linux-kernel - [PATCH 02/11] uml - hostfs: fix double free

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Date:	Mon, 05 Mar 2007 21:49:00 +0100
From:	Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>
To:	Andrew Morton <akpm@...l.org>
Cc:	Jeff Dike <jdike@...toit.com>, linux-kernel@...r.kernel.org,
	user-mode-linux-devel@...ts.sourceforge.net
Subject: [PATCH 02/11] uml - hostfs: fix double free

From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>

Fix double free in the error path - when name is assigned into root_inode we do
not own it any more and we must not kfree() it - see patch for details.

Thanks to William Stearns for the initial report.

CC: William Stearns <wstearns@...ox.com>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>
---

 fs/hostfs/hostfs_kern.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index e965eb1..6f10e43 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -966,6 +966,9 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		goto out_put;
 
 	HOSTFS_I(root_inode)->host_filename = name;
+	/* Avoid that in the error path, iput(root_inode) frees again name through
+	 * hostfs_destroy_inode! */
+	name = NULL;
 
 	err = -ENOMEM;
 	sb->s_root = d_alloc_root(root_inode);
@@ -977,7 +980,7 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
                 /* No iput in this case because the dput does that for us */
                 dput(sb->s_root);
                 sb->s_root = NULL;
-		goto out_free;
+		goto out;
         }
 
 	return(0);


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