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authorVadim Zhukov <zhuk@openbsd.org>2015-07-26 17:24:02 +0000
committerVadim Zhukov <zhuk@openbsd.org>2015-07-26 17:24:02 +0000
commit26edde87e46f2601656361736472e216e8acf707 (patch)
tree94b5146987d937e6816cd5d96f4540cb96442d96
parentedf4632491d75d7e56c5293de3c33dc2de74231d (diff)
downloadopendoas-26edde87e46f2601656361736472e216e8acf707.tar.gz
Implement command matching without execution. This just extends
functionality of the -C flag, so we are not introducing more garbage. Input and okay from jmc@ (documentation) and tedu@ (everything).
-rw-r--r--doas.122
-rw-r--r--doas.c63
2 files changed, 68 insertions, 17 deletions
diff --git a/doas.1 b/doas.1
index 5220eb5..63153c6 100644
--- a/doas.1
+++ b/doas.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: doas.1,v 1.9 2015/07/21 16:12:04 tedu Exp $
+.\" $OpenBSD: doas.1,v 1.10 2015/07/21 17:49:33 jmc Exp $
.\"
.\"Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
.\"
@@ -30,6 +30,13 @@
The
.Nm
utility executes the given command as another user.
+The
+.Ar command
+argument is mandatory unless
+.Fl C
+or
+.Fl s
+is specified.
.Pp
The options are as follows:
.Bl -tag -width tenletters
@@ -37,6 +44,19 @@ The options are as follows:
Parse and check the configuration file
.Ar config ,
then exit.
+If
+.Ar command
+is supplied,
+.Nm
+will also perform command matching.
+In the latter case
+either
+.Sq permit ,
+.Sq permit nopass
+or
+.Sq deny
+will be printed on standard output, depending on command
+matching results.
No command is executed.
.It Fl s
Execute the shell from
diff --git a/doas.c b/doas.c
index 00292e3..7963926 100644
--- a/doas.c
+++ b/doas.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: doas.c,v 1.20 2015/07/22 16:35:03 zhuk Exp $ */
+/* $OpenBSD: doas.c,v 1.21 2015/07/24 06:36:42 zhuk Exp $ */
/*
* Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
*
@@ -152,7 +152,7 @@ permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr,
}
static void
-parseconfig(const char *filename)
+parseconfig(const char *filename, int checkperms)
{
extern FILE *yyfp;
extern int yyparse(void);
@@ -160,16 +160,21 @@ parseconfig(const char *filename)
yyfp = fopen(filename, "r");
if (!yyfp) {
- fprintf(stderr, "doas is not enabled.\n");
+ if (checkperms)
+ fprintf(stderr, "doas is not enabled.\n");
+ else
+ warn("could not open config file");
exit(1);
}
- if (fstat(fileno(yyfp), &sb) != 0)
- err(1, "fstat(\"%s\")", filename);
- if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
- errx(1, "%s is writable by group or other", filename);
- if (sb.st_uid != 0)
- errx(1, "%s is not owned by root", filename);
+ if (checkperms) {
+ if (fstat(fileno(yyfp), &sb) != 0)
+ err(1, "fstat(\"%s\")", filename);
+ if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
+ errx(1, "%s is writable by group or other", filename);
+ if (sb.st_uid != 0)
+ errx(1, "%s is not owned by root", filename);
+ }
yyparse();
fclose(yyfp);
@@ -277,11 +282,32 @@ fail(void)
exit(1);
}
+static int
+checkconfig(const char *confpath, int argc, char **argv,
+ uid_t uid, gid_t *groups, int ngroups, uid_t target) {
+ struct rule *rule;
+
+ setresuid(uid, uid, uid);
+ parseconfig(confpath, 0);
+ if (!argc)
+ exit(0);
+
+ if (permit(uid, groups, ngroups, &rule, target, argv[0],
+ (const char **)argv + 1)) {
+ printf("permit%s\n", (rule->options & NOPASS) ? " nopass" : "");
+ return 1;
+ } else {
+ printf("deny\n");
+ return 0;
+ }
+}
+
int
main(int argc, char **argv, char **envp)
{
const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:"
"/usr/local/bin:/usr/local/sbin";
+ const char *confpath = NULL;
char *shargv[] = { NULL, NULL };
char *sh;
const char *cmd;
@@ -296,13 +322,11 @@ main(int argc, char **argv, char **envp)
int i, ch;
int sflag = 0;
- uid = getuid();
while ((ch = getopt(argc, argv, "C:su:")) != -1) {
switch (ch) {
case 'C':
- setresuid(uid, uid, uid);
- parseconfig(optarg);
- exit(0);
+ confpath = optarg;
+ break;
case 'u':
if (parseuid(optarg, &target) != 0)
errx(1, "unknown user");
@@ -318,11 +342,13 @@ main(int argc, char **argv, char **envp)
argv += optind;
argc -= optind;
- if ((!sflag && !argc) || (sflag && argc))
+ if (confpath) {
+ if (sflag)
+ usage();
+ } else if ((!sflag && !argc) || (sflag && argc))
usage();
- parseconfig("/etc/doas.conf");
-
+ uid = getuid();
pw = getpwuid(uid);
if (!pw)
err(1, "getpwuid failed");
@@ -343,6 +369,11 @@ main(int argc, char **argv, char **envp)
argc = 1;
}
+ if (confpath)
+ exit(!checkconfig(confpath, argc, argv, uid, groups, ngroups,
+ target));
+ parseconfig("/etc/doas.conf", 1);
+
cmd = argv[0];
if (strlcpy(cmdline, argv[0], sizeof(cmdline)) >= sizeof(cmdline))
errx(1, "command line too long");