3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <j...@suse.cz>


[ Upstream commit abdc0eb06964fe1d2fea6dd1391b734d0590365d ]

When session starts beyond offset 2^31 the arithmetics in
udf_check_vsd() would overflow. Make sure the computation is done in
large enough type.

Reported-by: Cezary Sliwa <sl...@ifpan.edu.pl>
Signed-off-by: Jan Kara <j...@suse.cz>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 fs/udf/super.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -706,7 +706,7 @@ static loff_t udf_check_vsd(struct super
        else
                sectorsize = sb->s_blocksize;
 
-       sector += (sbi->s_session << sb->s_blocksize_bits);
+       sector += (((loff_t)sbi->s_session) << sb->s_blocksize_bits);
 
        udf_debug("Starting at sector %u (%ld byte sectors)\n",
                  (unsigned int)(sector >> sb->s_blocksize_bits),


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