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1 | // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- |
2 | // vim: ts=8 sw=2 smarttab | |
3 | /* | |
4 | * Ceph - scalable distributed file system | |
5 | * | |
6 | * Copyright (C) 2014 Red Hat | |
7 | * | |
8 | * This is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License version 2.1, as published by the Free Software | |
11 | * Foundation. See file COPYING. | |
12 | * | |
13 | */ | |
14 | ||
15 | ||
16 | #include <errno.h> | |
17 | #include <fcntl.h> | |
18 | ||
19 | #include <boost/spirit/include/qi.hpp> | |
20 | #include <boost/spirit/include/phoenix_operator.hpp> | |
21 | #include <boost/spirit/include/phoenix.hpp> | |
22 | ||
23 | #include "common/debug.h" | |
24 | #include "MDSAuthCaps.h" | |
25 | ||
26 | #define dout_subsys ceph_subsys_mds | |
27 | ||
28 | #undef dout_prefix | |
29 | #define dout_prefix *_dout << "MDSAuthCap " | |
30 | ||
31 | using std::ostream; | |
32 | using std::string; | |
33 | namespace qi = boost::spirit::qi; | |
34 | namespace ascii = boost::spirit::ascii; | |
35 | namespace phoenix = boost::phoenix; | |
36 | ||
37 | template <typename Iterator> | |
38 | struct MDSCapParser : qi::grammar<Iterator, MDSAuthCaps()> | |
39 | { | |
40 | MDSCapParser() : MDSCapParser::base_type(mdscaps) | |
41 | { | |
42 | using qi::char_; | |
43 | using qi::int_; | |
44 | using qi::uint_; | |
45 | using qi::lexeme; | |
46 | using qi::alnum; | |
47 | using qi::_val; | |
48 | using qi::_1; | |
49 | using qi::_2; | |
50 | using qi::_3; | |
51 | using qi::eps; | |
52 | using qi::lit; | |
53 | ||
54 | spaces = +(lit(' ') | lit('\n') | lit('\t')); | |
55 | ||
56 | quoted_path %= | |
57 | lexeme[lit("\"") >> *(char_ - '"') >> '"'] | | |
58 | lexeme[lit("'") >> *(char_ - '\'') >> '\'']; | |
59 | unquoted_path %= +char_("a-zA-Z0-9_./-"); | |
60 | ||
61 | // match := [path=<path>] [uid=<uid> [gids=<gid>[,<gid>...]] | |
62 | path %= (spaces >> lit("path") >> lit('=') >> (quoted_path | unquoted_path)); | |
63 | uid %= (spaces >> lit("uid") >> lit('=') >> uint_); | |
64 | uintlist %= (uint_ % lit(',')); | |
65 | gidlist %= -(spaces >> lit("gids") >> lit('=') >> uintlist); | |
66 | match = -( | |
67 | (uid >> gidlist)[_val = phoenix::construct<MDSCapMatch>(_1, _2)] | | |
68 | (path >> uid >> gidlist)[_val = phoenix::construct<MDSCapMatch>(_1, _2, _3)] | | |
69 | (path)[_val = phoenix::construct<MDSCapMatch>(_1)]); | |
70 | ||
71 | // capspec = * | r[w] | |
72 | capspec = spaces >> ( | |
73 | lit("*")[_val = MDSCapSpec(true, true, true, true)] | |
74 | | | |
75 | (lit("rwp"))[_val = MDSCapSpec(true, true, false, true)] | |
76 | | | |
77 | (lit("rw"))[_val = MDSCapSpec(true, true, false, false)] | |
78 | | | |
79 | (lit("r"))[_val = MDSCapSpec(true, false, false, false)] | |
80 | ); | |
81 | ||
82 | grant = lit("allow") >> (capspec >> match)[_val = phoenix::construct<MDSCapGrant>(_1, _2)]; | |
83 | grants %= (grant % (*lit(' ') >> (lit(';') | lit(',')) >> *lit(' '))); | |
84 | mdscaps = grants [_val = phoenix::construct<MDSAuthCaps>(_1)]; | |
85 | } | |
86 | qi::rule<Iterator> spaces; | |
87 | qi::rule<Iterator, string()> quoted_path, unquoted_path; | |
88 | qi::rule<Iterator, MDSCapSpec()> capspec; | |
89 | qi::rule<Iterator, string()> path; | |
