sudo/plugins/sudoers/parse_ldif.c

779 lines
21 KiB
C

/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2018-2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#include <ctype.h>
#include <sudoers.h>
#include <sudo_ldap.h>
#include <redblack.h>
#include <strlist.h>
#include <gram.h>
struct sudo_role {
STAILQ_ENTRY(sudo_role) entries;
char *cn;
char *notbefore;
char *notafter;
double order;
struct sudoers_str_list *cmnds;
struct sudoers_str_list *hosts;
struct sudoers_str_list *users;
struct sudoers_str_list *runasusers;
struct sudoers_str_list *runasgroups;
struct sudoers_str_list *options;
};
STAILQ_HEAD(sudo_role_list, sudo_role);
static void
sudo_role_free(struct sudo_role *role)
{
debug_decl(sudo_role_free, SUDOERS_DEBUG_UTIL);
if (role != NULL) {
free(role->cn);
free(role->notbefore);
free(role->notafter);
str_list_free(role->cmnds);
str_list_free(role->hosts);
str_list_free(role->users);
str_list_free(role->runasusers);
str_list_free(role->runasgroups);
str_list_free(role->options);
free(role);
}
debug_return;
}
static struct sudo_role *
sudo_role_alloc(void)
{
struct sudo_role *role;
debug_decl(sudo_role_alloc, SUDOERS_DEBUG_UTIL);
role = calloc(1, sizeof(*role));
if (role != NULL) {
role->cmnds = str_list_alloc();
role->hosts = str_list_alloc();
role->users = str_list_alloc();
role->runasusers = str_list_alloc();
role->runasgroups = str_list_alloc();
role->options = str_list_alloc();
if (role->cmnds == NULL || role->hosts == NULL ||
role->users == NULL || role->runasusers == NULL ||
role->runasgroups == NULL || role->options == NULL) {
sudo_role_free(role);
role = NULL;
}
}
debug_return_ptr(role);
}
/*
* Parse an LDIF line, filling in attribute name and value.
* Modifies line, decodes base64 attribute values if present.
* See http://www.faqs.org/rfcs/rfc2849.html
*/
static bool
ldif_parse_attribute(char *line, char **name, char **value)
{
bool encoded = false;
char *attr, *cp, *ep, *colon;
size_t len;
debug_decl(ldif_parse_attribute, SUDOERS_DEBUG_UTIL);
/* Parse attribute name: [a-zA-Z][a-zA-Z0-9-]*: */
if (!isalpha((unsigned char)*line))
debug_return_bool(false);
for (cp = line + 1; *cp != ':' && *cp != '\0'; cp++) {
if (!isalnum((unsigned char)*cp) && *cp != '-')
debug_return_bool(false);
}
if (*cp != ':')
debug_return_bool(false);
colon = cp++;
/* Check for foo:: base64str. */
if (*cp == ':') {
encoded = true;
cp++;
}
/* Trim leading and trailing space. */
while (*cp == ' ')
cp++;
ep = cp + strlen(cp);
while (ep > cp && ep[-1] == ' ') {
ep--;
/* Don't trim escaped trailing space if not base64. */
if (!encoded && ep != cp && ep[-1] == '\\')
break;
*ep = '\0';
}
attr = cp;
if (encoded) {
/*
* Decode base64 inline and add NUL-terminator.
* The copy allows us to provide a useful message on error.
*/
char *copy = strdup(attr);
if (copy == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
len = base64_decode(attr, (unsigned char *)copy, strlen(copy));
if (len == (size_t)-1) {
free(copy);
debug_return_bool(false);
}
memcpy(attr, copy, len);
attr[len] = '\0';
free(copy);
}
*colon = '\0';
*name = line;
*value = attr;
debug_return_bool(true);
}
/*
* Allocate a struct sudoers_string, store str in it and
* insert into the specified strlist.
*/
static void
ldif_store_string(const char *str, struct sudoers_str_list *strlist, bool sorted)
{
struct sudoers_string *ls;
debug_decl(ldif_store_string, SUDOERS_DEBUG_UTIL);
if ((ls = sudoers_string_alloc(str)) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
if (!sorted) {
STAILQ_INSERT_TAIL(strlist, ls, entries);
} else {
struct sudoers_string *prev, *next;
/* Insertion sort, list is small. */
prev = STAILQ_FIRST(strlist);
if (prev == NULL || strcasecmp(str, prev->str) <= 0) {
STAILQ_INSERT_HEAD(strlist, ls, entries);
} else {
while ((next = STAILQ_NEXT(prev, entries)) != NULL) {
if (strcasecmp(str, next->str) <= 0)
break;
prev = next;
}
STAILQ_INSERT_AFTER(strlist, prev, ls, entries);
}
}
debug_return;
}
/*
* Iterator for sudo_ldap_role_to_priv().
