void namespace_unshare_pid(void) {
config_rewind();
#ifdef NS_CLONE_NEWPID
if ( ( getenv("SINGULARITY_NO_NAMESPACE_PID") == NULL ) && // Flawfinder: ignore (only checking for existance of envar)
( config_get_key_bool("allow pid ns", 1) > 0 ) ) {
unsetenv("SINGULARITY_NO_NAMESPACE_PID");
message(DEBUG, "Virtualizing PID namespace\n");
if ( unshare(CLONE_NEWPID) < 0 ) {
message(ERROR, "Could not virtualize PID namespace: %s\n", strerror(errno));
ABORT(255);
}
} else {
message(VERBOSE, "Not virtualizing PID namespace\n");
}
#else
#ifdef NS_CLONE_PID
if ( ( getenv("SINGULARITY_NO_NAMESPACE_PID") == NULL ) && // Flawfinder: ignore (only checking for existance of envar)
( config_get_key_bool("allow pid ns", 1) > 0 ) ) {
unsetenv("SINGULARITY_NO_NAMESPACE_PID");
message(DEBUG, "Virtualizing PID namespace\n");
if ( unshare(CLONE_NEWPID) < 0 ) {
message(ERROR, "Could not virtualize PID namespace: %s\n", strerror(errno));
ABORT(255);
}
} else {
message(VERBOSE, "Not virtualizing PID namespace\n");
}
#endif
#endif
}
int main(int argc, char ** argv) {
FILE *containerimage_fp;
FILE *loop_fp;
FILE *config_fp;
char *containerimage;
char *containername;
char *containerpath;
char *username;
char *command;
char *tmpdir;
char *loop_dev_lock;
char *loop_dev_cache;
char *loop_dev = 0;
char *config_path;
char *tmp_config_string;
char cwd[PATH_MAX];
int cwd_fd;
int tmpdirlock_fd;
int containerimage_fd;
int loop_dev_lock_fd;
int gid_list_count;
int retval = 0;
uid_t uid;
gid_t gid;
gid_t *gid_list;
pid_t namespace_fork_pid = 0;
struct passwd *pw;
//****************************************************************************//
// Init
//****************************************************************************//
signal(SIGINT, sighandler);
signal(SIGKILL, sighandler);
signal(SIGQUIT, sighandler);
openlog("Singularity", LOG_CONS | LOG_NDELAY, LOG_LOCAL0);
// Get all user/group info
uid = getuid();
gid = getgid();
gid_list_count = getgroups(0, NULL);
gid_list = (gid_t *) malloc(sizeof(gid_t) * gid_list_count);
if ( getgroups(gid_list_count, gid_list) < 0 ) {
fprintf(stderr, "ABORT: Could not obtain current supplementary group list: %s\n", strerror(errno));
return(255);
}
pw = getpwuid(uid);
// Check to make sure we are installed correctly
if ( seteuid(0) < 0 ) {
fprintf(stderr, "ABORT: Check installation, must be performed by root.\n");
return(255);
}
// Lets start off as the calling UID
if ( seteuid(uid) < 0 ) {
fprintf(stderr, "ABORT: Could not set effective uid to %d: %s\n", uid, strerror(errno));
return(255);
}
if ( setegid(gid) < 0 ) {
fprintf(stderr, "ABORT: Could not set effective gid to %d: %s\n", gid, strerror(errno));
return(255);
}
username = pw->pw_name;
containerimage = getenv("SINGULARITY_IMAGE");
command = getenv("SINGULARITY_COMMAND");
unsetenv("SINGULARITY_COMMAND");
unsetenv("SINGULARITY_EXEC");
config_path = (char *) malloc(strlen(SYSCONFDIR) + 30);
snprintf(config_path, strlen(SYSCONFDIR) + 30, "%s/singularity/singularity.conf", SYSCONFDIR);
// Figure out where we start
if ( (cwd_fd = open(".", O_RDONLY)) < 0 ) {
fprintf(stderr, "ABORT: Could not open cwd fd (%s)!\n", strerror(errno));
