diff options
author | djm@openbsd.org <djm@openbsd.org> | 2019-07-05 04:55:40 +0000 |
---|---|---|
committer | Damien Miller <djm@mindrot.org> | 2019-07-08 11:44:49 +1000 |
commit | 569b650f93b561c09c655f83f128e1dfffe74101 (patch) | |
tree | f40a1711f9f0cfa063a8acbb70870cdaf1b3d49f /sftp-realpath.c | |
parent | b8e2b797362526437e0642a6c2f2970d794f2561 (diff) |
upstream: add a local implementation of BSD realpath() for
sftp-server use ahead of OpenBSD's realpath changing to match POSIX;
ok deraadt@ (thanks for snaps testing)
OpenBSD-Commit-ID: 4f8cbf7ed8679f6237264301d104ecec64885d55
Diffstat (limited to 'sftp-realpath.c')
-rw-r--r-- | sftp-realpath.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/sftp-realpath.c b/sftp-realpath.c new file mode 100644 index 000000000..0ed808f46 --- /dev/null +++ b/sftp-realpath.c | |||
@@ -0,0 +1,224 @@ | |||
1 | /* $OpenBSD: sftp-realpath.c,v 1.1 2019/07/05 04:55:40 djm Exp $ */ | ||
2 | /* | ||
3 | * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru> | ||
4 | * | ||
5 | * Redistribution and use in source and binary forms, with or without | ||
6 | * modification, are permitted provided that the following conditions | ||
7 | * are met: | ||
8 | * 1. Redistributions of source code must retain the above copyright | ||
9 | * notice, this list of conditions and the following disclaimer. | ||
10 | * 2. Redistributions in binary form must reproduce the above copyright | ||
11 | * notice, this list of conditions and the following disclaimer in the | ||
12 | * documentation and/or other materials provided with the distribution. | ||
13 | * 3. The names of the authors may not be used to endorse or promote | ||
14 | * products derived from this software without specific prior written | ||
15 | * permission. | ||
16 | * | ||
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | ||
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | ||
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||
27 | * SUCH DAMAGE. | ||
28 | */ | ||
29 | |||
30 | #include <sys/types.h> | ||
31 | #include <sys/param.h> | ||
32 | #include <sys/stat.h> | ||
33 | |||
34 | #include <errno.h> | ||
35 | #include <stdlib.h> | ||
36 | #include <stddef.h> | ||
37 | #include <string.h> | ||
38 | #include <unistd.h> | ||
39 | #include <limits.h> | ||
40 | |||
41 | #ifndef SYMLOOP_MAX | ||
42 | # define SYMLOOP_MAX 32 | ||
43 | #endif | ||
44 | |||
45 | /* XXX rewrite sftp-server to use POSIX realpath and remove this hack */ | ||
46 | |||
47 | char *sftp_realpath(const char *path, char *resolved); | ||
48 | |||
49 | /* | ||
50 | * char *realpath(const char *path, char resolved[PATH_MAX]); | ||
51 | * | ||
52 | * Find the real name of path, by removing all ".", ".." and symlink | ||
53 | * components. Returns (resolved) on success, or (NULL) on failure, | ||
54 | * in which case the path which caused trouble is left in (resolved). | ||
55 | */ | ||
56 | char * | ||
57 | sftp_realpath(const char *path, char *resolved) | ||
58 | { | ||
59 | struct stat sb; | ||
60 | char *p, *q, *s; | ||
61 | size_t left_len, resolved_len; | ||
62 | unsigned symlinks; | ||
63 | int serrno, slen, mem_allocated; | ||
64 | char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; | ||
65 | |||
66 | if (path[0] == '\0') { | ||
67 | errno = ENOENT; | ||
68 | return (NULL); | ||
69 | } | ||
70 | |||
71 | serrno = errno; | ||
72 | |||
73 | if (resolved == NULL) { | ||
74 | resolved = malloc(PATH_MAX); | ||
75 | if (resolved == NULL) | ||
76 | return (NULL); | ||
77 | mem_allocated = 1; | ||
78 | } else | ||
79 | mem_allocated = 0; | ||
80 | |||
81 | symlinks = 0; | ||
82 | if (path[0] == '/') { | ||
83 | resolved[0] = '/'; | ||
84 | resolved[1] = '\0'; | ||
85 | if (path[1] == '\0') | ||
86 | return (resolved); | ||
87 | resolved_len = 1; | ||
88 | left_len = strlcpy(left, path + 1, sizeof(left)); | ||
89 | } else { | ||
90 | if (getcwd(resolved, PATH_MAX) == NULL) { | ||
91 | if (mem_allocated) | ||
92 | free(resolved); | ||
93 | else | ||
94 | strlcpy(resolved, ".", PATH_MAX); | ||
95 | return (NULL); | ||
