From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Jan 2014 17:37:55 +0000 (-0500)
Subject: __dentry_path() fixes
X-Git-Tag: v3.14-rc1~78^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f6500801522c61782d4990fa1ad96154cb397cd4;p=kernel%2Fkernel-generic.git

__dentry_path() fixes

* we need to save the starting point for restarts
* reject pathologically short buffers outright

Spotted-by: Denys Vlasenko <dvlasenk@redhat.com>
Spotted-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/dcache.c b/fs/dcache.c
index fdbe230..265e0ce 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3116,19 +3116,22 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
+static char *__dentry_path(struct dentry *d, char *buf, int buflen)
 {
+	struct dentry *dentry;
 	char *end, *retval;
 	int len, seq = 0;
 	int error = 0;
 
+	if (buflen < 2)
+		goto Elong;
+
 	rcu_read_lock();
 restart:
+	dentry = d;
 	end = buf + buflen;
 	len = buflen;
 	prepend(&end, &len, "\0", 1);
-	if (buflen < 1)
-		goto Elong;
 	/* Get '/' right */
 	retval = end-1;
 	*retval = '/';