Add d/patches/check-sector-and-cluster-size. Fix for https://github.com/relan/exfat...

diff --git a/debian/changelog b/debian/changelog
index 37145bf1cea3b19b145b2ef78b3974927ac1cfa4..300f2e9f54ba8eb80928f8b4084a5f759baf1e5d 100644 (file)
--- a/debian/changelog
+++ b/debian/changelog
@@ -2,6 +2,9 @@ exfat-utils (1.1.0-3) UNRELEASED; urgency=medium
 
   * Add quilt to build-deps.
   * Add --with quilt to dh invocation in d/rules.
+  * Add d/patches/check-sector-and-cluster-size. Fix for
+    https://github.com/relan/exfat/issues/5 found and reported by
+    The Fuzzing Project.
 
  -- Sven Hoexter <hoexter@debian.org>  Thu, 29 Oct 2015 09:03:18 +0100
 

diff --git a/debian/patches/check-sector-and-cluster-size b/debian/patches/check-sector-and-cluster-size
new file mode 100644 (file)
index 0000000..98280d1
--- /dev/null
+++ b/debian/patches/check-sector-and-cluster-size
@@ -0,0 +1,48 @@
+Patch for https://github.com/relan/exfat/issues/5
+See also:
+https://blog.fuzzing-project.org/25-Heap-overflow-and-endless-loop-in-exfatfsck-exfat-utils.html
+Index: exfat-utils/libexfat/mount.c
+===================================================================
+--- exfat-utils.orig/libexfat/mount.c
++++ exfat-utils/libexfat/mount.c
+@@ -208,6 +208,23 @@ int exfat_mount(struct exfat* ef, const
+               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
+               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))
+       {

diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644 (file)
index 0000000..64264cf
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1 @@
+check-sector-and-cluster-size