return(1);
}
if ( getcwd(cwd, PATH_MAX) == NULL ) {
fprintf(stderr, "Could not obtain current directory path: %s\n", strerror(errno));
return(1);
}
if ( containerimage == NULL ) {
fprintf(stderr, "ABORT: SINGULARITY_IMAGE undefined!\n");
return(1);
}
if ( is_file(containerimage) != 0 ) {
fprintf(stderr, "ABORT: Container image path is invalid: %s\n", containerimage);
return(1);
}
if ( is_file(config_path) != 0 ) {
fprintf(stderr, "ABORT: Configuration file not found: %s\n", config_path);
return(255);
}
if ( is_owner(config_path, 0) != 0 ) {
fprintf(stderr, "ABORT: Configuration file is not owned by root: %s\n", config_path);
return(255);
}
// TODO: Offer option to only run containers owned by root (so root can approve
// containers)
if ( uid == 0 && is_owner(containerimage, 0) < 0 ) {
fprintf(stderr, "ABORT: Root should only run containers that root owns!\n");
return(1);
}
containername = basename(strdup(containerimage));
tmpdir = strjoin("/tmp/.singularity-", file_id(containerimage));
loop_dev_lock = joinpath(tmpdir, "loop_dev.lock");
loop_dev_cache = joinpath(tmpdir, "loop_dev");
containerpath = (char *) malloc(strlen(tmpdir) + 5);
snprintf(containerpath, strlen(tmpdir) + 5, "%s/mnt", tmpdir);
syslog(LOG_NOTICE, "User=%s[%d], Command=%s, Container=%s, CWD=%s, Arg1=%s", username, uid, command, containerimage, cwd, argv[1]);
//****************************************************************************//
// Setup
//****************************************************************************//
if ( ( config_fp = fopen(config_path, "r") ) == NULL ) {
fprintf(stderr, "ERROR: Could not open config file %s: %s\n", config_path, strerror(errno));
return(255);
}
if ( getenv("SINGULARITY_WRITABLE") == NULL ) {
if ( ( containerimage_fp = fopen(containerimage, "r") ) == NULL ) {
fprintf(stderr, "ERROR: Could not open image read only %s: %s\n", containerimage, strerror(errno));
return(255);
}
containerimage_fd = fileno(containerimage_fp);
if ( flock(containerimage_fd, LOCK_SH | LOCK_NB) < 0 ) {
fprintf(stderr, "ABORT: Image is locked by another process\n");
return(5);
}
} else {
if ( ( containerimage_fp = fopen(containerimage, "r+") ) == NULL ) {
fprintf(stderr, "ERROR: Could not open image read/write %s: %s\n", containerimage, strerror(errno));
return(255);
}
containerimage_fd = fileno(containerimage_fp);
if ( flock(containerimage_fd, LOCK_EX | LOCK_NB) < 0 ) {
fprintf(stderr, "ABORT: Image is locked by another process\n");
return(5);
}
}
//****************************************************************************//
// We are now running with escalated privileges until we exec
//****************************************************************************//
if ( seteuid(0) < 0 ) {
fprintf(stderr, "ABORT: Could not escalate effective user privileges %s\n", strerror(errno));
return(255);
}
if ( setegid(0) < 0 ) {
fprintf(stderr, "ABORT: Could not escalate effective group privileges: %s\n", strerror(errno));
return(255);
}
if ( s_mkpath(tmpdir, 0755) < 0 ) {
fprintf(stderr, "ABORT: Could not create temporary directory %s: %s\n", tmpdir, strerror(errno));
