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/* $OpenBSD: parse.y,v 1.8 2023/11/25 12:00:39 florian Exp $ */
/*
* Copyright (c) 2018 Florian Obser <florian@openbsd.org>
* Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
* Copyright (c) 2004 Ryan McBride <mcbride@openbsd.org>
* Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
* Copyright (c) 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2001 Daniel Hartmeier. All rights reserved.
* Copyright (c) 2001 Theo de Raadt. All rights reserved.
*
* 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.
*/
%{
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <event.h>
#include <imsg.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <vis.h>
#include "log.h"
#include "dhcpleased.h"
#include "frontend.h"
TAILQ_HEAD(files, file) files = TAILQ_HEAD_INITIALIZER(files);
static struct file {
TAILQ_ENTRY(file) entry;
FILE *stream;
char *name;
size_t ungetpos;
size_t ungetsize;
u_char *ungetbuf;
int eof_reached;
int lineno;
int errors;
} *file, *topfile;
struct file *pushfile(const char *, int);
int popfile(void);
int check_file_secrecy(int, const char *);
int yyparse(void);
int yylex(void);
int yyerror(const char *, ...)
__attribute__((__format__ (printf, 1, 2)))
__attribute__((__nonnull__ (1)));
int kw_cmp(const void *, const void *);
int lookup(char *);
int igetc(void);
int lgetc(int);
void lungetc(int);
int findeol(void);
TAILQ_HEAD(symhead, sym) symhead = TAILQ_HEAD_INITIALIZER(symhead);
struct sym {
TAILQ_ENTRY(sym) entry;
int used;
int persist;
char *nam;
char *val;
};
int symset(const char *, const char *, int);
char *symget(const char *);
static struct dhcpleased_conf *conf;
static int errors;
static struct iface_conf *iface_conf;
struct iface_conf *conf_get_iface(char *);
typedef struct {
union {
int64_t number;
char *string;
} v;
int lineno;
} YYSTYPE;
%}
%token DHCP_IFACE ERROR SEND VENDOR CLASS ID CLIENT IGNORE DNS ROUTES HOST NAME
%token NO PREFER IPV6
%token <v.string> STRING
%token <v.number> NUMBER
%type <v.string> string
%%
grammar : /* empty */
| grammar '\n'
| grammar varset '\n'
| grammar dhcp_iface '\n'
| grammar error '\n' { file->errors++; }
;
string : string STRING {
if (asprintf(&$$, "%s %s", $1, $2) == -1) {
free($1);
free($2);
yyerror("string: asprintf");
YYERROR;
}
free($1);
free($2);
}
| STRING
;
varset : STRING '=' string {
char *s = $1;
if (log_getverbose() == 1)
printf("%s = \"%s\"\n", $1, $3);
while (*s++) {
if (isspace((unsigned char)*s)) {
yyerror("macro name cannot contain "
"whitespace");
free($1);
free($3);
YYERROR;
}
}
if (symset($1, $3, 0) == -1)
fatal("cannot store variable");
free($1);
free($3);
}
;
optnl : '\n' optnl /* zero or more newlines */
| /*empty*/
;
nl : '\n' optnl /* one or more newlines */
;
dhcp_iface : DHCP_IFACE STRING {
iface_conf = conf_get_iface($2);
} '{' iface_block '}' {
iface_conf = NULL;
}
;
iface_block : optnl ifaceopts_l
| optnl
;
ifaceopts_l : ifaceopts_l ifaceoptsl nl
| ifaceoptsl optnl
;
ifaceoptsl : SEND VENDOR CLASS ID STRING {
ssize_t len;
char buf[256];
if (iface_conf->vc_id != NULL) {
yyerror("vendor class id already set");
YYERROR;
}
len = strnunvis(buf, $5, sizeof(buf));
free($5);
if (len == -1) {
yyerror("invalid vendor class id");
YYERROR;
}
if ((size_t)len >= sizeof(buf)) {
yyerror("vendor class id too long");
YYERROR;
}
iface_conf->vc_id_len = 2 + strlen(buf);
iface_conf->vc_id = malloc(iface_conf->vc_id_len);
if (iface_conf->vc_id == NULL) {
yyerror("malloc");
YYERROR;
}
iface_conf->vc_id[0] = DHO_DHCP_CLASS_IDENTIFIER;
iface_conf->vc_id[1] = iface_conf->vc_id_len - 2;
memcpy(&iface_conf->vc_id[2], buf,
iface_conf->vc_id_len - 2);
}
| SEND CLIENT ID STRING {
size_t i;
ssize_t len;
int not_hex = 0, val;
char buf[256], *hex, *p, excess;
if (iface_conf->c_id != NULL) {
