trunk/src/sandbox.c

/*
**    Path sandbox for the gentoo linux portage package system, initially
**    based on the ROCK Linux Wrapper for getting a list of created files
**
**  to integrate with bash, bash should have been built like this
**
**  ./configure --prefix=<prefix> --host=<host> --without-gnu-malloc
**
**  it's very important that the --enable-static-link option is NOT specified
**    
**    Copyright (C) 2001 Geert Bevin, Uwyn, http://www.uwyn.com
**    Distributed under the terms of the GNU General Public License, v2 or later 
**    Author : Geert Bevin <gbevin@uwyn.com>
**  $Header$
*/

/* #define _GNU_SOURCE */

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#include "sandbox.h"

struct sandbox_info_t {
        char sandbox_log[SB_PATH_MAX];
        char sandbox_debug_log[SB_PATH_MAX];
        char sandbox_dir[SB_PATH_MAX];
        char sandbox_lib[SB_PATH_MAX];
        char sandbox_rc[SB_PATH_MAX];
        char *sandbox_pids_file;
        char portage_tmp_dir[SB_PATH_MAX];
        char var_tmp_dir[SB_PATH_MAX];
        char tmp_dir[SB_PATH_MAX];
        char *home_dir;
} sandbox_info_t;

static char *tmp_dir;

static int cleaned_up = 0;
static int print_debug = 0;
static int stop_called = 0;

/* Read pids file, and load active pids into an array.  Return number of pids in array */
int load_active_pids(int fd, int **pids)
{
        char *data = NULL;
        char *ptr = NULL, *ptr2 = NULL;
        int my_pid;
        int num_pids = 0;
        long len;

        pids[0] = NULL;

        len = file_length(fd);

        /* Allocate and zero datablock to read pids file */
        data = (char *)malloc((len + 1) * sizeof(char));
        memset(data, 0, len + 1);

        /* Start at beginning of file */
        lseek(fd, 0L, SEEK_SET);

        /* read entire file into a buffer */
        read(fd, data, len);

        ptr = data;

        /* Loop and read all pids */
        while (1) {
                /* Find new line */
                ptr2 = strchr(ptr, '\n');
                if (ptr2 == NULL)
                        break;  /* No more PIDs */

                /* Clear the \n. And  ptr  should have a null-terminated decimal string */
                ptr2[0] = 0;

                my_pid = atoi(ptr);

                /* If the PID is still alive, add it to our array */
                if ((0 != my_pid) && (0 == kill(my_pid, 0))) {
                        pids[0] = (int *)realloc(pids[0], (num_pids + 1) * sizeof(int));
                        pids[0][num_pids] = my_pid;
                        num_pids++;
                }

                /* Put ptr past the NULL we just wrote */
                ptr = ptr2 + 1;
        }

        if (data)
                free(data);
        data = NULL;

        return num_pids;
}

int write_pids_file(struct sandbox_info_t *sandbox_info)
{
        int pids_file = -1;
        int *pids_array = NULL;
        int num_of_pids = 0;
        int i = 0, success = 1;
        
        char pid_string[SB_BUF_LEN];
        
        if (file_exist(sandbox_info->sandbox_pids_file, 1) < 0) {
                fprintf(stderr, ">>> %s is not a regular file\n",
                                sandbox_info->sandbox_pids_file);
                return -1;
        } else {
                pids_file = file_open(sandbox_info->sandbox_pids_file,
                                "r+", 1, 0664, "portage");
                if (-1 == pids_file)
                        return -1;
        }
        
        /* Grab still active pids */
        num_of_pids = load_active_pids(pids_file, &pids_array);

        /* Zero out file */
        file_truncate(pids_file);

        /* Output active pids, and append our pid */
        for (i = 0; i < num_of_pids + 1; i++) {
                /* Time for our entry */
                if (i == num_of_pids)
                        sprintf(pid_string, "%d\n", getpid());
                else
                        sprintf(pid_string, "%d\n", pids_array[i]);

                if (write(pids_file, pid_string, strlen(pid_string)) != strlen(pid_string)) {
                        success = 0;
                        break;
                }
        }

