Annotation of embedaddon/sudo/src/load_plugins.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (c) 2009-2011 Todd C. Miller <Todd.Miller@courtesan.com>
                      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: #include <config.h>
                     18: 
                     19: #include <sys/types.h>
                     20: #include <sys/param.h>
                     21: #include <sys/stat.h>
                     22: #include <stdio.h>
                     23: #ifdef STDC_HEADERS
                     24: # include <stdlib.h>
                     25: # include <stddef.h>
                     26: #else
                     27: # ifdef HAVE_STDLIB_H
                     28: #  include <stdlib.h>
                     29: # endif
                     30: #endif /* STDC_HEADERS */
                     31: #ifdef HAVE_STRING_H
                     32: # include <string.h>
                     33: #endif /* HAVE_STRING_H */
                     34: #ifdef HAVE_STRINGS_H
                     35: # include <strings.h>
                     36: #endif /* HAVE_STRINGS_H */
                     37: #ifdef HAVE_UNISTD_H
                     38: # include <unistd.h>
                     39: #endif /* HAVE_UNISTD_H */
                     40: #ifdef HAVE_DLOPEN
                     41: # include <dlfcn.h>
                     42: #else
                     43: # include "compat/dlfcn.h"
                     44: #endif
                     45: #include <errno.h>
                     46: 
                     47: #include "sudo.h"
                     48: #include "sudo_plugin.h"
                     49: #include "sudo_plugin_int.h"
                     50: 
                     51: #ifndef RTLD_GLOBAL
                     52: # define RTLD_GLOBAL   0
                     53: #endif
                     54: 
                     55: #ifdef _PATH_SUDO_NOEXEC
                     56: const char *noexec_path = _PATH_SUDO_NOEXEC;
                     57: #endif
                     58: 
                     59: /*
                     60:  * Read in /etc/sudo.conf
                     61:  * Returns a list of plugins.
                     62:  */
                     63: static struct plugin_info_list *
                     64: sudo_read_conf(const char *conf_file)
                     65: {
                     66:     FILE *fp;
                     67:     char *cp, *name, *path;
                     68:     struct plugin_info *info;
                     69:     static struct plugin_info_list pil; /* XXX */
                     70: 
                     71:     if ((fp = fopen(conf_file, "r")) == NULL)
                     72:        goto done;
                     73: 
                     74:     while ((cp = sudo_parseln(fp)) != NULL) {
                     75:        /* Skip blank or comment lines */
                     76:        if (*cp == '\0')
                     77:            continue;
                     78: 
                     79:        /* Look for a line starting with "Path" */
                     80:        if (strncasecmp(cp, "Path", 4) == 0) {
                     81:            /* Parse line */
                     82:            if ((name = strtok(cp + 4, " \t")) == NULL ||
                     83:                (path = strtok(NULL, " \t")) == NULL) {
                     84:                continue;
                     85:            }
                     86:            if (strcasecmp(name, "askpass") == 0)
                     87:                askpass_path = estrdup(path);
                     88: #ifdef _PATH_SUDO_NOEXEC
                     89:            else if (strcasecmp(name, "noexec") == 0)
                     90:                noexec_path = estrdup(path);
                     91: #endif
                     92:            continue;
                     93:        }
                     94: 
                     95:        /* Look for a line starting with "Plugin" */
                     96:        if (strncasecmp(cp, "Plugin", 6) == 0) {
                     97:            /* Parse line */
                     98:            if ((name = strtok(cp + 6, " \t")) == NULL ||
                     99:                (path = strtok(NULL, " \t")) == NULL) {
                    100:                continue;
                    101:            }
                    102:            info = emalloc(sizeof(*info));
                    103:            info->symbol_name = estrdup(name);
                    104:            info->path = estrdup(path);
                    105:            info->prev = info;
                    106:            info->next = NULL;
                    107:            tq_append(&pil, info);
                    108:            continue;
                    109:        }
                    110:     }
                    111:     fclose(fp);
                    112: 
                    113: done:
                    114:     if (tq_empty(&pil)) {
                    115:        /* Default policy plugin */
                    116:        info = emalloc(sizeof(*info));
                    117:        info->symbol_name = "sudoers_policy";
                    118:        info->path = SUDOERS_PLUGIN;
                    119:        info->prev = info;
                    120:        info->next = NULL;
                    121:        tq_append(&pil, info);
                    122: 
                    123:        /* Default I/O plugin */
                    124:        info = emalloc(sizeof(*info));
                    125:        info->symbol_name = "sudoers_io";
                    126:        info->path = SUDOERS_PLUGIN;
                    127:        info->prev = info;
                    128:        info->next = NULL;
                    129:        tq_append(&pil, info);
                    130:     }
                    131: 
                    132:     return &pil;
                    133: }
                    134: 
                    135: /*
                    136:  * Load the plugins listed in conf_file.
