/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
* based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
* Internet Initiative Japan, Inc (IIJ)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include "defs.h"
#include "command.h"
#include "log.h"
#include "id.h"
#include "systems.h"
#define issep(ch) ((ch) == ' ' || (ch) == '\t')
FILE *
OpenSecret(const char *file)
{
FILE *fp;
char line[100];
snprintf(line, sizeof line, "%s/%s", PPP_CONFDIR, file);
fp = ID0fopen(line, "r");
if (fp == NULL)
log_Printf(LogWARN, "OpenSecret: Can't open %s.\n", line);
return (fp);
}
void
CloseSecret(FILE *fp)
{
fclose(fp);
}
/* Move string from ``from'' to ``to'', interpreting ``~'' and $.... */
const char *
InterpretArg(const char *from, char *to)
{
char *ptr, *startto, *endto;
struct passwd *pwd;
int instring;
size_t len;
const char *env;
instring = 0;
startto = to;
endto = to + LINE_LEN - 1;
while(issep(*from))
from++;
while (*from != '\0') {
switch (*from) {
case '"':
instring = !instring;
*to++ = *from++;
break;
case '\\':
switch (*++from) {
case '$':
case '~':
break; /* Swallow the escapes */
default:
*to++ = '\\'; /* Pass the escapes on, maybe skipping \# */
break;
}
*to++ = *from++;
break;
case '$':
if (from[1] == '$') {
*to = '\0'; /* For an empty var name below */
from += 2;
} else if (from[1] == '{') {
ptr = strchr(from+2, '}');
if (ptr) {
len = ptr - from - 2;
if (endto - to < (int)len )
len = endto - to;
if (len) {
strncpy(to, from+2, len);
to[len] = '\0';
from = ptr+1;
} else {
*to++ = *from++;
continue;
}
} else {
*to++ = *from++;
continue;
}
} else {
ptr = to;
for (from++; (isalnum(*from) || *from == '_') && ptr < endto; from++)
*ptr++ = *from;
*ptr = '\0';
}
if (*to == '\0')
*to++ = '$';
else if ((env = getenv(to)) != NULL) {
strncpy(to, env, endto - to);
*endto = '\0';
to += strlen(to);
}
break;
case '~':
ptr = strchr(++from, '/');
len = ptr ? (size_t)(ptr - from) : strlen(from);
if (len == 0)
pwd = getpwuid(ID0realuid());
else {
strncpy(to, from, len);
to[len] = '\0';
pwd = getpwnam(to);
}
if (pwd == NULL)
*to++ = '~';
else {
strncpy(to, pwd->pw_dir, endto - to);
*endto = '\0';
to += strlen(to);
from += len;
}
endpwent();
break;
default:
*to++ = *from++;
break;
}
}
while (to > startto) {
to--;
if (!issep(*to)) {
to++;
break;
}
}
*to = '\0';
return from;
}
#define CTRL_UNKNOWN (0)
#define CTRL_INCLUDE (1)
static int
DecodeCtrlCommand(char *line, char *arg)
{
const char *end;
if (!strncasecmp(line, "include", 7) && issep(line[7])) {
end = InterpretArg(line+8, arg);
if (*end && *end != '#')
log_Printf(LogWARN, "usage: !include filename\n");
else
return CTRL_INCLUDE;
}
return CTRL_UNKNOWN;
}
/*
* Initialised in system_IsValid(), set in ReadSystem(),
* used by system_IsValid()
*/
static int modeok;
static int userok;
static int modereq;
int
AllowUsers(struct cmdargs const *arg)
{
/* arg->bundle may be NULL (see system_IsValid()) ! */
int f;
struct passwd *pwd;
if (userok == -1)
userok = 0;
pwd = getpwuid(ID0realuid());
if (pwd != NULL)
for (f = arg->argn; f < arg->argc; f++)
if (!strcmp("*", arg->argv[f]) || !strcmp(pwd->pw_name, arg->argv[f])) {
userok = 1;
break;
}
endpwent();
return 0;
}
int
AllowModes(struct cmdargs const *arg)
{
/* arg->bundle may be NULL (see system_IsValid()) ! */
int f, mode, allowed;
allowed = 0;
for (f = arg->argn; f < arg->argc; f++) {
mode = Nam2mode(arg->argv[f]);
if (mode == PHYS_NONE || mode == PHYS_ALL)
log_Printf(LogWARN, "allow modes: %s: Invalid mode\n", arg->argv[f]);
else
allowed |= mode;
}
modeok = modereq & allowed ? 1 : 0;
return 0;
}
static char *
strip(char *line)
{
int len;
len = strlen(line);
while (len && (line[len-1] == '\n' || line[len-1] == '\r' ||
issep(line[len-1])))
line[--len] = '\0';
while (issep(*line))
line++;
if (*line == '#')
*line = '\0';
return line;
}
static int
xgets(char *buf, int buflen, FILE *fp)
{
int len, n;
n = 0;
while (fgets(buf, buflen-1, fp)) {
n++;
buf[buflen-1] = '\0';
len = strlen(buf);
while (len && (buf[len-1] == '\n' || buf[len-1] == '\r'))
buf[--len] = '\0';
if (len && buf[len-1] == '\\') {
buf += len - 1;
buflen -= len - 1;
if (!buflen) /* No buffer space */
break;
} else
break;
}
return n;
}
