Be more paranoid, and check to make sure the length of the string or OID

isn't so large as to cause the end offset to wrap around.

svn path=/trunk/; revision=4766

1 files changed, 17 insertions, 1 deletions

diff --git a/asn1.c b/asn1.c
index 1c7c2852ea..4570c0da22 100644
--- a/asn1.c
+++ b/asn1.c
@@ -1,7 +1,7 @@
 /* asn1.c
  * Routines for ASN.1 BER dissection
  *
- * $Id: asn1.c,v 1.9 2002/02/20 22:46:21 guy Exp $
+ * $Id: asn1.c,v 1.10 2002/02/21 02:05:53 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -68,6 +68,8 @@
 #include <winsock.h>
 #endif
 
+#include <limits.h>
+
 #include <glib.h>
 #include <epan/tvbuff.h>
 #include "asn1.h"
@@ -649,6 +651,13 @@ asn1_string_value_decode ( ASN1_SCK *asn1, int enc_len, guchar **octets)
     eoc = asn1->offset + enc_len;
 
     /*
+     * Check for an overflow, and clamp "eoc" at the maximum if we
+     * get it.
+     */
+    if (eoc < asn1->offset || eoc < 0)
+	eoc = INT_MAX;
+
+    /*
      * First, make sure the entire string is in the tvbuff, and throw
      * an exception if it isn't.  If the length is bogus, this should
      * keep us from trying to allocate an immensely large buffer.
@@ -811,6 +820,13 @@ asn1_oid_value_decode ( ASN1_SCK *asn1, int enc_len, subid_t **oid, guint *len)
     eoc = asn1->offset + enc_len;
 
     /*
+     * Check for an overflow, and clamp "eoc" at the maximum if we
+     * get it.
+     */
+    if (eoc < asn1->offset || eoc < 0)
+	eoc = INT_MAX;
+
+    /*
      * First, make sure the entire string is in the tvbuff, and throw
      * an exception if it isn't.  If the length is bogus, this should
      * keep us from trying to allocate an immensely large buffer.