yyerror("client-id already set");
YYERROR;
}
/* parse as hex string including the type byte */
if ((hex = strdup($4)) == NULL) {
free($4);
yyerror("malloc");
YYERROR;
}
for (i = 0; (p = strsep(&hex, ":")) != NULL && i <
sizeof(buf); ) {
if (sscanf(p, "%x%c", &val, &excess) != 1 ||
val < 0 || val > 0xff) {
not_hex = 1;
break;
}
buf[i++] = (val & 0xff);
}
if (p != NULL && i == sizeof(buf))
not_hex = 1;
free(hex);
if (not_hex) {
len = strnunvis(buf, $4, sizeof(buf));
free($4);
if (len == -1) {
yyerror("invalid client-id");
YYERROR;
}
if ((size_t)len >= sizeof(buf)) {
yyerror("client-id too long");
YYERROR;
}
iface_conf->c_id_len = 2 + len;
iface_conf->c_id = malloc(iface_conf->c_id_len);
if (iface_conf->c_id == NULL) {
yyerror("malloc");
YYERROR;
}
memcpy(&iface_conf->c_id[2], buf,
iface_conf->c_id_len - 2);
} else {
free($4);
iface_conf->c_id_len = 2 + i;
iface_conf->c_id = malloc(iface_conf->c_id_len);
if (iface_conf->c_id == NULL) {
yyerror("malloc");
YYERROR;
}
memcpy(&iface_conf->c_id[2], buf,
iface_conf->c_id_len - 2);
}
iface_conf->c_id[0] = DHO_DHCP_CLIENT_IDENTIFIER;
iface_conf->c_id[1] = iface_conf->c_id_len - 2;
}
| SEND HOST NAME STRING {
if (iface_conf->h_name != NULL) {
free($4);
yyerror("host name already set");
YYERROR;
}
if (strlen($4) > 255) {
free($4);
yyerror("host name too long");
YYERROR;
}
iface_conf->h_name = $4;
}
| SEND NO HOST NAME {
if (iface_conf->h_name != NULL) {
yyerror("host name already set");
YYERROR;
}
if ((iface_conf->h_name = strdup("")) == NULL) {
yyerror("malloc");
YYERROR;
}
}
| IGNORE ROUTES {
iface_conf->ignore |= IGN_ROUTES;
}
| IGNORE DNS {
iface_conf->ignore |= IGN_DNS;
}
| IGNORE STRING {
int res;
if (iface_conf->ignore_servers_len >= MAX_SERVERS) {
yyerror("too many servers to ignore");
free($2);
YYERROR;
}
res = inet_pton(AF_INET, $2,
&iface_conf->ignore_servers[
iface_conf->ignore_servers_len++]);
if (res != 1) {
yyerror("Invalid server IP %s", $2);
free($2);
YYERROR;
}
free($2);
}
| PREFER IPV6 {
iface_conf->prefer_ipv6 = 1;
}
;
%%
struct keywords {
const char *k_name;
int k_val;
};
int
yyerror(const char *fmt, ...)
{
va_list ap;
char *msg;
file->errors++;
va_start(ap, fmt);
if (vasprintf(&msg, fmt, ap) == -1)
fatalx("yyerror vasprintf");
va_end(ap);
logit(LOG_CRIT, "%s:%d: %s", file->name, yylval.lineno, msg);
free(msg);
return (0);
}
int
kw_cmp(const void *k, const void *e)
{
return (strcmp(k, ((const struct keywords *)e)->k_name));
}
int
lookup(char *s)
{
/* This has to be sorted always. */
static const struct keywords keywords[] = {
{"class", CLASS},
{"client", CLIENT},
{"dns", DNS},
{"host", HOST},
{"id", ID},
{"ignore", IGNORE},
{"interface", DHCP_IFACE},
{"ipv6", IPV6},
{"name", NAME},
{"no", NO},
{"prefer", PREFER},
{"routes", ROUTES},
{"send", SEND},
{"vendor", VENDOR},
};
const struct keywords *p;
p = bsearch(s, keywords, sizeof(keywords)/sizeof(keywords[0]),
sizeof(keywords[0]), kw_cmp);
if (p)
return (p->k_val);
else
return (STRING);
}
#define START_EXPAND 1
#define DONE_EXPAND 2
static int expanding;
int
igetc(void)
{
int c;
while (1) {
if (file->ungetpos > 0)
c = file->ungetbuf[--file->ungetpos];
else
c = getc(file->stream);
if (c == START_EXPAND)
expanding = 1;
else if (c == DONE_EXPAND)
expanding = 0;
else
break;
}
return (c);
}
int
lgetc(int quotec)
{
int c, next;
if (quotec) {
if ((c = igetc()) == EOF) {
yyerror("reached end of file while parsing "
"quoted string");
if (file == topfile || popfile() == EOF)
return (EOF);
return (quotec);
}
return (c);
}
while ((c = igetc()) == '\\') {
next = igetc();
if (next != '\n') {
c = next;
break;
}
yylval.lineno = file->lineno;
file->lineno++;
}
if (c == EOF) {
/*
* Fake EOL when hit EOF for the first time. This gets line
* count right if last line in included file is syntactically
* invalid and has no newline.