90 | qi::rule<Iterator, uint32_t()> uid; | |
91 | qi::rule<Iterator, std::vector<uint32_t>() > uintlist; | |
92 | qi::rule<Iterator, std::vector<uint32_t>() > gidlist; | |
93 | qi::rule<Iterator, MDSCapMatch()> match; | |
94 | qi::rule<Iterator, MDSCapGrant()> grant; | |
95 | qi::rule<Iterator, std::vector<MDSCapGrant>()> grants; | |
96 | qi::rule<Iterator, MDSAuthCaps()> mdscaps; | |
97 | }; | |
98 | ||
99 | void MDSCapMatch::normalize_path() | |
100 | { | |
101 | // drop any leading / | |
102 | while (path.length() && path[0] == '/') { | |
103 | path = path.substr(1); | |
104 | } | |
105 | ||
106 | // drop dup // | |
107 | // drop . | |
108 | // drop .. | |
109 | } | |
110 | ||
111 | bool MDSCapMatch::match(const std::string &target_path, | |
112 | const int caller_uid, | |
113 | const int caller_gid, | |
114 | const vector<uint64_t> *caller_gid_list) const | |
115 | { | |
116 | if (uid != MDS_AUTH_UID_ANY) { | |
117 | if (uid != caller_uid) | |
118 | return false; | |
119 | bool gid_matched = false; | |
120 | if (std::find(gids.begin(), gids.end(), caller_gid) != gids.end()) | |
121 | gid_matched = true; | |
122 | if (caller_gid_list) { | |
123 | for (auto i = caller_gid_list->begin(); i != caller_gid_list->end(); ++i) { | |
124 | if (std::find(gids.begin(), gids.end(), *i) != gids.end()) { | |
125 | gid_matched = true; | |
126 | break; | |
127 | } | |
128 | } | |
129 | } | |
130 | if (!gid_matched) | |
131 | return false; | |
132 | } | |
133 | ||
134 | if (!match_path(target_path)) { | |
135 | return false; | |
136 | } | |
137 | ||
138 | return true; | |
139 | } | |
140 | ||
141 | bool MDSCapMatch::match_path(const std::string &target_path) const | |
142 | { | |
143 | if (path.length()) { | |
144 | if (target_path.find(path) != 0) | |
145 | return false; | |
146 | // if path doesn't already have a trailing /, make sure the target | |
147 | // does so that path=/foo doesn't match target_path=/food | |
148 | if (target_path.length() > path.length() && | |
149 | path[path.length()-1] != '/' && | |
150 | target_path[path.length()] != '/') | |
151 | return false; | |
152 | } | |
153 | ||
154 | return true; | |
155 | } | |
156 | ||
157 | /** | |
158 | * Is the client *potentially* able to access this path? Actual | |
159 | * permission will depend on uids/modes in the full is_capable. | |
160 | */ | |
161 | bool MDSAuthCaps::path_capable(const std::string &inode_path) const | |
162 | { | |
163 | for (const auto &i : grants) { | |
164 | if (i.match.match_path(inode_path)) { | |
165 | return true; | |
166 | } | |
167 | } | |
168 | ||
169 | return false; | |
170 | } | |
171 | ||
172 | /** | |
173 | * For a given filesystem path, query whether this capability carries` | |
174 | * authorization to read or write. | |
175 | * | |
176 | * This is true if any of the 'grant' clauses in the capability match the | |
177 | * requested path + op. | |
178 | */ | |
179 | bool MDSAuthCaps::is_capable(const std::string &inode_path, | |
180 | uid_t inode_uid, gid_t inode_gid, | |
181 | unsigned inode_mode, | |
182 | uid_t caller_uid, gid_t caller_gid, | |
183 | const vector<uint64_t> *caller_gid_list, | |
184 | unsigned mask, | |
185 | uid_t new_uid, gid_t new_gid) const | |
186 | { | |
187 | if (cct) | |
