linux-ext4 - [PATCH] e2image: fix overflow in l2 table processing

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Message-Id: <20210422052448.29802-1-artem.blagodarenko@gmail.com>
Date:   Thu, 22 Apr 2021 01:24:48 -0400
From:   Artem Blagodarenko <artem.blagodarenko@...il.com>
To:     linux-ext4@...r.kernel.org
Cc:     adilger.kernel@...ger.ca,
        Artem Blagodarenko <artem.blagodarenko@...il.com>,
        Alexey Lyashkov <c17817@...y.com>,
        Artem Blagodarenko <c17828@...y.com>
Subject: [PATCH] e2image: fix overflow in l2 table processing

For a large partition during e2image capture process
it is possible to overflow offset at multiply operation.
This leads to the situation when data is written to the
position at the start of the image instead of the image end.

Let's use the right cast to avoid integer overflow.

Signed-off-by: Alexey Lyashkov <c17817@...y.com>
Signed-off-by: Artem Blagodarenko <c17828@...y.com>
HPE-bug-id: LUS-9368
---
 lib/ext2fs/qcow2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/ext2fs/qcow2.c b/lib/ext2fs/qcow2.c
index ee701f7a..20824170 100644
--- a/lib/ext2fs/qcow2.c
+++ b/lib/ext2fs/qcow2.c
@@ -238,7 +238,7 @@ int qcow2_write_raw_image(int qcow2_fd, int raw_fd,
 			if (offset == 0)
 				continue;
 
-			off_out = (l1_index * img.l2_size) +
+			off_out = ((__u64)l1_index * img.l2_size) +
 				  l2_index;
 			off_out <<= img.cluster_bits;
 			ret = qcow2_copy_data(qcow2_fd, raw_fd, offset,
-- 
2.18.4