This has been added to avoid the situation where some host ctype.h functions

return true for characters > 127.  I.e. they are allowing extended ASCII
characters through which then cause problems.  E.g. marking superscript '2' as
a number then causes the common (ch - '0') conversion to number to fail
miserably.  Likewise letters with diacritical marks can also cause problems.

If a non-ASCII character set is being used (currently only EBCDIC), it is
adjusted for.

The implementation uses a single table with a bit for each of the defined
classes.  These functions accept an int argument and fail for
values out of range or for characters outside of the ASCII set.  They will
work for both signed and unsigned character inputs.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4102)

1 files changed, 4 insertions, 16 deletions

diff --git a/crypto/asn1/f_string.c b/crypto/asn1/f_string.c
index b9258bb..cfb895f 100644
--- a/crypto/asn1/f_string.c
+++ b/crypto/asn1/f_string.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -8,7 +8,7 @@
  */
 
 #include <stdio.h>
-#include <ctype.h>
+#include "internal/ctype.h"
 #include "internal/cryptlib.h"
 #include <openssl/buffer.h>
 #include <openssl/asn1.h>
@@ -47,7 +47,7 @@ int i2a_ASN1_STRING(BIO *bp, const ASN1_STRING *a, int type)
 
 int a2i_ASN1_STRING(BIO *bp, ASN1_STRING *bs, char *buf, int size)
 {
-    int i, j, k, m, n, again, bufsize, spec_char;
+    int i, j, k, m, n, again, bufsize;
     unsigned char *s = NULL, *sp;
     unsigned char *bufp;
     int num = 0, slen = 0, first = 1;
@@ -74,19 +74,7 @@ int a2i_ASN1_STRING(BIO *bp, ASN1_STRING *bs, char *buf, int size)
         again = (buf[i - 1] == '\\');
 
         for (j = i - 1; j > 0; j--) {
-#ifndef CHARSET_EBCDIC
-            spec_char = (!(((buf[j] >= '0') && (buf[j] <= '9')) ||
-                  ((buf[j] >= 'a') && (buf[j] <= 'f')) ||
-                  ((buf[j] >= 'A') && (buf[j] <= 'F'))));
-#else
-            /*
-             * This #ifdef is not strictly necessary, since the characters
-             * A...F a...f 0...9 are contiguous (yes, even in EBCDIC - but
-             * not the whole alphabet). Nevertheless, isxdigit() is faster.
-             */
-            spec_char = (!isxdigit(buf[j]));
-#endif
-            if (spec_char) {
+            if (!ossl_isxdigit(buf[j])) {
                 i = j;
                 break;
             }