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Date:: Thu Nov 17 10:16:20 2022 UTC
Message:: fix group membership check in gotd auth ok op@
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  1 0ccf3acb 2022-11-16 stsp /*
  2 0ccf3acb 2022-11-16 stsp  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
  3 0ccf3acb 2022-11-16 stsp  * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
  4 0ccf3acb 2022-11-16 stsp  *
  5 0ccf3acb 2022-11-16 stsp  * Permission to use, copy, modify, and distribute this software for any
  6 0ccf3acb 2022-11-16 stsp  * purpose with or without fee is hereby granted, provided that the above
  7 0ccf3acb 2022-11-16 stsp  * copyright notice and this permission notice appear in all copies.
  8 0ccf3acb 2022-11-16 stsp  *
  9 0ccf3acb 2022-11-16 stsp  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 10 0ccf3acb 2022-11-16 stsp  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 11 0ccf3acb 2022-11-16 stsp  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 12 0ccf3acb 2022-11-16 stsp  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 13 0ccf3acb 2022-11-16 stsp  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 14 0ccf3acb 2022-11-16 stsp  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 15 0ccf3acb 2022-11-16 stsp  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 16 0ccf3acb 2022-11-16 stsp  */
 17 0ccf3acb 2022-11-16 stsp 
 18 0ccf3acb 2022-11-16 stsp #include <sys/types.h>
 19 0ccf3acb 2022-11-16 stsp #include <sys/queue.h>
 20 0ccf3acb 2022-11-16 stsp #include <sys/uio.h>
 21 0ccf3acb 2022-11-16 stsp 
 22 0ccf3acb 2022-11-16 stsp #include <errno.h>
 23 0ccf3acb 2022-11-16 stsp #include <event.h>
 24 ddbe612c 2022-11-17 stsp #include <grp.h>
 25 0ccf3acb 2022-11-16 stsp #include <limits.h>
 26 0ccf3acb 2022-11-16 stsp #include <pwd.h>
 27 0ccf3acb 2022-11-16 stsp #include <grp.h>
 28 0ccf3acb 2022-11-16 stsp #include <sha1.h>
 29 0ccf3acb 2022-11-16 stsp #include <stdint.h>
 30 0ccf3acb 2022-11-16 stsp #include <stdio.h>
 31 0ccf3acb 2022-11-16 stsp #include <stdlib.h>
 32 0ccf3acb 2022-11-16 stsp #include <imsg.h>
 33 ddbe612c 2022-11-17 stsp #include <unistd.h>
 34 0ccf3acb 2022-11-16 stsp 
 35 0ccf3acb 2022-11-16 stsp #include "got_error.h"
 36 0ccf3acb 2022-11-16 stsp 
 37 0ccf3acb 2022-11-16 stsp #include "gotd.h"
 38 ddbe612c 2022-11-17 stsp #include "log.h"
 39 0ccf3acb 2022-11-16 stsp #include "auth.h"
 40 0ccf3acb 2022-11-16 stsp 
 41 0ccf3acb 2022-11-16 stsp static int
 42 0ccf3acb 2022-11-16 stsp parseuid(const char *s, uid_t *uid)
 43 0ccf3acb 2022-11-16 stsp {
