Detect and handle invalid number of FATs

If the number of FATs field in the boot sector is zero, give
an appropriate error code.

Change-Id: I56545fb322a9d4c94aea8ddbd4879701617100e4
Signed-off-by: Sebastian Rasmussen <sebastian.rasmussen@stericsson.com>
Signed-off-by: Christian Bejram <christian.bejram@stericsson.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/boot.c b/boot.c
index 6e797fd..52bf011 100644
--- a/boot.c
+++ b/boot.c
@@ -205,6 +205,10 @@ readboot(dosfs, boot)
 		pfatal("Invalid sector size: %u", boot->BytesPerSec);
 		return FSFATAL;
 	}
+	if (boot->FATs == 0) {
+		pfatal("Invalid number of FATs: %u", boot->FATs);
+		return FSFATAL;
+	}
 	if (boot->Sectors) {
 		boot->HugeSectors = 0;
 		boot->NumSectors = boot->Sectors;