Files
sudo/plugins/sudoers/pwutil.c

717 lines
17 KiB
C

/*
* Copyright (c) 1996, 1998-2005, 2007-2011
* Todd C. Miller <Todd.Miller@courtesan.com>
*
* 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.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
# include <memory.h>
# endif
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_SETAUTHDB
# include <usersec.h>
#endif /* HAVE_SETAUTHDB */
#include <pwd.h>
#include <grp.h>
#include "sudoers.h"
#include "redblack.h"
/*
* The passwd and group caches.
*/
static struct rbtree *pwcache_byuid, *pwcache_byname;
static struct rbtree *grcache_bygid, *grcache_byname;
static int cmp_pwuid(const void *, const void *);
static int cmp_pwnam(const void *, const void *);
static int cmp_grgid(const void *, const void *);
#define cmp_grnam cmp_pwnam
#define ptr_to_item(p) ((struct cache_item *)((char *)(p) - sizeof(struct cache_item)))
struct cache_item {
unsigned int refcnt;
/* key */
union {
uid_t uid;
gid_t gid;
char *name;
} k;
/* datum */
union {
struct passwd *pw;
struct group *gr;
} d;
};
/*
* Compare by uid.
*/
static int
cmp_pwuid(const void *v1, const void *v2)
{
const struct cache_item *ci1 = (const struct cache_item *) v1;
const struct cache_item *ci2 = (const struct cache_item *) v2;
return ci1->k.uid - ci2->k.uid;
}
/*
* Compare by user name.
*/
static int
cmp_pwnam(const void *v1, const void *v2)
{
const struct cache_item *ci1 = (const struct cache_item *) v1;
const struct cache_item *ci2 = (const struct cache_item *) v2;
return strcmp(ci1->k.name, ci2->k.name);
}
#define FIELD_SIZE(src, name, size) \
do { \
if (src->name) { \
size = strlen(src->name) + 1; \
total += size; \
} \
} while (0)
#define FIELD_COPY(src, dst, name, size) \
do { \
if (src->name) { \
memcpy(cp, src->name, size); \
dst->name = cp; \
cp += size; \
} \
} while (0)
/*
* Dynamically allocate space for a struct item plus the key and data
* elements. If name is non-NULL it is used as the key, else the
* uid is the key. Fills in datum from struct password.
*
* We would like to fill in the encrypted password too but the
* call to the shadow function could overwrite the pw buffer (NIS).
*/
static struct cache_item *
make_pwitem(const struct passwd *pw, const char *name)
{
char *cp;
const char *pw_shell;
size_t nsize, psize, csize, gsize, dsize, ssize, total;
struct cache_item *item;
struct passwd *newpw;
/* If shell field is empty, expand to _PATH_BSHELL. */
pw_shell = (pw->pw_shell == NULL || pw->pw_shell[0] == '\0')
? _PATH_BSHELL : pw->pw_shell;
/* Allocate in one big chunk for easy freeing. */
nsize = psize = csize = gsize = dsize = ssize = 0;
total = sizeof(struct cache_item) + sizeof(struct passwd);
FIELD_SIZE(pw, pw_name, nsize);
FIELD_SIZE(pw, pw_passwd, psize);
#ifdef HAVE_LOGIN_CAP_H
FIELD_SIZE(pw, pw_class, csize);
#endif
FIELD_SIZE(pw, pw_gecos, gsize);
FIELD_SIZE(pw, pw_dir, dsize);
/* Treat shell specially since we expand "" -> _PATH_BSHELL */
ssize = strlen(pw_shell) + 1;
total += ssize;
if (name != NULL)
total += strlen(name) + 1;
/* Allocate space for struct item, struct passwd and the strings. */
if ((item = malloc(total)) == NULL)
return NULL;
cp = (char *) item + sizeof(struct cache_item);
/*
* Copy in passwd contents and make strings relative to space
* at the end of the buffer.