 44 0ccf3acb 2022-11-16 stsp 	struct passwd *pw;
 45 0ccf3acb 2022-11-16 stsp 	const char *errstr;
 46 0ccf3acb 2022-11-16 stsp 
 47 0ccf3acb 2022-11-16 stsp 	if ((pw = getpwnam(s)) != NULL) {
 48 0ccf3acb 2022-11-16 stsp 		*uid = pw->pw_uid;
 49 0ccf3acb 2022-11-16 stsp 		if (*uid == UID_MAX)
 50 0ccf3acb 2022-11-16 stsp 			return -1;
 51 0ccf3acb 2022-11-16 stsp 		return 0;
 52 0ccf3acb 2022-11-16 stsp 	}
 53 0ccf3acb 2022-11-16 stsp 	*uid = strtonum(s, 0, UID_MAX - 1, &errstr);
 54 0ccf3acb 2022-11-16 stsp 	if (errstr)
 55 0ccf3acb 2022-11-16 stsp 		return -1;
 56 0ccf3acb 2022-11-16 stsp 	return 0;
 57 0ccf3acb 2022-11-16 stsp }
 58 0ccf3acb 2022-11-16 stsp 
 59 0ccf3acb 2022-11-16 stsp static int
 60 0ccf3acb 2022-11-16 stsp uidcheck(const char *s, uid_t desired)
 61 0ccf3acb 2022-11-16 stsp {
 62 0ccf3acb 2022-11-16 stsp 	uid_t uid;
 63 0ccf3acb 2022-11-16 stsp 
 64 0ccf3acb 2022-11-16 stsp 	if (parseuid(s, &uid) != 0)
 65 0ccf3acb 2022-11-16 stsp 		return -1;
 66 0ccf3acb 2022-11-16 stsp 	if (uid != desired)
 67 0ccf3acb 2022-11-16 stsp 		return -1;
 68 0ccf3acb 2022-11-16 stsp 	return 0;
 69 0ccf3acb 2022-11-16 stsp }
 70 0ccf3acb 2022-11-16 stsp 
 71 0ccf3acb 2022-11-16 stsp static int
 72 0ccf3acb 2022-11-16 stsp parsegid(const char *s, gid_t *gid)
 73 0ccf3acb 2022-11-16 stsp {
 74 0ccf3acb 2022-11-16 stsp 	struct group *gr;
 75 0ccf3acb 2022-11-16 stsp 	const char *errstr;
 76 0ccf3acb 2022-11-16 stsp 
 77 0ccf3acb 2022-11-16 stsp 	if ((gr = getgrnam(s)) != NULL) {
 78 0ccf3acb 2022-11-16 stsp 		*gid = gr->gr_gid;
 79 0ccf3acb 2022-11-16 stsp 		if (*gid == GID_MAX)
 80 0ccf3acb 2022-11-16 stsp 			return -1;
 81 0ccf3acb 2022-11-16 stsp 		return 0;
 82 0ccf3acb 2022-11-16 stsp 	}
 83 0ccf3acb 2022-11-16 stsp 	*gid = strtonum(s, 0, GID_MAX - 1, &errstr);
 84 0ccf3acb 2022-11-16 stsp 	if (errstr)
 85 0ccf3acb 2022-11-16 stsp 		return -1;
 86 0ccf3acb 2022-11-16 stsp 	return 0;
 87 0ccf3acb 2022-11-16 stsp }
 88 0ccf3acb 2022-11-16 stsp 
 89 0ccf3acb 2022-11-16 stsp static int
 90 0ccf3acb 2022-11-16 stsp match_identifier(const char *identifier, gid_t *groups, int ngroups,
 91 0ccf3acb 2022-11-16 stsp     uid_t euid, gid_t egid)
 92 0ccf3acb 2022-11-16 stsp {
 93 0ccf3acb 2022-11-16 stsp 	int i;
 94 0ccf3acb 2022-11-16 stsp 
 95 0ccf3acb 2022-11-16 stsp 	if (identifier[0] == ':') {
 96 0ccf3acb 2022-11-16 stsp 		gid_t rgid;
 97 0ccf3acb 2022-11-16 stsp 		if (parsegid(identifier + 1, &rgid) == -1)
 98 0ccf3acb 2022-11-16 stsp 			return 0;
 99 ddbe612c 2022-11-17 stsp 		if (rgid == egid)
100 ddbe612c 2022-11-17 stsp 			return 1;
101 0ccf3acb 2022-11-16 stsp 		for (i = 0; i < ngroups; i++) {
