inetd: fix order of array index check and array access
[oweals/busybox.git] / networking / inetd.c
index 58ae089d11e5ece9a4343055ce13be16927481dd..8148925ce30998f3db50e89c17b326103e68755f 100644 (file)
 //usage:       "[-fe] [-q N] [-R N] [CONFFILE]"
 //usage:#define inetd_full_usage "\n\n"
 //usage:       "Listen for network connections and launch programs\n"
-//usage:     "\nOptions:"
 //usage:     "\n       -f      Run in foreground"
 //usage:     "\n       -e      Log to stderr"
-//usage:     "\n       -q N    Socket listen queue (default: 128)"
+//usage:     "\n       -q N    Socket listen queue (default: 128)"
 //usage:     "\n       -R N    Pause services after N connects/min"
 //usage:     "\n               (default: 0 - disabled)"
 
 #include <syslog.h>
+#include <sys/resource.h> /* setrlimit */
+#include <sys/socket.h> /* un.h may need this */
 #include <sys/un.h>
 
 #include "libbb.h"
 
 #if ENABLE_FEATURE_INETD_RPC
-#include <rpc/rpc.h>
-#include <rpc/pmap_clnt.h>
+# if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
+#  error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support"
+# endif
+# include <rpc/rpc.h>
+# include <rpc/pmap_clnt.h>
 #endif
 
 #if !BB_MMU
 #define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
 #endif
 
-#define _PATH_INETDPID  "/var/run/inetd.pid"
-
 #define CNT_INTERVAL    60      /* servers in CNT_INTERVAL sec. */
 #define RETRYTIME       60      /* retry after bind or server fail */
 
@@ -355,10 +357,26 @@ struct BUG_G_too_big {
        config_filename = "/etc/inetd.conf"; \
 } while (0)
 
+#if 1
+# define dbg(...) ((void)0)
+#else
+# define dbg(...) \
+do { \
+       int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
+       if (dbg_fd >= 0) { \
+               fdprintf(dbg_fd, "%d: ", getpid()); \
+               fdprintf(dbg_fd, __VA_ARGS__); \
+               close(dbg_fd); \
+       } \
+} while (0)
+#endif
+
 static void maybe_close(int fd)
 {
-       if (fd >= 0)
+       if (fd >= 0) {
                close(fd);
+               dbg("closed fd:%d\n", fd);
+       }
 }
 
 // TODO: move to libbb?
@@ -462,7 +480,9 @@ static void remove_fd_from_set(int fd)
 {
        if (fd >= 0) {
                FD_CLR(fd, &allsock);
+               dbg("stopped listening on fd:%d\n", fd);
                maxsock = -1;
+               dbg("maxsock:%d\n", maxsock);
        }
 }
 
@@ -470,8 +490,10 @@ static void add_fd_to_set(int fd)
 {
        if (fd >= 0) {
                FD_SET(fd, &allsock);
+               dbg("started listening on fd:%d\n", fd);
                if (maxsock >= 0 && fd > maxsock) {
                        prev_maxsock = maxsock = fd;
+                       dbg("maxsock:%d\n", maxsock);
                        if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
                                bump_nofile();
                }
@@ -490,6 +512,7 @@ static void recalculate_maxsock(void)
                        maxsock = fd;
                fd++;
        }
+       dbg("recalculated maxsock:%d\n", maxsock);
        prev_maxsock = maxsock;
        if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
                bump_nofile();
@@ -547,8 +570,13 @@ static void prepare_socket_fd(servtab_t *sep)
                rearm_alarm();
                return;
        }
-       if (sep->se_socktype == SOCK_STREAM)
+
+       if (sep->se_socktype == SOCK_STREAM) {
                listen(fd, global_queuelen);
+               dbg("new sep->se_fd:%d (stream)\n", fd);
+       } else {
+               dbg("new sep->se_fd:%d (!stream)\n", fd);
+       }
 
        add_fd_to_set(fd);
        sep->se_fd = fd;
@@ -617,7 +645,7 @@ static servtab_t *dup_servtab(servtab_t *sep)
 }
 
