g10: Fix out-of-bounds read.

* g10/armor.c (use_armor_filter): We need two bytes for 'is_armored'.

Signed-off-by: Justus Winter <justus@g10code.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/g10/armor.c b/g10/armor.c
index fb7465595..e4503b8b4 100644
--- a/g10/armor.c
+++ b/g10/armor.c
@@ -274,15 +274,17 @@ is_armored( const byte *buf )
 int
 use_armor_filter( IOBUF a )
 {
-    byte buf[1];
+    byte buf[2];
     int n;
 
     /* fixme: there might be a problem with iobuf_peek */
-    n = iobuf_peek(a, buf, 1 );
+    n = iobuf_peek (a, buf, 2);
     if( n == -1 )
 	return 0; /* EOF, doesn't matter whether armored or not */
     if( !n )
 	return 1; /* can't check it: try armored */
+    if (n != 2)
+	return 0; /* short buffer */
     return is_armored(buf);
 }