/* Values for ``how'' in ReadSystem */
#define SYSTEM_EXISTS 1
#define SYSTEM_VALIDATE 2
#define SYSTEM_EXEC 3
static char *
GetLabel(char *line, const char *filename, int linenum)
{
char *argv[MAXARGS];
int argc, len;
argc = MakeArgs(line, argv, MAXARGS, PARSE_REDUCE);
if (argc == 2 && !strcmp(argv[1], ":"))
return argv[0];
if (argc != 1 || (len = strlen(argv[0])) < 2 || argv[0][len-1] != ':') {
log_Printf(LogWARN, "Bad label in %s (line %d) - missing colon\n",
filename, linenum);
return NULL;
}
argv[0][len-1] = '\0'; /* Lose the ':' */
return argv[0];
}
/* Returns -2 for ``file not found'' and -1 for ``label not found'' */
static int
ReadSystem(struct bundle *bundle, const char *name, const char *file,
struct prompt *prompt, struct datalink *cx, int how)
{
FILE *fp;
char *cp;
int n, len;
char line[LINE_LEN];
char filename[PATH_MAX];
int linenum;
int argc;
char *argv[MAXARGS];
int allowcmd;
int indent;
char arg[LINE_LEN];
struct prompt *op;
if (*file == '/')
snprintf(filename, sizeof filename, "%s", file);
else
snprintf(filename, sizeof filename, "%s/%s", PPP_CONFDIR, file);
fp = ID0fopen(filename, "r");
if (fp == NULL) {
log_Printf(LogDEBUG, "ReadSystem: Can't open %s.\n", filename);
return -2;
}
log_Printf(LogDEBUG, "ReadSystem: Checking %s (%s).\n", name, filename);
linenum = 0;
while ((n = xgets(line, sizeof line, fp))) {
linenum += n;
if (issep(*line))
continue;
cp = strip(line);
switch (*cp) {
case '\0': /* empty/comment */
break;
case '!':
switch (DecodeCtrlCommand(cp+1, arg)) {
case CTRL_INCLUDE:
log_Printf(LogCOMMAND, "%s: Including \"%s\"\n", filename, arg);
n = ReadSystem(bundle, name, arg, prompt, cx, how);
log_Printf(LogCOMMAND, "%s: Done include of \"%s\"\n", filename, arg);
if (!n) {
fclose(fp);
return 0; /* got it */
}
break;
default:
log_Printf(LogWARN, "%s: %s: Invalid command\n", filename, cp);
break;
}
break;
default:
if ((cp = GetLabel(cp, filename, linenum)) == NULL)
continue;
if (strcmp(cp, name) == 0) {
/* We're in business */
if (how == SYSTEM_EXISTS) {
fclose(fp);
return 0;
}
while ((n = xgets(line, sizeof line, fp))) {
linenum += n;
indent = issep(*line);
cp = strip(line);
if (*cp == '\0') /* empty / comment */
continue;
if (!indent) { /* start of next section */
if (*cp != '!' && how == SYSTEM_EXEC)
cp = GetLabel(cp, filename, linenum);
break;
}
len = strlen(cp);
if ((argc = command_Expand_Interpret(cp, len, argv, cp - line)) < 0)
log_Printf(LogWARN, "%s: %d: Syntax error\n", filename, linenum);
else {
allowcmd = argc > 0 && !strcasecmp(argv[0], "allow");
if ((how != SYSTEM_EXEC && allowcmd) ||
(how == SYSTEM_EXEC && !allowcmd)) {
/*
* Disable any context so that warnings are given to everyone,
* including syslog.
*/
op = log_PromptContext;
log_PromptContext = NULL;
command_Run(bundle, argc, (char const *const *)argv, prompt,
name, cx);
log_PromptContext = op;
}
}
}
fclose(fp); /* everything read - get out */
return 0;
}
break;
}
}
fclose(fp);
return -1;
}
const char *
system_IsValid(const char *name, struct prompt *prompt, int mode)
{
/*
* Note: The ReadSystem() calls only result in calls to the Allow*
* functions. arg->bundle will be set to NULL for these commands !
*/
int def, how, rs;
int defuserok;
def = !strcmp(name, "default");
how = ID0realuid() == 0 ? SYSTEM_EXISTS : SYSTEM_VALIDATE;
userok = -1;
modeok = 1;
modereq = mode;
rs = ReadSystem(NULL, "default", CONFFILE, prompt, NULL, how);
defuserok = userok;
userok = -1;
if (!def) {
if (rs == -1)
rs = 0; /* we don't care that ``default'' doesn't exist */
if (rs == 0)
rs = ReadSystem(NULL, name, CONFFILE, prompt, NULL, how);
if (rs == -1)
return "Configuration label not found";
if (rs == -2)
return PPP_CONFDIR "/" CONFFILE " : File not found";
}
if (userok == -1)
userok = defuserok;
if (how == SYSTEM_EXISTS)
userok = modeok = 1;
if (!userok)
return "User access denied";
if (!modeok)
return "Mode denied for this label";
return NULL;
}
int
system_Select(struct bundle *bundle, const char *name, const char *file,
struct prompt *prompt, struct datalink *cx)
{
userok = modeok = 1;
modereq = PHYS_ALL;
return ReadSystem(bundle, name, file, prompt, cx, SYSTEM_EXEC);
}
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