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/* $OpenBSD: parse.y,v 1.29 2021/10/22 15:03:28 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/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include "log.h"
#include "unwind.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 *);
int check_pref_uniq(enum uw_resolver_type);
static struct uw_conf *conf;
static int errors;
void clear_config(struct uw_conf *xconf);
struct sockaddr_storage *host_ip(const char *);
typedef struct {
union {
int64_t number;
char *string;
struct force_tree force;
} v;
int lineno;
} YYSTYPE;
%}
%token INCLUDE ERROR
%token FORWARDER DOT PORT ODOT_FORWARDER ODOT_AUTOCONF ODOT_DHCP
%token AUTHENTICATION NAME PREFERENCE RECURSOR AUTOCONF DHCP STUB
%token BLOCK LIST LOG FORCE ACCEPT BOGUS
%token <v.string> STRING
%token <v.number> NUMBER
%type <v.number> port dot prefopt log acceptbogus
%type <v.string> string authname
%type <v.force> force_list
%%
grammar : /* empty */
| grammar include '\n'
| grammar '\n'
| grammar varset '\n'
| grammar uw_pref '\n'
| grammar uw_forwarder '\n'
| grammar block_list '\n'
| grammar force '\n'
| grammar error '\n' { file->errors++; }
;
include : INCLUDE STRING {
struct file *nfile;
if ((nfile = pushfile($2, 0)) == NULL) {
yyerror("failed to include file %s", $2);
free($2);
YYERROR;
}
free($2);
file = nfile;
lungetc('\n');
}
;
string : string STRING {
if (asprintf(&$$, "%s %s", $1, $2) == -1) {
free($1);
free($2);
yyerror("string: asprintf");
YYERROR;
}
free($1);
free($2);
}
| STRING
;
varset : STRING '=' string {
char *s = $1;
if (cmd_opts & OPT_VERBOSE)
printf("%s = \"%s\"\n", $1, $3);
while (*s++) {
if (isspace((unsigned char)*s)) {
yyerror("macro name cannot contain "
"whitespace");
free($1);
free($3);
YYERROR;
}
}
if (symset($1, $3, 0) == -1)
fatal("cannot store variable");
free($1);
free($3);
}
;
optnl : '\n' optnl /* zero or more newlines */
| /*empty*/
;
block_list : BLOCK LIST STRING log {
if (conf->blocklist_file != NULL) {
yyerror("block list already "
"configured");
free($3);
YYERROR;
} else {
conf->blocklist_file = strdup($3);
if (conf->blocklist_file == NULL)
err(1, "strdup");
free($3);
conf->blocklist_log = $4;
}
}
;
uw_pref : PREFERENCE {
conf->res_pref.len = 0;
memset(conf->enabled_resolvers, 0,
sizeof(conf->enabled_resolvers));
} pref_block
;
pref_block : '{' optnl prefopts_l '}'
| prefoptsl
;
prefopts_l : prefopts_l prefoptsl optnl
| prefoptsl optnl
;
prefoptsl : prefopt {
if (!check_pref_uniq($1))
YYERROR;
if (conf->res_pref.len >= UW_RES_NONE) {
yyerror("preference list too long");
YYERROR;
}
conf->res_pref.types[conf->res_pref.len++] = $1;
conf->enabled_resolvers[$1] = 1;
}
;
prefopt : DOT { $$ = UW_RES_DOT; }
| FORWARDER { $$ = UW_RES_FORWARDER; }
| ODOT_FORWARDER { $$ = UW_RES_ODOT_FORWARDER; }
| RECURSOR { $$ = UW_RES_RECURSOR; }
| AUTOCONF { $$ = UW_RES_AUTOCONF; }
| DHCP { $$ = UW_RES_AUTOCONF; }
| ODOT_AUTOCONF { $$ = UW_RES_ODOT_AUTOCONF; }
| ODOT_DHCP { $$ = UW_RES_ODOT_AUTOCONF; }
| STUB { $$ = UW_RES_ASR; }
;
uw_forwarder : FORWARDER forwarder_block
;
forwarder_block : '{' optnl forwarderopts_l '}'
| forwarderoptsl
;
forwarderopts_l : forwarderopts_l forwarderoptsl optnl
| forwarderoptsl optnl
;
forwarderoptsl : STRING port authname dot {
struct uw_forwarder *uw_fwd;
struct sockaddr_storage *ss;
if ((ss = host_ip($1)) == NULL) {
yyerror("%s is not an ip-address", $1);
free($1);
YYERROR;
}
free(ss);
if ((uw_fwd = calloc(1, sizeof(*uw_fwd))) ==
NULL)
err(1, NULL);
if ($2 < 0 || $2 > (int)USHRT_MAX) {
yyerror("invalid port: %lld", $2);
free($1);
free(uw_fwd);
YYERROR;
}
if ($2 == 0)
uw_fwd->port = $4 == DOT ? 853 : 53;
else
uw_fwd->port = $2;
if ($3 != NULL && $4 == 0) {
yyerror("authentication name can only "
"be used with DoT");
free($1);
free(uw_fwd);
YYERROR;
}
if (strlcpy(uw_fwd->ip, $1, sizeof(uw_fwd->ip))
>= sizeof(uw_fwd->ip)) {
free(uw_fwd);
yyerror("forwarder %s too long", $1);
free($1);
YYERROR;
}
if ($4 == DOT && $3 != NULL) {
if (strlcpy(uw_fwd->auth_name, $3,
sizeof(uw_fwd->auth_name))
>= sizeof(uw_fwd->auth_name)) {
free(uw_fwd);
yyerror("authentication name "