return(255);
}
if ( is_owner(tmpdir, 0) < 0 ) {
fprintf(stderr, "ABORT: Container working directory has wrong ownership: %s\n", tmpdir);
syslog(LOG_ERR, "Container working directory has wrong ownership: %s", tmpdir);
return(255);
}
tmpdirlock_fd = open(tmpdir, O_RDONLY);
if ( tmpdirlock_fd < 0 ) {
fprintf(stderr, "ERROR: Could not obtain file descriptor on %s: %s\n", tmpdir, strerror(errno));
return(255);
}
if ( flock(tmpdirlock_fd, LOCK_SH | LOCK_NB) < 0 ) {
fprintf(stderr, "ERROR: Could not obtain shared lock on %s: %s\n", tmpdir, strerror(errno));
return(255);
}
if ( ( loop_dev_lock_fd = open(loop_dev_lock, O_CREAT | O_RDWR, 0644) ) < 0 ) {
fprintf(stderr, "ERROR: Could not open loop_dev_lock %s: %s\n", loop_dev_lock, strerror(errno));
return(255);
}
if ( s_mkpath(containerpath, 0755) < 0 ) {
fprintf(stderr, "ABORT: Could not create directory %s: %s\n", containerpath, strerror(errno));
return(255);
}
if ( is_owner(containerpath, 0) < 0 ) {
fprintf(stderr, "ABORT: Container directory is not root owned: %s\n", containerpath);
syslog(LOG_ERR, "Container directory has wrong ownership: %s", tmpdir);
return(255);
}
if ( flock(loop_dev_lock_fd, LOCK_EX | LOCK_NB) == 0 ) {
loop_dev = obtain_loop_dev();
if ( ( loop_fp = fopen(loop_dev, "r+") ) < 0 ) {
fprintf(stderr, "ERROR: Failed to open loop device %s: %s\n", loop_dev, strerror(errno));
syslog(LOG_ERR, "Failed to open loop device %s: %s", loop_dev, strerror(errno));
return(255);
}
if ( associate_loop(containerimage_fp, loop_fp, 1) < 0 ) {
fprintf(stderr, "ERROR: Could not associate %s to loop device %s\n", containerimage, loop_dev);
syslog(LOG_ERR, "Failed to associate %s to loop device %s", containerimage, loop_dev);
return(255);
}
if ( fileput(loop_dev_cache, loop_dev) < 0 ) {
fprintf(stderr, "ERROR: Could not write to loop_dev_cache %s: %s\n", loop_dev_cache, strerror(errno));
return(255);
}
flock(loop_dev_lock_fd, LOCK_SH | LOCK_NB);
} else {
flock(loop_dev_lock_fd, LOCK_SH);
if ( ( loop_dev = filecat(loop_dev_cache) ) == NULL ) {
fprintf(stderr, "ERROR: Could not retrieve loop_dev_cache from %s\n", loop_dev_cache);
return(255);
}
if ( ( loop_fp = fopen(loop_dev, "r") ) < 0 ) {
fprintf(stderr, "ERROR: Failed to open loop device %s: %s\n", loop_dev, strerror(errno));
return(255);
}
}
//****************************************************************************//
// Management fork
//****************************************************************************//
namespace_fork_pid = fork();
if ( namespace_fork_pid == 0 ) {
//****************************************************************************//
// Setup namespaces
//****************************************************************************//
if ( unshare(CLONE_NEWNS) < 0 ) {
fprintf(stderr, "ABORT: Could not virtualize mount namespace: %s\n", strerror(errno));
return(255);
}
// Privatize the mount namespaces (thank you for the pointer Doug Jacobsen!)
if ( mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) < 0 ) {
// I am not sure if this error needs to be caught, maybe it will fail
// on older kernels? If so, we can fix then.