*/
newpw = (struct passwd *) cp;
memcpy(newpw, pw, sizeof(struct passwd));
cp += sizeof(struct passwd);
FIELD_COPY(pw, newpw, pw_name, nsize);
FIELD_COPY(pw, newpw, pw_passwd, psize);
#ifdef HAVE_LOGIN_CAP_H
FIELD_COPY(pw, newpw, pw_class, csize);
#endif
FIELD_COPY(pw, newpw, pw_gecos, gsize);
FIELD_COPY(pw, newpw, pw_dir, dsize);
/* Treat shell specially since we expand "" -> _PATH_BSHELL */
memcpy(cp, pw_shell, ssize);
newpw->pw_shell = cp;
cp += ssize;
/* Set key and datum. */
if (name != NULL) {
memcpy(cp, name, strlen(name) + 1);
item->k.name = cp;
} else {
item->k.uid = pw->pw_uid;
}
item->d.pw = newpw;
item->refcnt = 1;
return item;
}
void
pw_addref(struct passwd *pw)
{
ptr_to_item(pw)->refcnt++;
}
static void
pw_delref_item(void *v)
{
struct cache_item *item = v;
if (--item->refcnt == 0)
efree(item);
}
void
pw_delref(struct passwd *pw)
{
pw_delref_item(ptr_to_item(pw));
}
/*
* Get a password entry by uid and allocate space for it.
* Fills in pw_passwd from shadow file if necessary.
*/
struct passwd *
sudo_getpwuid(uid_t uid)
{
struct cache_item key, *item;
struct rbnode *node;
key.k.uid = uid;
if ((node = rbfind(pwcache_byuid, &key)) != NULL) {
item = (struct cache_item *) node->data;
goto done;
}
/*
* Cache passwd db entry if it exists or a negative response if not.
*/
#ifdef HAVE_SETAUTHDB
aix_setauthdb(IDtouser(uid));
#endif
if ((key.d.pw = getpwuid(uid)) != NULL) {
item = make_pwitem(key.d.pw, NULL);
if (rbinsert(pwcache_byuid, item) != NULL)
errorx(1, "unable to cache uid %u (%s), already exists",
(unsigned int) uid, item->d.pw->pw_name);
} else {
item = emalloc(sizeof(*item));
item->refcnt = 1;
item->k.uid = uid;
item->d.pw = NULL;
if (rbinsert(pwcache_byuid, item) != NULL)
errorx(1, "unable to cache uid %u, already exists",
(unsigned int) uid);
}
#ifdef HAVE_SETAUTHDB
aix_restoreauthdb();
#endif
done:
item->refcnt++;
return item->d.pw;
}
/*
* Get a password entry by name and allocate space for it.
* Fills in pw_passwd from shadow file if necessary.
*/
struct passwd *
sudo_getpwnam(const char *name)
{
struct cache_item key, *item;
struct rbnode *node;
size_t len;
key.k.name = (char *) name;
if ((node = rbfind(pwcache_byname, &key)) != NULL) {
item = (struct cache_item *) node->data;
goto done;
}
/*
* Cache passwd db entry if it exists or a negative response if not.
*/
#ifdef HAVE_SETAUTHDB
aix_setauthdb((char *) name);
#endif
if ((key.d.pw = getpwnam(name)) != NULL) {
item = make_pwitem(key.d.pw, name);
if (rbinsert(pwcache_byname, item) != NULL)
errorx(1, "unable to cache user %s, already exists", name);
} else {
len = strlen(name) + 1;
item = emalloc(sizeof(*item) + len);
item->refcnt = 1;
item->k.name = (char *) item + sizeof(*item);
memcpy(item->k.name, name, len);
item->d.pw = NULL;
if (rbinsert(pwcache_byname, item) != NULL)
errorx(1, "unable to cache user %s, already exists", name);
}
#ifdef HAVE_SETAUTHDB
aix_restoreauthdb();
#endif
done:
item->refcnt++;
return item->d.pw;
}
/*
* Take a uid in string form "#123" and return a faked up passwd struct.