                    137:  */
                    138: int
                    139: sudo_load_plugins(const char *conf_file,
                    140:     struct plugin_container *policy_plugin,
                    141:     struct plugin_container_list *io_plugins)
                    142: {
                    143:     struct generic_plugin *plugin;
                    144:     struct plugin_container *container;
                    145:     struct plugin_info *info;
                    146:     struct plugin_info_list *plugin_list;
                    147:     struct stat sb;
                    148:     void *handle;
                    149:     char path[PATH_MAX];
                    150:     int rval = FALSE;
                    151: 
                    152:     /* Parse sudo.conf */
                    153:     plugin_list = sudo_read_conf(conf_file);
                    154: 
                    155:     tq_foreach_fwd(plugin_list, info) {
                    156:        if (info->path[0] == '/') {
                    157:            if (strlcpy(path, info->path, sizeof(path)) >= sizeof(path)) {
                    158:                warningx(_("%s: %s"), info->path, strerror(ENAMETOOLONG));
                    159:                goto done;
                    160:            }
                    161:        } else {
                    162:            if (snprintf(path, sizeof(path), "%s%s", _PATH_SUDO_PLUGIN_DIR,
                    163:                info->path) >= sizeof(path)) {
                    164:                warningx(_("%s%s: %s"), _PATH_SUDO_PLUGIN_DIR, info->path,
                    165:                    strerror(ENAMETOOLONG));
                    166:                goto done;
                    167:            }
                    168:        }
                    169:        if (stat(path, &sb) != 0) {
                    170:            warning("%s", path);
                    171:            goto done;
                    172:        }
                    173:        if (sb.st_uid != ROOT_UID) {
                    174:            warningx(_("%s must be owned by uid %d"), path, ROOT_UID);
                    175:            goto done;
                    176:        }
                    177:        if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
                    178:            warningx(_("%s must be only be writable by owner"), path);
                    179:            goto done;
                    180:        }
                    181: 
                    182:        /* Open plugin and map in symbol */
                    183:        handle = dlopen(path, RTLD_LAZY|RTLD_GLOBAL);
                    184:        if (!handle) {
                    185:            warningx(_("unable to dlopen %s: %s"), path, dlerror());
                    186:            goto done;
                    187:        }
                    188:        plugin = dlsym(handle, info->symbol_name);
                    189:        if (!plugin) {
                    190:            warningx(_("%s: unable to find symbol %s"), path,
                    191:                info->symbol_name);
                    192:            goto done;
                    193:        }
                    194: 
                    195:        if (plugin->type != SUDO_POLICY_PLUGIN && plugin->type != SUDO_IO_PLUGIN) {
                    196:            warningx(_("%s: unknown policy type %d"), path, plugin->type);
                    197:            goto done;
                    198:        }
                    199:        if (SUDO_API_VERSION_GET_MAJOR(plugin->version) != SUDO_API_VERSION_MAJOR) {
                    200:            warningx(_("%s: incompatible policy major version %d, expected %d"),
                    201:                path, SUDO_API_VERSION_GET_MAJOR(plugin->version),
                    202:                SUDO_API_VERSION_MAJOR);
                    203:            goto done;
                    204:        }
                    205:        if (plugin->type == SUDO_POLICY_PLUGIN) {
                    206:            if (policy_plugin->handle) {
                    207:                warningx(_("%s: only a single policy plugin may be loaded"),
                    208:                    conf_file);
                    209:                goto done;
                    210:            }
                    211:            policy_plugin->handle = handle;
                    212:            policy_plugin->name = info->symbol_name;
                    213:            policy_plugin->u.generic = plugin;
                    214:        } else if (plugin->type == SUDO_IO_PLUGIN) {
                    215:            container = emalloc(sizeof(*container));
                    216:            container->prev = container;
                    217:            container->next = NULL;
                    218:            container->handle = handle;
                    219:            container->name = info->symbol_name;
                    220:            container->u.generic = plugin;
                    221:            tq_append(io_plugins, container);
                    222:        }
                    223:     }
                    224:     if (policy_plugin->handle == NULL) {
                    225:        warningx(_("%s: at least one policy plugin must be specified"),
                    226:            conf_file);
                    227:        goto done;
                    228:     }
                    229:     if (policy_plugin->u.policy->check_policy == NULL) {
                    230:        warningx(_("policy plugin %s does not include a check_policy method"),
                    231:            policy_plugin->name);
                    232:        goto done;
                    233:     }
                    234: 
                    235:     rval = TRUE;
                    236: 
                    237: done:
                    238:     return rval;
                    239: }

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