        /* Clean pids_array */
        if (pids_array)
                free(pids_array);

        /* We're done with the pids file */
        file_close(pids_file);

        if (!success)
                return -1;

        return 0;
}

int sandbox_setup(char *argv[], struct sandbox_info_t *sandbox_info)
{
        if (NULL == realpath(getenv(ENV_PORTAGE_TMPDIR) ? getenv(ENV_PORTAGE_TMPDIR)
                                                      : PORTAGE_TMPDIR,
                                sandbox_info->portage_tmp_dir)) {
                perror(">>> get portage_tmp_dir");
                return -1;
        }
        
        if (NULL == realpath(VAR_TMPDIR, sandbox_info->var_tmp_dir)) {
                perror(">>> get var_tmp_dir");
                return -1;
        }
        
        if (-1 == get_tmp_dir(sandbox_info->tmp_dir)) {
                perror(">>> get tmp_dir");
                return -1;
        }
        tmp_dir = sandbox_info->tmp_dir;

        sandbox_info->home_dir = getenv("HOME");
        if (!sandbox_info->home_dir) {
                sandbox_info->home_dir = tmp_dir;
                setenv("HOME", sandbox_info->home_dir, 1);
        }

        /* Generate base sandbox path */
        snprintf(sandbox_info->sandbox_dir, SB_PATH_MAX, "%s/",
                        get_sandbox_path(argv[0]));

        /* Generate sandbox lib path */
        snprintf(sandbox_info->sandbox_lib, SB_PATH_MAX, "%s",
                        get_sandbox_lib(sandbox_info->sandbox_dir));

        /* Generate sandbox pids-file path */
        sandbox_info->sandbox_pids_file = get_sandbox_pids_file(tmp_dir);

        /* Generate sandbox bashrc path */
        snprintf(sandbox_info->sandbox_rc, SB_PATH_MAX, "%s",
                        get_sandbox_rc(sandbox_info->sandbox_dir));

        /* Generate sandbox log full path */
        snprintf(sandbox_info->sandbox_log, SB_PATH_MAX, "%s",
                        get_sandbox_log(tmp_dir));

        /* Generate sandbox debug log full path */
        snprintf(sandbox_info->sandbox_debug_log, SB_PATH_MAX, "%s",
                        get_sandbox_debug_log(tmp_dir));

        return 0;
}

void sandbox_cleanup()
{
        int i = 0;
        int success = 1;
        int pids_file = -1, num_of_pids = 0;
        int *pids_array = NULL;
        char pid_string[SB_BUF_LEN];
        char *sandbox_pids_file;

        /* Generate sandbox pids-file path */
        sandbox_pids_file = get_sandbox_pids_file(tmp_dir);

        /* Remove this sandbox's bash pid from the global pids
         * file if we have not already done so */
        if (0 == cleaned_up) {
                cleaned_up = 1;
                success = 1;

                if (print_debug)
                        printf("Cleaning up pids file.\n");

                /* Stat the PIDs file, make sure it exists and is a regular file */
                if (file_exist(sandbox_pids_file, 1) <= 0) {
                        fprintf(stderr, ">>> pids file is not a regular file\n");
                        success = 0;
                        /* We should really not fail if the pidsfile is missing here, but
                         * rather just exit cleanly, as there is still some cleanup to do */
                        return;
                }

                pids_file = file_open(sandbox_pids_file, "r+", 1, 0664, "portage");
                if (-1 == pids_file) {
                        success = 0;
                        /* Nothing more to do here */
                        return;
                }

                /* Load "still active" pids into an array */
                num_of_pids = load_active_pids(pids_file, &pids_array);
                //printf("pids: %d\r\n", num_of_pids);


                file_truncate(pids_file);

                /* if pids are still running, write only the running pids back to the file */
                if (num_of_pids > 1) {
                        for (i = 0; i < num_of_pids; i++) {
                                if (pids_array[i] != getpid()) {
                                        sprintf(pid_string, "%d\n", pids_array[i]);

                                        if (write(pids_file, pid_string, strlen(pid_string)) != strlen(pid_string)) {
                                                perror(">>> pids file write");
                                                success = 0;
                                                break;
                                        }
                                }
                        }

