linux-kernel - [PATCH 22/24] namei: trim the arguments of get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 20 Apr 2015 19:13:06 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Neil Brown <neilb@...e.de>, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: [PATCH 22/24] namei: trim the arguments of get_link()

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

same story as the previous commit

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 37 +++++++++++++++----------------------
 1 file changed, 15 insertions(+), 22 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index a8d6751..425986a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -878,10 +878,10 @@ static int may_linkat(struct path *link)
 	return -EPERM;
 }
 
-static __always_inline char *
-get_link(struct path *link, struct nameidata *nd, void **p)
+static __always_inline char *get_link(struct nameidata *nd, struct path *next)
 {
-	struct dentry *dentry = link->dentry;
+	struct saved *last = nd->stack + nd->depth;
+	struct dentry *dentry = next->dentry;
 	struct inode *inode = dentry->d_inode;
 	void *cookie;
 	int error;
@@ -889,8 +889,10 @@ get_link(struct path *link, struct nameidata *nd, void **p)
 
 	BUG_ON(nd->flags & LOOKUP_RCU);
 
-	if (link->mnt == nd->path.mnt)
-		mntget(link->mnt);
+	if (next->mnt == nd->path.mnt)
+		mntget(next->mnt);
+
+	last->link = *next;
 
 	res = ERR_PTR(-ELOOP);
 	if (unlikely(nd->total_link_count >= 40))
@@ -899,7 +901,7 @@ get_link(struct path *link, struct nameidata *nd, void **p)
 	cond_resched();
 	nd->total_link_count++;
 
-	touch_atime(link);
+	touch_atime(&last->link);
 	nd_set_link(NULL);
 
 	error = security_inode_follow_link(dentry);
@@ -914,16 +916,16 @@ get_link(struct path *link, struct nameidata *nd, void **p)
 
 	res = nd_get_link(nd);
 	if (!IS_ERR(res)) {
-		*p = cookie;
+		last->cookie = cookie;
 		return res;
 	}
 
 	if (inode->i_op->put_link)
 		inode->i_op->put_link(dentry, res, cookie);
 out:
-	*p = NULL;
+	last->cookie = NULL;
 	path_put(&nd->path);
-	path_put(link);
+	path_put(&last->link);
 	return res;
 }
 
@@ -931,12 +933,10 @@ static int follow_link(struct nameidata *nd, struct path *link)
 {
 	char *s;
 	int error = may_follow_link(link, nd);
-	struct saved *last = nd->stack + nd->depth;
 	if (unlikely(error))
 		return error;
 	nd->flags |= LOOKUP_PARENT;
-	last->link = *link;
-	s = get_link(&last->link, nd, &last->cookie);
+	s = get_link(nd, link);
 	if (unlikely(IS_ERR(s)))
 		return PTR_ERR(s);
 	if (unlikely(!s))
@@ -1779,7 +1779,6 @@ static inline u64 hash_name(const char *name)
  */
 static int link_path_walk(const char *name, struct nameidata *nd)
 {
-	struct saved *last = nd->stack;
 	struct path next;
 	int err;
 
@@ -1858,16 +1857,13 @@ Walked:
 
 			nd->depth++;
 			nd->link_count++;
-			last++;
 
-			last->link = next;
-			s = get_link(&last->link, nd, &last->cookie);
+			s = get_link(nd, &next);
 
 			if (unlikely(IS_ERR(s))) {
 				err = PTR_ERR(s);
 				nd->link_count--;
 				nd->depth--;
-				last--;
 				goto Err;
 			}
 			err = 0;
@@ -1876,7 +1872,6 @@ Walked:
 				put_link(nd);
 				nd->link_count--;
 				nd->depth--;
-				last--;
 			} else {
 				if (*s == '/') {
 					if (!nd->root.mnt)
@@ -1889,7 +1884,7 @@ Walked:
 						;
 				}
 				nd->inode = nd->path.dentry->d_inode;
-				last->name = name;
+				nd->stack[nd->depth].name = name;
 				if (!*s)
 					goto OK;
 				name = s;
@@ -1907,17 +1902,15 @@ Err:
 		put_link(nd);
 		nd->link_count--;
 		nd->depth--;
-		last--;
 	}
 	return err;
 OK:
 	if (unlikely(nd->depth)) {
-		name = last->name;
+		name = nd->stack[nd->depth].name;
 		err = walk_component(nd, &next, LOOKUP_FOLLOW);
 		put_link(nd);
 		nd->link_count--;
 		nd->depth--;
-		last--;
 		goto Walked;
 	}
 	return 0;
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/