102 ddbe612c 2022-11-17 stsp 			if (rgid == groups[i])
103 0ccf3acb 2022-11-16 stsp 				break;
104 0ccf3acb 2022-11-16 stsp 		}
105 0ccf3acb 2022-11-16 stsp 		if (i == ngroups)
106 0ccf3acb 2022-11-16 stsp 			return 0;
107 0ccf3acb 2022-11-16 stsp 	} else if (uidcheck(identifier, euid) != 0)
108 0ccf3acb 2022-11-16 stsp 		return 0;
109 0ccf3acb 2022-11-16 stsp 
110 0ccf3acb 2022-11-16 stsp 	return 1;
111 0ccf3acb 2022-11-16 stsp }
112 0ccf3acb 2022-11-16 stsp 
113 0ccf3acb 2022-11-16 stsp const struct got_error *
114 0ccf3acb 2022-11-16 stsp gotd_auth_check(struct gotd_access_rule_list *rules, const char *repo_name,
115 ddbe612c 2022-11-17 stsp     uid_t euid, gid_t egid, int required_auth)
116 0ccf3acb 2022-11-16 stsp {
117 0ccf3acb 2022-11-16 stsp 	struct gotd_access_rule *rule;
118 0ccf3acb 2022-11-16 stsp 	enum gotd_access access = GOTD_ACCESS_DENIED;
119 ddbe612c 2022-11-17 stsp 	struct passwd *pw;
120 ddbe612c 2022-11-17 stsp 	gid_t groups[NGROUPS_MAX];
121 ddbe612c 2022-11-17 stsp 	int ngroups = NGROUPS_MAX;
122 0ccf3acb 2022-11-16 stsp 
123 ddbe612c 2022-11-17 stsp 	pw = getpwuid(euid);
124 ddbe612c 2022-11-17 stsp 	if (pw == NULL)
125 ddbe612c 2022-11-17 stsp 		return got_error_from_errno("getpwuid");
126 ddbe612c 2022-11-17 stsp 
127 ddbe612c 2022-11-17 stsp 	if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups) == -1)
128 ddbe612c 2022-11-17 stsp 		log_warnx("group membership list truncated");
129 ddbe612c 2022-11-17 stsp 
130 0ccf3acb 2022-11-16 stsp 	STAILQ_FOREACH(rule, rules, entry) {
131 0ccf3acb 2022-11-16 stsp 		if (!match_identifier(rule->identifier, groups, ngroups,
132 0ccf3acb 2022-11-16 stsp 		    euid, egid))
133 0ccf3acb 2022-11-16 stsp 			continue;
134 0ccf3acb 2022-11-16 stsp 
135 0ccf3acb 2022-11-16 stsp 		access = rule->access;
136 0ccf3acb 2022-11-16 stsp 		if (rule->access == GOTD_ACCESS_PERMITTED &&
137 0ccf3acb 2022-11-16 stsp 		    (rule->authorization & required_auth) != required_auth)
138 0ccf3acb 2022-11-16 stsp 			access = GOTD_ACCESS_DENIED;
139 0ccf3acb 2022-11-16 stsp 	}
140 0ccf3acb 2022-11-16 stsp 
141 0ccf3acb 2022-11-16 stsp 	if (access == GOTD_ACCESS_DENIED)
142 0ccf3acb 2022-11-16 stsp 		return got_error_set_errno(EACCES, repo_name);
143 0ccf3acb 2022-11-16 stsp 
144 0ccf3acb 2022-11-16 stsp 	if (access == GOTD_ACCESS_PERMITTED)
145 0ccf3acb 2022-11-16 stsp 		return NULL;
146 0ccf3acb 2022-11-16 stsp 
147 0ccf3acb 2022-11-16 stsp 	/* should not happen, this would be a bug */
148 0ccf3acb 2022-11-16 stsp 	return got_error_msg(GOT_ERR_NOT_IMPL, "bad access rule");
149 0ccf3acb 2022-11-16 stsp }