                        file_close(pids_file);
                        pids_file = -1;
                } else {

                        file_close(pids_file);
                        pids_file = -1;

                        /* remove the pidsfile, as this was the last sandbox */
                        unlink(sandbox_pids_file);
                }

                if (pids_array != NULL)
                        free(pids_array);
                pids_array = NULL;
        }

        free(sandbox_pids_file);
}

int print_sandbox_log(char *sandbox_log)
{
        int sandbox_log_file = -1;
        char *beep_count_env = NULL;
        int i, color, beep_count = 0;
        long len = 0;
        char *buffer = NULL;

        sandbox_log_file = file_open(sandbox_log, "r", 1, 0664, "portage");
        if (-1 == sandbox_log_file)
                return 0;

        len = file_length(sandbox_log_file);
        buffer = (char *)malloc((len + 1) * sizeof(char));
        memset(buffer, 0, len + 1);
        read(sandbox_log_file, buffer, len);
        file_close(sandbox_log_file);

        color = ((getenv("NOCOLOR") != NULL) ? 0 : 1);

        if (color)
                printf("\e[31;01m");
        printf("--------------------------- ACCESS VIOLATION SUMMARY ---------------------------");
        if (color)
                printf("\033[0m");
        if (color)
                printf("\e[31;01m");
        printf("\nLOG FILE = \"%s\"", sandbox_log);
        if (color)
                printf("\033[0m");
        printf("\n\n");
        printf("%s", buffer);
        if (buffer)
                free(buffer);
        buffer = NULL;
        printf("\e[31;01m--------------------------------------------------------------------------------\033[0m\n");

        beep_count_env = getenv(ENV_SANDBOX_BEEP);
        if (beep_count_env)
                beep_count = atoi(beep_count_env);
        else
                beep_count = DEFAULT_BEEP_COUNT;

        for (i = 0; i < beep_count; i++) {
                fputc('\a', stderr);
                if (i < beep_count - 1)
                        sleep(1);
        }
        return 1;
}

void stop(int signum)
{
        if (stop_called == 0) {
                stop_called = 1;
                printf("Caught signal %d in pid %d\r\n", signum, getpid());
                sandbox_cleanup();
        } else {
                fprintf(stderr, "Pid %d alreadly caught signal and is still cleaning up\n", getpid());
        }
}

void get_sandbox_write_envvar(char *buf, struct sandbox_info_t *sandbox_info)
{
        /* bzero out entire buffer then append trailing 0 */
        memset(buf, 0, SB_BUF_LEN);

        /* these could go into make.globals later on */
        snprintf(buf, SB_BUF_LEN,
                 "%s:%s/.gconfd/lock:%s/.bash_history:%s:%s:%s:%s",
                 "/dev/zero:/dev/fd/:/dev/null:/dev/pts/:"
                 "/dev/vc/:/dev/pty:/dev/tty:/dev/console:"
                 "/dev/shm/ngpt:/var/log/scrollkeeper.log:"
                 "/usr/tmp/conftest:/usr/lib/conftest:"
                 "/usr/lib32/conftest:/usr/lib64/conftest:"
                 "/usr/tmp/cf:/usr/lib/cf:/usr/lib32/cf:/usr/lib64/cf",
                 sandbox_info->home_dir, sandbox_info->home_dir,
                 (NULL != sandbox_info->portage_tmp_dir) ? sandbox_info->portage_tmp_dir : tmp_dir,
                 sandbox_info->tmp_dir, sandbox_info->var_tmp_dir,
                 "/tmp/:/var/tmp/");
}

void get_sandbox_predict_envvar(char *buf, struct sandbox_info_t *sandbox_info)
{
        /* bzero out entire buffer then append trailing 0 */
        memset(buf, 0, SB_BUF_LEN);

