 @@ static int copy_one_buf32(void *data, int count, struct drm_buf_entry *from)
 			      .size = from->buf_size,
 			      .low_mark = from->low_mark,
 			      .high_mark = from->high_mark};
-	return copy_to_user(to + count, &v, offsetof(drm_buf_desc32_t, flags));
+
+	if (copy_to_user(to + count, &v, offsetof(drm_buf_desc32_t, flags)))
+		return -EFAULT;
+	return 0;
 }
 
 static int drm_legacy_infobufs32(struct drm_device *dev, void *data,
-- 
2.20.1

  parent reply	other threads:[~2019-06-18 13:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-18 12:56 [PATCH] drm: return -EFAULT if copy_one_buf() fails Dan Carpenter
2019-06-18 12:58 ` Dan Carpenter
2019-06-18 13:18 ` Dan Carpenter [this message]
2019-06-18 17:16   ` [PATCH v2] drm: return -EFAULT if copy_to_user() fails Sean Paul
2019-06-25 23:18     ` Al Viro
2019-06-25 23:17 ` [PATCH] drm: return -EFAULT if copy_one_buf() fails Al Viro

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