[patch] fs: NULL dereference in posix_acl_to_xattr()

Dan Carpenter
2014-02-14T09:05:49Z

This patch moves the dereference of "buffer" after the check for NULL.
The only place which passes a NULL parameter is gfs2_set_acl().

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 11c54fd51e16..9e363e41dacc 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -723,7 +723,7 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
void *buffer, size_t size)
{
posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
- posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
+ posix_acl_xattr_entry *ext_entry;
int real_size, n;

real_size = posix_acl_xattr_size(acl->a_count);
@@ -731,7 +731,8 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
return real_size;
if (real_size > size)
return -ERANGE;
-
+
+ ext_entry = ext_acl->a_entries;
ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);

for (n=0; n < acl->a_count; n++, ext_entry++) {