X-Git-Url: https://git.sven.stormbind.net/?a=blobdiff_plain;f=libexfat%2Fmount.c;fp=libexfat%2Fmount.c;h=9a29cbecb0a78f02efbe06fc8d642b2d954dbb0d;hb=c8deb72613a42ecc828ed873fd8c6899e61658fd;hp=2ebf43625315701e99eba3a543250420a44ce60c;hpb=aadc44d1ba43437545f2fdbecf9374d8a6697682;p=sven%2Ffuse-exfat.git

diff --git a/libexfat/mount.c b/libexfat/mount.c
index 2ebf436..9a29cbe 100644
--- a/libexfat/mount.c
+++ b/libexfat/mount.c
@@ -30,23 +30,32 @@
 
 static uint64_t rootdir_size(const struct exfat* ef)
 {
-	uint64_t clusters = 0;
+	uint32_t clusters = 0;
+	uint32_t clusters_max = le32_to_cpu(ef->sb->cluster_count);
 	cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
 
-	while (!CLUSTER_INVALID(rootdir_cluster))
+	/* Iterate all clusters of the root directory to calculate its size.
+	   It can't be contiguous because there is no flag to indicate this. */
+	do
 	{
-		clusters++;
-		/* root directory cannot be contiguous because there is no flag
-		   to indicate this */
+		if (clusters == clusters_max) /* infinite loop detected */
+		{
+			exfat_error("root directory cannot occupy all %d clusters",
+					clusters);
+			return 0;
+		}
+		if (CLUSTER_INVALID(rootdir_cluster))
+		{
+			exfat_error("bad cluster %#x while reading root directory",
+					rootdir_cluster);
+			return 0;
+		}
 		rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
+		clusters++;
 	}
-	if (rootdir_cluster != EXFAT_CLUSTER_END)
-	{
-		exfat_error("bad cluster %#x while reading root directory",
-				rootdir_cluster);
-		return 0;
-	}
-	return clusters * CLUSTER_SIZE(*ef->sb);
+	while (rootdir_cluster != EXFAT_CLUSTER_END);
+
+	return (uint64_t) clusters * CLUSTER_SIZE(*ef->sb);
 }
 
 static const char* get_option(const char* options, const char* option_name)
@@ -208,6 +217,23 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 		exfat_error("exFAT file system is not found");
 		return -EIO;
 	}
+	/* sector cannot be smaller than 512 bytes */
+	if (ef->sb->sector_bits < 9)
+	{
+		exfat_close(ef->dev);
+		exfat_error("too small sector size: 2^%hhd", ef->sb->sector_bits);
+		free(ef->sb);
+		return -EIO;
+	}
+	/* officially exFAT supports cluster size up to 32 MB */
+	if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
+	{
+		exfat_close(ef->dev);
+		exfat_error("too big cluster size: 2^(%hhd+%hhd)",
+				ef->sb->sector_bits, ef->sb->spc_bits);
+		free(ef->sb);
+		return -EIO;
+	}
 	ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
 	if (ef->zero_cluster == NULL)
 	{
@@ -242,16 +268,6 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 		free(ef->sb);
 		return -EIO;
 	}
-	/* officially exFAT supports cluster size up to 32 MB */
-	if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
-	{
-		free(ef->zero_cluster);
-		exfat_close(ef->dev);
-		exfat_error("too big cluster size: 2^%d",
-				(int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
-		free(ef->sb);
-		return -EIO;
-	}
 	if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
 			exfat_get_size(ef->dev))
 	{