fprintf(stderr, "ABORT: Could not make mountspaces private: %s\n", strerror(errno));
return(255);
}
#ifdef NS_CLONE_NEWPID
if ( getenv("SINGULARITY_NO_NAMESPACE_PID") == NULL ) {
unsetenv("SINGULARITY_NO_NAMESPACE_PID");
if ( unshare(CLONE_NEWPID) < 0 ) {
fprintf(stderr, "ABORT: Could not virtualize PID namespace: %s\n", strerror(errno));
return(255);
}
}
#else
#ifdef NS_CLONE_PID
// This is for older legacy CLONE_PID
if ( getenv("SINGULARITY_NO_NAMESPACE_PID") == NULL ) {
unsetenv("SINGULARITY_NO_NAMESPACE_PID");
if ( unshare(CLONE_PID) < 0 ) {
fprintf(stderr, "ABORT: Could not virtualize PID namespace: %s\n", strerror(errno));
return(255);
}
}
#endif
#endif
#ifdef NS_CLONE_FS
if ( getenv("SINGULARITY_NO_NAMESPACE_FS") == NULL ) {
unsetenv("SINGULARITY_NO_NAMESPACE_FS");
if ( unshare(CLONE_FS) < 0 ) {
fprintf(stderr, "ABORT: Could not virtualize file system namespace: %s\n", strerror(errno));
return(255);
}
}
#endif
#ifdef NS_CLONE_FILES
if ( getenv("SINGULARITY_NO_NAMESPACE_FILES") == NULL ) {
unsetenv("SINGULARITY_NO_NAMESPACE_FILES");
if ( unshare(CLONE_FILES) < 0 ) {
fprintf(stderr, "ABORT: Could not virtualize file descriptor namespace: %s\n", strerror(errno));
return(255);
}
}
#endif
//****************************************************************************//
// Mount image
//****************************************************************************//
if ( getenv("SINGULARITY_WRITABLE") == NULL ) {
unsetenv("SINGULARITY_WRITABLE");
if ( mount_image(loop_dev, containerpath, 0) < 0 ) {
fprintf(stderr, "ABORT: exiting...\n");
return(255);
}
} else {
if ( mount_image(loop_dev, containerpath, 1) < 0 ) {
fprintf(stderr, "ABORT: exiting...\n");
return(255);
}
}
//****************************************************************************//
// Check image
//****************************************************************************//
if ( is_exec(joinpath(containerpath, "/bin/sh")) < 0 ) {
fprintf(stderr, "ERROR: Container image does not have a valid /bin/sh\n");
return(1);
}
//****************************************************************************//
// Bind mounts
//****************************************************************************//
if ( getenv("SINGULARITY_CONTAIN") == NULL ) {
unsetenv("SINGULARITY_CONTAIN");
rewind(config_fp);
while ( ( tmp_config_string = config_get_key_value(config_fp, "bind path") ) != NULL ) {
if ( ( is_file(tmp_config_string) != 0 ) && ( is_dir(tmp_config_string) != 0 ) ) {
fprintf(stderr, "ERROR: Non existant bind source path: '%s'\n", tmp_config_string);
continue;
}
if ( ( is_file(joinpath(containerpath, tmp_config_string)) != 0 ) && ( is_dir(joinpath(containerpath, tmp_config_string)) != 0 ) ) {
fprintf(stderr, "WARNING: Non existant bind container destination path: '%s'\n", tmp_config_string);
continue;
}
if ( mount_bind(tmp_config_string, joinpath(containerpath, tmp_config_string), 0) < 0 ) {
fprintf(stderr, "ABORTING!\n");
return(255);
}
}
if (is_file(joinpath(containerpath, "/etc/nsswitch.conf")) == 0 ) {
if ( is_file(joinpath(SYSCONFDIR, "/singularity/default-nsswitch.conf")) == 0 ) {
if ( mount_bind(joinpath(SYSCONFDIR, "/singularity/default-nsswitch.conf"), joinpath(containerpath, "/etc/nsswitch.conf"), 0) != 0 ) {
fprintf(stderr, "ABORT: Could not bind /etc/nsswitch.conf\n");
return(255);
}
} else {
