[PATCH 3.2 060/221] autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation

Ben Hutchings
2015-05-05T01:43:12Z

From: Al Viro <viro@zeniv.linux.org.uk>

commit 0a280962dc6e117e0e4baa668453f753579265d9 upstream.

X-Coverup: just ask spender
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/autofs4/dev-ioctl.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -95,7 +95,7 @@ static int check_dev_ioctl_version(int c
*/
static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
{
- struct autofs_dev_ioctl tmp;
+ struct autofs_dev_ioctl tmp, *res;

if (copy_from_user(&tmp, in, sizeof(tmp)))
return ERR_PTR(-EFAULT);
@@ -106,7 +106,11 @@ static struct autofs_dev_ioctl *copy_dev
if (tmp.size > (PATH_MAX + sizeof(tmp)))
return ERR_PTR(-ENAMETOOLONG);

- return memdup_user(in, tmp.size);
+ res = memdup_user(in, tmp.size);
+ if (!IS_ERR(res))
+ res->size = tmp.size;
+
+ return res;
}

static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)