linux-kernel - [PATCH] eCryptfs: Regression in unencrypted filename symlinks

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Message-ID: <20090207000649.GA10560@boomer>
Date:	Fri, 6 Feb 2009 18:06:51 -0600
From:	Tyler Hicks <tyhicks@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dave Kleikamp <shaggy@...ux.vnet.ibm.com>
Subject: [PATCH] eCryptfs: Regression in unencrypted filename symlinks

The addition of filename encryption caused a regression in unencrypted
filename symlink support.  ecryptfs_copy_filename() is used when dealing
with unencrypted filenames and it reported that the new, copied filename
was a character longer than it should have been.

This caused the return value of readlink() to count the NULL byte of the
symlink target.  Most applications don't care about the extra NULL byte,
but a version control system (bzr) helped in discovering the bug.

Signed-off-by: Tyler Hicks <tyhicks@...ux.vnet.ibm.com>
---
 fs/ecryptfs/crypto.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index c01e043..f6caeb1 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1716,7 +1716,7 @@ static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
 {
 	int rc = 0;
 
-	(*copied_name) = kmalloc((name_size + 2), GFP_KERNEL);
+	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
 	if (!(*copied_name)) {
 		rc = -ENOMEM;
 		goto out;
@@ -1726,7 +1726,7 @@ static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
 						 * in printing out the
 						 * string in debug
 						 * messages */
-	(*copied_name_size) = (name_size + 1);
+	(*copied_name_size) = name_size;
 out:
 	return rc;
 }
-- 
1.5.3.7

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