/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * * SPDX-License-Identifier: curl * ***************************************************************************/ /* Escape and unescape URL encoding in strings. The functions return a new * allocated string or NULL if an error occurred. */ #include "curl_setup.h" #include #include "urldata.h" #include "warnless.h" #include "escape.h" #include "strdup.h" /* The last 3 #include files should be in this order */ #include "curl_printf.h" #include "curl_memory.h" #include "memdebug.h" /* Portable character check (remember EBCDIC). Do not use isalnum() because its behavior is altered by the current locale. See https://datatracker.ietf.org/doc/html/rfc3986#section-2.3 */ bool Curl_isunreserved(unsigned char in) { switch(in) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g': case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n': case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u': case 'v': case 'w': case 'x': case 'y': case 'z': case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G': case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z': case '-': case '.': case '_': case '~': return TRUE; default: break; } return FALSE; } /* for ABI-compatibility with previous versions */ char *curl_escape(const char *string, int inlength) { return curl_easy_escape(NULL, string, inlength); } /* for ABI-compatibility with previous versions */ char *curl_unescape(const char *string, int length) { return curl_easy_unescape(NULL, string, length, NULL); } /* Escapes for URL the given unescaped string of given length. * 'data' is ignored since 7.82.0. */ char *curl_easy_escape(struct Curl_easy *data, const char *string, int inlength) { size_t length; struct dynbuf d; (void)data; if(inlength < 0) return NULL; Curl_dyn_init(&d, CURL_MAX_INPUT_LENGTH * 3); length = (inlength?(size_t)inlength:strlen(string)); if(!length) return strdup(""); while(length--) { unsigned char in = *string++; /* treat the characters unsigned */ if(Curl_isunreserved(in)) { /* append this */ if(Curl_dyn_addn(&d, &in, 1)) return NULL; } else { /* encode it */ const char hex[] = "0123456789ABCDEF"; char out[3]={'%'}; out[1] = hex[in>>4]; out[2] = hex[in & 0xf]; if(Curl_dyn_addn(&d, out, 3)) return NULL; } } return Curl_dyn_ptr(&d); } static const unsigned char hextable[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0, /* 0x30 - 0x3f */ 0, 10, 11, 12, 13, 14, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 - 0x4f */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 - 0x5f */ 0, 10, 11, 12, 13, 14, 15 /* 0x60 - 0x66 */ }; /* the input is a single hex digit */ #define onehex2dec(x) hextable[x - '0'] /* * Curl_urldecode() URL decodes the given string. * * Returns a pointer to a malloced string in *ostring with length given in * *olen. If length == 0, the length is assumed to be strlen(string). * * ctrl options: * - REJECT_NADA: accept everything * - REJECT_CTRL: rejects control characters (byte codes lower than 32) in * the data * - REJECT_ZERO: rejects decoded zero bytes * * The values for the enum starts at 2, to make the assert detect legacy * invokes that used TRUE/FALSE (0 and 1). */ CURLcode Curl_urldecode(const char *string, size_t length, char **ostring, size_t *olen, enum urlreject ctrl) { size_t alloc; char *ns; DEBUGASSERT(string); DEBUGASSERT(ctrl >= REJECT_NADA); /* crash on TRUE/FALSE */ alloc = (length?length:strlen(string)); ns = malloc(alloc + 1); if(!ns) return CURLE_OUT_OF_MEMORY; /* store output string */ *ostring = ns; while(alloc) { unsigned char in = *string; if(('%' == in) && (alloc > 2) && ISXDIGIT(string[1]) && ISXDIGIT(string[2])) { /* this is two hexadecimal digits following a '%' */ in = (unsigned char)(onehex2dec(string[1]) << 4) | onehex2dec(string[2]); string += 3; alloc -= 3; } else { string++; alloc--; } if(((ctrl == REJECT_CTRL) && (in < 0x20)) || ((ctrl == REJECT_ZERO) && (in == 0))) { Curl_safefree(*ostring); return CURLE_URL_MALFORMAT; } *ns++ = in; } *ns = 0; /* terminate it */ if(olen) /* store output size */ *olen = ns - *ostring; return CURLE_OK; } /* * Unescapes the given URL escaped string of given length. Returns a * pointer to a malloced string with length given in *olen. * If length == 0, the length is assumed to be strlen(string). * If olen == NULL, no output length is stored. * 'data' is ignored since 7.82.0. */ char *curl_easy_unescape(struct Curl_easy *data, const char *string, int length, int *olen) { char *str = NULL; (void)data; if(length >= 0) { size_t inputlen = (size_t)length; size_t outputlen; CURLcode res = Curl_urldecode(string, inputlen, &str, &outputlen, REJECT_NADA); if(res) return NULL; if(olen) { if(outputlen <= (size_t) INT_MAX) *olen = curlx_uztosi(outputlen); else /* too large to return in an int, fail! */ Curl_safefree(str); } } return str; } /* For operating systems/environments that use different malloc/free systems for the app and for this library, we provide a free that uses the library's memory system */ void curl_free(void *p) { free(p); }