tmux/server-acl.c

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/* $OpenBSD$ */
/*
* Copyright (c) 2021 Holland Schutte, Jayson Morberg
* Copyright (c) 2021 Dallas Lyons <dallasdlyons@gmail.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 MIND, 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.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <ctype.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "tmux.h"
struct server_acl_user {
uid_t uid;
int flags;
#define SERVER_ACL_READONLY 0x1
RB_ENTRY(server_acl_user) entry;
};
static int
server_acl_cmp(struct server_acl_user *user1, struct server_acl_user *user2)
{
if (user1->uid < user2->uid)
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return (-1);
return (user1->uid > user2->uid);
}
RB_HEAD(server_acl_entries, server_acl_user) server_acl_entries;
RB_GENERATE_STATIC(server_acl_entries, server_acl_user, entry, server_acl_cmp);
/* Initialize server_acl tree. */
void
server_acl_init(void)
{
RB_INIT(&server_acl_entries);
if (getuid() != 0)
server_acl_user_allow(0);
server_acl_user_allow(getuid());
}
/* Find user entry. */
struct server_acl_user*
server_acl_user_find(uid_t uid)
{
struct server_acl_user find = { .uid = uid };
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return (RB_FIND(server_acl_entries, &server_acl_entries, &find));
}
/* Display the tree. */
void
server_acl_display(struct cmdq_item *item)
{
struct server_acl_user *loop;
struct passwd *pw;
const char *name;
RB_FOREACH(loop, server_acl_entries, &server_acl_entries) {
if (loop->uid == 0)
continue;
if ((pw = getpwuid(loop->uid)) != NULL)
name = pw->pw_name;
else
name = "unknown";
if (loop->flags == SERVER_ACL_READONLY)
cmdq_print(item, "%s (R)", name);
else
cmdq_print(item, "%s (W)", name);
}
}
/* Allow a user. */
void
server_acl_user_allow(uid_t uid)
{
struct server_acl_user *user;
user = server_acl_user_find(uid);
if (user == NULL) {
user = xcalloc(1, sizeof *user);
user->uid = uid;
RB_INSERT(server_acl_entries, &server_acl_entries, user);
}
}
/* Deny a user (remove from the tree). */
void
server_acl_user_deny(uid_t uid)
{
struct server_acl_user *user;
user = server_acl_user_find(uid);
if (user != NULL) {
RB_REMOVE(server_acl_entries, &server_acl_entries, user);
free(user);
}
}
/* Allow this user write access. */
void
server_acl_user_allow_write(uid_t uid)
{
struct server_acl_user *user;
struct client *c;
user = server_acl_user_find(uid);
if (user == NULL)
return;
user->flags &= ~SERVER_ACL_READONLY;
TAILQ_FOREACH(c, &clients, entry) {
uid = proc_get_peer_uid(c->peer);
if (uid != (uid_t)-1 && uid == user->uid)
c->flags &= ~CLIENT_READONLY;
}
}
/* Deny this user write access. */
void
server_acl_user_deny_write(uid_t uid)
{
struct server_acl_user *user;
struct client *c;
user = server_acl_user_find(uid);
if (user == NULL)
return;
user->flags |= SERVER_ACL_READONLY;
TAILQ_FOREACH(c, &clients, entry) {
uid = proc_get_peer_uid(c->peer);
if (uid != (uid_t)-1 && uid == user->uid)
c->flags |= CLIENT_READONLY;
}
}
/*
* Check if the client's UID exists in the ACL list and if so, set as read only
* if needed. Return false if the user does not exist.
*/
int
server_acl_join(struct client *c)
{
struct server_acl_user *user;
uid_t uid;
uid = proc_get_peer_uid(c->peer);
if (uid == (uid_t)-1)
return (0);
user = server_acl_user_find(uid);
if (user == NULL)
return (0);
if (user->flags & SERVER_ACL_READONLY)
c->flags |= CLIENT_READONLY;
return (1);
}
/* Get UID for user entry. */
uid_t
server_acl_get_uid(struct server_acl_user *user)
{
return (user->uid);
}