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Systemd/src/import/pull-common.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#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 "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(
const char *url,
const char *image_root,
int dt,
const char *prefix,
const char *suffix,
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) {
const char *a, *b;
char *u;
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)) {
free(u);
continue;
}
r = strv_consume(&l, 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, bool force_local) {
const char *p;
int r;
assert(final);
assert(local);
if (!image_root)
image_root = "/var/lib/machines";
p = strjoina(image_root, "/", local);
if (force_local)
(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.
* When that happens, a URL hash is used instead. Paths returned by this function
* can be later used with tempfn_random() which adds 16 bytes to the resulting 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(
PullJob **ret,
const char *url,
int (*strip_suffixes)(const char *name, char **ret),
const char *suffix,
CurlGlue *glue,
PullJobFinished on_finished,
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 = job;
job = NULL;
return 0;
}
int pull_make_verification_jobs(
PullJob **ret_checksum_job,
PullJob **ret_signature_job,
ImportVerify verify,
const char *url,
CurlGlue *glue,
PullJobFinished on_finished,
void *userdata) {
_cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;
int r;
const char *chksums = NULL;
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;
/* 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 = checksum_job;
*ret_signature_job = signature_job;
checksum_job = signature_job = NULL;
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)) {
log_error("Cannot verify checksum, could not determine server-side file name.");
return -EBADMSG;
}
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')) {
log_error("DOWNLOAD INVALID: Checksum of %s file did not checkout, file has been tampered with.", fn);
return -EBADMSG;
}
log_info("SHA256 checksum of %s is valid.", job->url);
return 1;
}
int pull_verify(PullJob *main_job,
PullJob *roothash_job,
PullJob *settings_job,
PullJob *checksum_job,
PullJob *signature_job) {
_cleanup_close_pair_ int gpg_pipe[2] = { -1, -1 };
_cleanup_close_ int sig_file = -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(main_job);
assert(main_job->state == PULL_JOB_DONE);
if (!checksum_job)
return 0;
assert(main_job->calc_checksum);
assert(main_job->checksum);
assert(checksum_job->state == PULL_JOB_DONE);
if (!checksum_job->payload || checksum_job->payload_size <= 0) {
log_error("Checksum is empty, cannot verify.");
return -EBADMSG;
}
r = verify_one(checksum_job, main_job);
if (r < 0)
return r;
r = verify_one(checksum_job, roothash_job);
if (r < 0)
return r;
r = verify_one(checksum_job, settings_job);
if (r < 0)
return r;
if (!signature_job)
return 0;
if (checksum_job->style == VERIFICATION_PER_FILE)
signature_job = checksum_job;
assert(signature_job->state == PULL_JOB_DONE);
if (!signature_job->payload || signature_job->payload_size <= 0) {
log_error("Signature is empty, cannot verify.");
return -EBADMSG;
}
r = pipe2(gpg_pipe, O_CLOEXEC);
if (r < 0)
return log_error_errno(errno, "Failed to create pipe for gpg: %m");
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_job->payload, signature_job->payload_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 tempory 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 */
};
unsigned 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);
}
cmd[k++] = strjoina("--homedir=", gpg_home);
/* We add the user keyring only to the command line
* arguments, if it's around since gpg fails
* otherwise. */
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 (checksum_job->style == VERIFICATION_PER_DIRECTORY) {
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], checksum_job->payload, checksum_job->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 (sig_file >= 0)
(void) unlink(sig_file_path);
if (gpg_home_created)
(void) rm_rf(gpg_home, REMOVE_ROOT|REMOVE_PHYSICAL);
return r;
}
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