svn commit: r336236 - head/sbin/fsck_msdosfs

[Xin LI]

Author: delphij
Date: Fri Jul 13 02:02:16 2018
New Revision: 336236
URL: https://svnweb.freebsd.org/changeset/base/336236

Log:
  Detect and handle invalid number of FATs
  
  If the number of FATs field in the boot sector is zero, give
  an appropriate error code.
  
  Obtained from:	Android https://android.googlesource.com/platform/external/fsck_msdos/+/6c29bbe8d58e6fe8755935a04166ecf82ff31f47%5E%21/
  MFC after:	2 weeks

Modified:
  head/sbin/fsck_msdosfs/boot.c

Modified: head/sbin/fsck_msdosfs/boot.c
==============================================================================
--- head/sbin/fsck_msdosfs/boot.c	Fri Jul 13 00:37:47 2018	(r336235)
+++ head/sbin/fsck_msdosfs/boot.c	Fri Jul 13 02:02:16 2018	(r336236)
@@ -87,6 +87,10 @@ readboot(int dosfs, struct bootblock *boot)
 		pfatal("Invalid sector size: %u", boot->bpbBytesPerSec);
 		return FSFATAL;
 	}
+	if (boot->bpbFATs == 0) {
+		pfatal("Invalid number of FATs: %u", boot->bpbFATs);
+		return FSFATAL;
+	}
 	if (!boot->bpbRootDirEnts)
 		boot->flags |= FAT32;
 	if (boot->flags & FAT32) {