[PATCH v2] drm: return -EFAULT if copy_to_user() fails

Dan Carpenter
2019-06-18T13:20:12Z

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