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-rw-r--r--usr.bin/doas/parse.y343
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diff --git a/usr.bin/doas/parse.y b/usr.bin/doas/parse.y
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+/* $OpenBSD: parse.y,v 1.27 2018/07/11 07:39:22 krw Exp $ */
+/*
+ * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
+ *
+ * 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 <ctype.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+
+#include "doas.h"
+
+typedef struct {
+ union {
+ struct {
+ int action;
+ int options;
+ const char *cmd;
+ const char **cmdargs;
+ const char **envlist;
+ };
+ const char **strlist;
+ const char *str;
+ };
+ int lineno;
+ int colno;
+} yystype;
+#define YYSTYPE yystype
+
+FILE *yyfp;
+
+struct rule **rules;
+int nrules;
+static int maxrules;
+
+int parse_errors = 0;
+
+static void yyerror(const char *, ...);
+static int yylex(void);
+
+static size_t
+arraylen(const char **arr)
+{
+ size_t cnt = 0;
+
+ while (*arr) {
+ cnt++;
+ arr++;
+ }
+ return cnt;
+}
+
+%}
+
+%token TPERMIT TDENY TAS TCMD TARGS
+%token TNOPASS TPERSIST TKEEPENV TSETENV
+%token TSTRING
+
+%%
+
+grammar: /* empty */
+ | grammar '\n'
+ | grammar rule '\n'
+ | error '\n'
+ ;
+
+rule: action ident target cmd {
+ struct rule *r;
+ r = calloc(1, sizeof(*r));
+ if (!r)
+ errx(1, "can't allocate rule");
+ r->action = $1.action;
+ r->options = $1.options;
+ r->envlist = $1.envlist;
+ r->ident = $2.str;
+ r->target = $3.str;
+ r->cmd = $4.cmd;
+ r->cmdargs = $4.cmdargs;
+ if (nrules == maxrules) {
+ if (maxrules == 0)
+ maxrules = 63;
+ else
+ maxrules *= 2;
+ if (!(rules = reallocarray(rules, maxrules,
+ sizeof(*rules))))
+ errx(1, "can't allocate rules");
+ }
+ rules[nrules++] = r;
+ } ;
+
+action: TPERMIT options {
+ $$.action = PERMIT;
+ $$.options = $2.options;
+ $$.envlist = $2.envlist;
+ } | TDENY {
+ $$.action = DENY;
+ $$.options = 0;
+ $$.envlist = NULL;
+ } ;
+
+options: /* none */ {
+ $$.options = 0;
+ $$.envlist = NULL;
+ } | options option {
+ $$.options = $1.options | $2.options;
+ $$.envlist = $1.envlist;
+ if (($$.options & (NOPASS|PERSIST)) == (NOPASS|PERSIST)) {
+ yyerror("can't combine nopass and persist");
+ YYERROR;
+ }
+ if ($2.envlist) {
+ if ($$.envlist) {
+ yyerror("can't have two setenv sections");
+ YYERROR;
+ } else
+ $$.envlist = $2.envlist;
+ }
+ } ;
+option: TNOPASS {
+ $$.options = NOPASS;
+ $$.envlist = NULL;
+ } | TPERSIST {
+ $$.options = PERSIST;
+ $$.envlist = NULL;
+ } | TKEEPENV {
+ $$.options = KEEPENV;
+ $$.envlist = NULL;
+ } | TSETENV '{' strlist '}' {
+ $$.options = 0;
+ $$.envlist = $3.strlist;
+ } ;
+
+strlist: /* empty */ {
+ if (!($$.strlist = calloc(1, sizeof(char *))))
+ errx(1, "can't allocate strlist");
+ } | strlist TSTRING {
+ int nstr = arraylen($1.strlist);
+ if (!($$.strlist = reallocarray($1.strlist, nstr + 2,
+ sizeof(char *))))
+ errx(1, "can't allocate strlist");
+ $$.strlist[nstr] = $2.str;
+ $$.strlist[nstr + 1] = NULL;
+ } ;
+
+
+ident: TSTRING {
+ $$.str = $1.str;
+ } ;
+
+target: /* optional */ {
+ $$.str = NULL;
+ } | TAS TSTRING {
+ $$.str = $2.str;
+ } ;
+
+cmd: /* optional */ {
+ $$.cmd = NULL;
+ $$.cmdargs = NULL;
+ } | TCMD TSTRING args {
+ $$.cmd = $2.str;
+ $$.cmdargs = $3.cmdargs;
+ } ;
+
+args: /* empty */ {
+ $$.cmdargs = NULL;
+ } | TARGS strlist {
+ $$.cmdargs = $2.strlist;
+ } ;
+
+%%
+
+void
+yyerror(const char *fmt, ...)
