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/*-
* Copyright (C) 2005 Diomidis Spinellis. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/syslog.h>
#include "portald.h"
/* Usage conventions for the pipe's endpoints. */
#define READ_END 0
#define WRITE_END 1
static int errlog(void);
static int parse_argv(char *args, char **argv);
int portal_pipe(struct portal_cred *pcr, char *key, char **v,
int kso __unused, int *fdp)
{
int fd[2]; /* Pipe endpoints. */
int caller_end; /* The pipe end we will use. */
int process_end; /* The pipe end the spawned process will use. */
int redirect_fd; /* The fd to redirect on the spawned process. */
char pbuf[MAXPATHLEN];
int error = 0;
int i;
char **argv;
int argc;
struct portal_cred save_area;
/* Validate open mode, and assign roles. */
if ((pcr->pcr_flag & FWRITE) && (pcr->pcr_flag & FREAD))
/* Don't allow both on a single fd. */
return (EINVAL);
else if (pcr->pcr_flag & FREAD) {
/*
* The caller reads from the pipe,
* the spawned process writes to it.
*/
caller_end = READ_END;
process_end = WRITE_END;
redirect_fd = STDOUT_FILENO;
} else if (pcr->pcr_flag & FWRITE) {
/*
* The caller writes to the pipe,
* the spawned process reads from it.
*/
caller_end = WRITE_END;
process_end = READ_END;
redirect_fd = STDIN_FILENO;
} else
return (EINVAL);
/* Get and check command line. */
pbuf[0] = '/';
strcpy(pbuf+1, key + (v[1] ? strlen(v[1]) : 0));
argc = parse_argv(pbuf, NULL);
if (argc == 0)
return (ENOENT);
/* Swap privileges. */
if (set_user_credentials(pcr, &save_area) < 0)
return (errno);
/* Redirect and spawn the specified process. */
fd[READ_END] = fd[WRITE_END] = -1;
if (pipe(fd) < 0) {
error = errno;
goto done;
}
switch (fork()) {
case -1: /* Error */
error = errno;
break;
default: /* Parent */
(void)close(fd[process_end]);
break;
case 0: /* Child */
argv = (char **)malloc((argc + 1) * sizeof(char *));
if (argv == 0) {
syslog(LOG_ALERT,
"malloc: failed to get space for %d pointers",
argc + 1);
exit(EXIT_FAILURE);
}
parse_argv(pbuf, argv);
if (dup2(fd[process_end], redirect_fd) < 0) {
syslog(LOG_ERR, "dup2: %m");
exit(EXIT_FAILURE);
}
(void)close(fd[caller_end]);
(void)close(fd[process_end]);
if (errlog() < 0) {
syslog(LOG_ERR, "errlog: %m");
exit(EXIT_FAILURE);
}
if (execv(argv[0], argv) < 0) {
syslog(LOG_ERR, "execv(%s): %m", argv[0]);
exit(EXIT_FAILURE);
}
/* NOTREACHED */
}
done:
/* Re-establish our privileges. */
if (restore_credentials(&save_area) < 0)
error = errno;
/* Set return fd value. */
if (error == 0)
*fdp = fd[caller_end];
else {
for (i = 0; i < 2; i++)
if (fd[i] >= 0)
(void)close(fd[i]);
*fdp = -1;
}
return (error);
}
/*
* Redirect stderr to the system log.
* Return 0 if ok.
* Return -1 with errno set on error.
*/
static int
errlog(void)
{
int fd[2];
char buff[1024];
FILE *f;
int ret = 0;
if (pipe(fd) < 0)
return (-1);
switch (fork()) {
case -1: /* Error */
return (-1);
case 0: /* Child */
if ((f = fdopen(fd[READ_END], "r")) == NULL) {
syslog(LOG_ERR, "fdopen: %m");
exit(EXIT_FAILURE);
}
(void)close(fd[WRITE_END]);
while (fgets(buff, sizeof(buff), f) != NULL)
syslog(LOG_ERR, "exec: %s", buff);
exit(EXIT_SUCCESS);
/* NOTREACHED */
default: /* Parent */
if (dup2(fd[WRITE_END], STDERR_FILENO) < 0)
ret = -1;
(void)close(fd[READ_END]);
(void)close(fd[WRITE_END]);
break;
}
return (ret);
}
/*
* Parse the args string as a space-separated argument vector.
* If argv is not NULL, split the string into its constituent
* components, and set argv to point to the beginning of each
* string component; NULL-terminating argv.
* Return the number of string components.
*/
static int
parse_argv(char *args, char **argv)
{
int count = 0;
char *p;
enum {WORD, SPACE} state = SPACE;
for (p = args; *p; p++)
switch (state) {
case WORD:
if (isspace(*p)) {
if (argv)
*p = '\0';
state = SPACE;
}
break;
case SPACE:
if (!isspace(*p)) {
if (argv)
argv[count] = p;
count++;
state = WORD;
}
}
if (argv)
argv[count] = NULL;
return (count);
}
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