188 | ldout(cct, 10) << __func__ << " inode(path /" << inode_path | |
189 | << " owner " << inode_uid << ":" << inode_gid | |
190 | << " mode 0" << std::oct << inode_mode << std::dec | |
191 | << ") by caller " << caller_uid << ":" << caller_gid | |
192 | // << "[" << caller_gid_list << "]"; | |
193 | << " mask " << mask | |
194 | << " new " << new_uid << ":" << new_gid | |
195 | << " cap: " << *this << dendl; | |
196 | ||
197 | for (std::vector<MDSCapGrant>::const_iterator i = grants.begin(); | |
198 | i != grants.end(); | |
199 | ++i) { | |
200 | ||
201 | if (i->match.match(inode_path, caller_uid, caller_gid, caller_gid_list) && | |
202 | i->spec.allows(mask & (MAY_READ|MAY_EXECUTE), mask & MAY_WRITE)) { | |
203 | // we have a match; narrow down GIDs to those specifically allowed here | |
204 | vector<uint64_t> gids; | |
205 | if (std::find(i->match.gids.begin(), i->match.gids.end(), caller_gid) != | |
206 | i->match.gids.end()) { | |
207 | gids.push_back(caller_gid); | |
208 | } | |
209 | if (caller_gid_list) { | |
210 | std::set_intersection(i->match.gids.begin(), i->match.gids.end(), | |
211 | caller_gid_list->begin(), caller_gid_list->end(), | |
212 | std::back_inserter(gids)); | |
213 | std::sort(gids.begin(), gids.end()); | |
214 | } | |
215 | ||
216 | ||
217 | // Spec is non-allowing if caller asked for set pool but spec forbids it | |
218 | if (mask & MAY_SET_VXATTR) { | |
219 | if (!i->spec.allows_set_vxattr()) { | |
220 | continue; | |
221 | } | |
222 | } | |
223 | ||
224 | // check unix permissions? | |
225 | if (i->match.uid == MDSCapMatch::MDS_AUTH_UID_ANY) { | |
226 | return true; | |
227 | } | |
228 | ||
229 | // chown/chgrp | |
230 | if (mask & MAY_CHOWN) { | |
231 | if (new_uid != caller_uid || // you can't chown to someone else | |
232 | inode_uid != caller_uid) { // you can't chown from someone else | |
233 | continue; | |
234 | } | |
235 | } | |
236 | if (mask & MAY_CHGRP) { | |
237 | // you can only chgrp *to* one of your groups... if you own the file. | |
238 | if (inode_uid != caller_uid || | |
239 | std::find(gids.begin(), gids.end(), new_gid) == | |
240 | gids.end()) { | |
241 | continue; | |
242 | } | |
243 | } | |
244 | ||
245 | if (inode_uid == caller_uid) { | |
246 | if ((!(mask & MAY_READ) || (inode_mode & S_IRUSR)) && | |
247 | (!(mask & MAY_WRITE) || (inode_mode & S_IWUSR)) && | |
248 | (!(mask & MAY_EXECUTE) || (inode_mode & S_IXUSR))) { | |
249 | return true; | |
250 | } | |
251 | } else if (std::find(gids.begin(), gids.end(), | |
252 | inode_gid) != gids.end()) { | |
253 | if ((!(mask & MAY_READ) || (inode_mode & S_IRGRP)) && | |
254 | (!(mask & MAY_WRITE) || (inode_mode & S_IWGRP)) && | |
255 | (!(mask & MAY_EXECUTE) || (inode_mode & S_IXGRP))) { | |
256 | return true; | |
257 | } | |
258 | } else { | |
259 | if ((!(mask & MAY_READ) || (inode_mode & S_IROTH)) && | |
260 | (!(mask & MAY_WRITE) || (inode_mode & S_IWOTH)) && | |
261 | (!(mask & MAY_EXECUTE) || (inode_mode & S_IXOTH))) { | |
262 | return true; | |
263 | } | |
264 | } | |
265 | } | |
266 | } | |
267 | ||
268 | return false; | |
269 | } | |
270 | ||
271 | void MDSAuthCaps::set_allow_all() | |
272 | { | |
273 | grants.clear(); | |
274 | grants.push_back(MDSCapGrant( | |
275 | MDSCapSpec(true, true, true, true), | |
