crypto/openssh/sftp-usergroup.c

   1 /*
   2  * Copyright (c) 2022 Damien Miller <djm@mindrot.org>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 /* sftp client user/group lookup and caching */
  18
  19 #include "includes.h"
  20
  21 #include <sys/types.h>
  22 #include <openbsd-compat/sys-tree.h>
  23
  24 #include <stdlib.h>
  25 #include <stdarg.h>
  26 #include <string.h>
  27
  28 #include "log.h"
  29 #include "xmalloc.h"
  30
  31 #include "sftp-common.h"
  32 #include "sftp-client.h"
  33 #include "sftp-usergroup.h"
  34
  35 /* Tree of id, name */
  36 struct idname {
  37         u_int id;
  38         char *name;
  39         RB_ENTRY(idname) entry;
  40         /* XXX implement bounded cache as TAILQ */
  41 };
  42 static int
  43 idname_cmp(struct idname *a, struct idname *b)
  44 {
  45         if (a->id == b->id)
  46                 return 0;
  47         return a->id > b->id ? 1 : -1;
  48 }
  49 RB_HEAD(idname_tree, idname);
  50 RB_GENERATE_STATIC(idname_tree, idname, entry, idname_cmp)
  51
  52 static struct idname_tree user_idname = RB_INITIALIZER(&user_idname);
  53 static struct idname_tree group_idname = RB_INITIALIZER(&group_idname);
  54
  55 static void
  56 idname_free(struct idname *idname)
  57 {
  58         if (idname == NULL)
  59                 return;
  60         free(idname->name);
  61         free(idname);
  62 }
  63
  64 static void
  65 idname_enter(struct idname_tree *tree, u_int id, const char *name)
  66 {
  67         struct idname *idname;
  68
  69         if ((idname = xcalloc(1, sizeof(*idname))) == NULL)
  70                 fatal_f("alloc");
  71         idname->id = id;
  72         idname->name = xstrdup(name);
  73         if (RB_INSERT(idname_tree, tree, idname) != NULL)
  74                 idname_free(idname);
  75 }
  76
  77 static const char *
  78 idname_lookup(struct idname_tree *tree, u_int id)
  79 {
  80         struct idname idname, *found;
  81
  82         memset(&idname, 0, sizeof(idname));
  83         idname.id = id;
  84         if ((found = RB_FIND(idname_tree, tree, &idname)) != NULL)
  85                 return found->name;
  86         return NULL;
  87 }
  88
  89 static void
  90 freenames(char **names, u_int nnames)
  91 {
  92         u_int i;
  93
  94         if (names == NULL)
  95                 return;
  96         for (i = 0; i < nnames; i++)
  97                 free(names[i]);
  98         free(names);
  99 }
 100
 101 static void
 102 lookup_and_record(struct sftp_conn *conn,
 103     u_int *uids, u_int nuids, u_int *gids, u_int ngids)
 104 {
 105         int r;
 106         u_int i;
 107         char **usernames = NULL, **groupnames = NULL;
 108
 109         if ((r = sftp_get_users_groups_by_id(conn, uids, nuids, gids, ngids,
 110             &usernames, &groupnames)) != 0) {
 111                 debug_fr(r, "sftp_get_users_groups_by_id");
 112                 return;
 113         }
 114         for (i = 0; i < nuids; i++) {
 115                 if (usernames[i] == NULL) {
 116                         debug3_f("uid %u not resolved", uids[i]);
 117                         continue;
 118                 }
 119                 debug3_f("record uid %u => \"%s\"", uids[i], usernames[i]);
 120                 idname_enter(&user_idname, uids[i], usernames[i]);
 121         }
 122         for (i = 0; i < ngids; i++) {
 123                 if (groupnames[i] == NULL) {
 124                         debug3_f("gid %u not resolved", gids[i]);
 125                         continue;
 126                 }
 127                 debug3_f("record gid %u => \"%s\"", gids[i], groupnames[i]);
 128                 idname_enter(&group_idname, gids[i], groupnames[i]);
