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/*
* Handle the mapping of uid/gid and user/group names between systems.
*
* Copyright (C) 1996 Andrew Tridgell
* Copyright (C) 1996 Paul Mackerras
* Copyright (C) 2004-2014 Wayne Davison
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, visit the http://fsf.org website.
*/
/* If the source username/group does not exist on the target then use
* the numeric IDs. Never do any mapping for uid=0 or gid=0 as these
* are special. */
#include "rsync.h"
#include "ifuncs.h"
#include "itypes.h"
#include "io.h"
extern int am_root;
extern int preserve_uid;
extern int preserve_gid;
extern int preserve_acls;
extern int numeric_ids;
extern gid_t our_gid;
extern char *usermap;
extern char *groupmap;
#ifdef HAVE_GETGROUPS
# ifndef GETGROUPS_T
# define GETGROUPS_T gid_t
# endif
#endif
#define NFLAGS_WILD_NAME_MATCH (1<<0)
#define NFLAGS_NAME_MATCH (1<<1)
union name_or_id {
const char *name;
id_t max_id;
};
struct idlist {
struct idlist *next;
union name_or_id u;
id_t id, id2;
uint16 flags;
};
static struct idlist *uidlist, *uidmap;
static struct idlist *gidlist, *gidmap;
static id_t id_parse(const char *num_str)
{
id_t tmp, num = 0;
const char *cp = num_str;
while (*cp) {
if (!isDigit(cp)) {
invalid_num:
rprintf(FERROR, "Invalid ID number: %s\n", num_str);
exit_cleanup(RERR_SYNTAX);
}
tmp = num * 10 + *cp++ - '0';
if (tmp < num)
goto invalid_num;
num = tmp;
}
return num;
}
static struct idlist *add_to_list(struct idlist **root, id_t id, union name_or_id noiu,
id_t id2, uint16 flags)
{
struct idlist *node = new(struct idlist);
if (!node)
out_of_memory("add_to_list");
node->next = *root;
node->u = noiu;
node->id = id;
node->id2 = id2;
node->flags = flags;
*root = node;
return node;
}
/* turn a uid into a user name */
char *uid_to_user(uid_t uid)
{
struct passwd *pass = getpwuid(uid);
if (pass)
return strdup(pass->pw_name);
return NULL;
}
/* turn a gid into a group name */
char *gid_to_group(gid_t gid)
{
struct group *grp = getgrgid(gid);
if (grp)
return strdup(grp->gr_name);
return NULL;
}
/* Parse a user name or (optionally) a number into a uid */
int user_to_uid(const char *name, uid_t *uid_p, BOOL num_ok)
{
struct passwd *pass;
if (!name || !*name)
return 0;
if (num_ok && name[strspn(name, "0123456789")] == '\0') {
*uid_p = id_parse(name);
return 1;
}
if (!(pass = getpwnam(name)))
return 0;
*uid_p = pass->pw_uid;
return 1;
}
/* Parse a group name or (optionally) a number into a gid */
int group_to_gid(const char *name, gid_t *gid_p, BOOL num_ok)
{
struct group *grp;
if (!name || !*name)
return 0;
if (num_ok && name[strspn(name, "0123456789")] == '\0') {
*gid_p = id_parse(name);
return 1;
}
if (!(grp = getgrnam(name)))
return 0;
*gid_p = grp->gr_gid;
return 1;
}
static int is_in_group(gid_t gid)
{
#ifdef HAVE_GETGROUPS
static gid_t last_in;
static int ngroups = -2, last_out = -1;
static GETGROUPS_T *gidset;
int n;
if (gid == last_in && last_out >= 0)
return last_out;
if (ngroups < -1) {
if ((ngroups = getgroups(0, NULL)) < 0)
ngroups = 0;
gidset = new_array(GETGROUPS_T, ngroups+1);
if (!gidset)
out_of_memory("is_in_group");
if (ngroups > 0)
ngroups = getgroups(ngroups, gidset);
/* The default gid might not be in the list on some systems. */
for (n = 0; n < ngroups; n++) {
if (gidset[n] == our_gid)
break;
}
if (n == ngroups)
gidset[ngroups++] = our_gid;
if (DEBUG_GTE(OWN, 2)) {
int pos;
char *gidbuf = new_array(char, ngroups*21+32);
if (!gidbuf)
out_of_memory("is_in_group");
pos = snprintf(gidbuf, 32, "process has %d gid%s: ",
ngroups, ngroups == 1? "" : "s");
for (n = 0; n < ngroups; n++) {
pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
}
rprintf(FINFO, "%s\n", gidbuf);
free(gidbuf);
}
}
last_in = gid;
for (n = 0; n < ngroups; n++) {
if (gidset[n] == gid)
return last_out = 1;
}
return last_out = 0;
#else
return gid == our_gid;
#endif
}