276 | MDSCapMatch())); | |
277 | } | |
278 | ||
279 | bool MDSAuthCaps::parse(CephContext *c, const std::string& str, ostream *err) | |
280 | { | |
281 | // Special case for legacy caps | |
282 | if (str == "allow") { | |
283 | grants.clear(); | |
284 | grants.push_back(MDSCapGrant(MDSCapSpec(true, true, false, true), MDSCapMatch())); | |
285 | return true; | |
286 | } | |
287 | ||
288 | MDSCapParser<std::string::const_iterator> g; | |
289 | std::string::const_iterator iter = str.begin(); | |
290 | std::string::const_iterator end = str.end(); | |
291 | ||
292 | bool r = qi::phrase_parse(iter, end, g, ascii::space, *this); | |
293 | cct = c; // set after parser self-assignment | |
294 | if (r && iter == end) { | |
295 | for (auto& grant : grants) { | |
296 | std::sort(grant.match.gids.begin(), grant.match.gids.end()); | |
297 | } | |
298 | return true; | |
299 | } else { | |
300 | // Make sure no grants are kept after parsing failed! | |
301 | grants.clear(); | |
302 | ||
303 | if (err) | |
304 | *err << "MDSAuthCaps parse failed, stopped at '" << std::string(iter, end) | |
305 | << "' of '" << str << "'\n"; | |
306 | return false; | |
307 | } | |
308 | } | |
309 | ||
310 | ||
311 | bool MDSAuthCaps::allow_all() const | |
312 | { | |
313 | for (std::vector<MDSCapGrant>::const_iterator i = grants.begin(); i != grants.end(); ++i) { | |
314 | if (i->match.is_match_all() && i->spec.allow_all()) { | |
315 | return true; | |
316 | } | |
317 | } | |
318 | ||
319 | return false; | |
320 | } | |
321 | ||
322 | ||
323 | ostream &operator<<(ostream &out, const MDSCapMatch &match) | |
324 | { | |
325 | if (match.path.length()) { | |
326 | out << "path=\"/" << match.path << "\""; | |
327 | if (match.uid != MDSCapMatch::MDS_AUTH_UID_ANY) { | |
328 | out << " "; | |
329 | } | |
330 | } | |
331 | if (match.uid != MDSCapMatch::MDS_AUTH_UID_ANY) { | |
332 | out << "uid=" << match.uid; | |
333 | if (!match.gids.empty()) { | |
334 | out << " gids="; | |
335 | for (std::vector<gid_t>::const_iterator p = match.gids.begin(); | |
336 | p != match.gids.end(); | |
337 | ++p) { | |
338 | if (p != match.gids.begin()) | |
339 | out << ','; | |
340 | out << *p; | |
341 | } | |
342 | } | |
343 | } | |
344 | ||
345 | return out; | |
346 | } | |
347 | ||
348 | ||
349 | ostream &operator<<(ostream &out, const MDSCapSpec &spec) | |
350 | { | |
351 | if (spec.any) { | |
352 | out << "*"; | |
353 | } else { | |
354 | if (spec.read) { | |
355 | out << "r"; | |
356 | } | |
357 | if (spec.write) { | |
358 | out << "w"; | |
359 | } | |
360 | } | |
361 | ||
362 | return out; | |
363 | } | |
364 | ||
365 | ||
366 | ostream &operator<<(ostream &out, const MDSCapGrant &grant) | |
367 | { | |
368 | out << "allow "; | |
369 | out << grant.spec; | |
370 | if (!grant.match.is_match_all()) { | |
371 | out << " " << grant.match; | |
372 | } | |
373 | ||
374 | return out; | |
375 | } | |
376 | ||
377 | ||
378 | ostream &operator<<(ostream &out, const MDSAuthCaps &cap) | |
379 | { | |
380 | out << "MDSAuthCaps["; | |
381 | for (size_t i = 0; i < cap.grants.size(); ++i) { | |
382 | out << cap.grants[i]; | |
383 | if (i < cap.grants.size() - 1) { | |
384 | out << ", "; | |
385 | } | |
386 | } | |
387 | out << "]"; | |
388 | ||
389 | return out; | |
390 | } | |
391 |