*/
if (file->eof_reached == 0) {
file->eof_reached = 1;
return ('\n');
}
while (c == EOF) {
if (file == topfile || popfile() == EOF)
return (EOF);
c = igetc();
}
}
return (c);
}
void
lungetc(int c)
{
if (c == EOF)
return;
if (file->ungetpos >= file->ungetsize) {
void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
if (p == NULL)
err(1, "lungetc");
file->ungetbuf = p;
file->ungetsize *= 2;
}
file->ungetbuf[file->ungetpos++] = c;
}
int
findeol(void)
{
int c;
/* Skip to either EOF or the first real EOL. */
while (1) {
c = lgetc(0);
if (c == '\n') {
file->lineno++;
break;
}
if (c == EOF)
break;
}
return (ERROR);
}
int
yylex(void)
{
char buf[8096];
char *p, *val;
int quotec, next, c;
int token;
top:
p = buf;
while ((c = lgetc(0)) == ' ' || c == '\t')
; /* nothing */
yylval.lineno = file->lineno;
if (c == '#')
while ((c = lgetc(0)) != '\n' && c != EOF)
; /* nothing */
if (c == '$' && !expanding) {
while (1) {
if ((c = lgetc(0)) == EOF)
return (0);
if (p + 1 >= buf + sizeof(buf) - 1) {
yyerror("string too long");
return (findeol());
}
if (isalnum(c) || c == '_') {
*p++ = c;
continue;
}
*p = '\0';
lungetc(c);
break;
}
val = symget(buf);
if (val == NULL) {
yyerror("macro '%s' not defined", buf);
return (findeol());
}
p = val + strlen(val) - 1;
lungetc(DONE_EXPAND);
while (p >= val) {
lungetc((unsigned char)*p);
p--;
}
lungetc(START_EXPAND);
goto top;
}
switch (c) {
case '\'':
case '"':
quotec = c;
while (1) {
if ((c = lgetc(quotec)) == EOF)
return (0);
if (c == '\n') {
file->lineno++;
continue;
} else if (c == '\\') {
if ((next = lgetc(quotec)) == EOF)
return (0);
if (next == quotec || next == ' ' ||
next == '\t')
c = next;
else if (next == '\n') {
file->lineno++;
continue;
} else
lungetc(next);
} else if (c == quotec) {
*p = '\0';
break;
} else if (c == '\0') {
yyerror("syntax error");
return (findeol());
}
if (p + 1 >= buf + sizeof(buf) - 1) {
yyerror("string too long");
return (findeol());
}
*p++ = c;
}
yylval.v.string = strdup(buf);
if (yylval.v.string == NULL)
err(1, "yylex: strdup");
return (STRING);
}
#define allowed_to_end_number(x) \
(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
if (c == '-' || isdigit(c)) {
do {
*p++ = c;
if ((size_t)(p-buf) >= sizeof(buf)) {
yyerror("string too long");
return (findeol());
}
} while ((c = lgetc(0)) != EOF && isdigit(c));
lungetc(c);
if (p == buf + 1 && buf[0] == '-')
goto nodigits;
if (c == EOF || allowed_to_end_number(c)) {
const char *errstr = NULL;
*p = '\0';
yylval.v.number = strtonum(buf, LLONG_MIN,
LLONG_MAX, &errstr);
if (errstr) {
yyerror("\"%s\" invalid number: %s",
buf, errstr);
return (findeol());
}
return (NUMBER);
} else {
nodigits:
while (p > buf + 1)
lungetc((unsigned char)*--p);
c = (unsigned char)*--p;
if (c == '-')
return (c);
}
}
#define allowed_in_string(x) \
(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
x != '{' && x != '}' && \
x != '!' && x != '=' && x != '#' && \
x != ','))
if (isalnum(c) || c == ':' || c == '_') {
do {
*p++ = c;
if ((size_t)(p-buf) >= sizeof(buf)) {
yyerror("string too long");
return (findeol());
}
} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
lungetc(c);
*p = '\0';
if ((token = lookup(buf)) == STRING)
if ((yylval.v.string = strdup(buf)) == NULL)
err(1, "yylex: strdup");
return (token);
}
if (c == '\n') {
yylval.lineno = file->lineno;
file->lineno++;
}
if (c == EOF)
return (0);
return (c);
}
int
check_file_secrecy(int fd, const char *fname)
{
struct stat st;
if (fstat(fd, &st)) {
log_warn("cannot stat %s", fname);
return (-1);
}
if (st.st_uid != 0 && st.st_uid != getuid()) {
log_warnx("%s: owner not root or current user", fname);
return (-1);
}