/* Add a uid/gid to its list of ids. Only called on receiving side. */
static struct idlist *recv_add_id(struct idlist **idlist_ptr, struct idlist *idmap,
id_t id, const char *name)
{
struct idlist *node;
union name_or_id noiu;
int flag;
id_t id2;
noiu.name = name; /* ensure that add_to_list() gets the raw value. */
if (!name)
name = "";
for (node = idmap; node; node = node->next) {
if (node->flags & NFLAGS_WILD_NAME_MATCH) {
if (!wildmatch(node->u.name, name))
continue;
} else if (node->flags & NFLAGS_NAME_MATCH) {
if (strcmp(node->u.name, name) != 0)
continue;
} else if (node->u.max_id) {
if (id < node->id || id > node->u.max_id)
continue;
} else {
if (node->id != id)
continue;
}
break;
}
if (node)
id2 = node->id2;
else if (*name && id) {
if (idlist_ptr == &uidlist) {
uid_t uid;
id2 = user_to_uid(name, &uid, False) ? uid : id;
} else {
gid_t gid;
id2 = group_to_gid(name, &gid, False) ? gid : id;
}
} else
id2 = id;
flag = idlist_ptr == &gidlist && !am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0;
node = add_to_list(idlist_ptr, id, noiu, id2, flag);
if (DEBUG_GTE(OWN, 2)) {
rprintf(FINFO, "%sid %u(%s) maps to %u\n",
idlist_ptr == &uidlist ? "u" : "g",
(unsigned)id, name, (unsigned)id2);
}
return node;
}
/* this function is a definate candidate for a faster algorithm */
uid_t match_uid(uid_t uid)
{
static struct idlist *last = NULL;
struct idlist *list;
if (last && uid == last->id)
return last->id2;
for (list = uidlist; list; list = list->next) {
if (list->id == uid)
break;
}
if (!list)
list = recv_add_id(&uidlist, uidmap, uid, NULL);
last = list;
return list->id2;
}
gid_t match_gid(gid_t gid, uint16 *flags_ptr)
{
static struct idlist *last = NULL;
struct idlist *list;
if (last && gid == last->id)
list = last;
else {
for (list = gidlist; list; list = list->next) {
if (list->id == gid)
break;
}
if (!list)
list = recv_add_id(&gidlist, gidmap, gid, NULL);
last = list;
}
if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
*flags_ptr |= FLAG_SKIP_GROUP;
return list->id2;
}
/* Add a uid to the list of uids. Only called on sending side. */
const char *add_uid(uid_t uid)
{
struct idlist *list;
struct idlist *node;
union name_or_id noiu;
if (uid == 0) /* don't map root */
return NULL;
for (list = uidlist; list; list = list->next) {
if (list->id == uid)
return NULL;
}
noiu.name = uid_to_user(uid);
node = add_to_list(&uidlist, uid, noiu, 0, 0);
return node->u.name;
}
/* Add a gid to the list of gids. Only called on sending side. */
const char *add_gid(gid_t gid)
{
struct idlist *list;
struct idlist *node;
union name_or_id noiu;
if (gid == 0) /* don't map root */
return NULL;
for (list = gidlist; list; list = list->next) {
if (list->id == gid)
return NULL;
}
noiu.name = gid_to_group(gid);
node = add_to_list(&gidlist, gid, noiu, 0, 0);
return node->u.name;
}
/* send a complete uid/gid mapping to the peer */
void send_id_list(int f)
{
struct idlist *list;
if (preserve_uid || preserve_acls) {
int len;
/* we send sequences of uid/byte-length/name */
for (list = uidlist; list; list = list->next) {
if (!list->u.name)
continue;
len = strlen(list->u.name);
write_varint30(f, list->id);
write_byte(f, len);
write_buf(f, list->u.name, len);
}
/* terminate the uid list with a 0 uid. We explicitly exclude
* 0 from the list */
write_varint30(f, 0);
}
if (preserve_gid || preserve_acls) {
int len;
for (list = gidlist; list; list = list->next) {
if (!list->u.name)
continue;
len = strlen(list->u.name);
write_varint30(f, list->id);
write_byte(f, len);
write_buf(f, list->u.name, len);
}
write_varint30(f, 0);
}
}
uid_t recv_user_name(int f, uid_t uid)
{
struct idlist *node;
int len = read_byte(f);
char *name = new_array(char, len+1);
if (!name)
out_of_memory("recv_user_name");
read_sbuf(f, name, len);
if (numeric_ids < 0) {
free(name);
name = NULL;
}
node = recv_add_id(&uidlist, uidmap, uid, name); /* node keeps name's memory */
return node->id2;
}
gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
{
struct idlist *node;
int len = read_byte(f);
char *name = new_array(char, len+1);
if (!name)
out_of_memory("recv_group_name");
read_sbuf(f, name, len);
if (numeric_ids < 0) {
free(name);
name = NULL;
}
node = recv_add_id(&gidlist, gidmap, gid, name); /* node keeps name's memory */
if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
*flags_ptr |= FLAG_SKIP_GROUP;
return node->id2;
}
/* recv a complete uid/gid mapping from the peer and map the uid/gid
* in the file list to local names */
void recv_id_list(int f, struct file_list *flist)
{
id_t id;
int i;
if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
/* read the uid list */
while ((id = read_varint30(f)) != 0)
recv_user_name(f, id);
}
if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
/* read the gid list */
while ((id = read_varint30(f)) != 0)
recv_group_name(f, id, NULL);
}
/* Now convert all the uids/gids from sender values to our values. */
#ifdef SUPPORT_ACLS
if (preserve_acls && (!numeric_ids || usermap || groupmap))
match_acl_ids();
#endif
if (am_root && preserve_uid && (!numeric_ids || usermap)) {
for (i = 0; i < flist->used; i++)
F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
}
if (preserve_gid && (!am_root || !numeric_ids || groupmap)) {
for (i = 0; i < flist->used; i++) {
F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]),
&flist->files[i]->flags);
}
}
}
void parse_name_map(char *map, BOOL usernames)
{
struct idlist **idmap_ptr = usernames ? &uidmap : &gidmap;
struct idlist **idlist_ptr = usernames ? &uidlist : &gidlist;
char *colon, *cp = map + strlen(map);
union name_or_id noiu;
id_t id1;
uint16 flags;
/* Parse the list in reverse, so the order in the struct is right. */
while (1) {
while (cp > map && cp[-1] != ',') cp--;
if (!(colon = strchr(cp, ':'))) {
rprintf(FERROR, "No colon found in --%smap: %s\n",
usernames ? "user" : "group", cp);
exit_cleanup(RERR_SYNTAX);
}
if (!colon[1]) {
rprintf(FERROR, "No name found after colon --%smap: %s\n",
usernames ? "user" : "group", cp);
exit_cleanup(RERR_SYNTAX);
}
*colon = '\0';
if (isDigit(cp)) {
char *dash = strchr(cp, '-');
if (strspn(cp, "0123456789-") != (size_t)(colon - cp)
|| (dash && (!dash[1] || strchr(dash+1, '-')))) {
rprintf(FERROR, "Invalid number in --%smap: %s\n",
usernames ? "user" : "group", cp);
exit_cleanup(RERR_SYNTAX);
}
if (dash) {
*dash = '\0';
noiu.max_id = id_parse(dash+1);
} else
noiu.max_id = 0;
flags = 0;
id1 = id_parse(cp);
if (dash)
*dash = '-';
} else if (strpbrk(cp, "*[?")) {
flags = NFLAGS_WILD_NAME_MATCH;
noiu.name = cp;
id1 = 0;
} else {
flags = NFLAGS_NAME_MATCH;
noiu.name = cp;
id1 = 0;
}
if (usernames) {
uid_t uid;
if (user_to_uid(colon+1, &uid, True))
add_to_list(idmap_ptr, id1, noiu, uid, flags);
else {
rprintf(FERROR,
"Unknown --usermap name on receiver: %s\n",
colon+1);
}
} else {
gid_t gid;
if (group_to_gid(colon+1, &gid, True))
add_to_list(idmap_ptr, id1, noiu, gid, flags);
else {
rprintf(FERROR,
"Unknown --groupmap name on receiver: %s\n",
colon+1);
}
}
if (cp == map)
break;
*--cp = '\0'; /* replace comma */
}
/* The 0 user/group doesn't get its name sent, so add it explicitly. */
recv_add_id(idlist_ptr, *idmap_ptr, 0,
numeric_ids ? NULL : usernames ? uid_to_user(0) : gid_to_group(0));
}
#ifdef HAVE_GETGROUPLIST
const char *getallgroups(uid_t uid, gid_t *gid_list, int *size_ptr)
{
struct passwd *pw;
if ((pw = getpwuid(uid)) == NULL)
return "getpwuid failed";
/* Get all the process's groups, with the pw_gid group first. */
if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list, size_ptr) < 0)
return "getgrouplist failed";
/* Paranoia: is the default group not first in the list? */
if (gid_list[0] != pw->pw_gid) {
int j;
for (j = 0; j < *size_ptr; j++) {
if (gid_list[j] == pw->pw_gid) {
gid_list[j] = gid_list[0];
gid_list[0] = pw->pw_gid;
break;
}
}
}
return NULL;
}
#endif