+{
+ va_list va;
+
+ fprintf(stderr, "doas: ");
+ va_start(va, fmt);
+ vfprintf(stderr, fmt, va);
+ va_end(va);
+ fprintf(stderr, " at line %d\n", yylval.lineno + 1);
+ parse_errors++;
+}
+
+static struct keyword {
+ const char *word;
+ int token;
+} keywords[] = {
+ { "deny", TDENY },
+ { "permit", TPERMIT },
+ { "as", TAS },
+ { "cmd", TCMD },
+ { "args", TARGS },
+ { "nopass", TNOPASS },
+ { "persist", TPERSIST },
+ { "keepenv", TKEEPENV },
+ { "setenv", TSETENV },
+};
+
+int
+yylex(void)
+{
+ char buf[1024], *ebuf, *p, *str;
+ int i, c, quotes = 0, escape = 0, qpos = -1, nonkw = 0;
+
+ p = buf;
+ ebuf = buf + sizeof(buf);
+
+repeat:
+ /* skip whitespace first */
+ for (c = getc(yyfp); c == ' ' || c == '\t'; c = getc(yyfp))
+ yylval.colno++;
+
+ /* check for special one-character constructions */
+ switch (c) {
+ case '\n':
+ yylval.colno = 0;
+ yylval.lineno++;
+ /* FALLTHROUGH */
+ case '{':
+ case '}':
+ return c;
+ case '#':
+ /* skip comments; NUL is allowed; no continuation */
+ while ((c = getc(yyfp)) != '\n')
+ if (c == EOF)
+ goto eof;
+ yylval.colno = 0;
+ yylval.lineno++;
+ return c;
+ case EOF:
+ goto eof;
+ }
+
+ /* parsing next word */
+ for (;; c = getc(yyfp), yylval.colno++) {
+ switch (c) {
+ case '\0':
+ yyerror("unallowed character NUL in column %d",
+ yylval.colno + 1);
+ escape = 0;
+ continue;
+ case '\\':
+ escape = !escape;
+ if (escape)
+ continue;
+ break;
+ case '\n':
+ if (quotes)
+ yyerror("unterminated quotes in column %d",
+ qpos + 1);
+ if (escape) {
+ nonkw = 1;
+ escape = 0;
+ yylval.colno = 0;
+ yylval.lineno++;
+ continue;
+ }
+ goto eow;
+ case EOF:
+ if (escape)
+ yyerror("unterminated escape in column %d",
+ yylval.colno);
+ if (quotes)
+ yyerror("unterminated quotes in column %d",
+ qpos + 1);
+ goto eow;
+ /* FALLTHROUGH */
+ case '{':
+ case '}':
+ case '#':
+ case ' ':
+ case '\t':
+ if (!escape && !quotes)
+ goto eow;
+ break;
+ case '"':
+ if (!escape) {
+ quotes = !quotes;
+ if (quotes) {
+ nonkw = 1;
+ qpos = yylval.colno;
+ }
+ continue;
+ }
+ }
+ *p++ = c;
+ if (p == ebuf) {
+ yyerror("too long line");
+ p = buf;
+ }
+ escape = 0;
+ }
+
+eow:
+ *p = 0;
+ if (c != EOF)
+ ungetc(c, yyfp);
+ if (p == buf) {
+ /*
+ * There could be a number of reasons for empty buffer,
+ * and we handle all of them here, to avoid cluttering
+ * the main loop.
+ */
+ if (c == EOF)
+ goto eof;
+ else if (qpos == -1) /* accept, e.g., empty args: cmd foo args "" */
+ goto repeat;
+ }
+ if (!nonkw) {
+ for (i = 0; i < sizeof(keywords) / sizeof(keywords[0]); i++) {
+ if (strcmp(buf, keywords[i].word) == 0)
+ return keywords[i].token;
+ }
+ }
+ if ((str = strdup(buf)) == NULL)
+ err(1, "%s", __func__);
+ yylval.str = str;
+ return TSTRING;
+
+eof:
+ if (ferror(yyfp))
+ yyerror("input error reading config");
+ return 0;
+}
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