 /* gcc generates much more code if this is inlined */
-static servtab_t *parse_one_line(void)
+static NOINLINE servtab_t *parse_one_line(void)
 {
        int argc;
        char *token[6+MAXARGV];
@@ -647,6 +675,8 @@ static servtab_t *parse_one_line(void)
                         * default host for the following lines. */
                        free(default_local_hostname);
                        default_local_hostname = sep->se_local_hostname;
+                       /*sep->se_local_hostname = NULL; - redundant */
+                       /* (we'll overwrite this field anyway) */
                        goto more;
                }
        } else
@@ -660,10 +690,10 @@ static servtab_t *parse_one_line(void)
  parse_err:
                bb_error_msg("parse error on line %u, line is ignored",
                                parser->lineno);
-               free_servtab_strings(sep);
                /* Just "goto more" can make sep to carry over e.g.
                 * "rpc"-ness (by having se_rpcver_lo != 0).
                 * We will be more paranoid: */
+               free_servtab_strings(sep);
                free(sep);
                goto new;
        }
@@ -787,7 +817,7 @@ static servtab_t *parse_one_line(void)
        }
 #endif
        argc = 0;
-       while ((arg = token[6+argc]) != NULL && argc < MAXARGV)
+       while (argc < MAXARGV && (arg = token[6+argc]) != NULL)
                sep->se_argv[argc++] = xstrdup(arg);
        /* Some inetd.conf files have no argv's, not even argv[0].
         * Fix them up.
@@ -1010,7 +1040,7 @@ static void reread_config_file(int sig UNUSED_PARAM)
         * new config file doesnt have them. */
        block_CHLD_HUP_ALRM(&omask);
        sepp = &serv_list;
-       while ((sep = *sepp)) {
+       while ((sep = *sepp) != NULL) {
                if (sep->se_checked) {
                        sepp = &sep->se_next;
                        continue;
@@ -1102,7 +1132,7 @@ static void clean_up_and_exit(int sig UNUSED_PARAM)
                if (ENABLE_FEATURE_CLEAN_UP)
                        close(sep->se_fd);
        }
-       remove_pidfile(_PATH_INETDPID);
+       remove_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
        exit(EXIT_SUCCESS);
 }
 
@@ -1151,7 +1181,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                setgroups(1, &gid);
        }
 
-       write_pidfile(_PATH_INETDPID);
+       write_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
 
        /* never fails under Linux (except if you pass it bad arguments) */
        getrlimit(RLIMIT_NOFILE, &rlim_ofile);
@@ -1204,11 +1234,13 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        }
                        continue;
                }
+               dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
 
                for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
                        if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
                                continue;
 
+                       dbg("ready fd:%d\n", sep->se_fd);
                        ready_fd_cnt--;
                        ctrl = sep->se_fd;
                        accepted_fd = -1;
@@ -1216,6 +1248,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        if (!sep->se_wait) {
                                if (sep->se_socktype == SOCK_STREAM) {
                                        ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
+                                       dbg("accepted_fd:%d\n", accepted_fd);
                                        if (ctrl < 0) {
                                                if (errno != EINTR)
                                                        bb_perror_msg("accept (for %s)", sep->se_service);
@@ -1236,19 +1269,22 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
  * (can create many copies of same child, etc).
  * Parent must create and use new socket instead. */
                                        new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
+                                       dbg("new_udp_fd:%d\n", new_udp_fd);
                                        if (new_udp_fd < 0) { /* error: eat packet, forget about it */
  udp_err:
                                                recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
                                                continue;
                                        }
                                        setsockopt_reuseaddr(new_udp_fd);
-                                       /* TODO: better do bind after vfork in parent,
+                                       /* TODO: better do bind after fork in parent,
                                         * so that we don't have two wildcard bound sockets
                                         * even for a brief moment? */
                                        if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
+                                               dbg("bind(new_udp_fd) failed\n");
                                                close(new_udp_fd);
                                                goto udp_err;
                                        }
+                                       dbg("bind(new_udp_fd) succeeded\n");
                                }
                        }
 
@@ -1276,6 +1312,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                                        sep->se_count = 0;
                                                        rearm_alarm(); /* will revive it in RETRYTIME sec */
                                                        restore_sigmask(&omask);
+                                                       maybe_close(new_udp_fd);
                                                        maybe_close(accepted_fd);
                                                        continue; /* -> check next fd in fd set */
                                                }
@@ -1296,17 +1333,18 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        bb_perror_msg("vfork"+1);
                                        sleep(1);
                                        restore_sigmask(&omask);
+                                       maybe_close(new_udp_fd);
                                        maybe_close(accepted_fd);
                                        continue; /* -> check next fd in fd set */
                                }
                                if (pid == 0)
                                        pid--; /* -1: "we did fork and we are child" */
                        }
-                       /* if pid == 0 here, we never forked */
+                       /* if pid == 0 here, we didn't fork */
 
