#include <sys/prctl.h>

#include "alloc-util.h"

#include "btrfs-util.h"

#include "capability-util.h"

#include "copy.h"

#include "dirent-util.h"

#include "escape.h"

#include "fd-util.h"

#include "io-util.h"

#include "path-util.h"

#include "process-util.h"

#include "pull-common.h"

#include "pull-job.h"

#include "rlimit-util.h"

#include "rm-rf.h"

#include "signal-util.h"

#include "siphash24.h"

#include "string-util.h"

#include "strv.h"

#include "util.h"

#include "web-util.h"

#define FILENAME_ESCAPE "/.#\"\'"

#define HASH_URL_THRESHOLD_LENGTH (_POSIX_PATH_MAX - 16)

int pull_find_old_etags(

char ***etags) {

_cleanup_free_ char *escaped_url = NULL;

_cleanup_closedir_ DIR *d = NULL;

_cleanup_strv_free_ char **l = NULL;

struct dirent *de;

int r;

assert(url);

assert(etags);

if (!image_root)

image_root = "/var/lib/machines";

escaped_url = xescape(url, FILENAME_ESCAPE);

if (!escaped_url)

return -ENOMEM;

d = opendir(image_root);

if (!d) {

if (errno == ENOENT) {

*etags = NULL;

return 0;

}

return -errno;

}

FOREACH_DIRENT_ALL(de, d, return -errno) {

_cleanup_free_ char *u = NULL;

const char *a, *b;

if (de->d_type != DT_UNKNOWN &&

de->d_type != dt)

continue;

if (prefix) {

a = startswith(de->d_name, prefix);

if (!a)

continue;

} else

a = de->d_name;

a = startswith(a, escaped_url);

if (!a)

continue;

a = startswith(a, ".");

if (!a)

continue;

if (suffix) {

b = endswith(de->d_name, suffix);

if (!b)

continue;

} else

b = strchr(de->d_name, 0);

if (a >= b)

continue;

r = cunescape_length(a, b - a, 0, &u);

if (r < 0)

return r;

if (!http_etag_is_valid(u))

continue;

r = strv_consume(&l, TAKE_PTR(u));

if (r < 0)

return r;

}

*etags = TAKE_PTR(l);

return 0;

}

int pull_make_local_copy(const char *final, const char *image_root, const char *local, PullFlags flags) {

const char *p;

int r;

assert(final);

assert(local);

if (!image_root)

image_root = "/var/lib/machines";

p = prefix_roota(image_root, local);

if (FLAGS_SET(flags, PULL_FORCE))

(void) rm_rf(p, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);

r = btrfs_subvol_snapshot(final, p,

BTRFS_SNAPSHOT_QUOTA|

BTRFS_SNAPSHOT_FALLBACK_COPY|

BTRFS_SNAPSHOT_FALLBACK_DIRECTORY|

BTRFS_SNAPSHOT_RECURSIVE);

if (r < 0)

return log_error_errno(r, "Failed to create local image: %m");

log_info("Created new local image '%s'.", local);

return 0;

}

static int hash_url(const char *url, char **ret) {

uint64_t h;

static const sd_id128_t k = SD_ID128_ARRAY(df,89,16,87,01,cc,42,30,98,ab,4a,19,a6,a5,63,4f);

assert(url);

h = siphash24(url, strlen(url), k.bytes);

if (asprintf(ret, "%"PRIx64, h) < 0)

return -ENOMEM;

return 0;

}

int pull_make_path(const char *url, const char *etag, const char *image_root, const char *prefix, const char *suffix, char **ret) {

_cleanup_free_ char *escaped_url = NULL, *escaped_etag = NULL;

char *path;

assert(url);

assert(ret);

if (!image_root)

image_root = "/var/lib/machines";

escaped_url = xescape(url, FILENAME_ESCAPE);

if (!escaped_url)

return -ENOMEM;

if (etag) {

escaped_etag = xescape(etag, FILENAME_ESCAPE);

if (!escaped_etag)

return -ENOMEM;

}

path = strjoin(image_root, "/", strempty(prefix), escaped_url, escaped_etag ? "." : "",

strempty(escaped_etag), strempty(suffix));

if (!path)

return -ENOMEM;

/* URLs might make the path longer than the maximum allowed length for a file name.

if (strlen(path) >= HASH_URL_THRESHOLD_LENGTH) {

_cleanup_free_ char *hash = NULL;

int r;

free(path);

r = hash_url(url, &hash);

if (r < 0)

return r;

path = strjoin(image_root, "/", strempty(prefix), hash, escaped_etag ? "." : "",

strempty(escaped_etag), strempty(suffix));

if (!path)

return -ENOMEM;

}

*ret = path;

return 0;

}

int pull_make_auxiliary_job(

void *userdata) {

_cleanup_free_ char *last_component = NULL, *ll = NULL, *auxiliary_url = NULL;