96 | } | ||
97 | resolved_len = strlen(resolved); | ||
98 | left_len = strlcpy(left, path, sizeof(left)); | ||
99 | } | ||
100 | if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) { | ||
101 | errno = ENAMETOOLONG; | ||
102 | goto err; | ||
103 | } | ||
104 | |||
105 | /* | ||
106 | * Iterate over path components in `left'. | ||
107 | */ | ||
108 | while (left_len != 0) { | ||
109 | /* | ||
110 | * Extract the next path component and adjust `left' | ||
111 | * and its length. | ||
112 | */ | ||
113 | p = strchr(left, '/'); | ||
114 | s = p ? p : left + left_len; | ||
115 | if (s - left >= (ptrdiff_t)sizeof(next_token)) { | ||
116 | errno = ENAMETOOLONG; | ||
117 | goto err; | ||
118 | } | ||
119 | memcpy(next_token, left, s - left); | ||
120 | next_token[s - left] = '\0'; | ||
121 | left_len -= s - left; | ||
122 | if (p != NULL) | ||
123 | memmove(left, s + 1, left_len + 1); | ||
124 | if (resolved[resolved_len - 1] != '/') { | ||
125 | if (resolved_len + 1 >= PATH_MAX) { | ||
126 | errno = ENAMETOOLONG; | ||
127 | goto err; | ||
128 | } | ||
129 | resolved[resolved_len++] = '/'; | ||
130 | resolved[resolved_len] = '\0'; | ||
131 | } | ||
132 | if (next_token[0] == '\0') | ||
133 | continue; | ||
134 | else if (strcmp(next_token, ".") == 0) | ||
135 | continue; | ||
136 | else if (strcmp(next_token, "..") == 0) { | ||
137 | /* | ||
138 | * Strip the last path component except when we have | ||
139 | * single "/" | ||
140 | */ | ||
141 | if (resolved_len > 1) { | ||
142 | resolved[resolved_len - 1] = '\0'; | ||
143 | q = strrchr(resolved, '/') + 1; | ||
144 | *q = '\0'; | ||
145 | resolved_len = q - resolved; | ||
146 | } | ||
147 | continue; | ||
148 | } | ||
149 | |||
150 | /* | ||
151 | * Append the next path component and lstat() it. If | ||
152 | * lstat() fails we still can return successfully if | ||
153 | * there are no more path components left. | ||
154 | */ | ||
155 | resolved_len = strlcat(resolved, next_token, PATH_MAX); | ||
156 | if (resolved_len >= PATH_MAX) { | ||
157 | errno = ENAMETOOLONG; | ||
158 | goto err; | ||
159 | } | ||
160 | if (lstat(resolved, &sb) != 0) { | ||
161 | if (errno == ENOENT && p == NULL) { | ||
162 | errno = serrno; | ||
163 | return (resolved); | ||
164 | } | ||
165 | goto err; | ||
166 | } | ||
167 | if (S_ISLNK(sb.st_mode)) { | ||
168 | if (symlinks++ > SYMLOOP_MAX) { | ||
169 | errno = ELOOP; | ||
170 | goto err; | ||
171 | } | ||
172 | slen = readlink(resolved, symlink, sizeof(symlink) - 1); | ||
173 | if (slen < 0) | ||
174 | goto err; | ||
175 | symlink[slen] = '\0'; | ||
176 | if (symlink[0] == '/') { | ||
177 | resolved[1] = 0; | ||
178 | resolved_len = 1; | ||
179 | } else if (resolved_len > 1) { | ||
180 | /* Strip the last path component. */ | ||
181 | resolved[resolved_len - 1] = '\0'; | ||
182 | q = strrchr(resolved, '/') + 1; | ||
183 | *q = '\0'; | ||
184 | resolved_len = q - resolved; | ||
185 | } | ||
186 | |||
187 | /* | ||
188 | * If there are any path components left, then | ||
189 | * append them to symlink. The result is placed | ||
190 | * in `left'. | ||
191 | */ | ||
192 | if (p != NULL) { | ||
193 | if (symlink[slen - 1] != '/') { | ||
194 | if (slen + 1 >= | ||
195 | (ptrdiff_t)sizeof(symlink)) { | ||
196 | errno = ENAMETOOLONG; | ||
197 | goto err; | ||
198 | } | ||
199 | symlink[slen] = '/'; | ||
200 | symlink[slen + 1] = 0; | ||
201 | } | ||
202 | left_len = strlcat(symlink, left, sizeof(symlink)); | ||
203 | if (left_len >= sizeof(symlink)) { | ||
204 | errno = ENAMETOOLONG; | ||
205 | goto err; | ||
206 | } | ||
207 | } | ||
208 | left_len = strlcpy(left, symlink, sizeof(left)); | ||
209 | } | ||
210 | } | ||
211 | |||
212 | /* | ||
213 | * Remove trailing slash except when the resolved pathname | ||
214 | * is a single "/". | ||
215 | */ | ||
216 | if (resolved_len > 1 && resolved[resolved_len - 1] == '/') | ||
217 | resolved[resolved_len - 1] = '\0'; | ||
218 | return (resolved); | ||
219 | |||
220 | err: | ||
221 | if (mem_allocated) | ||
222 | free(resolved); | ||
223 | return (NULL); | ||
224 | } | ||