crontab: clear env if run by non-root, so that we can use PATH now

crontab: make "-c /tmp/ -e" work

1 files changed, 8 insertions, 10 deletions

diff --git a/miscutils/crontab.c b/miscutils/crontab.c
index b292535b1..a1fe2c5a5 100644
--- a/miscutils/crontab.c
+++ b/miscutils/crontab.c
@@ -15,9 +15,6 @@
 #ifndef CRONTABS
 #define CRONTABS        "/var/spool/cron/crontabs"
 #endif
-#ifndef TMPDIR
-#define TMPDIR          "/var/spool/cron"
-#endif
 #ifndef CRONUPDATE
 #define CRONUPDATE      "cron.update"
 #endif
@@ -37,7 +34,7 @@ static void change_user(const struct passwd *pas)
         if (chdir(pas->pw_dir) < 0) {
                 bb_perror_msg("chdir(%s) by %s failed",
                                 pas->pw_dir, pas->pw_name);
-                xchdir(TMPDIR);
+                xchdir("/tmp");
         }
 }
 
@@ -62,9 +59,7 @@ static void edit_file(const struct passwd *pas, const char *file)
                         ptr = PATH_VI;
         }
 
-        /* TODO: clean up the environment!!! */
-        /* not execlp - we won't use PATH */
-        execl(ptr, ptr, file, NULL);
+        BB_EXECLP(ptr, ptr, file, NULL);
         bb_perror_msg_and_die("exec %s", ptr);
 }
 
@@ -136,9 +131,12 @@ int crontab_main(int argc, char **argv)
         opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir);
         argv += optind;
 
-        if (opt_ler & (OPT_u|OPT_c))
-                if (my_uid != geteuid())
+        if (my_uid != geteuid()) { /* run by non-root? */
+                if (opt_ler & (OPT_u|OPT_c))
                         bb_error_msg_and_die("only root can use -c or -u");
+                /* Clear dangerous stuff, set PATH */
+                sanitize_env_for_suid();
+        }
 
         if (opt_ler & OPT_u) {
                 pas = getpwnam(user_name);
@@ -194,7 +192,7 @@ int crontab_main(int argc, char **argv)
                 }
 
         case OPT_e: /* Edit */
-                tmp_fname = xasprintf(TMPDIR "/crontab.%u", (unsigned)getpid());
+                tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid());
                 fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
                 xmove_fd(fd, STDIN_FILENO);
                 fd = open(pas->pw_name, O_RDONLY);