gen_test_char.c

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/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#ifdef CROSS_COMPILE
 
#include <ctype.h>
#define apr_isalnum(c) (isalnum(((unsigned char)(c))))
#define apr_isalpha(c) (isalpha(((unsigned char)(c))))
#define apr_iscntrl(c) (iscntrl(((unsigned char)(c))))
#define apr_isprint(c) (isprint(((unsigned char)(c))))
#define APR_HAVE_STDIO_H 1
#define APR_HAVE_STRING_H 1
 
#else
 
#include "apr.h"
#include "apr_lib.h"
 
#endif
 
#if defined(WIN32) || defined(OS2)
#define NEED_ENHANCED_ESCAPES
#endif
 
#if APR_HAVE_STDIO_H
#include <stdio.h>
#endif
#if APR_HAVE_STRING_H
#include <string.h>
#endif
 
/* A bunch of functions in util.c scan strings looking for certain characters.
 * To make that more efficient we encode a lookup table.
 */
#define T_ESCAPE_SHELL_CMD    (0x01)
#define T_ESCAPE_PATH_SEGMENT (0x02)
#define T_OS_ESCAPE_PATH      (0x04)
#define T_HTTP_TOKEN_STOP     (0x08)
#define T_ESCAPE_LOGITEM      (0x10)
#define T_ESCAPE_FORENSIC     (0x20)
#define T_ESCAPE_URLENCODED   (0x40)
#define T_HTTP_CTRLS          (0x80)
#define T_VCHAR_OBSTEXT      (0x100)
#define T_URI_UNRESERVED     (0x200)
 
int main(int argc, char *argv[])
{
    unsigned c;
    unsigned short flags;
 
    printf("/* this file is automatically generated by gen_test_char, "
           "do not edit */\n"
           "#define T_ESCAPE_SHELL_CMD     (%u)\n"
           "#define T_ESCAPE_PATH_SEGMENT  (%u)\n"
           "#define T_OS_ESCAPE_PATH       (%u)\n"
           "#define T_HTTP_TOKEN_STOP      (%u)\n"
           "#define T_ESCAPE_LOGITEM       (%u)\n"
           "#define T_ESCAPE_FORENSIC      (%u)\n"
           "#define T_ESCAPE_URLENCODED    (%u)\n"
           "#define T_HTTP_CTRLS           (%u)\n"
           "#define T_VCHAR_OBSTEXT        (%u)\n"
           "#define T_URI_UNRESERVED       (%u)\n"
           "\n"
           "static const unsigned short test_char_table[256] = {",
           T_ESCAPE_SHELL_CMD,
           T_ESCAPE_PATH_SEGMENT,
           T_OS_ESCAPE_PATH,
           T_HTTP_TOKEN_STOP,
           T_ESCAPE_LOGITEM,
           T_ESCAPE_FORENSIC,
           T_ESCAPE_URLENCODED,
           T_HTTP_CTRLS,
           T_VCHAR_OBSTEXT,
           T_URI_UNRESERVED
        );
 
    for (c = 0; c < 256; ++c) {
        flags = 0;
        if (c % 8 == 0)
            printf("\n    ");
 
        /* escape_shell_cmd */
#ifdef NEED_ENHANCED_ESCAPES
        /* Win32/OS2 have many of the same vulnerable characters
         * as Unix sh, plus the carriage return and percent char.
         * The proper escaping of these characters varies from unix
         * since Win32/OS2 use carets or doubled-double quotes,
         * and neither lf nor cr can be escaped.  We escape unix
         * specific as well, to assure that cross-compiled unix
         * applications behave similarly when invoked on win32/os2.
         *
         * Rem please keep in-sync with apr's list in win32/filesys.c
         */
        if (c && strchr("&;`'\"|*?~<>^()[]{}$\\\n\r%", c)) {
            flags |= T_ESCAPE_SHELL_CMD;
        }
#else
        if (c && strchr("&;`'\"|*?~<>^()[]{}$\\\n", c)) {
            flags |= T_ESCAPE_SHELL_CMD;
        }
#endif
 
        if (!apr_isalnum(c) && !strchr("$-_.+!*'(),:@&=~", c)) {
            flags |= T_ESCAPE_PATH_SEGMENT;
        }
 
        if (!apr_isalnum(c) && !strchr("$-_.+!*'(),:;@&=/~", c)) {
            flags |= T_OS_ESCAPE_PATH;
        }
 
        if (!apr_isalnum(c) && !strchr(".-*_ ", c)) {
            flags |= T_ESCAPE_URLENCODED;
        }
 
        /* Stop for any non-'token' character, including ctrls, obs-text,
         * and "tspecials" (RFC2068) a.k.a. "separators" (RFC2616), which
         * is easier to express as characters remaining in the ASCII token set
         */
        if (!c || !(apr_isalnum(c) || strchr("!#$%&'*+-.^_`|~", c))) {
            flags |= T_HTTP_TOKEN_STOP;
        }
 
        /* Catch CTRLs other than VCHAR, HT and SP, and obs-text (RFC7230 3.2)
         * This includes only the C0 plane, not C1 (which is obs-text itself.)
         * XXX: We should verify that all ASCII C0 ctrls/DEL corresponding to
         * the current EBCDIC translation are captured, and ASCII C1 ctrls
         * corresponding are all permitted (as they fall under obs-text rule)
         */
        if (!c || (apr_iscntrl(c) && c != '\t')) {
            flags |= T_HTTP_CTRLS;
        }
 
        /* From RFC3986, the specific sets of gen-delims, sub-delims (2.2),
         * and unreserved (2.3) that are possible somewhere within a URI.
         * Spec requires all others to be %XX encoded, including obs-text.
         */
        if (c && !apr_iscntrl(c) && c != ' ') {
            flags |= T_VCHAR_OBSTEXT;
        }
 
        /* For logging, escape all control characters,
         * double quotes (because they delimit the request in the log file)
         * backslashes (because we use backslash for escaping)
         * and 8-bit chars with the high bit set
         */
        if (c && (!apr_isprint(c) || c == '"' || c == '\\' || apr_iscntrl(c))) {
            flags |= T_ESCAPE_LOGITEM;
        }
 
        /* For forensic logging, escape all control characters, top bit set,
         * :, | (used as delimiters) and % (used for escaping).
         */
        if (!apr_isprint(c) || c == ':' || c == '|' || c == '%'
            || apr_iscntrl(c) || !c) {
            flags |= T_ESCAPE_FORENSIC;
        }
 
        /* Characters in the RFC 3986 "unreserved" set.
         * https://datatracker.ietf.org/doc/html/rfc3986#section-2.3 */
        if (c && (apr_isalnum(c) || strchr("-._~", c))) {
            flags |= T_URI_UNRESERVED;
        }
        
        printf("0x%03x%c", flags, (c < 255) ? ',' : ' ');
    }
 
    printf("\n};\n\n");
 
    printf(
      "/* we assume the folks using this ensure 0 <= c < 256... which means\n"
      " * you need a cast to (unsigned char) first, you can't just plug a\n"
      " * char in here and get it to work, because if char is signed then it\n"
      " * will first be sign extended.\n"
      " */\n"
      "#define TEST_CHAR(c, f) (test_char_table[(unsigned char)(c)] & (f))\n"
    );
 
    return 0;
}