Fix the ASN1 sanity check: correct header length

calculation and check overflow against LONG_MAX.

diff --git a/CHANGES b/CHANGES
index 5aff39d71fc641594b834ae04c6a5bb64e8d01ed..9042dac243a12a4de12b0bb57547133739c3ed2b 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,12 @@
 
  Changes between 0.9.6e and 0.9.6f  [XX xxx XXXX]
 
+  *) Fix ASN1 checks. Check for overflow by comparing with LONG_MAX
+     and get fix the header length calculation.
+     [Florian Weimer <Weimer@CERT.Uni-Stuttgart.DE>,
+       Alon Kantor <alonk@checkpoint.com> (and others),
+       Steve Henson]
+
   *) Use proper error handling instead of 'assertions' in buffer
      overflow checks added in 0.9.6e.  This prevents DoS (the
      assertions could call abort()).

diff --git a/crypto/asn1/asn1_lib.c b/crypto/asn1/asn1_lib.c
index 1fe3fbc1fa78165471a08fae3618fb10d0778505..be6d5f4f17d1f26d49f182b71b027d1688e708fe 100644 (file)
--- a/crypto/asn1/asn1_lib.c
+++ b/crypto/asn1/asn1_lib.c
@@ -57,6 +57,7 @@
  */
 
 #include <stdio.h>
+#include <limits.h>
 #include "cryptlib.h"
 #include <openssl/asn1.h>
 #include <openssl/asn1_mac.h>
@@ -124,7 +125,7 @@ int ASN1_get_object(unsigned char **pp, long *plength, int *ptag, int *pclass,
                (int)(omax+ *pp));
 
 #endif
-       if (*plength > (omax - (*pp - p)))
+       if (*plength > (omax - (*p - *pp)))
                {
                ASN1err(ASN1_F_ASN1_GET_OBJECT,ASN1_R_TOO_LONG);
                /* Set this so that even if things are not long enough
@@ -141,7 +142,7 @@ err:
 static int asn1_get_length(unsigned char **pp, int *inf, long *rl, int max)
        {
        unsigned char *p= *pp;
-       long ret=0;
+       unsigned long ret=0;
        int i;
 
        if (max-- < 1) return(0);
@@ -170,10 +171,10 @@ static int asn1_get_length(unsigned char **pp, int *inf, long *rl, int max)
                else
                        ret=i;
                }
-       if (ret < 0)
+       if (ret > LONG_MAX)
                return 0;
        *pp=p;
-       *rl=ret;
+       *rl=(long)ret;
        return(1);
        }