PR: 2696

Submitted by: Rob Austein <sra@hactrn.net>

Fix inverted range problem in RFC3779 code.

Thanks to Andrew Chi for generating test cases for this bug.

crypto/x509v3/v3_asid.c

@@ -358,6 +358,20 @@ static int ASIdentifierChoice_is_canonical(ASIdentifierChoice *choice)
       goto done;
   }
 
+  /*
+   * Check for inverted range.
+   */
+  i = sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1;
+  {
+    ASIdOrRange *a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
+    ASN1_INTEGER *a_min, *a_max;
+    if (a != NULL && a->type == ASIdOrRange_range) {
+      extract_min_max(a, &a_min, &a_max);
+      if (ASN1_INTEGER_cmp(a_min, a_max) > 0)
+	goto done;
+    }
+  }
+
   ret = 1;
 
  done:
@@ -392,9 +406,18 @@ static int ASIdentifierChoice_canonize(ASIdentifierChoice *choice)
     return 1;
 
   /*
-   * We have a list.  Sort it.
+   * If not a list, or if empty list, it's broken.
+   */
+  if (choice->type != ASIdentifierChoice_asIdsOrRanges ||
+      sk_ASIdOrRange_num(choice->u.asIdsOrRanges) == 0) {
+    X509V3err(X509V3_F_ASIDENTIFIERCHOICE_CANONIZE,
+	      X509V3_R_EXTENSION_VALUE_ERROR);
+    return 0;
+  }
+
+  /*
+   * We have a non-empty list.  Sort it.
    */
-  OPENSSL_assert(choice->type == ASIdentifierChoice_asIdsOrRanges);
   sk_ASIdOrRange_sort(choice->u.asIdsOrRanges);
 
   /*
@@ -414,6 +437,13 @@ static int ASIdentifierChoice_canonize(ASIdentifierChoice *choice)
      */
     OPENSSL_assert(ASN1_INTEGER_cmp(a_min, b_min) <= 0);
 
+    /*
+     * Punt inverted ranges.
+     */
+    if (ASN1_INTEGER_cmp(a_min, a_max) > 0 ||
+	ASN1_INTEGER_cmp(b_min, b_max) > 0)
+      goto done;
+
     /*
      * Check for overlaps.
      */
@@ -465,12 +495,26 @@ static int ASIdentifierChoice_canonize(ASIdentifierChoice *choice)
 	break;
       }
       ASIdOrRange_free(b);
-      sk_ASIdOrRange_delete(choice->u.asIdsOrRanges, i + 1);
+      (void) sk_ASIdOrRange_delete(choice->u.asIdsOrRanges, i + 1);
       i--;
       continue;
     }
   }
 
+  /*
+   * Check for final inverted range.
+   */
+  i = sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1;
+  {
+    ASIdOrRange *a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
+    ASN1_INTEGER *a_min, *a_max;
+    if (a != NULL && a->type == ASIdOrRange_range) {
+      extract_min_max(a, &a_min, &a_max);
+      if (ASN1_INTEGER_cmp(a_min, a_max) > 0)
+	goto done;
+    }
+  }
+
   OPENSSL_assert(ASIdentifierChoice_is_canonical(choice)); /* Paranoia */
 
   ret = 1;
@@ -498,6 +542,7 @@ static void *v2i_ASIdentifiers(const struct v3_ext_method *method,
 			       struct v3_ext_ctx *ctx,
 			       STACK_OF(CONF_VALUE) *values)
 {
+  ASN1_INTEGER *min = NULL, *max = NULL;
   ASIdentifiers *asid = NULL;
   int i;
 
@@ -508,7 +553,6 @@ static void *v2i_ASIdentifiers(const struct v3_ext_method *method,
 
   for (i = 0; i < sk_CONF_VALUE_num(values); i++) {
     CONF_VALUE *val = sk_CONF_VALUE_value(values, i);
-    ASN1_INTEGER *min = NULL, *max = NULL;
     int i1, i2, i3, is_range, which;
 
     /*
@@ -578,18 +622,19 @@ static void *v2i_ASIdentifiers(const struct v3_ext_method *method,
       max = s2i_ASN1_INTEGER(NULL, s + i2);
       OPENSSL_free(s);
       if (min == NULL || max == NULL) {
-	ASN1_INTEGER_free(min);
-	ASN1_INTEGER_free(max);
 	X509V3err(X509V3_F_V2I_ASIDENTIFIERS, ERR_R_MALLOC_FAILURE);
 	goto err;
       }
+      if (ASN1_INTEGER_cmp(min, max) > 0) {
+	X509V3err(X509V3_F_V2I_ASIDENTIFIERS, X509V3_R_EXTENSION_VALUE_ERROR);
+	goto err;
+      }
     }
     if (!v3_asid_add_id_or_range(asid, which, min, max)) {
-      ASN1_INTEGER_free(min);
-      ASN1_INTEGER_free(max);
       X509V3err(X509V3_F_V2I_ASIDENTIFIERS, ERR_R_MALLOC_FAILURE);
       goto err;
     }
+    min = max = NULL;
   }
 
   /*
@@ -601,6 +646,8 @@ static void *v2i_ASIdentifiers(const struct v3_ext_method *method,
 
  err:
   ASIdentifiers_free(asid);
+  ASN1_INTEGER_free(min);
+  ASN1_INTEGER_free(max);
   return NULL;
 }