[PATCH] e2image: fix overflow in l2 table processing

[PATCH] e2image: fix overflow in l2 table processing

[Artem Blagodarenko]

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@cray.com>
Signed-off-by: Artem Blagodarenko <c17828@cray.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

Re: [PATCH] e2image: fix overflow in l2 table processing

[Theodore Ts'o]

On Thu, Apr 22, 2021 at 01:24:48AM -0400, Artem Blagodarenko wrote:
> 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@cray.com>
> Signed-off-by: Artem Blagodarenko <c17828@cray.com>
> HPE-bug-id: LUS-9368

Thanks, applied.

					- Ted