linux-kernel - [PATCH v3 063/110] namei: we never need more than MAXSYMLINKS entries in nd->stack

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Message-Id: <1431367690-5223-63-git-send-email-viro@ZenIV.linux.org.uk>
Date:	Mon, 11 May 2015 19:07:23 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Neil Brown <neilb@...e.de>, Christoph Hellwig <hch@...radead.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v3 063/110] namei: we never need more than MAXSYMLINKS entries in nd->stack

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

The only reason why we needed one more was that purely nested
MAXSYMLINKS symlinks could lead to path_init() using that many
entries in addition to nd->stack[0] which it left unused.

That can't happen now - path_init() starts with entry 0 (and
trailing_symlink() is called only when we'd already encountered
one symlink, so no more than MAXSYMLINKS-1 are left).

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index d12b16c..b939f48 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -528,7 +528,7 @@ static void restore_nameidata(struct nameidata *nd)
 
 static int __nd_alloc_stack(struct nameidata *nd)
 {
-	struct saved *p = kmalloc((MAXSYMLINKS + 1) * sizeof(struct saved),
+	struct saved *p = kmalloc(MAXSYMLINKS * sizeof(struct saved),
 				  GFP_KERNEL);
 	if (unlikely(!p))
 		return -ENOMEM;
-- 
2.1.4

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