* Takes a pointer to a struct sudoers_string *.
* Returns the string or NULL if we've reached the end.
*/
static char *
sudoers_string_iter(void **vp)
{
struct sudoers_string *ls = *vp;
if (ls == NULL)
return NULL;
*vp = STAILQ_NEXT(ls, entries);
return ls->str;
}
static int
role_order_cmp(const void *va, const void *vb)
{
const struct sudo_role *a = *(const struct sudo_role **)va;
const struct sudo_role *b = *(const struct sudo_role **)vb;
debug_decl(role_order_cmp, SUDOERS_DEBUG_LDAP);
debug_return_int(a->order < b->order ? -1 :
(a->order > b->order ? 1 : 0));
}
/*
* Parse list of sudoOption and store in the parse tree's defaults list.
*/
static void
ldif_store_options(struct sudoers_parse_tree *parse_tree,
struct sudoers_str_list *options)
{
struct defaults *d;
struct sudoers_string *ls;
char *var, *val;
debug_decl(ldif_store_options, SUDOERS_DEBUG_UTIL);
STAILQ_FOREACH(ls, options, entries) {
if ((d = calloc(1, sizeof(*d))) == NULL ||
(d->binding = malloc(sizeof(*d->binding))) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
TAILQ_INIT(&d->binding->members);
d->binding->refcnt = 1;
d->type = DEFAULTS;
d->op = sudo_ldap_parse_option(ls->str, &var, &val);
if ((d->var = strdup(var)) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
if (val != NULL) {
if ((d->val = strdup(val)) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
}
TAILQ_INSERT_TAIL(&parse_tree->defaults, d, entries);
}
debug_return;
}
static int
str_list_cmp(const void *aa, const void *bb)
{
const struct sudoers_str_list *a = aa;
const struct sudoers_str_list *b = bb;
const struct sudoers_string *lsa = STAILQ_FIRST(a);
const struct sudoers_string *lsb = STAILQ_FIRST(b);
int ret;
while (lsa != NULL && lsb != NULL) {
if ((ret = strcasecmp(lsa->str, lsb->str)) != 0)
return ret;
lsa = STAILQ_NEXT(lsa, entries);
lsb = STAILQ_NEXT(lsb, entries);
}
return lsa == lsb ? 0 : (lsa == NULL ? -1 : 1);
}
static int
str_list_cache(struct rbtree *cache, struct sudoers_str_list **strlistp)
{
struct sudoers_str_list *strlist = *strlistp;
struct rbnode *node;
int ret;
debug_decl(str_list_cache, SUDOERS_DEBUG_UTIL);
ret = rbinsert(cache, strlist, &node);
switch (ret) {
case 0:
/* new entry, take a ref for the cache */
strlist->refcnt++;
break;
case 1:
/* already exists, use existing and take a ref. */
str_list_free(strlist);
strlist = node->data;
strlist->refcnt++;
*strlistp = strlist;
break;
}
debug_return_int(ret);
}
/*
* Convert a sudoRole to sudoers format and store in the parse tree.
*/
static void
role_to_sudoers(struct sudoers_parse_tree *parse_tree, struct sudo_role *role,
bool store_options, bool reuse_userspec, bool reuse_privilege,
bool reuse_runas)
{
struct privilege *priv;
struct sudoers_string *ls;
struct userspec *us;
struct member *m;
debug_decl(role_to_sudoers, SUDOERS_DEBUG_UTIL);
/*
* TODO: use cn to create a UserAlias if multiple users in it?