if (st.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO)) {
log_warnx("%s: group writable or world read/writable", fname);
return (-1);
}
return (0);
}
struct file *
pushfile(const char *name, int secret)
{
struct file *nfile;
if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
log_warn("calloc");
return (NULL);
}
if ((nfile->name = strdup(name)) == NULL) {
log_warn("strdup");
free(nfile);
return (NULL);
}
if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
free(nfile->name);
free(nfile);
return (NULL);
} else if (secret &&
check_file_secrecy(fileno(nfile->stream), nfile->name)) {
fclose(nfile->stream);
free(nfile->name);
free(nfile);
return (NULL);
}
nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
nfile->ungetsize = 16;
nfile->ungetbuf = malloc(nfile->ungetsize);
if (nfile->ungetbuf == NULL) {
log_warn("malloc");
fclose(nfile->stream);
free(nfile->name);
free(nfile);
return (NULL);
}
TAILQ_INSERT_TAIL(&files, nfile, entry);
return (nfile);
}
int
popfile(void)
{
struct file *prev;
if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
prev->errors += file->errors;
TAILQ_REMOVE(&files, file, entry);
fclose(file->stream);
free(file->name);
free(file->ungetbuf);
free(file);
file = prev;
return (file ? 0 : EOF);
}
struct dhcpleased_conf *
parse_config(const char *filename)
{
extern const char default_conffile[];
struct sym *sym, *next;
conf = config_new_empty();
file = pushfile(filename, 0);
if (file == NULL) {
/* no default config file is fine */
if (errno == ENOENT && filename == default_conffile)
return (conf);
log_warn("%s", filename);
free(conf);
return (NULL);
}
topfile = file;
yyparse();
errors = file->errors;
popfile();
/* Free macros and check which have not been used. */
TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
if ((log_getverbose() == 2) && !sym->used)
fprintf(stderr, "warning: macro '%s' not used\n",
sym->nam);
if (!sym->persist) {
free(sym->nam);
free(sym->val);
TAILQ_REMOVE(&symhead, sym, entry);
free(sym);
}
}
if (errors) {
config_clear(conf);
return (NULL);
}
return (conf);
}
int
symset(const char *nam, const char *val, int persist)
{
struct sym *sym;
TAILQ_FOREACH(sym, &symhead, entry) {
if (strcmp(nam, sym->nam) == 0)
break;
}
if (sym != NULL) {
if (sym->persist == 1)
return (0);
else {
free(sym->nam);
free(sym->val);
TAILQ_REMOVE(&symhead, sym, entry);
free(sym);
}
}
if ((sym = calloc(1, sizeof(*sym))) == NULL)
return (-1);
sym->nam = strdup(nam);
if (sym->nam == NULL) {
free(sym);
return (-1);
}
sym->val = strdup(val);
if (sym->val == NULL) {
free(sym->nam);
free(sym);
return (-1);
}
sym->used = 0;
sym->persist = persist;
TAILQ_INSERT_TAIL(&symhead, sym, entry);
return (0);
}
int
cmdline_symset(char *s)
{
char *sym, *val;
int ret;
if ((val = strrchr(s, '=')) == NULL)
return (-1);
sym = strndup(s, val - s);
if (sym == NULL)
errx(1, "%s: strndup", __func__);
ret = symset(sym, val + 1, 1);
free(sym);
return (ret);
}
char *
symget(const char *nam)
{
struct sym *sym;
TAILQ_FOREACH(sym, &symhead, entry) {
if (strcmp(nam, sym->nam) == 0) {
sym->used = 1;
return (sym->val);
}
}
return (NULL);
}
struct iface_conf *
conf_get_iface(char *name)
{
struct iface_conf *iface;
size_t n;
SIMPLEQ_FOREACH(iface, &conf->iface_list, entry) {
if (strcmp(name, iface->name) == 0)
return (iface);
}
iface = calloc(1, sizeof(*iface));
if (iface == NULL)
errx(1, "%s: calloc", __func__);
n = strlcpy(iface->name, name, sizeof(iface->name));
if (n >= sizeof(iface->name))
errx(1, "%s: name too long", __func__);
SIMPLEQ_INSERT_TAIL(&conf->iface_list, iface, entry);
return (iface);
}
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