        /* these should go into make.globals later on */
        snprintf(buf, SB_BUF_LEN, "%s/.:"
                 "/usr/lib/python2.0/:"
                 "/usr/lib/python2.1/:"
                 "/usr/lib/python2.2/:"
                 "/usr/lib/python2.3/:"
                 "/usr/lib/python2.4/:"
                 "/usr/lib/python2.5/:"
                 "/usr/lib/python3.0/:",
                 sandbox_info->home_dir);
}

int sandbox_setenv(char **env, char *name, char *val) {
        char **tmp_env = env;
        char *tmp_string = NULL;

        /* XXX: We add the new variable to the end (no replacing).  If this
         *      is changed, we need to fix sandbox_setup_environ() below */
        while (NULL != *tmp_env)
                tmp_env++;

        /* strlen(name) + strlen(val) + '=' + '\0' */
        /* FIXME: Should probably free this at some stage - more neatness than
         *        a real leak that will cause issues. */
        tmp_string = calloc(strlen(name) + strlen(val) + 2, sizeof(char *));
        if (NULL == tmp_string) {
                perror(">>> out of memory (sandbox_setenv)");
                exit(1);
        }

        snprintf(tmp_string, strlen(name) + strlen(val) + 2, "%s=%s",
                        name, val);
        *tmp_env = tmp_string;

        return 0;
}

/* We setup the environment child side only to prevent issues with
 * setting LD_PRELOAD parent side */
char **sandbox_setup_environ(struct sandbox_info_t *sandbox_info,
                char *sandbox_write_envvar, char *sandbox_predict_envvar)
{
        int env_size = 0;
        int have_ld_preload = 0;
        
        char **new_environ;
        char **env_ptr = environ;
        char *ld_preload_envvar = NULL;
        char *orig_ld_preload_envvar = NULL;

        /* Unset these, as its easier than replacing when setting up our
         * new environment below */
        unsetenv(ENV_SANDBOX_DIR);
        unsetenv(ENV_SANDBOX_LIB);
        unsetenv(ENV_SANDBOX_BASHRC);
        unsetenv(ENV_SANDBOX_LOG);
        unsetenv(ENV_SANDBOX_DEBUG_LOG);
        
        if (NULL != getenv(ENV_LD_PRELOAD)) {
                have_ld_preload = 1;
                orig_ld_preload_envvar = getenv(ENV_LD_PRELOAD);

                /* FIXME: Should probably free this at some stage - more neatness
                 *        than a real leak that will cause issues. */
                ld_preload_envvar = calloc(strlen(orig_ld_preload_envvar) +
                                strlen(sandbox_info->sandbox_lib) + 2,
                                sizeof(char *));
                if (NULL == ld_preload_envvar)
                        return NULL;
                snprintf(ld_preload_envvar, strlen(orig_ld_preload_envvar) +
                                strlen(sandbox_info->sandbox_lib) + 2, "%s %s",
                                sandbox_info->sandbox_lib, orig_ld_preload_envvar);
        } else {
                /* FIXME: Should probably free this at some stage - more neatness
                 *        than a real leak that will cause issues. */
                ld_preload_envvar = strndup(sandbox_info->sandbox_lib,
                                strlen(sandbox_info->sandbox_lib));
                if (NULL == ld_preload_envvar)
                        return NULL;
        }
        /* Do not unset this, as strange things might happen */
        /* unsetenv(ENV_LD_PRELOAD); */

        while (NULL != *env_ptr) {
                env_size++;
                env_ptr++;
        }

        /* FIXME: Should probably free this at some stage - more neatness than
         *        a real leak that will cause issues. */
        new_environ = calloc((env_size + 15 + 1) * sizeof(char *), sizeof(char *));
        if (NULL == new_environ)
                return NULL;

        /* First add our new variables to the beginning - this is due to some
         * weirdness that I cannot remember */
        sandbox_setenv(new_environ, ENV_SANDBOX_DIR, sandbox_info->sandbox_dir);
        sandbox_setenv(new_environ, ENV_SANDBOX_LIB, sandbox_info->sandbox_lib);
        sandbox_setenv(new_environ, ENV_SANDBOX_BASHRC, sandbox_info->sandbox_rc);
        sandbox_setenv(new_environ, ENV_SANDBOX_LOG, sandbox_info->sandbox_log);
        sandbox_setenv(new_environ, ENV_SANDBOX_DEBUG_LOG,
                        sandbox_info->sandbox_debug_log);
        /* If LD_PRELOAD was not set, set it here, else do it below */
        if (1 != have_ld_preload)
                sandbox_setenv(new_environ, ENV_LD_PRELOAD, ld_preload_envvar);