*/
if (reuse_userspec) {
/* Reuse the previous userspec */
us = TAILQ_LAST(&parse_tree->userspecs, userspec_list);
} else {
/* Allocate a new userspec and fill in the user list. */
if ((us = calloc(1, sizeof(*us))) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
TAILQ_INIT(&us->privileges);
TAILQ_INIT(&us->users);
STAILQ_INIT(&us->comments);
STAILQ_FOREACH(ls, role->users, entries) {
char *user = ls->str;
if ((m = calloc(1, sizeof(*m))) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
m->negated = sudo_ldap_is_negated(&user);
switch (*user) {
case '\0':
/* Empty RunAsUser means run as the invoking user. */
m->type = MYSELF;
break;
case '+':
m->type = NETGROUP;
break;
case '%':
m->type = USERGROUP;
break;
case 'A':
if (strcmp(user, "ALL") == 0) {
m->type = ALL;
break;
}
FALLTHROUGH;
default:
m->type = WORD;
break;
}
if (m->type != ALL && m->type != MYSELF) {
if ((m->name = strdup(user)) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
}
TAILQ_INSERT_TAIL(&us->users, m, entries);
}
}
/* Add source role as a comment. */
if (role->cn != NULL) {
struct sudoers_comment *comment = NULL;
if (reuse_userspec) {
/* Try to reuse comment too. */
STAILQ_FOREACH(comment, &us->comments, entries) {
if (strncasecmp(comment->str, "sudoRole ", 9) == 0) {
char *tmpstr;
if (asprintf(&tmpstr, "%s, %s", comment->str, role->cn) == -1) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
free(comment->str);
comment->str = tmpstr;
break;
}
}
}
if (comment == NULL) {
/* Create a new comment. */
if ((comment = malloc(sizeof(*comment))) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
if (asprintf(&comment->str, "sudoRole %s", role->cn) == -1) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
STAILQ_INSERT_TAIL(&us->comments, comment, entries);
}
}
/* Convert role to sudoers privilege. */
priv = sudo_ldap_role_to_priv(role->cn, STAILQ_FIRST(role->hosts),
STAILQ_FIRST(role->runasusers), STAILQ_FIRST(role->runasgroups),
STAILQ_FIRST(role->cmnds), STAILQ_FIRST(role->options),
role->notbefore, role->notafter, true, store_options,
sudoers_string_iter);
if (priv == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
if (reuse_privilege && !TAILQ_EMPTY(&us->privileges)) {
/* Hostspec unchanged, append cmndlist to previous privilege. */
struct privilege *prev_priv = TAILQ_LAST(&us->privileges, privilege_list);
if (reuse_runas) {
/* Runas users and groups same if as in previous privilege. */
struct cmndspec *cmndspec = TAILQ_FIRST(&priv->cmndlist);
const struct cmndspec *prev_cmndspec =
TAILQ_LAST(&prev_priv->cmndlist, cmndspec_list);
struct member_list *runasuserlist = prev_cmndspec->runasuserlist;
struct member_list *runasgrouplist = prev_cmndspec->runasgrouplist;
/* Free duplicate runas lists. */
if (cmndspec->runasuserlist != NULL) {
free_members(cmndspec->runasuserlist);
free(cmndspec->runasuserlist);
}
if (cmndspec->runasgrouplist != NULL) {
free_members(cmndspec->runasgrouplist);
free(cmndspec->runasgrouplist);
}
/* Update cmndspec with previous runas lists. */
TAILQ_FOREACH(cmndspec, &priv->cmndlist, entries) {
cmndspec->runasuserlist = runasuserlist;
cmndspec->runasgrouplist = runasgrouplist;
}
}
TAILQ_CONCAT(&prev_priv->cmndlist, &priv->cmndlist, entries);
free_privilege(priv);
} else {
TAILQ_INSERT_TAIL(&us->privileges, priv, entries);
}
/* Add finished userspec to the list if new. */
if (!reuse_userspec)
TAILQ_INSERT_TAIL(&parse_tree->userspecs, us, entries);
debug_return;
}
/*
* Convert the list of sudoRoles to sudoers format and store in the parse tree.
*/
static void
ldif_to_sudoers(struct sudoers_parse_tree *parse_tree,
struct sudo_role_list *roles, unsigned int numroles, bool store_options)
{
struct sudo_role **role_array, *role = NULL;
unsigned int n;
debug_decl(ldif_to_sudoers, SUDOERS_DEBUG_UTIL);
/* Convert from list of roles to array and sort by order. */
role_array = reallocarray(NULL, numroles + 1, sizeof(*role_array));
if (role_array == NULL)
sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
for (n = 0; n < numroles; n++) {
if ((role = STAILQ_FIRST(roles)) == NULL)
break; /* cannot happen */
STAILQ_REMOVE_HEAD(roles, entries);
role_array[n] = role;
}
role_array[n] = NULL;
qsort(role_array, numroles, sizeof(*role_array), role_order_cmp);
/*
* Iterate over roles in sorted order, converting to sudoers.