_cleanup_(pull_job_unrefp) PullJob *job = NULL;

const char *q;

int r;

assert(ret);

assert(url);

assert(strip_suffixes);

assert(glue);

r = import_url_last_component(url, &last_component);

if (r < 0)

return r;

r = strip_suffixes(last_component, &ll);

if (r < 0)

return r;

q = strjoina(ll, suffix);

r = import_url_change_last_component(url, q, &auxiliary_url);

if (r < 0)

return r;

r = pull_job_new(&job, auxiliary_url, glue, userdata);

if (r < 0)

return r;

job->on_finished = on_finished;

job->compressed_max = job->uncompressed_max = 1ULL * 1024ULL * 1024ULL;

*ret = TAKE_PTR(job);

return 0;

}

int pull_make_verification_jobs(

void *userdata) {

_cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;

int r;

assert(ret_checksum_job);

assert(ret_signature_job);

assert(verify >= 0);

assert(verify < _IMPORT_VERIFY_MAX);

assert(url);

assert(glue);

if (verify != IMPORT_VERIFY_NO) {

_cleanup_free_ char *checksum_url = NULL, *fn = NULL;

const char *chksums = NULL;

/* Queue jobs for the checksum file for the image. */

r = import_url_last_component(url, &fn);

if (r < 0)

return r;

chksums = strjoina(fn, ".sha256");

r = import_url_change_last_component(url, chksums, &checksum_url);

if (r < 0)

return r;

r = pull_job_new(&checksum_job, checksum_url, glue, userdata);

if (r < 0)

return r;

checksum_job->on_finished = on_finished;

checksum_job->uncompressed_max = checksum_job->compressed_max = 1ULL * 1024ULL * 1024ULL;

}

if (verify == IMPORT_VERIFY_SIGNATURE) {

_cleanup_free_ char *signature_url = NULL;

/* Queue job for the SHA256SUMS.gpg file for the image. */

r = import_url_change_last_component(url, "SHA256SUMS.gpg", &signature_url);

if (r < 0)

return r;

r = pull_job_new(&signature_job, signature_url, glue, userdata);

if (r < 0)

return r;

signature_job->on_finished = on_finished;

signature_job->uncompressed_max = signature_job->compressed_max = 1ULL * 1024ULL * 1024ULL;

}

*ret_checksum_job = TAKE_PTR(checksum_job);

*ret_signature_job = TAKE_PTR(signature_job);

return 0;

}

static int verify_one(PullJob *checksum_job, PullJob *job) {

_cleanup_free_ char *fn = NULL;

const char *line, *p;

int r;

assert(checksum_job);

if (!job)

return 0;

assert(IN_SET(job->state, PULL_JOB_DONE, PULL_JOB_FAILED));

/* Don't verify the checksum if we didn't actually successfully download something new */

if (job->state != PULL_JOB_DONE)

return 0;

if (job->error != 0)

return 0;

if (job->etag_exists)

return 0;

assert(job->calc_checksum);

assert(job->checksum);

r = import_url_last_component(job->url, &fn);

if (r < 0)

return log_oom();

if (!filename_is_valid(fn))

return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),

"Cannot verify checksum, could not determine server-side file name.");

line = strjoina(job->checksum, " *", fn, "\n");

p = memmem(checksum_job->payload,

checksum_job->payload_size,

line,

strlen(line));

if (!p) {

line = strjoina(job->checksum, " ", fn, "\n");

p = memmem(checksum_job->payload,

checksum_job->payload_size,

line,

strlen(line));

}

if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n'))

return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),

"DOWNLOAD INVALID: Checksum of %s file did not checkout, file has been tampered with.", fn);

log_info("SHA256 checksum of %s is valid.", job->url);

return 1;

}

static int verify_gpg(

const void *payload, size_t payload_size,

const void *signature, size_t signature_size) {

_cleanup_close_pair_ int gpg_pipe[2] = { -1, -1 };

char sig_file_path[] = "/tmp/sigXXXXXX", gpg_home[] = "/tmp/gpghomeXXXXXX";

_cleanup_(sigkill_waitp) pid_t pid = 0;

bool gpg_home_created = false;

int r;

assert(payload || payload_size == 0);

assert(signature || signature_size == 0);

r = pipe2(gpg_pipe, O_CLOEXEC);

if (r < 0)

return log_error_errno(errno, "Failed to create pipe for gpg: %m");

if (signature_size > 0) {

_cleanup_close_ int sig_file = -1;

sig_file = mkostemp(sig_file_path, O_RDWR);

if (sig_file < 0)

return log_error_errno(errno, "Failed to create temporary file: %m");

r = loop_write(sig_file, signature, signature_size, false);

if (r < 0) {

log_error_errno(r, "Failed to write to temporary file: %m");

goto finish;

}

}

if (!mkdtemp(gpg_home)) {

r = log_error_errno(errno, "Failed to create temporary home for gpg: %m");

goto finish;

}

gpg_home_created = true;

r = safe_fork("(gpg)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);

if (r < 0)

return r;

if (r == 0) {

const char *cmd[] = {

"gpg",

"--no-options",

"--no-default-keyring",

"--no-auto-key-locate",

"--no-auto-check-trustdb",

"--batch",

"--trust-model=always",

NULL, /* --homedir= */

NULL, /* --keyring= */

NULL, /* --verify */

NULL, /* signature file */

NULL, /* dash */

NULL /* trailing NULL */

};

size_t k = ELEMENTSOF(cmd) - 6;

