sysv: ensure fast symlinks are NUL-terminated

Ensure fast symlink targets are NUL-terminated, even if corrupted
on-disk.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/sysv/inode.c b/fs/sysv/inode.c
index df0d435baa48..3d81bf58dae2 100644
--- a/fs/sysv/inode.c
+++ b/fs/sysv/inode.c
@@ -27,6 +27,7 @@
 #include <linux/init.h>
 #include <linux/buffer_head.h>
 #include <linux/vfs.h>
+#include <linux/namei.h>
 #include <asm/byteorder.h>
 #include "sysv.h"
 
@@ -163,8 +164,11 @@ void sysv_set_inode(struct inode *inode, dev_t rdev)
                 if (inode->i_blocks) {
                         inode->i_op = &sysv_symlink_inode_operations;
                         inode->i_mapping->a_ops = &sysv_aops;
-                } else
+                } else {
                         inode->i_op = &sysv_fast_symlink_inode_operations;
+                        nd_terminate_link(SYSV_I(inode)->i_data, inode->i_size,
+                                sizeof(SYSV_I(inode)->i_data) - 1);
+                }
         } else
                 init_special_inode(inode, inode->i_mode, rdev);
 }