Add more error checking and use named constants when useful.

ok sthen@ tedu@

diff --git a/doas.c b/doas.c
index 47ae35ada88b03cd7aec9ba31d4599f256327a8b..31222a6e5040fa1ad7951acf2ce85bc58a7cc3ea 100644 (file)
--- a/doas.c
+++ b/doas.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: doas.c,v 1.5 2015/07/16 22:11:01 nicm Exp $ */
+/* $OpenBSD: doas.c,v 1.6 2015/07/16 23:22:08 nicm Exp $ */
 /*
  * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
  *
@@ -244,8 +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;
@@ -276,17 +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");
@@ -317,7 +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);
 }