/* Child */

gpg_pipe[1] = safe_close(gpg_pipe[1]);

r = rearrange_stdio(gpg_pipe[0], -1, STDERR_FILENO);

if (r < 0) {

log_error_errno(r, "Failed to rearrange stdin/stdout: %m");

_exit(EXIT_FAILURE);

}

(void) rlimit_nofile_safe();

cmd[k++] = strjoina("--homedir=", gpg_home);

/* We add the user keyring only to the command line arguments, if it's around since gpg fails

if (access(USER_KEYRING_PATH, F_OK) >= 0)

cmd[k++] = "--keyring=" USER_KEYRING_PATH;

else

cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;

cmd[k++] = "--verify";

if (signature) {

cmd[k++] = sig_file_path;

cmd[k++] = "-";

cmd[k++] = NULL;

}

execvp("gpg2", (char * const *) cmd);

execvp("gpg", (char * const *) cmd);

log_error_errno(errno, "Failed to execute gpg: %m");

_exit(EXIT_FAILURE);

}

gpg_pipe[0] = safe_close(gpg_pipe[0]);

r = loop_write(gpg_pipe[1], payload, payload_size, false);

if (r < 0) {

log_error_errno(r, "Failed to write to pipe: %m");

goto finish;

}

gpg_pipe[1] = safe_close(gpg_pipe[1]);

r = wait_for_terminate_and_check("gpg", pid, WAIT_LOG_ABNORMAL);

pid = 0;

if (r < 0)

goto finish;

if (r != EXIT_SUCCESS) {

log_error("DOWNLOAD INVALID: Signature verification failed.");

r = -EBADMSG;

} else {

log_info("Signature verification succeeded.");

r = 0;

}

finish:

if (signature_size > 0)

(void) unlink(sig_file_path);

if (gpg_home_created)

(void) rm_rf(gpg_home, REMOVE_ROOT|REMOVE_PHYSICAL);

return r;

}

int pull_verify(ImportVerify verify,

PullJob *verity_job) {

VerificationStyle style;

PullJob *j;

int r;

assert(main_job);

assert(main_job->state == PULL_JOB_DONE);

if (verify == IMPORT_VERIFY_NO)

return 0;

assert(main_job->calc_checksum);

assert(main_job->checksum);

assert(checksum_job);

assert(checksum_job->state == PULL_JOB_DONE);

if (!checksum_job->payload || checksum_job->payload_size <= 0)

return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),

"Checksum is empty, cannot verify.");

FOREACH_POINTER(j, main_job, settings_job, roothash_job, roothash_signature_job, verity_job) {

r = verify_one(checksum_job, j);

if (r < 0)

return r;

}

if (verify == IMPORT_VERIFY_CHECKSUM)

return 0;

r = verification_style_from_url(checksum_job->url, &style);

if (r < 0)

return log_error_errno(r, "Failed to determine verification style from URL '%s': %m", checksum_job->url);

if (style == VERIFICATION_PER_DIRECTORY) {

assert(signature_job);

assert(signature_job->state == PULL_JOB_DONE);

if (!signature_job->payload || signature_job->payload_size <= 0)

return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),

"Signature is empty, cannot verify.");

return verify_gpg(checksum_job->payload, checksum_job->payload_size, signature_job->payload, signature_job->payload_size);

} else

return verify_gpg(checksum_job->payload, checksum_job->payload_size, NULL, 0);

}

int verification_style_from_url(const char *url, VerificationStyle *ret) {

_cleanup_free_ char *last = NULL;

int r;

assert(url);

assert(ret);

/* Determines which kind of verification style is appropriate for this url */

r = import_url_last_component(url, &last);

if (r < 0)

return r;

if (streq(last, "SHA256SUMS")) {

*ret = VERIFICATION_PER_DIRECTORY;

return 0;

}

if (endswith(last, ".sha256")) {

*ret = VERIFICATION_PER_FILE;

return 0;

}

return -EINVAL;

}

int pull_job_restart_with_sha256sum(PullJob *j, char **ret) {

VerificationStyle style;

int r;

assert(j);

/* Generic implementation of a PullJobNotFound handler, that restarts the job requesting SHA256SUMS */

r = verification_style_from_url(j->url, &style);

if (r < 0)

return log_error_errno(r, "Failed to determine verification style of URL '%s': %m", j->url);

if (style == VERIFICATION_PER_DIRECTORY) /* Nothing to do anymore */

return 0;

assert(style == VERIFICATION_PER_FILE); /* This must have been .sha256 style URL before */

log_debug("Got 404 for %s, now trying to get SHA256SUMS instead.", j->url);

r = import_url_change_last_component(j->url, "SHA256SUMS", ret);

if (r < 0)

return log_error_errno(r, "Failed to replace SHA256SUMS suffix: %m");

return 1;

}