*/
struct passwd *
sudo_fakepwnam(const char *user, gid_t gid)
{
struct cache_item *item;
struct passwd *pw;
struct rbnode *node;
size_t len, namelen;
int i;
namelen = strlen(user);
len = sizeof(*item) + sizeof(*pw) + namelen + 1 /* pw_name */ +
sizeof("*") /* pw_passwd */ + sizeof("") /* pw_gecos */ +
sizeof("/") /* pw_dir */ + sizeof(_PATH_BSHELL);
for (i = 0; i < 2; i++) {
item = emalloc(len);
zero_bytes(item, sizeof(*item) + sizeof(*pw));
pw = (struct passwd *) ((char *)item + sizeof(*item));
pw->pw_uid = (uid_t) atoi(user + 1);
pw->pw_gid = gid;
pw->pw_name = (char *)pw + sizeof(struct passwd);
memcpy(pw->pw_name, user, namelen + 1);
pw->pw_passwd = pw->pw_name + namelen + 1;
memcpy(pw->pw_passwd, "*", 2);
pw->pw_gecos = pw->pw_passwd + 2;
pw->pw_gecos[0] = '\0';
pw->pw_dir = pw->pw_gecos + 1;
memcpy(pw->pw_dir, "/", 2);
pw->pw_shell = pw->pw_dir + 2;
memcpy(pw->pw_shell, _PATH_BSHELL, sizeof(_PATH_BSHELL));
item->refcnt = 1;
item->d.pw = pw;
if (i == 0) {
/* Store by uid, overwriting cached version. */
item->k.uid = pw->pw_uid;
if ((node = rbinsert(pwcache_byuid, item)) != NULL) {
pw_delref_item(node->data);
node->data = item;
}
} else {
/* Store by name, overwriting cached version. */
item->k.name = pw->pw_name;
if ((node = rbinsert(pwcache_byname, item)) != NULL) {
pw_delref_item(node->data);
node->data = item;
}
}
}
item->refcnt++;
return pw;
}
void
sudo_setpwent(void)
{
setpwent();
if (pwcache_byuid == NULL)
pwcache_byuid = rbcreate(cmp_pwuid);
if (pwcache_byname == NULL)
pwcache_byname = rbcreate(cmp_pwnam);
}
void
sudo_freepwcache(void)
{
if (pwcache_byuid != NULL) {
rbdestroy(pwcache_byuid, pw_delref_item);
pwcache_byuid = NULL;
}
if (pwcache_byname != NULL) {
rbdestroy(pwcache_byname, pw_delref_item);
pwcache_byname = NULL;
}
}
void
sudo_endpwent(void)
{
endpwent();
sudo_freepwcache();
}
/*
* Compare by gid.
*/
static int
cmp_grgid(const void *v1, const void *v2)
{
const struct cache_item *ci1 = (const struct cache_item *) v1;
const struct cache_item *ci2 = (const struct cache_item *) v2;
return ci1->k.gid - ci2->k.gid;
}
/*
* Dynamically allocate space for a struct item plus the key and data
* elements. If name is non-NULL it is used as the key, else the
* gid is the key. Fills in datum from struct group.
*/
struct cache_item *
make_gritem(const struct group *gr, const char *name)
{
char *cp;
size_t nsize, psize, nmem, total, len;
struct cache_item *item;
struct group *newgr;
/* Allocate in one big chunk for easy freeing. */
nsize = psize = nmem = 0;
total = sizeof(struct cache_item) + sizeof(struct group);
FIELD_SIZE(gr, gr_name, nsize);
FIELD_SIZE(gr, gr_passwd, psize);
if (gr->gr_mem) {
for (nmem = 0; gr->gr_mem[nmem] != NULL; nmem++)
total += strlen(gr->gr_mem[nmem]) + 1;
nmem++;
total += sizeof(char *) * nmem;
}
if (name != NULL)
total += strlen(name) + 1;
if ((item = malloc(total)) == NULL)
return NULL;
cp = (char *) item + sizeof(struct cache_item);
/*
* Copy in group contents and make strings relative to space
* at the end of the buffer. Note that gr_mem must come
* immediately after struct group to guarantee proper alignment.
