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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        Dave Kleikamp <dave.kleikamp@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 105/247] fs/jfs: fix potential integer overflow on shift of a int
Date:   Mon,  1 Mar 2021 17:12:05 +0100
Message-Id: <20210301161036.812542682@linuxfoundation.org>
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From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 4208c398aae4c2290864ba15c3dab7111f32bec1 ]

The left shift of int 32 bit integer constant 1 is evaluated using 32 bit
arithmetic and then assigned to a signed 64 bit integer. In the case where
l2nb is 32 or more this can lead to an overflow.  Avoid this by shifting
the value 1LL instead.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: b40c2e665cd5 ("fs/jfs: TRIM support for JFS Filesystem")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/jfs/jfs_dmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 49263e220dbcf..687b07b9b4f62 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -1669,7 +1669,7 @@ s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
 		} else if (rc == -ENOSPC) {
 			/* search for next smaller log2 block */
 			l2nb = BLKSTOL2(nblocks) - 1;
-			nblocks = 1 << l2nb;
+			nblocks = 1LL << l2nb;
 		} else {
 			/* Trim any already allocated blocks */
 			jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
-- 
2.27.0