 129         }
 130         freenames(usernames, nuids);
 131         freenames(groupnames, ngids);
 132 }
 133
 134 static int
 135 has_id(u_int id, u_int *ids, u_int nids)
 136 {
 137         u_int i;
 138
 139         if (nids == 0)
 140                 return 0;
 141
 142         /* XXX O(N^2) */
 143         for (i = 0; i < nids; i++) {
 144                 if (ids[i] == id)
 145                         break;
 146         }
 147         return i < nids;
 148 }
 149
 150 static void
 151 collect_ids_from_glob(glob_t *g, int user, u_int **idsp, u_int *nidsp)
 152 {
 153         u_int id, i, n = 0, *ids = NULL;
 154
 155         for (i = 0; g->gl_pathv[i] != NULL; i++) {
 156                 if (user) {
 157                         if (ruser_name(g->gl_statv[i]->st_uid) != NULL)
 158                                 continue; /* Already seen */
 159                         id = (u_int)g->gl_statv[i]->st_uid;
 160                 } else {
 161                         if (rgroup_name(g->gl_statv[i]->st_gid) != NULL)
 162                                 continue; /* Already seen */
 163                         id = (u_int)g->gl_statv[i]->st_gid;
 164                 }
 165                 if (has_id(id, ids, n))
 166                         continue;
 167                 ids = xrecallocarray(ids, n, n + 1, sizeof(*ids));
 168                 ids[n++] = id;
 169         }
 170         *idsp = ids;
 171         *nidsp = n;
 172 }
 173
 174 void
 175 get_remote_user_groups_from_glob(struct sftp_conn *conn, glob_t *g)
 176 {
 177         u_int *uids = NULL, nuids = 0, *gids = NULL, ngids = 0;
 178
 179         if (!sftp_can_get_users_groups_by_id(conn))
 180                 return;
 181
 182         collect_ids_from_glob(g, 1, &uids, &nuids);
 183         collect_ids_from_glob(g, 0, &gids, &ngids);
 184         lookup_and_record(conn, uids, nuids, gids, ngids);
 185         free(uids);
 186         free(gids);
 187 }
 188
 189 static void
 190 collect_ids_from_dirents(SFTP_DIRENT **d, int user, u_int **idsp, u_int *nidsp)
 191 {
 192         u_int id, i, n = 0, *ids = NULL;
 193
 194         for (i = 0; d[i] != NULL; i++) {
 195                 if (user) {
 196                         if (ruser_name((uid_t)(d[i]->a.uid)) != NULL)
 197                                 continue; /* Already seen */
 198                         id = d[i]->a.uid;
 199                 } else {
 200                         if (rgroup_name((gid_t)(d[i]->a.gid)) != NULL)
 201                                 continue; /* Already seen */
 202                         id = d[i]->a.gid;
 203                 }
 204                 if (has_id(id, ids, n))
 205                         continue;
 206                 ids = xrecallocarray(ids, n, n + 1, sizeof(*ids));
 207                 ids[n++] = id;
 208         }
 209         *idsp = ids;
 210         *nidsp = n;
 211 }
 212
 213 void
 214 get_remote_user_groups_from_dirents(struct sftp_conn *conn, SFTP_DIRENT **d)
 215 {
 216         u_int *uids = NULL, nuids = 0, *gids = NULL, ngids = 0;
 217
 218         if (!sftp_can_get_users_groups_by_id(conn))
 219                 return;
 220
 221         collect_ids_from_dirents(d, 1, &uids, &nuids);
 222         collect_ids_from_dirents(d, 0, &gids, &ngids);
 223         lookup_and_record(conn, uids, nuids, gids, ngids);
 224         free(uids);
 225         free(gids);
 226 }
 227
 228 const char *
 229 ruser_name(uid_t uid)
 230 {
 231         return idname_lookup(&user_idname, (u_int)uid);
 232 }
 233
 234 const char *
 235 rgroup_name(uid_t gid)
 236 {
 237         return idname_lookup(&group_idname, (u_int)gid);
 238 }
 239