upstream: use ppoll() instead of pselect() with djm

OpenBSD-Commit-ID: 980f87c9564d5d2ad55722b7a6f44f21284cd215

diff --git a/sshd.c b/sshd.c
index ea63d0307097c85a5197913973b5791af243b333..6953d04d8f2494307c54971f7b1449247cfe723a 100644 (file)
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.578 2021/07/19 02:21:50 dtucker Exp $ */
+/* $OpenBSD: sshd.c,v 1.579 2021/11/14 18:47:43 deraadt Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -64,6 +64,7 @@
 #include <paths.h>
 #endif
 #include <grp.h>
+#include <poll.h>
 #include <pwd.h>
 #include <signal.h>
 #include <stdarg.h>
@@ -1132,8 +1133,8 @@ server_listen(void)
 static void
 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
 {
-       fd_set *fdset;
-       int i, j, ret, maxfd;
+       struct pollfd *pfd = NULL;
+       int i, j, ret;
        int ostartups = -1, startups = 0, listening = 0, lameduck = 0;
        int startup_p[2] = { -1 , -1 };
        char c = 0;
@@ -1143,12 +1144,6 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
        u_char rnd[256];
        sigset_t nsigset, osigset;
 
-       /* setup fd set for accept */
-       fdset = NULL;
-       maxfd = 0;
-       for (i = 0; i < num_listen_socks; i++)
-               if (listen_socks[i] > maxfd)
-                       maxfd = listen_socks[i];
        /* pipes connected to unauthenticated child sshd processes */
        startup_pipes = xcalloc(options.max_startups, sizeof(int));
        startup_flags = xcalloc(options.max_startups, sizeof(int));
@@ -1158,7 +1153,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
        /*
         * Prepare signal mask that we use to block signals that might set
         * received_sigterm or received_sighup, so that we are guaranteed
-        * to immediately wake up the pselect if a signal is received after
+        * to immediately wake up the ppoll if a signal is received after
         * the flag is checked.
         */
        sigemptyset(&nsigset);
@@ -1167,6 +1162,9 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
        sigaddset(&nsigset, SIGTERM);
        sigaddset(&nsigset, SIGQUIT);
 
+       pfd = xcalloc(num_listen_socks + options.max_startups,
+           sizeof(struct pollfd));
+
        /*
         * Stay listening for connections until the system crashes or
         * the daemon is killed with a signal.
@@ -1198,27 +1196,29 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
                                sighup_restart();
                        }
                }
-               free(fdset);
-               fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
-                   sizeof(fd_mask));
 
-               for (i = 0; i < num_listen_socks; i++)
-                       FD_SET(listen_socks[i], fdset);
-               for (i = 0; i < options.max_startups; i++)
+               for (i = 0; i < num_listen_socks; i++) {
+                       pfd[i].fd = listen_socks[i];
+                       pfd[i].events = POLLIN;
+               }
+               for (i = 0; i < options.max_startups; i++) {
+                       pfd[num_listen_socks+i].fd = startup_pipes[i];
                        if (startup_pipes[i] != -1)
-                               FD_SET(startup_pipes[i], fdset);
+                               pfd[num_listen_socks+i].events = POLLIN;
+               }
 
                /* Wait until a connection arrives or a child exits. */
-               ret = pselect(maxfd+1, fdset, NULL, NULL, NULL, &osigset);
+               ret = ppoll(pfd, num_listen_socks + options.max_startups,
+                   NULL, &osigset);
                if (ret == -1 && errno != EINTR)
-                       error("pselect: %.100s", strerror(errno));
+                       error("ppoll: %.100s", strerror(errno));
                sigprocmask(SIG_SETMASK, &osigset, NULL);
                if (ret == -1)
                        continue;
 
                for (i = 0; i < options.max_startups; i++) {
                        if (startup_pipes[i] == -1 ||
-                           !FD_ISSET(startup_pipes[i], fdset))
+                           !(pfd[num_listen_socks+i].revents & POLLIN))
                                continue;
                        switch (read(startup_pipes[i], &c, sizeof(c))) {
                        case -1:
@@ -1249,7 +1249,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
                        }
                }
                for (i = 0; i < num_listen_socks; i++) {
-                       if (!FD_ISSET(listen_socks[i], fdset))
+                       if (!(pfd[i].revents & POLLIN))
                                continue;
                        fromlen = sizeof(from);
                        *newsock = accept(listen_socks[i],
@@ -1286,8 +1286,6 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
                        for (j = 0; j < options.max_startups; j++)
                                if (startup_pipes[j] == -1) {
                                        startup_pipes[j] = startup_p[0];
-                                       if (maxfd < startup_p[0])
-                                               maxfd = startup_p[0];
                                        startups++;
                                        startup_flags[j] = 1;
                                        break;
@@ -1315,6 +1313,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
                                        send_rexec_state(config_s[0], cfg);
                                        close(config_s[0]);
                                }
+                               free(pfd);
                                return;
                        }
 
@@ -1357,6 +1356,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
                                        (void)atomicio(vwrite, startup_pipe,
                                            "\0", 1);
                                }
+                               free(pfd);
                                return;
                        }