*/
for (n = 0, role = NULL; n < numroles; n++) {
bool reuse_userspec = false;
bool reuse_privilege = false;
bool reuse_runas = false;
struct sudo_role *prev_role = role;
role = role_array[n];
/* Check whether we can reuse the previous user and host specs */
if (prev_role != NULL && role->users == prev_role->users) {
reuse_userspec = true;
/*
* Since options are stored per-privilege we can't
* append to the previous privilege's cmndlist if
* we are storing options.
*/
if (!store_options) {
if (role->hosts == prev_role->hosts) {
reuse_privilege = true;
/* Reuse runasusers and runasgroups if possible. */
if (role->runasusers == prev_role->runasusers &&
role->runasgroups == prev_role->runasgroups)
reuse_runas = true;
}
}
}
role_to_sudoers(parse_tree, role, store_options, reuse_userspec,
reuse_privilege, reuse_runas);
}
/* Clean up. */
for (n = 0; n < numroles; n++)
sudo_role_free(role_array[n]);
free(role_array);
debug_return;
}
/*
* Given a cn with possible quoted characters, return a copy of
* the cn with quote characters ('\\') removed.
* The caller is responsible for freeing the returned string.
*/
static
char *unquote_cn(const char *src)
{
char *dst, *new_cn;
size_t len;
debug_decl(unquote_cn, SUDOERS_DEBUG_UTIL);
len = strlen(src);
if ((new_cn = malloc(len + 1)) == NULL)
debug_return_str(NULL);
for (dst = new_cn; *src != '\0';) {
if (src[0] == '\\' && src[1] != '\0')
src++;
*dst++ = *src++;
}
*dst = '\0';
debug_return_str(new_cn);
}
/*
* Parse a sudoers file in LDIF format, https://tools.ietf.org/html/rfc2849
* Parsed sudoRole objects are stored in the specified parse_tree which
* must already be initialized.
*/
bool
sudoers_parse_ldif(struct sudoers_parse_tree *parse_tree,
FILE *fp, const char *sudoers_base, bool store_options)
{
struct sudo_role_list roles = STAILQ_HEAD_INITIALIZER(roles);
struct sudo_role *role = NULL;
struct rbtree *usercache, *groupcache, *hostcache;
unsigned numroles = 0;
bool in_role = false;
size_t linesize = 0;
char *attr, *name, *line = NULL, *savedline = NULL;
size_t savedlen = 0;
bool mismatch = false;
int errors = 0;
debug_decl(sudoers_parse_ldif, SUDOERS_DEBUG_UTIL);
/*
* We cache user, group and host lists to make it easy to detect when there
* are identical lists (simple pointer compare). This makes it possible
* to merge multiple sudoRole objects into a single UserSpec and/or
* Privilege. The lists are sorted since LDAP order is arbitrary.
*/
usercache = rbcreate(str_list_cmp);
groupcache = rbcreate(str_list_cmp);
hostcache = rbcreate(str_list_cmp);
if (usercache == NULL || groupcache == NULL || hostcache == NULL)
sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
/* Read through input, parsing into sudo_roles and global defaults. */
for (;;) {
int ch;
ssize_t len = getdelim(&line, &linesize, '\n', fp);
/* Trim trailing return or newline. */
while (len > 0 && (line[len - 1] == '\r' || line[len - 1] == '\n'))
line[--len] = '\0';
/* Blank line or EOF terminates an entry. */
if (len <= 0) {
if (in_role) {
if (role->cn != NULL && strcasecmp(role->cn, "defaults") == 0) {
ldif_store_options(parse_tree, role->options);
sudo_role_free(role);
} else if (STAILQ_EMPTY(role->users) ||
STAILQ_EMPTY(role->hosts) || STAILQ_EMPTY(role->cmnds)) {
/* Incomplete role. */
sudo_warnx(U_("ignoring incomplete sudoRole: cn: %s"),
role->cn ? role->cn : "UNKNOWN");
sudo_role_free(role);
} else {
/* Cache users, hosts, runasusers and runasgroups. */
if (str_list_cache(usercache, &role->users) == -1 ||
str_list_cache(hostcache, &role->hosts) == -1 ||
str_list_cache(usercache, &role->runasusers) == -1 ||
