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Subject[ 04/52] dm verity: fix overflow check
Date
3.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Mikulas Patocka <mpatocka@redhat.com>

commit 1d55f6bcc0331d744cd5b56c4ee79e3809438161 upstream.

This patch fixes sector_t overflow checking in dm-verity.

Without this patch, the code checks for overflow only if sector_t is
smaller than long long, not if sector_t and long long have the same size.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-verity.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -718,8 +718,8 @@ static int verity_ctr(struct dm_target *
v->hash_dev_block_bits = ffs(num) - 1;

if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
- num_ll << (v->data_dev_block_bits - SECTOR_SHIFT) !=
- (sector_t)num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) {
+ (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
+ >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
ti->error = "Invalid data blocks";
r = -EINVAL;
goto bad;
@@ -733,8 +733,8 @@ static int verity_ctr(struct dm_target *
}

if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 ||
- num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT) !=
- (sector_t)num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) {
+ (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
+ >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
ti->error = "Invalid hash start";
r = -EINVAL;
goto bad;



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