[PATCH 07/24] namei: expand nested_symlink() in its only caller

Al Viro
2015-04-20T18:19:58Z

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

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 61 +++++++++++++++++++++++--------------------------------------
1 file changed, 23 insertions(+), 38 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 4c6ce01f..a1f6271 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1632,43 +1632,6 @@ out_err:
}

/*
- * This limits recursive symlink follows to 8, while
- * limiting consecutive symlinks to 40.
- *
- * Without that kind of total limit, nasty chains of consecutive
- * symlinks can cause almost arbitrarily long lookups.
- */
-static inline int nested_symlink(struct path *path, struct nameidata *nd)
-{
- int res;
-
- if (unlikely(nd->link_count >= MAX_NESTED_LINKS)) {
- path_put_conditional(path, nd);
- path_put(&nd->path);
- return -ELOOP;
- }
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
-
- nd->depth++;
- nd->link_count++;
-
- do {
- struct path link = *path;
- void *cookie;
-
- res = follow_link(&link, nd, &cookie);
- if (res)
- break;
- res = walk_component(nd, path, LOOKUP_FOLLOW);
- put_link(nd, &link, cookie);
- } while (res > 0);
-
- nd->link_count--;
- nd->depth--;
- return res;
-}
-
-/*
* We can do the critical dentry name comparison and hashing
* operations one word at a time, but we are limited to:
*
@@ -1859,7 +1822,29 @@ static int link_path_walk(const char *name, struct nameidata *nd)
return err;

if (err) {
- err = nested_symlink(&next, nd);
+ if (unlikely(nd->link_count >= MAX_NESTED_LINKS)) {
+ path_put_conditional(&next, nd);
+ path_put(&nd->path);
+ return -ELOOP;
+ }
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
+
+ nd->depth++;
+ nd->link_count++;
+
+ do {
+ struct path link = next;
+ void *cookie;
+
+ err = follow_link(&link, nd, &cookie);
+ if (err)
+ break;
+ err = walk_component(nd, &next, LOOKUP_FOLLOW);
+ put_link(nd, &link, cookie);
+ } while (err > 0);
+
+ nd->link_count--;
+ nd->depth--;
if (err)
return err;
}
--
2.1.4