*/
newgr = (struct group *)cp;
memcpy(newgr, gr, sizeof(struct group));
cp += sizeof(struct group);
if (gr->gr_mem) {
newgr->gr_mem = (char **)cp;
cp += sizeof(char *) * nmem;
for (nmem = 0; gr->gr_mem[nmem] != NULL; nmem++) {
len = strlen(gr->gr_mem[nmem]) + 1;
memcpy(cp, gr->gr_mem[nmem], len);
newgr->gr_mem[nmem] = cp;
cp += len;
}
newgr->gr_mem[nmem] = NULL;
}
FIELD_COPY(gr, newgr, gr_passwd, psize);
FIELD_COPY(gr, newgr, gr_name, nsize);
/* Set key and datum. */
if (name != NULL) {
memcpy(cp, name, strlen(name) + 1);
item->k.name = cp;
} else {
item->k.gid = gr->gr_gid;
}
item->d.gr = newgr;
item->refcnt = 1;
return item;
}
void
gr_addref(struct group *gr)
{
ptr_to_item(gr)->refcnt++;
}
static void
gr_delref_item(void *v)
{
struct cache_item *item = v;
if (--item->refcnt == 0)
efree(item);
}
void
gr_delref(struct group *gr)
{
gr_delref_item(ptr_to_item(gr));
}
/*
* Get a group entry by gid and allocate space for it.
*/
struct group *
sudo_getgrgid(gid_t gid)
{
struct cache_item key, *item;
struct rbnode *node;
key.k.gid = gid;
if ((node = rbfind(grcache_bygid, &key)) != NULL) {
item = (struct cache_item *) node->data;
goto done;
}
/*
* Cache group db entry if it exists or a negative response if not.
*/
if ((key.d.gr = getgrgid(gid)) != NULL) {
item = make_gritem(key.d.gr, NULL);
if (rbinsert(grcache_bygid, item) != NULL)
errorx(1, "unable to cache gid %u (%s), already exists",
(unsigned int) gid, key.d.gr->gr_name);
} else {
item = emalloc(sizeof(*item));
item->refcnt = 1;
item->k.gid = gid;
item->d.gr = NULL;
if (rbinsert(grcache_bygid, item) != NULL)
errorx(1, "unable to cache gid %u, already exists",
(unsigned int) gid);
}
done:
item->refcnt++;
return item->d.gr;
}
/*
* Get a group entry by name and allocate space for it.
*/
struct group *
sudo_getgrnam(const char *name)
{
struct cache_item key, *item;
struct rbnode *node;
size_t len;
key.k.name = (char *) name;
if ((node = rbfind(grcache_byname, &key)) != NULL) {
item = (struct cache_item *) node->data;
goto done;
}
/*
* Cache group db entry if it exists or a negative response if not.
*/
if ((key.d.gr = getgrnam(name)) != NULL) {
item = make_gritem(key.d.gr, name);
if (rbinsert(grcache_byname, item) != NULL)
errorx(1, "unable to cache group %s, already exists", name);
} else {
len = strlen(name) + 1;
item = emalloc(sizeof(*item) + len);
item->refcnt = 1;
item->k.name = (char *) item + sizeof(*item);
memcpy(item->k.name, name, len);
item->d.gr = NULL;
if (rbinsert(grcache_byname, item) != NULL)
errorx(1, "unable to cache group %s, already exists", name);
}
done:
item->refcnt++;
return item->d.gr;
}
/*
* Take a gid in string form "#123" and return a faked up group struct.