        if (!getenv(ENV_SANDBOX_DENY))
                sandbox_setenv(new_environ, ENV_SANDBOX_DENY, LD_PRELOAD_FILE);

        if (!getenv(ENV_SANDBOX_READ))
                sandbox_setenv(new_environ, ENV_SANDBOX_READ, "/");

        if (!getenv(ENV_SANDBOX_WRITE))
                sandbox_setenv(new_environ, ENV_SANDBOX_WRITE, sandbox_write_envvar);

        if (!getenv(ENV_SANDBOX_PREDICT))
                sandbox_setenv(new_environ, ENV_SANDBOX_PREDICT, sandbox_predict_envvar);

        /* This one should NEVER be set in ebuilds, as it is the one
         * private thing libsandbox.so use to test if the sandbox
         * should be active for this pid, or not.
         *
         * azarah (3 Aug 2002)
         */

        sandbox_setenv(new_environ, "SANDBOX_ACTIVE", "armedandready");

        env_size = 0;
        while (NULL != new_environ[env_size])
                env_size++;

        /* Now add the rest */
        env_ptr = environ;
        while (NULL != *env_ptr) {
                if ((1 == have_ld_preload) &&
                    (strstr(*env_ptr, LD_PRELOAD_EQ) == *env_ptr))
                        /* If LD_PRELOAD was set, and this is it in the original
                         * environment, replace it with our new copy */
                        /* XXX: The following works as it just add whatever as
                         *      the last variable to nev_environ */
                        sandbox_setenv(new_environ, ENV_LD_PRELOAD,
                                        ld_preload_envvar);
                else
                        new_environ[env_size + (env_ptr - environ)] = *env_ptr;
                env_ptr++;
        }

        return new_environ;
}

int spawn_shell(char *argv_bash[], char *env[])
{
        int pid;
        int status = 0;
        int ret = 0;

        pid = fork();

        /* Child's process */
        if (0 == pid) {
                execve(argv_bash[0], argv_bash, env);
                return 0;
        } else if (pid < 0) {
                return 0;
        }
        ret = waitpid(pid, &status, 0);
        if ((-1 == ret) || (status > 0))
                return 0;

        return 1;
}

int main(int argc, char **argv)
{
        int i = 0, success = 1;
        int sandbox_log_presence = 0;
        long len;

        struct sandbox_info_t sandbox_info;

        char **sandbox_environ;
        char sandbox_write_envvar[SB_BUF_LEN];
        char sandbox_predict_envvar[SB_BUF_LEN];
        char **argv_bash = NULL;

        char *run_str = "-c";
        char *home_dir = NULL;
        char *tmp_string = NULL;

        /* Only print info if called with no arguments .... */
        if (argc < 2)
                print_debug = 1;

        if (print_debug)
                printf("========================== Gentoo linux path sandbox ===========================\n");

        /* check if a sandbox is already running */
        if (NULL != getenv(ENV_SANDBOX_ON)) {
                fprintf(stderr, "Not launching a new sandbox instance\n");
                fprintf(stderr, "Another one is already running in this process hierarchy.\n");
                exit(1);
        } else {

                /* determine the location of all the sandbox support files */
                if (print_debug)
                        printf("Detection of the support files.\n");

                if (-1 == sandbox_setup(argv, &sandbox_info)) {
                        perror(">>> setup");
                        exit(1);
                }
                
                /* verify the existance of required files */
                if (print_debug)
                        printf("Verification of the required files.\n");

#ifndef SB_HAVE_64BIT_ARCH
                if (file_exist(sandbox_info.sandbox_lib, 0) <= 0) {
                        fprintf(stderr, "Could not open the sandbox library at '%s'.\n",
                                        sandbox_info.sandbox_lib);
                        return -1;
                }
#endif
                if (file_exist(sandbox_info.sandbox_rc, 0) <= 0) {
                        fprintf(stderr, "Could not open the sandbox rc file at '%s'.\n",
                                        sandbox_info.sandbox_rc);
                        return -1;
                }

