[v2.6.34-stable 126/165] hfs: add sanity check for file name length

[Paul Gortmaker]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit bc5b8a9003132ae44559edd63a1623b7b99dfb68 upstream.

On a corrupted file system the ->len field could be wrong leading to
a buffer overflow.

Reported-and-acked-by: Clement LECIGNE <clement.lecigne@xxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 fs/hfs/trans.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
index e673a88..b1ce4c7 100644
--- a/fs/hfs/trans.c
+++ b/fs/hfs/trans.c
@@ -40,6 +40,8 @@ int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in)
 
 	src = in->name;
 	srclen = in->len;
+	if (srclen > HFS_NAMELEN)
+		srclen = HFS_NAMELEN;
 	dst = out;
 	dstlen = HFS_MAX_NAMELEN;
 	if (nls_io) {
-- 
1.7.12.rc2

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