From: Sven Hoexter <sven@stormbind.net>
Date: Thu, 5 Nov 2015 18:59:53 +0000 (+0100)
Subject: Add the fix for https://github.com/relan/exfat/issues/5 found and reported by The... 
X-Git-Tag: debian/1.1.0-2+deb8u1~2^2~2
X-Git-Url: https://git.sven.stormbind.net/?p=sven%2Ffuse-exfat.git;a=commitdiff_plain;h=170181399a026ca44aea0840b498dcff8a931b73

Add the fix for https://github.com/relan/exfat/issues/5 found and reported by The Fuzzing Project. Check sector and cluster size.
---

diff --git a/debian/changelog b/debian/changelog
index 5949e25..b3b2dde 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+fuse-exfat (1.1.0-2+deb8u1) UNRELEASED; urgency=medium
+
+  * Add the fix for https://github.com/relan/exfat/issues/5 found
+    and reported by The Fuzzing Project. Check sector and cluster size.
+
+ --
+
 fuse-exfat (1.1.0-2) unstable; urgency=low
 
   * Remove debian/watch - recent changes at Google code required
diff --git a/libexfat/mount.c b/libexfat/mount.c
index 2ebf436..2456187 100644
--- a/libexfat/mount.c
+++ b/libexfat/mount.c
@@ -208,6 +208,23 @@ 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 +259,6 @@ 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))
 	{