Fixed integer overflow in block number calculation code.

git-svn-id: http://exfat.googlecode.com/svn/trunk@129 60bc1c72-a15a-11de-b98f-4500b42dc123

diff --git a/libexfat/cluster.c b/libexfat/cluster.c
index b53c31f..adebf30 100644 (file)
--- a/libexfat/cluster.c
+++ b/libexfat/cluster.c
@@ -29,12 +29,12 @@
 /*
  * Cluster to block.
  */
-static uint32_t c2b(const struct exfat* ef, cluster_t cluster)
+static off_t c2b(const struct exfat* ef, cluster_t cluster)
 {
        if (cluster < EXFAT_FIRST_DATA_CLUSTER)
                exfat_bug("invalid cluster number %u", cluster);
        return le32_to_cpu(ef->sb->cluster_block_start) +
-               ((cluster - EXFAT_FIRST_DATA_CLUSTER) << ef->sb->bpc_bits);
+               ((off_t) (cluster - EXFAT_FIRST_DATA_CLUSTER) << ef->sb->bpc_bits);
 }
 
 /*
@@ -42,7 +42,7 @@ static uint32_t c2b(const struct exfat* ef, cluster_t cluster)
  */
 off_t exfat_c2o(const struct exfat* ef, cluster_t cluster)
 {
-       return (off_t) c2b(ef, cluster) << ef->sb->block_bits;
+       return c2b(ef, cluster) << ef->sb->block_bits;
 }
 
 /*