                        if (pid > 0) { /* parent */
                                if (sep->se_wait) {
-                                       /* tcp wait: we passed listening socket to child,
+                                       /* wait: we passed socket to child,
                                         * will wait for child to terminate */
                                        sep->se_wait = pid;
                                        remove_fd_from_set(sep->se_fd);
@@ -1315,17 +1353,19 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        /* udp nowait: child connected the socket,
                                         * we created and will use new, unconnected one */
                                        xmove_fd(new_udp_fd, sep->se_fd);
+                                       dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
                                }
                                restore_sigmask(&omask);
                                maybe_close(accepted_fd);
                                continue; /* -> check next fd in fd set */
                        }
 
-                       /* we are either child or didn't vfork at all */
+                       /* we are either child or didn't fork at all */
 #ifdef INETD_BUILTINS_ENABLED
                        if (sep->se_builtin) {
-                               if (pid) { /* "pid" is -1: we did vfork */
+                               if (pid) { /* "pid" is -1: we did fork */
                                        close(sep->se_fd); /* listening socket */
+                                       dbg("closed sep->se_fd:%d\n", sep->se_fd);
                                        logmode = LOGMODE_NONE; /* make xwrite etc silent */
                                }
                                restore_sigmask(&omask);
@@ -1333,7 +1373,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        sep->se_builtin->bi_stream_fn(ctrl, sep);
                                else
                                        sep->se_builtin->bi_dgram_fn(ctrl, sep);
-                               if (pid) /* we did vfork */
+                               if (pid) /* we did fork */
                                        _exit(EXIT_FAILURE);
                                maybe_close(accepted_fd);
                                continue; /* -> check next fd in fd set */
@@ -1343,9 +1383,14 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        setsid();
                        /* "nowait" udp */
                        if (new_udp_fd >= 0) {
-                               len_and_sockaddr *lsa = xzalloc_lsa(sep->se_family);
+                               len_and_sockaddr *lsa;
+                               int r;
+
+                               close(new_udp_fd);
+                               dbg("closed new_udp_fd:%d\n", new_udp_fd);
+                               lsa = xzalloc_lsa(sep->se_family);
                                /* peek at the packet and remember peer addr */
-                               int r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
+                               r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
                                        &lsa->u.sa, &lsa->len);
                                if (r < 0)
                                        goto do_exit1;
@@ -1353,6 +1398,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                 * only packets from this peer will be recv'ed,
                                 * and bare write()/send() will work on it */
                                connect(ctrl, &lsa->u.sa, lsa->len);
+                               dbg("connected ctrl:%d to remote peer\n", ctrl);
                                free(lsa);
                        }
                        /* prepare env and exec program */
@@ -1370,7 +1416,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                bb_error_msg("non-root must run services as himself");
                                goto do_exit1;
                        }
-                       if (pwd->pw_uid) {
+                       if (pwd->pw_uid != 0) {
                                if (sep->se_group)
                                        pwd->pw_gid = grp->gr_gid;
                                /* initgroups, setgid, setuid: */
@@ -1389,6 +1435,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                         */
                        xmove_fd(ctrl, STDIN_FILENO);
                        xdup2(STDIN_FILENO, STDOUT_FILENO);
+                       dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
                        /* manpages of inetd I managed to find either say
                         * that stderr is also redirected to the network,
                         * or do not talk about redirection at all (!) */
@@ -1401,6 +1448,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        maybe_close(sep2->se_fd);
                        sigaction_set(SIGPIPE, &saved_pipe_handler);
                        restore_sigmask(&omask);
+                       dbg("execing:'%s'\n", sep->se_program);
                        BB_EXECVP(sep->se_program, sep->se_argv);
                        bb_perror_msg("can't execute '%s'", sep->se_program);
  do_exit1:
@@ -1608,7 +1656,7 @@ static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
 {
        time_t t;
 
-       t = time(NULL);
+       time(&t);
        fdprintf(s, "%.24s\r\n", ctime(&t));
 }
 static void FAST_FUNC daytime_dg(int s, servtab_t *sep)