commit: 1d55f6bcc0331d744cd5b56c4ee79e3809438161
From: Mikulas Patocka <[email protected]>
Date: Wed, 26 Sep 2012 23:45:48 +0100
Subject: dm verity: fix overflow check

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 <[email protected]>
Cc: [email protected]
Signed-off-by: Alasdair G Kergon <[email protected]>
---
 drivers/md/dm-verity.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 254d192..892ae27 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -718,8 +718,8 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, 
char **argv)
        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 *ti, unsigned argc, 
char **argv)
        }
 
        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;
-- 
1.7.3.4
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