str_list_cache(groupcache, &role->runasgroups) == -1) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
/* Store finished role. */
STAILQ_INSERT_TAIL(&roles, role, entries);
numroles++;
}
role = NULL;
in_role = false;
}
if (len == -1) {
/* EOF */
break;
}
mismatch = false;
continue;
}
if (savedline != NULL) {
char *tmp;
/* Append to saved line. */
linesize = savedlen + (size_t)len + 1;
if ((tmp = realloc(savedline, linesize)) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
memcpy(tmp + savedlen, line, (size_t)len + 1);
free(line);
line = tmp;
savedline = NULL;
}
/* Check for folded line */
if ((ch = getc(fp)) == ' ') {
/* folded line, append to the saved portion. */
savedlen = (size_t)len;
savedline = line;
line = NULL;
linesize = 0;
continue;
}
ungetc(ch, fp); /* not folded, push back ch */
/* Skip comment lines or records that don't match the base. */
if (*line == '#' || mismatch)
continue;
/* Reject invalid LDIF. */
if (!ldif_parse_attribute(line, &name, &attr)) {
sudo_warnx(U_("invalid LDIF attribute: %s"), line);
errors++;
continue;
}
/* Parse dn and objectClass. */
if (strcasecmp(name, "dn") == 0) {
/* Compare dn to base, if specified. */
if (sudoers_base != NULL) {
/* Skip over cn if present. */
if (strncasecmp(attr, "cn=", 3) == 0) {
for (attr += 3; *attr != '\0'; attr++) {
/* Handle escaped ',' chars. */
if (*attr == '\\' && attr[1] != '\0')
attr++;
if (*attr == ',') {
attr++;
break;
}
}
}
if (strcasecmp(attr, sudoers_base) != 0) {
/* Doesn't match base, skip the rest of it. */
mismatch = true;
continue;
}
}
} else if (strcasecmp(name, "objectClass") == 0) {
if (strcasecmp(attr, "sudoRole") == 0) {
/* Allocate new role as needed. */
if (role == NULL) {
if ((role = sudo_role_alloc()) == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
}
in_role = true;
}
}
/* Not in a sudoRole, keep reading. */
if (!in_role)
continue;
/* Part of a sudoRole, parse it. */
if (strcasecmp(name, "cn") == 0) {
free(role->cn);
role->cn = unquote_cn(attr);
if (role->cn == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
} else if (strcasecmp(name, "sudoUser") == 0) {
ldif_store_string(attr, role->users, true);
} else if (strcasecmp(name, "sudoHost") == 0) {
ldif_store_string(attr, role->hosts, true);
} else if (strcasecmp(name, "sudoRunAs") == 0) {
ldif_store_string(attr, role->runasusers, true);
} else if (strcasecmp(name, "sudoRunAsUser") == 0) {
ldif_store_string(attr, role->runasusers, true);
} else if (strcasecmp(name, "sudoRunAsGroup") == 0) {
ldif_store_string(attr, role->runasgroups, true);
} else if (strcasecmp(name, "sudoCommand") == 0) {
ldif_store_string(attr, role->cmnds, false);
} else if (strcasecmp(name, "sudoOption") == 0) {
ldif_store_string(attr, role->options, false);
} else if (strcasecmp(name, "sudoOrder") == 0) {
char *ep;
role->order = strtod(attr, &ep);
if (ep == attr || *ep != '\0') {
sudo_warnx(U_("invalid sudoOrder attribute: %s"), attr);
errors++;
}
} else if (strcasecmp(name, "sudoNotBefore") == 0) {
free(role->notbefore);
role->notbefore = strdup(attr);
if (role->notbefore == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
} else if (strcasecmp(name, "sudoNotAfter") == 0) {
free(role->notafter);
role->notafter = strdup(attr);
if (role->notafter == NULL) {
sudo_fatalx(U_("%s: %s"), __func__,
U_("unable to allocate memory"));
}
}
}
sudo_role_free(role);
free(line);
free(savedline);
/* Convert from roles to sudoers data structures. */
if (numroles > 0)
ldif_to_sudoers(parse_tree, &roles, numroles, store_options);
/* Clean up. */
rbdestroy(usercache, str_list_free);
rbdestroy(groupcache, str_list_free);
rbdestroy(hostcache, str_list_free);
debug_return_bool(errors == 0);
}