diff options
Diffstat (limited to 'serverloop.c')
| -rw-r--r-- | serverloop.c | 157 |
1 files changed, 83 insertions, 74 deletions
diff --git a/serverloop.c b/serverloop.c index e8cfb9205a48..0541f028a650 100644 --- a/serverloop.c +++ b/serverloop.c @@ -1,4 +1,4 @@ -/* $OpenBSD: serverloop.c,v 1.228 2021/07/16 09:00:23 djm Exp $ */ +/* $OpenBSD: serverloop.c,v 1.231 2022/01/22 00:49:34 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -50,6 +50,9 @@ #include <fcntl.h> #include <pwd.h> #include <limits.h> +#ifdef HAVE_POLL_H +#include <poll.h> +#endif #include <signal.h> #include <string.h> #include <termios.h> @@ -158,27 +161,31 @@ client_alive_check(struct ssh *ssh) } /* - * Sleep in pselect() until we can do something. This will initialize the - * pselect masks. Upon return, the masks will indicate which descriptors - * have data or can accept data. Optionally, a maximum time can be specified - * for the duration of the wait (0 = infinite). + * Sleep in ppoll() until we can do something. + * Optionally, a maximum time can be specified for the duration of + * the wait (0 = infinite). */ static void wait_until_can_do_something(struct ssh *ssh, - int connection_in, int connection_out, - fd_set **readsetp, fd_set **writesetp, int *maxfdp, - u_int *nallocp, u_int64_t max_time_ms, sigset_t *sigsetp) + int connection_in, int connection_out, struct pollfd **pfdp, + u_int *npfd_allocp, u_int *npfd_activep, u_int64_t max_time_ms, + sigset_t *sigsetp, int *conn_in_readyp, int *conn_out_readyp) { struct timespec ts, *tsp; int ret; time_t minwait_secs = 0; int client_alive_scheduled = 0; + u_int p; /* time we last heard from the client OR sent a keepalive */ static time_t last_client_time; - /* Allocate and update pselect() masks for channel descriptors. */ - channel_prepare_select(ssh, readsetp, writesetp, maxfdp, - nallocp, &minwait_secs); + *conn_in_readyp = *conn_out_readyp = 0; + + /* Prepare channel poll. First two pollfd entries are reserved */ + channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, + 2, &minwait_secs); + if (*npfd_activep < 2) + fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ /* XXX need proper deadline system for rekey/client alive */ if (minwait_secs != 0) @@ -208,14 +215,11 @@ wait_until_can_do_something(struct ssh *ssh, /* wrong: bad condition XXX */ if (channel_not_very_much_buffered_data()) #endif - FD_SET(connection_in, *readsetp); - - /* - * If we have buffered packet data going to the client, mark that - * descriptor. - */ - if (ssh_packet_have_data_to_write(ssh)) - FD_SET(connection_out, *writesetp); + /* Monitor client connection on reserved pollfd entries */ + (*pfdp)[0].fd = connection_in; + (*pfdp)[0].events = POLLIN; + (*pfdp)[1].fd = connection_out; + (*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0; /* * If child has terminated and there is enough buffer space to read @@ -234,27 +238,32 @@ wait_until_can_do_something(struct ssh *ssh, } /* Wait for something to happen, or the timeout to expire. */ - ret = pselect((*maxfdp)+1, *readsetp, *writesetp, NULL, tsp, sigsetp); + ret = ppoll(*pfdp, *npfd_activep, tsp, sigsetp); if (ret == -1) { - memset(*readsetp, 0, *nallocp); - memset(*writesetp, 0, *nallocp); + for (p = 0; p < *npfd_activep; p++) + (*pfdp)[p].revents = 0; if (errno != EINTR) - error("pselect: %.100s", strerror(errno)); - } else if (client_alive_scheduled) { + fatal_f("ppoll: %.100s", strerror(errno)); + return; + } + + *conn_in_readyp = (*pfdp)[0].revents != 0; + *conn_out_readyp = (*pfdp)[1].revents != 0; + + if (client_alive_scheduled) { time_t now = monotime(); /* - * If the pselect timed out, or returned for some other reason + * If the ppoll timed out, or returned for some other reason * but we haven't heard from the client in time, send keepalive. */ if (ret == 0 || (last_client_time != 0 && last_client_time + options.client_alive_interval <= now)) { client_alive_check(ssh); last_client_time = now; - } else if (FD_ISSET(connection_in, *readsetp)) { + } else if (*conn_in_readyp) last_client_time = now; - } } } @@ -263,48 +272,40 @@ wait_until_can_do_something(struct ssh *ssh, * in buffers and processed later. */ static int -process_input(struct ssh *ssh, fd_set *readset, int connection_in) +process_input(struct ssh *ssh, int connection_in) { - int r, len; - char buf[16384]; + int r; - /* Read and buffer any input data from the client. */ - if (FD_ISSET(connection_in, readset)) { - len = read(connection_in, buf, sizeof(buf)); - if (len == 0) { + if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) + return 0; /* success */ + if (r == SSH_ERR_SYSTEM_ERROR) { + if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK) + return 0; + if (errno == EPIPE) { verbose("Connection closed by %.100s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); return -1; - } else if (len == -1) { - if (errno == EINTR || errno == EAGAIN || - errno == EWOULDBLOCK) - return 0; - verbose("Read error from remote host %s port %d: %s", - ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), - strerror(errno)); - cleanup_exit(255); } - /* Buffer any received data. */ - if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) - fatal_fr(r, "ssh_packet_process_incoming"); + verbose("Read error from remote host %s port %d: %s", + ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), + strerror(errno)); + cleanup_exit(255); } - return 0; + return -1; } /* * Sends data from internal buffers to client program stdin. */ static void -process_output(struct ssh *ssh, fd_set *writeset, int connection_out) +process_output(struct ssh *ssh, int connection_out) { int r; /* Send any buffered packet data to the client. */ - if (FD_ISSET(connection_out, writeset)) { - if ((r = ssh_packet_write_poll(ssh)) != 0) { - sshpkt_fatal(ssh, r, "%s: ssh_packet_write_poll", - __func__); - } + if ((r = ssh_packet_write_poll(ssh)) != 0) { + sshpkt_fatal(ssh, r, "%s: ssh_packet_write_poll", + __func__); } } @@ -333,9 +334,10 @@ collect_children(struct ssh *ssh) void server_loop2(struct ssh *ssh, Authctxt *authctxt) { - fd_set *readset = NULL, *writeset = NULL; - int r, max_fd; - u_int nalloc = 0, connection_in, connection_out; + struct pollfd *pfd = NULL; + u_int npfd_alloc = 0, npfd_active = 0; + int r, conn_in_ready, conn_out_ready; + u_int connection_in, connection_out; u_int64_t rekey_timeout_ms = 0; sigset_t bsigset, osigset; @@ -354,8 +356,6 @@ server_loop2(struct ssh *ssh, Authctxt *authctxt) ssh_signal(SIGQUIT, sigterm_handler); } - max_fd = MAXIMUM(connection_in, connection_out); - server_init_dispatch(ssh); for (;;) { @@ -374,15 +374,15 @@ server_loop2(struct ssh *ssh, Authctxt *authctxt) /* * Block SIGCHLD while we check for dead children, then pass - * the old signal mask through to pselect() so that it'll wake + * the old signal mask through to ppoll() so that it'll wake * up immediately if a child exits after we've called waitpid(). */ if (sigprocmask(SIG_BLOCK, &bsigset, &osigset) == -1) error_f("bsigset sigprocmask: %s", strerror(errno)); collect_children(ssh); wait_until_can_do_something(ssh, connection_in, connection_out, - &readset, &writeset, &max_fd, &nalloc, rekey_timeout_ms, - &osigset); + &pfd, &npfd_alloc, &npfd_active, rekey_timeout_ms, &osigset, + &conn_in_ready, &conn_out_ready); if (sigprocmask(SIG_UNBLOCK, &bsigset, &osigset) == -1) error_f("osigset sigprocmask: %s", strerror(errno)); @@ -393,18 +393,18 @@ server_loop2(struct ssh *ssh, Authctxt *authctxt) } if (!ssh_packet_is_rekeying(ssh)) - channel_after_select(ssh, readset, writeset); - if (process_input(ssh, readset, connection_in) < 0) + channel_after_poll(ssh, pfd, npfd_active); + if (conn_in_ready && + process_input(ssh, connection_in) < 0) break; /* A timeout may have triggered rekeying */ if ((r = ssh_packet_check_rekey(ssh)) != 0) fatal_fr(r, "cannot start rekeying"); - process_output(ssh, writeset, connection_out); + if (conn_out_ready) + process_output(ssh, connection_out); } collect_children(ssh); - - free(readset); - free(writeset); + free(pfd); /* free all channels, no more reads and writes */ channel_free_all(ssh); @@ -684,16 +684,17 @@ server_input_hostkeys_prove(struct ssh *ssh, struct sshbuf **respp) struct sshbuf *resp = NULL; struct sshbuf *sigbuf = NULL; struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL; - int r, ndx, kexsigtype, use_kexsigtype, success = 0; + int r, ndx, success = 0; const u_char *blob; + const char *sigalg, *kex_rsa_sigalg = NULL; u_char *sig = 0; size_t blen, slen; if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL) fatal_f("sshbuf_new"); - - kexsigtype = sshkey_type_plain( - sshkey_type_from_name(ssh->kex->hostkey_alg)); + if (sshkey_type_plain(sshkey_type_from_name( + ssh->kex->hostkey_alg)) == KEY_RSA) + kex_rsa_sigalg = ssh->kex->hostkey_alg; while (ssh_packet_remaining(ssh) > 0) { sshkey_free(key); key = NULL; @@ -726,16 +727,24 @@ server_input_hostkeys_prove(struct ssh *ssh, struct sshbuf **respp) * For RSA keys, prefer to use the signature type negotiated * during KEX to the default (SHA1). */ - use_kexsigtype = kexsigtype == KEY_RSA && - sshkey_type_plain(key->type) == KEY_RSA; + sigalg = NULL; + if (sshkey_type_plain(key->type) == KEY_RSA) { + if (kex_rsa_sigalg != NULL) + sigalg = kex_rsa_sigalg; + else if (ssh->kex->flags & KEX_RSA_SHA2_512_SUPPORTED) + sigalg = "rsa-sha2-512"; + else if (ssh->kex->flags & KEX_RSA_SHA2_256_SUPPORTED) + sigalg = "rsa-sha2-256"; + } + debug3_f("sign %s key (index %d) using sigalg %s", + sshkey_type(key), ndx, sigalg == NULL ? "default" : sigalg); if ((r = sshbuf_put_cstring(sigbuf, "hostkeys-prove-00@openssh.com")) != 0 || (r = sshbuf_put_stringb(sigbuf, ssh->kex->session_id)) != 0 || (r = sshkey_puts(key, sigbuf)) != 0 || (r = ssh->kex->sign(ssh, key_prv, key_pub, &sig, &slen, - sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), - use_kexsigtype ? ssh->kex->hostkey_alg : NULL)) != 0 || + sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), sigalg)) != 0 || (r = sshbuf_put_string(resp, sig, slen)) != 0) { error_fr(r, "assemble signature"); goto out; |