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Diffstat (limited to 'lib/dotdot.c')
| -rw-r--r-- | lib/dotdot.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/lib/dotdot.c b/lib/dotdot.c new file mode 100644 index 0000000..ae16941 --- /dev/null +++ b/lib/dotdot.c @@ -0,0 +1,170 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, 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 http://curl.haxx.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. + * + ***************************************************************************/ + +#include "curl_setup.h" + +#include "dotdot.h" + +#include "curl_memory.h" +/* The last #include file should be: */ +#include "memdebug.h" + +/* + * "Remove Dot Segments" + * http://tools.ietf.org/html/rfc3986#section-5.2.4 + */ + +/* + * Curl_dedotdotify() + * + * This function gets a zero-terminated path with dot and dotdot sequences + * passed in and strips them off according to the rules in RFC 3986 section + * 5.2.4. + * + * The function handles a query part ('?' + stuff) appended but it expects + * that fragments ('#' + stuff) have already been cut off. + * + * RETURNS + * + * an allocated dedotdotified output string + */ +char *Curl_dedotdotify(const char *input) +{ + size_t inlen = strlen(input); + char *clone; + size_t clen = inlen; /* the length of the cloned input */ + char *out = malloc(inlen+1); + char *outptr; + char *orgclone; + char *queryp; + if(!out) + return NULL; /* out of memory */ + + /* get a cloned copy of the input */ + clone = strdup(input); + if(!clone) { + free(out); + return NULL; + } + orgclone = clone; + outptr = out; + + /* + * To handle query-parts properly, we must find it and remove it during the + * dotdot-operation and then append it again at the end to the output + * string. + */ + queryp = strchr(clone, '?'); + if(queryp) + *queryp = 0; + + do { + + /* A. If the input buffer begins with a prefix of "../" or "./", then + remove that prefix from the input buffer; otherwise, */ + + if(!strncmp("./", clone, 2)) { + clone+=2; + clen-=2; + } + else if(!strncmp("../", clone, 3)) { + clone+=3; + clen-=3; + } + + /* B. if the input buffer begins with a prefix of "/./" or "/.", where + "." is a complete path segment, then replace that prefix with "/" in + the input buffer; otherwise, */ + else if(!strncmp("/./", clone, 3)) { + clone+=2; + clen-=2; + } + else if(!strcmp("/.", clone)) { + clone[1]='/'; + clone++; + clen-=1; + } + + /* C. if the input buffer begins with a prefix of "/../" or "/..", where + ".." is a complete path segment, then replace that prefix with "/" in + the input buffer and remove the last segment and its preceding "/" (if + any) from the output buffer; otherwise, */ + + else if(!strncmp("/../", clone, 4)) { + clone+=3; + clen-=3; + /* remove the last segment from the output buffer */ + while(outptr > out) { + outptr--; + if(*outptr == '/') + break; + } + *outptr = 0; /* zero-terminate where it stops */ + } + else if(!strcmp("/..", clone)) { + clone[2]='/'; + clone+=2; + clen-=2; + /* remove the last segment from the output buffer */ + while(outptr > out) { + outptr--; + if(*outptr == '/') + break; + } + *outptr = 0; /* zero-terminate where it stops */ + } + + /* D. if the input buffer consists only of "." or "..", then remove + that from the input buffer; otherwise, */ + + else if(!strcmp(".", clone) || !strcmp("..", clone)) { + *clone=0; + } + + else { + /* E. move the first path segment in the input buffer to the end of + the output buffer, including the initial "/" character (if any) and + any subsequent characters up to, but not including, the next "/" + character or the end of the input buffer. */ + + do { + *outptr++ = *clone++; + clen--; + } while(*clone && (*clone != '/')); + *outptr = 0; + } + + } while(*clone); + + if(queryp) { + size_t qlen; + /* There was a query part, append that to the output. The 'clone' string + may now have been altered so we copy from the original input string + from the correct index. */ + size_t oindex = queryp - orgclone; + qlen = strlen(&input[oindex]); + memcpy(outptr, &input[oindex], qlen+1); /* include the ending zero byte */ + } + + free(orgclone); + return out; +} |