                /* set up the required environment variables */
                if (print_debug)
                        printf("Setting up the required environment variables.\n");

                /* This one should not be child only, as we check above to see
                 * if we are already running (check sandbox_setup_environ).
                 * This needs to be set before calling sandbox_setup_environ(),
                 * else its not set for the child */
                setenv(ENV_SANDBOX_ON, "1", 0);

                /* Setup the child environment stuff */
                get_sandbox_write_envvar(sandbox_write_envvar, &sandbox_info);
                get_sandbox_predict_envvar(sandbox_predict_envvar, &sandbox_info);
                sandbox_environ = sandbox_setup_environ(&sandbox_info,
                                sandbox_write_envvar, sandbox_predict_envvar);
                if (NULL == sandbox_environ) {
                        perror(">>> out of memory (environ)");
                        exit(1);
                }

                /* if the portage temp dir was present, cd into it */
                if (NULL != sandbox_info.portage_tmp_dir)
                        chdir(sandbox_info.portage_tmp_dir);

                argv_bash = (char **)malloc(6 * sizeof(char *));
                argv_bash[0] = strdup("/bin/bash");
                argv_bash[1] = strdup("-rcfile");
                argv_bash[2] = strdup(sandbox_info.sandbox_rc);

                if (argc < 2)
                        argv_bash[3] = NULL;
                else
                        argv_bash[3] = strdup(run_str); /* "-c" */

                argv_bash[4] = NULL;    /* strdup(run_arg); */
                argv_bash[5] = NULL;

                if (argc >= 2) {
                        for (i = 1; i < argc; i++) {
                                if (NULL == argv_bash[4])
                                        len = 0;
                                else
                                        len = strlen(argv_bash[4]);

                                argv_bash[4] = (char *)realloc(argv_bash[4],
                                                (len + strlen(argv[i]) + 2) * sizeof(char));

                                if (0 == len)
                                        argv_bash[4][0] = 0;
                                if (1 != i)
                                        strcat(argv_bash[4], " ");

                                strcat(argv_bash[4], argv[i]);
                        }
                }

                /* set up the required signal handlers */
                signal(SIGHUP, &stop);
                signal(SIGINT, &stop);
                signal(SIGQUIT, &stop);
                signal(SIGTERM, &stop);

                /* Load our PID into PIDs file */
                if (-1 == write_pids_file(&sandbox_info)) {
                        perror(">>> pids file write");
                        exit(1);
                }

                /* STARTING PROTECTED ENVIRONMENT */
                if (print_debug) {
                        printf("The protected environment has been started.\n");
                        printf("--------------------------------------------------------------------------------\n");
                }

                if (print_debug)
                        printf("Shell being started in forked process.\n");

                /* Start Bash */
                if (!spawn_shell(argv_bash, sandbox_environ)) {
                        if (print_debug)
                                fprintf(stderr, ">>> shell process failed to spawn\n");
                        success = 0;
                }

                /* Free bash stuff */
                for (i = 0; i < 6; i++) {
                        if (argv_bash[i])
                                free(argv_bash[i]);
                        argv_bash[i] = NULL;
                }
                if (argv_bash)
                        free(argv_bash);
                argv_bash = NULL;

                if (print_debug)
                        printf("Cleaning up sandbox process\n");

                sandbox_cleanup();

                if (print_debug) {
                        printf("========================== Gentoo linux path sandbox ===========================\n");
                        printf("The protected environment has been shut down.\n");
                }

                if (file_exist(sandbox_info.sandbox_log, 0)) {
                        sandbox_log_presence = 1;
                        success = 1;
                        if (!print_sandbox_log(sandbox_info.sandbox_log))
                                success = 0;
                } else if (print_debug) {
                        printf("--------------------------------------------------------------------------------\n");
                }

                free(sandbox_info.sandbox_pids_file);

                if ((sandbox_log_presence) || (!success))
                        return 1;
                else
                        return 0;
        }
}

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