Add more error checking and use named constants when useful.

[opendoas.git] / doas.c

diff --git a/doas.c b/doas.c
index ec727df3931c02d2dac84efa3cf0c5aa6111c31e..31222a6e5040fa1ad7951acf2ce85bc58a7cc3ea 100644 (file)
--- a/doas.c
+++ b/doas.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: doas.c,v 1.4 2015/07/16 21:57:54 deraadt Exp $ */
+/* $OpenBSD: doas.c,v 1.6 2015/07/16 23:22:08 nicm Exp $ */
 /*
  * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
  *
@@ -14,7 +14,9 @@
  * 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/stat.h>
 
 #include <limits.h>
 #include <login_cap.h>
@@ -139,12 +141,21 @@ parseconfig(const char *filename)
 {
        extern FILE *yyfp;
        extern int yyparse(void);
+       struct stat sb;
 
        yyfp = fopen(filename, "r");
        if (!yyfp) {
                fprintf(stderr, "doas is not enabled.\n");
                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);
+
        yyparse();
        fclose(yyfp);
 }
@@ -233,8 +244,8 @@ fail(void)
 int
 main(int argc, char **argv, char **envp)
 {
-       char cmdline[1024];
-       char myname[32];
+       char cmdline[LINE_MAX];
+       char myname[_PW_NAME_LEN + 1];
        uid_t uid, target = 0;
        gid_t groups[NGROUPS_MAX + 1];
        int ngroups;
@@ -265,17 +276,21 @@ main(int argc, char **argv, char **envp)
                usage();
 
        cmd = argv[0];
-       strlcpy(cmdline, argv[0], sizeof(cmdline));
+       if (strlcpy(cmdline, argv[0], sizeof(cmdline)) >= sizeof(cmdline))
+               errx(1, "command line too long");
        for (i = 1; i < argc; i++) {
-               strlcat(cmdline, " ", sizeof(cmdline));
-               strlcat(cmdline, argv[i], sizeof(cmdline));
+               if (strlcat(cmdline, " ", sizeof(cmdline)) >= sizeof(cmdline))
+                       errx(1, "command line too long");
+               if (strlcat(cmdline, argv[i], sizeof(cmdline)) >= sizeof(cmdline))
+                       errx(1, "command line too long");
        }
 
        uid = getuid();
        pw = getpwuid(uid);
        if (!pw)
                err(1, "getpwuid failed");
-       strlcpy(myname, pw->pw_name, sizeof(myname));
+       if (strlcpy(myname, pw->pw_name, sizeof(myname)) >= sizeof(myname))
+               errx(1, "pw_name too long");
        ngroups = getgroups(NGROUPS_MAX, groups);
        if (ngroups == -1)
                err(1, "can't get groups");
@@ -306,7 +321,8 @@ main(int argc, char **argv, char **envp)
 
        syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s",
            myname, pw->pw_name, cmdline);
-       setenv("PATH", safepath, 1);
+       if (setenv("PATH", safepath, 1) == -1)
+               err(1, "failed to set PATH '%s'", safepath);
        execvpe(cmd, argv, envp);
        err(1, "%s", cmd);
 }