1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2022, 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 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.
*
***************************************************************************/
#include "curl_setup.h"
#include <curl/curl.h>
#include "dotdot.h"
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
/*
* "Remove Dot Segments"
* https://datatracker.ietf.org/doc/html/rfc3986#section-5.2.4
*/
/*
* Curl_dedotdotify()
* @unittest: 1395
*
* This function gets a null-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 */
*out = 0; /* null-terminates, for inputs like "./" */
/* get a cloned copy of the input */
clone = strdup(input);
if(!clone) {
free(out);
return NULL;
}
orgclone = clone;
outptr = out;
if(!*clone) {
/* zero length string, return that */
free(out);
return clone;
}
/*
* 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; /* null-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; /* null-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;
*out = 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 end zero byte */
}
free(orgclone);
return out;
}
|
