freebsd-skq/usr.sbin/ppp/systems.c
Pedro F. Giffuni 1de7b4b805 various: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:37:16 +00:00

486 lines
12 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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.
*
* $FreeBSD$
*/
#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);
}