"%s too long", $3);
free($1);
YYERROR;
}
}
if ($4 == DOT)
TAILQ_INSERT_TAIL(
&conf->uw_dot_forwarder_list,
uw_fwd, entry);
else {
TAILQ_INSERT_TAIL(
&conf->uw_forwarder_list,
uw_fwd, entry);
}
free($1);
}
;
port : PORT NUMBER { $$ = $2; }
| /* empty */ { $$ = 0; }
;
authname: AUTHENTICATION NAME STRING { $$ = $3; }
| /* empty */ { $$ = NULL; }
;
dot : DOT { $$ = DOT; }
| /* empty */ { $$ = 0; }
;
log : LOG { $$ = 1; }
| /* empty */ { $$ = 0; }
;
force : FORCE acceptbogus prefopt '{' force_list optnl '}' {
struct force_tree_entry *n, *nxt;
int error = 0;
RB_FOREACH_SAFE(n, force_tree, &$5, nxt) {
n->acceptbogus = $2;
n->type = $3;
RB_REMOVE(force_tree, &$5, n);
if (RB_INSERT(force_tree, &conf->force,
n)) {
yyerror("%s already in an force "
"list", n->domain);
error = 1;
}
}
if (error)
YYERROR;
}
;
acceptbogus: ACCEPT BOGUS { $$ = 1; }
| /* empty */ { $$ = 0; }
;
force_list: force_list optnl STRING {
struct force_tree_entry *e;
size_t len;
len = strlen($3);
e = malloc(sizeof(*e));
if (e == NULL)
err(1, NULL);
if (strlcpy(e->domain, $3, sizeof(e->domain)) >=
sizeof(e->domain)) {
yyerror("force %s too long", $3);
free($3);
YYERROR;
}
free($3);
if (len == 0 || e->domain[len-1] != '.') {
if (strlcat(e->domain, ".",
sizeof((e->domain))) >=
sizeof((e->domain))) {
yyerror("force %s too long", $3);
YYERROR;
}
}
if (RB_INSERT(force_tree, &$$, e) != NULL) {
log_warnx("duplicate force %s", e->domain);
free(e);
}
}
| /* empty */ {
RB_INIT(&$$);
}
;
%%
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[] = {
{"DoT", DOT},
{"accept", ACCEPT},
{"authentication", AUTHENTICATION},
{"autoconf", AUTOCONF},
{"block", BLOCK},
{"bogus", BOGUS},
{"dhcp", DHCP},
{"dot", DOT},
{"force", FORCE},
{"forwarder", FORWARDER},
{"include", INCLUDE},
{"list", LIST},
{"log", LOG},
{"name", NAME},
{"oDoT-autoconf", ODOT_AUTOCONF},
{"oDoT-dhcp", ODOT_DHCP},
{"oDoT-forwarder", ODOT_FORWARDER},
{"port", PORT},
{"preference", PREFERENCE},
{"recursor", RECURSOR},
{"stub", STUB},
{"tls", DOT},
};
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 uw_conf *
parse_config(char *filename)
{
static enum uw_resolver_type default_res_pref[] = {
UW_RES_DOT,
UW_RES_ODOT_FORWARDER,
UW_RES_FORWARDER,
UW_RES_RECURSOR,
UW_RES_ODOT_AUTOCONF,
UW_RES_AUTOCONF,
UW_RES_ASR};
struct sym *sym, *next;
int i;
conf = config_new_empty();
memcpy(&conf->res_pref.types, &default_res_pref,
sizeof(default_res_pref));
conf->res_pref.len = nitems(default_res_pref);
for (i = 0; i < conf->res_pref.len; i++)
conf->enabled_resolvers[conf->res_pref.types[i]] = 1;
file = pushfile(filename != NULL ? filename : _PATH_CONF_FILE, 0);
if (file == NULL) {
/* no default config file is fine */
if (errno == ENOENT && filename == NULL)
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 ((cmd_opts & OPT_VERBOSE2) && !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) {
clear_config(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);
}
void
clear_config(struct uw_conf *xconf)
{
struct uw_forwarder *uw_forwarder;
while ((uw_forwarder = TAILQ_FIRST(&xconf->uw_forwarder_list)) !=
NULL) {
TAILQ_REMOVE(&xconf->uw_forwarder_list, uw_forwarder, entry);
free(uw_forwarder);
}
while ((uw_forwarder = TAILQ_FIRST(&xconf->uw_dot_forwarder_list)) !=
NULL) {
TAILQ_REMOVE(&xconf->uw_dot_forwarder_list, uw_forwarder,
entry);
free(uw_forwarder);
}
free(xconf);
}
struct sockaddr_storage *
host_ip(const char *s)
{
struct addrinfo hints, *res;
struct sockaddr_storage *ss = NULL;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
hints.ai_flags = AI_NUMERICHOST;
if (getaddrinfo(s, "0", &hints, &res) == 0) {
if (res->ai_family == AF_INET ||
res->ai_family == AF_INET6) {
if ((ss = calloc(1, sizeof(*ss))) == NULL)
fatal(NULL);
memcpy(ss, res->ai_addr, res->ai_addrlen);
}
freeaddrinfo(res);
}
return (ss);
}
int
check_pref_uniq(enum uw_resolver_type type)
{
int i;
for (i = 0; i < conf->res_pref.len; i++)
if (conf->res_pref.types[i] == type) {
yyerror("%s is already in the preference list",
uw_resolver_type_str[type]);
return (0);
}
return (1);
}
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