fprintf(stderr, "WARNING: Template /etc/nsswitch.conf does not exist: %s\n", joinpath(SYSCONFDIR, "/singularity/default-nsswitch.conf"));
}
}
if ( uid != 0 ) { // If we are root, no need to mess with passwd or group
if (is_file(joinpath(containerpath, "/etc/passwd")) == 0 ) {
if ( is_file(joinpath(tmpdir, "/passwd")) < 0 ) {
if ( build_passwd(joinpath(containerpath, "/etc/passwd"), joinpath(tmpdir, "/passwd")) < 0 ) {
fprintf(stderr, "ABORT: Failed creating template password file\n");
return(255);
}
}
if ( mount_bind(joinpath(tmpdir, "/passwd"), joinpath(containerpath, "/etc/passwd"), 0) < 0 ) {
fprintf(stderr, "ABORT: Could not bind /etc/passwd\n");
return(255);
}
}
if (is_file(joinpath(containerpath, "/etc/group")) == 0 ) {
if ( is_file(joinpath(tmpdir, "/group")) < 0 ) {
if ( build_group(joinpath(containerpath, "/etc/group"), joinpath(tmpdir, "/group")) < 0 ) {
fprintf(stderr, "ABORT: Failed creating template group file\n");
return(255);
}
}
if ( mount_bind(joinpath(tmpdir, "/group"), joinpath(containerpath, "/etc/group"), 0) < 0 ) {
fprintf(stderr, "ABORT: Could not bind /etc/group\n");
return(255);
}
}
}
}
//****************************************************************************//
// Fork child in new namespaces
//****************************************************************************//
exec_fork_pid = fork();
if ( exec_fork_pid == 0 ) {
//****************************************************************************//
// Enter the file system
//****************************************************************************//
if ( chroot(containerpath) < 0 ) {
fprintf(stderr, "ABORT: failed enter CONTAINERIMAGE: %s\n", containerpath);
return(255);
}
if ( chdir("/") < 0 ) {
fprintf(stderr, "ABORT: Could not chdir after chroot to /: %s\n", strerror(errno));
return(1);
}
//****************************************************************************//
// Setup real mounts within the container
//****************************************************************************//
rewind(config_fp);
if ( config_get_key_bool(config_fp, "mount proc", 1) > 0 ) {
if ( is_dir("/proc") == 0 ) {
if ( mount("proc", "/proc", "proc", 0, NULL) < 0 ) {
fprintf(stderr, "ABORT: Could not mount /proc: %s\n", strerror(errno));
return(255);
}
}
}
rewind(config_fp);
if ( config_get_key_bool(config_fp, "mount sys", 1) > 0 ) {
if ( is_dir("/sys") == 0 ) {
if ( mount("sysfs", "/sys", "sysfs", 0, NULL) < 0 ) {
fprintf(stderr, "ABORT: Could not mount /sys: %s\n", strerror(errno));
return(255);
}
}
}
//****************************************************************************//
// Drop all privileges for good
//****************************************************************************//
if ( setgroups(gid_list_count, gid_list) < 0 ) {
fprintf(stderr, "ABOFT: Could not reset supplementary group list: %s\n", strerror(errno));
return(255);
}
if ( setregid(gid, gid) < 0 ) {
fprintf(stderr, "ABORT: Could not dump real and effective group privileges: %s\n", strerror(errno));
return(255);
}
if ( setreuid(uid, uid) < 0 ) {
fprintf(stderr, "ABORT: Could not dump real and effective user privileges: %s\n", strerror(errno));
return(255);
}
//****************************************************************************//
// Setup final environment
//****************************************************************************//
// After this, we exist only within the container... Let's make it known!