*/
struct group *
sudo_fakegrnam(const char *group)
{
struct cache_item *item;
struct group *gr;
struct rbnode *node;
size_t len, namelen;
int i;
namelen = strlen(group);
len = sizeof(*item) + sizeof(*gr) + namelen + 1;
for (i = 0; i < 2; i++) {
item = emalloc(len);
zero_bytes(item, sizeof(*item) + sizeof(*gr));
gr = (struct group *) ((char *)item + sizeof(*item));
gr->gr_gid = (gid_t) atoi(group + 1);
gr->gr_name = (char *)gr + sizeof(struct group);
memcpy(gr->gr_name, group, namelen + 1);
item->refcnt = 1;
item->d.gr = gr;
if (i == 0) {
/* Store by gid, overwriting cached version. */
item->k.gid = gr->gr_gid;
if ((node = rbinsert(grcache_bygid, item)) != NULL) {
gr_delref_item(node->data);
node->data = item;
}
} else {
/* Store by name, overwriting cached version. */
item->k.name = gr->gr_name;
if ((node = rbinsert(grcache_byname, item)) != NULL) {
gr_delref_item(node->data);
node->data = item;
}
}
}
item->refcnt++;
return gr;
}
void
sudo_setgrent(void)
{
setgrent();
if (grcache_bygid == NULL)
grcache_bygid = rbcreate(cmp_grgid);
if (grcache_byname == NULL)
grcache_byname = rbcreate(cmp_grnam);
}
void
sudo_freegrcache(void)
{
if (grcache_bygid != NULL) {
rbdestroy(grcache_bygid, gr_delref_item);
grcache_bygid = NULL;
}
if (grcache_byname != NULL) {
rbdestroy(grcache_byname, gr_delref_item);
grcache_byname = NULL;
}
}
void
sudo_endgrent(void)
{
endgrent();
sudo_freegrcache();
}
int
user_in_group(struct passwd *pw, const char *group)
{
#ifdef HAVE_MBR_CHECK_MEMBERSHIP
uuid_t gu, uu;
int ismember;
#else
char **gr_mem;
int i;
#endif
struct group *grp;
int retval = FALSE;
#ifdef HAVE_SETAUTHDB
aix_setauthdb(pw->pw_name);
#endif
grp = sudo_getgrnam(group);
#ifdef HAVE_SETAUTHDB
aix_restoreauthdb();
#endif
if (grp == NULL)
goto done;
/* check against user's primary (passwd file) gid */
if (grp->gr_gid == pw->pw_gid) {
retval = TRUE;
goto done;
}
#ifdef HAVE_MBR_CHECK_MEMBERSHIP
/* If we are matching the invoking user use the stashed uuid. */
if (strcmp(pw->pw_name, user_name) == 0) {
if (mbr_gid_to_uuid(grp->gr_gid, gu) == 0 &&
mbr_check_membership(user_uuid, gu, &ismember) == 0 && ismember) {
retval = TRUE;
goto done;
}
} else {
if (mbr_uid_to_uuid(pw->pw_uid, uu) == 0 &&
mbr_gid_to_uuid(grp->gr_gid, gu) == 0 &&
mbr_check_membership(uu, gu, &ismember) == 0 && ismember) {
retval = TRUE;
goto done;
}
}
#else /* HAVE_MBR_CHECK_MEMBERSHIP */
# ifdef HAVE_GETGROUPS
/*
* If we are matching the invoking or list user and that user has a
* supplementary group vector, check it.
*/
if (user_ngroups > 0 &&
strcmp(pw->pw_name, list_pw ? list_pw->pw_name : user_name) == 0) {
for (i = 0; i < user_ngroups; i++) {
if (grp->gr_gid == user_groups[i]) {
retval = TRUE;
goto done;
}
}
} else
# endif /* HAVE_GETGROUPS */
{
if (grp != NULL && grp->gr_mem != NULL) {
for (gr_mem = grp->gr_mem; *gr_mem; gr_mem++) {
if (strcmp(*gr_mem, pw->pw_name) == 0) {
retval = TRUE;
goto done;
}
}
}
}
#endif /* HAVE_MBR_CHECK_MEMBERSHIP */
done:
if (grp != NULL)
gr_delref(grp);
return retval;
}