sslutil: check for missing certificate and key files (issue5598)
Currently, sslutil._hostsettings() performs validation that web.cacerts
exists. However, client certificates are passed in to the function
and not all callers may validate them. This includes
httpconnection.readauthforuri(), which loads the [auth] section.
If a missing file is specified, the ssl module will raise a generic
IOException. And, it doesn't even give us the courtesy of telling
us which file is missing! Mercurial then prints a generic
"abort: No such file or directory" (or similar) error, leaving users
to scratch their head as to what file is missing.
This commit introduces explicit validation of all paths passed as
arguments to wrapsocket() and wrapserversocket(). Any missing file
is alerted about explicitly.
We should probably catch missing files earlier - as part of loading
the [auth] section. However, I think the sslutil functions should
check for file presence regardless of what callers do because that's
the only way to be sure that missing files are always detected.
/*
* Utilities about process handling - signal and subprocess (ex. pager)
*
* Copyright (c) 2011 Yuya Nishihara <yuya@tcha.org>
*
* This software may be used and distributed according to the terms of the
* GNU General Public License version 2 or any later version.
*/
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
#include "procutil.h"
#include "util.h"
static pid_t pagerpid = 0;
static pid_t peerpgid = 0;
static pid_t peerpid = 0;
static void forwardsignal(int sig)
{
assert(peerpid > 0);
if (kill(peerpid, sig) < 0)
abortmsgerrno("cannot kill %d", peerpid);
debugmsg("forward signal %d", sig);
}
static void forwardsignaltogroup(int sig)
{
/* prefer kill(-pgid, sig), fallback to pid if pgid is invalid */
pid_t killpid = peerpgid > 1 ? -peerpgid : peerpid;
if (kill(killpid, sig) < 0)
abortmsgerrno("cannot kill %d", killpid);
debugmsg("forward signal %d to %d", sig, killpid);
}
static void handlestopsignal(int sig)
{
sigset_t unblockset, oldset;
struct sigaction sa, oldsa;
if (sigemptyset(&unblockset) < 0)
goto error;
if (sigaddset(&unblockset, sig) < 0)
goto error;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
forwardsignal(sig);
if (raise(sig) < 0) /* resend to self */
goto error;
if (sigaction(sig, &sa, &oldsa) < 0)
goto error;
if (sigprocmask(SIG_UNBLOCK, &unblockset, &oldset) < 0)
goto error;
/* resent signal will be handled before sigprocmask() returns */
if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
goto error;
if (sigaction(sig, &oldsa, NULL) < 0)
goto error;
return;
error:
abortmsgerrno("failed to handle stop signal");
}
static void handlechildsignal(int sig UNUSED_)
{
if (peerpid == 0 || pagerpid == 0)
return;
/* if pager exits, notify the server with SIGPIPE immediately.
* otherwise the server won't get SIGPIPE if it does not write
* anything. (issue5278) */
if (waitpid(pagerpid, NULL, WNOHANG) == pagerpid)
kill(peerpid, SIGPIPE);
}
void setupsignalhandler(pid_t pid, pid_t pgid)
{
if (pid <= 0)
return;
peerpid = pid;
peerpgid = (pgid <= 1 ? 0 : pgid);
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
/* deadly signals meant to be sent to a process group:
* - SIGHUP: usually generated by the kernel, when termination of a
* process causes that process group to become orphaned
* - SIGINT: usually generated by the terminal */
sa.sa_handler = forwardsignaltogroup;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
if (sigaction(SIGHUP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGINT, &sa, NULL) < 0)
goto error;
/* terminate frontend by double SIGTERM in case of server freeze */
sa.sa_handler = forwardsignal;
sa.sa_flags |= SA_RESETHAND;
if (sigaction(SIGTERM, &sa, NULL) < 0)
goto error;
/* notify the worker about window resize events */
sa.sa_flags = SA_RESTART;
if (sigaction(SIGWINCH, &sa, NULL) < 0)
goto error;
/* forward user-defined signals */
if (sigaction(SIGUSR1, &sa, NULL) < 0)
goto error;
if (sigaction(SIGUSR2, &sa, NULL) < 0)
goto error;
/* propagate job control requests to worker */
sa.sa_handler = forwardsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCONT, &sa, NULL) < 0)
goto error;
sa.sa_handler = handlestopsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGTSTP, &sa, NULL) < 0)
goto error;
/* get notified when pager exits */
sa.sa_handler = handlechildsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) < 0)
goto error;
return;
error:
abortmsgerrno("failed to set up signal handlers");
}
void restoresignalhandler(void)
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
if (sigaction(SIGHUP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGTERM, &sa, NULL) < 0)
goto error;
if (sigaction(SIGWINCH, &sa, NULL) < 0)
goto error;
if (sigaction(SIGCONT, &sa, NULL) < 0)
goto error;
if (sigaction(SIGTSTP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGCHLD, &sa, NULL) < 0)
goto error;
/* ignore Ctrl+C while shutting down to make pager exits cleanly */
sa.sa_handler = SIG_IGN;
if (sigaction(SIGINT, &sa, NULL) < 0)
goto error;
peerpid = 0;
return;
error:
abortmsgerrno("failed to restore signal handlers");
}
/* This implementation is based on hgext/pager.py (post 369741ef7253)
* Return 0 if pager is not started, or pid of the pager */
pid_t setuppager(const char *pagercmd, const char *envp[])
{
assert(pagerpid == 0);
if (!pagercmd)
return 0;
int pipefds[2];
if (pipe(pipefds) < 0)
return 0;
pid_t pid = fork();
if (pid < 0)
goto error;
if (pid > 0) {
close(pipefds[0]);
if (dup2(pipefds[1], fileno(stdout)) < 0)
goto error;
if (isatty(fileno(stderr))) {
if (dup2(pipefds[1], fileno(stderr)) < 0)
goto error;
}
close(pipefds[1]);
pagerpid = pid;
return pid;
} else {
dup2(pipefds[0], fileno(stdin));
close(pipefds[0]);
close(pipefds[1]);
int r = execle("/bin/sh", "/bin/sh", "-c", pagercmd, NULL,
envp);
if (r < 0) {
abortmsgerrno("cannot start pager '%s'", pagercmd);
}
return 0;
}
error:
close(pipefds[0]);
close(pipefds[1]);
abortmsgerrno("failed to prepare pager");
return 0;
}
void waitpager(void)
{
if (pagerpid == 0)
return;
/* close output streams to notify the pager its input ends */
fclose(stdout);
fclose(stderr);
while (1) {
pid_t ret = waitpid(pagerpid, NULL, 0);
if (ret == -1 && errno == EINTR)
continue;
break;
}
}