if ( setenv("SINGULARITY_CONTAINER", "true", 0) != 0 ) {
fprintf(stderr, "ABORT: Could not set SINGULARITY_CONTAINER to 'true'\n");
return(1);
}
if ( is_dir(cwd) == 0 ) {
if ( chdir(cwd) < 0 ) {
fprintf(stderr, "ABORT: Could not chdir to: %s: %s\n", cwd, strerror(errno));
return(1);
}
} else {
if ( fchdir(cwd_fd) < 0 ) {
fprintf(stderr, "ABORT: Could not fchdir to cwd: %s\n", strerror(errno));
return(1);
}
}
//****************************************************************************//
// Execv to container process
//****************************************************************************//
if ( command == NULL ) {
fprintf(stderr, "No command specified, launching 'shell'\n");
command = strdup("shell");
}
if ( strcmp(command, "run") == 0 ) {
if ( is_exec("/singularity") == 0 ) {
argv[0] = strdup("/singularity");
if ( execv("/singularity", argv) != 0 ) {
fprintf(stderr, "ABORT: exec of /bin/sh failed: %s\n", strerror(errno));
}
} else {
fprintf(stderr, "No Singularity runscript found, launching 'shell'\n");
command = strdup("shell");
}
}
if ( strcmp(command, "exec") == 0 ) {
if ( argc <= 1 ) {
fprintf(stderr, "ABORT: Exec requires a command to run\n");
return(1);
}
if ( execvp(argv[1], &argv[1]) != 0 ) {
fprintf(stderr, "ABORT: execvp of '%s' failed: %s\n", argv[1], strerror(errno));
return(1);
}
}
if ( strcmp(command, "shell") == 0 ) {
char *prompt;
prompt = (char *) malloc(strlen(containername) + 16);
snprintf(prompt, strlen(containerimage) + 16, "Singularity/%s> ", containername);
setenv("PS1", prompt, 1);
if ( is_exec("/bin/bash") == 0 ) {
char *args[argc+2];
int i;
args[0] = strdup("/bin/bash");
args[1] = strdup("--norc");
args[2] = strdup("--noprofile");
for(i=1; i<=argc; i++) {
args[i+2] = argv[i];
}
if ( execv("/bin/bash", args) != 0 ) {
fprintf(stderr, "ABORT: exec of /bin/bash failed: %s\n", strerror(errno));
}
} else {
argv[0] = strdup("/bin/sh");
if ( execv("/bin/sh", argv) != 0 ) {
fprintf(stderr, "ABORT: exec of /bin/sh failed: %s\n", strerror(errno));
}
}
}
// If we get here... we fail on bad command
fprintf(stderr, "ABORT: Unrecognized Singularity command: %s\n", command);
return(1);
//****************************************************************************//
// Outer child waits for inner child
//****************************************************************************//
} else if ( exec_fork_pid > 0 ) {
int tmpstatus;
strncpy(argv[0], "Singularity: exec", strlen(argv[0]));
if ( seteuid(uid) < 0 ) {
fprintf(stderr, "ABORT: Could not set effective user privileges to %d: %s\n", uid, strerror(errno));
return(255);
}
waitpid(exec_fork_pid, &tmpstatus, 0);
retval = WEXITSTATUS(tmpstatus);
} else {
fprintf(stderr, "ABORT: Could not fork namespace process: %s\n", strerror(errno));
return(255);
}
return(retval);
} else if ( namespace_fork_pid > 0 ) {
int tmpstatus;
strncpy(argv[0], "Singularity: namespace", strlen(argv[0]));
if ( seteuid(uid) < 0 ) {
fprintf(stderr, "ABORT: Could not set effective user privileges to %d: %s\n", uid, strerror(errno));
return(255);
}
waitpid(namespace_fork_pid, &tmpstatus, 0);
retval = WEXITSTATUS(tmpstatus);
} else {
fprintf(stderr, "ABORT: Could not fork management process: %s\n", strerror(errno));
return(255);
}
//****************************************************************************//
// Final wrap up before exiting
//****************************************************************************//
if ( close(cwd_fd) < 0 ) {
fprintf(stderr, "ERROR: Could not close cwd_fd: %s\n", strerror(errno));
retval++;
}
if ( flock(tmpdirlock_fd, LOCK_EX | LOCK_NB) == 0 ) {
close(tmpdirlock_fd);
if ( seteuid(0) < 0 ) {
fprintf(stderr, "ABORT: Could not re-escalate effective user privileges: %s\n", strerror(errno));
return(255);
}
if ( s_rmdir(tmpdir) < 0 ) {
fprintf(stderr, "WARNING: Could not remove all files in %s: %s\n", tmpdir, strerror(errno));
}
// Dissociate loops from here Just in case autoflush didn't work.
(void)disassociate_loop(loop_fp);
if ( seteuid(uid) < 0 ) {
fprintf(stderr, "ABORT: Could not drop effective user privileges: %s\n", strerror(errno));
return(255);
}
} else {
// printf("Not removing tmpdir, lock still\n");
}
close(containerimage_fd);
close(tmpdirlock_fd);
free(loop_dev_lock);
free(containerpath);
free(tmpdir);
closelog();
return(retval);
}