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upstream: pack pollfd array before server_accept_loop() ppoll() 

call, and terminate sshd if ppoll() returns errno==EINVAL

avoids spin in ppoll when MaxStartups > RLIMIT_NOFILE, reported by
Daniel Micay

feedback/ok deraadt

OpenBSD-Commit-ID: dbab1c24993ac977ec24d83283b8b7528f7c2c15
This commit is contained in:
djm@openbsd.org 2022-03-01 01:59:19 +00:00 committed by Damien Miller
parent eceafbe0bd
commit 379b30120d
1 changed files with 19 additions and 10 deletions
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29
sshd.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: sshd.c,v 1.583 2022/02/01 07:57:32 dtucker Exp $ */
/* $OpenBSD: sshd.c,v 1.584 2022/03/01 01:59:19 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -1129,9 +1129,9 @@ static void
server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
{
struct pollfd *pfd = NULL;
int i, j, ret;
int i, j, ret, npfd;
int ostartups = -1, startups = 0, listening = 0, lameduck = 0;
int startup_p[2] = { -1 , -1 };
int startup_p[2] = { -1 , -1 }, *startup_pollfd;
char c = 0;
struct sockaddr_storage from;
socklen_t fromlen;
@ -1142,6 +1142,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
/* pipes connected to unauthenticated child sshd processes */
startup_pipes = xcalloc(options.max_startups, sizeof(int));
startup_flags = xcalloc(options.max_startups, sizeof(int));
startup_pollfd = xcalloc(options.max_startups, sizeof(int));
for (i = 0; i < options.max_startups; i++)
startup_pipes[i] = -1;
@ -1157,6 +1158,7 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
sigaddset(&nsigset, SIGTERM);
sigaddset(&nsigset, SIGQUIT);
/* sized for worst-case */
pfd = xcalloc(num_listen_socks + options.max_startups,
sizeof(struct pollfd));
@ -1196,24 +1198,31 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
pfd[i].fd = listen_socks[i];
pfd[i].events = POLLIN;
}
npfd = num_listen_socks;
for (i = 0; i < options.max_startups; i++) {
pfd[num_listen_socks+i].fd = startup_pipes[i];
if (startup_pipes[i] != -1)
pfd[num_listen_socks+i].events = POLLIN;
startup_pollfd[i] = -1;
if (startup_pipes[i] != -1) {
pfd[npfd].fd = startup_pipes[i];
pfd[npfd].events = POLLIN;
startup_pollfd[i] = npfd++;
}
}
/* Wait until a connection arrives or a child exits. */
ret = ppoll(pfd, num_listen_socks + options.max_startups,
NULL, &osigset);
if (ret == -1 && errno != EINTR)
ret = ppoll(pfd, npfd, NULL, &osigset);
if (ret == -1 && errno != EINTR) {
error("ppoll: %.100s", strerror(errno));
if (errno == EINVAL)
cleanup_exit(1); /* can't recover */
}
sigprocmask(SIG_SETMASK, &osigset, NULL);
if (ret == -1)
continue;
for (i = 0; i < options.max_startups; i++) {
if (startup_pipes[i] == -1 ||
!(pfd[num_listen_socks+i].revents & (POLLIN|POLLHUP)))
startup_pollfd[i] == -1 ||
!(pfd[startup_pollfd[i]].revents & (POLLIN|POLLHUP)))
continue;
switch (read(startup_pipes[i], &c, sizeof(c))) {
case -1: