1222 lines
54 KiB
C
1222 lines
54 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <sys/file.h>
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#if HAVE_OPENSSL
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#include <openssl/err.h>
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#endif
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#include "sd-id128.h"
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#include "blockdev-util.h"
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#include "chattr-util.h"
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#include "constants.h"
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#include "creds-util.h"
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#include "efi-api.h"
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#include "env-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "io-util.h"
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#include "memory-util.h"
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#include "mkdir.h"
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#include "openssl-util.h"
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#include "path-util.h"
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#include "random-util.h"
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#include "sparse-endian.h"
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#include "stat-util.h"
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#include "tpm2-util.h"
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#include "virt.h"
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#define PUBLIC_KEY_MAX (UINT32_C(1024) * UINT32_C(1024))
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bool credential_name_valid(const char *s) {
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/* We want that credential names are both valid in filenames (since that's our primary way to pass
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* them around) and as fdnames (which is how we might want to pass them around eventually) */
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return filename_is_valid(s) && fdname_is_valid(s);
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}
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static int get_credentials_dir_internal(const char *envvar, const char **ret) {
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const char *e;
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assert(ret);
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e = secure_getenv(envvar);
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if (!e)
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return -ENXIO;
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if (!path_is_absolute(e) || !path_is_normalized(e))
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return -EINVAL;
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*ret = e;
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return 0;
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}
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int get_credentials_dir(const char **ret) {
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return get_credentials_dir_internal("CREDENTIALS_DIRECTORY", ret);
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}
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int get_encrypted_credentials_dir(const char **ret) {
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return get_credentials_dir_internal("ENCRYPTED_CREDENTIALS_DIRECTORY", ret);
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}
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int read_credential(const char *name, void **ret, size_t *ret_size) {
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_cleanup_free_ char *fn = NULL;
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const char *d;
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int r;
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assert(ret);
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if (!credential_name_valid(name))
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return -EINVAL;
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r = get_credentials_dir(&d);
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if (r < 0)
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return r;
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fn = path_join(d, name);
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if (!fn)
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return -ENOMEM;
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return read_full_file_full(
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AT_FDCWD, fn,
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UINT64_MAX, SIZE_MAX,
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READ_FULL_FILE_SECURE,
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NULL,
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(char**) ret, ret_size);
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}
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int read_credential_strings_many_internal(
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const char *first_name, char **first_value,
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...) {
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_cleanup_free_ void *b = NULL;
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int r, ret = 0;
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/* Reads a bunch of credentials into the specified buffers. If the specified buffers are already
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* non-NULL frees them if a credential is found. Only supports string-based credentials
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* (i.e. refuses embedded NUL bytes) */
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if (!first_name)
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return 0;
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r = read_credential(first_name, &b, NULL);
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if (r == -ENXIO) /* no creds passed at all? propagate this */
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return r;
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if (r < 0)
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ret = r;
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else
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free_and_replace(*first_value, b);
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va_list ap;
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va_start(ap, first_value);
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for (;;) {
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_cleanup_free_ void *bb = NULL;
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const char *name;
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char **value;
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name = va_arg(ap, const char *);
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if (!name)
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break;
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value = va_arg(ap, char **);
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if (*value)
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continue;
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r = read_credential(name, &bb, NULL);
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if (r < 0) {
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if (ret >= 0)
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ret = r;
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} else
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free_and_replace(*value, bb);
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}
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va_end(ap);
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return ret;
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}
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int get_credential_user_password(const char *username, char **ret_password, bool *ret_is_hashed) {
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_cleanup_(erase_and_freep) char *creds_password = NULL;
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_cleanup_free_ char *cn = NULL;
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int r;
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/* Try to pick up the password for this account via the credentials logic */
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cn = strjoin("passwd.hashed-password.", username);
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if (!cn)
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return -ENOMEM;
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r = read_credential(cn, (void**) &creds_password, NULL);
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if (r == -ENOENT) {
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free(cn);
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cn = strjoin("passwd.plaintext-password.", username);
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if (!cn)
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return -ENOMEM;
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r = read_credential(cn, (void**) &creds_password, NULL);
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if (r < 0)
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log_debug_errno(r, "Couldn't read credential '%s', ignoring: %m", cn);
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else
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*ret_is_hashed = false;
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} else if (r < 0)
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log_debug_errno(r, "Couldn't read credential '%s', ignoring: %m", cn);
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else
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*ret_is_hashed = true;
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*ret_password = TAKE_PTR(creds_password);
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return r;
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}
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#if HAVE_OPENSSL
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#define CREDENTIAL_HOST_SECRET_SIZE 4096
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static const sd_id128_t credential_app_id =
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SD_ID128_MAKE(d3,ac,ec,ba,0d,ad,4c,df,b8,c9,38,15,28,93,6c,58);
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struct credential_host_secret_format {
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/* The hashed machine ID of the machine this belongs to. Why? We want to ensure that each machine
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* gets its own secret, even if people forget to flush out this secret file. Hence we bind it to the
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* machine ID, for which there's hopefully a better chance it will be flushed out. We use a hashed
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* machine ID instead of the literal one, because it's trivial to, and it might be a good idea not
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* being able to directly associate a secret key file with a host. */
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sd_id128_t machine_id;
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/* The actual secret key */
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uint8_t data[CREDENTIAL_HOST_SECRET_SIZE];
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} _packed_;
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static void warn_not_encrypted(int fd, CredentialSecretFlags flags, const char *dirname, const char *filename) {
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int r;
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assert(fd >= 0);
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assert(dirname);
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assert(filename);
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if (!FLAGS_SET(flags, CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED))
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return;
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r = fd_is_encrypted(fd);
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if (r < 0)
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log_debug_errno(r, "Failed to determine if credential secret file '%s/%s' is encrypted.",
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dirname, filename);
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else if (r == 0)
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log_warning("Credential secret file '%s/%s' is not located on encrypted media, using anyway.",
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dirname, filename);
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}
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static int make_credential_host_secret(
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int dfd,
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const sd_id128_t machine_id,
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CredentialSecretFlags flags,
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const char *dirname,
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const char *fn,
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void **ret_data,
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size_t *ret_size) {
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struct credential_host_secret_format buf;
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_cleanup_free_ char *t = NULL;
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_cleanup_close_ int fd = -EBADF;
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int r;
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assert(dfd >= 0);
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assert(fn);
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fd = openat(dfd, ".", O_CLOEXEC|O_WRONLY|O_TMPFILE, 0400);
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if (fd < 0) {
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log_debug_errno(errno, "Failed to create temporary credential file with O_TMPFILE, proceeding without: %m");
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if (asprintf(&t, "credential.secret.%016" PRIx64, random_u64()) < 0)
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return -ENOMEM;
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fd = openat(dfd, t, O_CLOEXEC|O_WRONLY|O_CREAT|O_EXCL|O_NOFOLLOW, 0400);
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if (fd < 0)
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return -errno;
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}
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r = chattr_secret(fd, 0);
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if (r < 0)
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log_debug_errno(r, "Failed to set file attributes for secrets file, ignoring: %m");
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buf = (struct credential_host_secret_format) {
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.machine_id = machine_id,
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};
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r = crypto_random_bytes(buf.data, sizeof(buf.data));
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if (r < 0)
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goto finish;
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r = loop_write(fd, &buf, sizeof(buf), false);
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if (r < 0)
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goto finish;
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if (fsync(fd) < 0) {
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r = -errno;
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goto finish;
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}
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warn_not_encrypted(fd, flags, dirname, fn);
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if (t) {
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r = rename_noreplace(dfd, t, dfd, fn);
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if (r < 0)
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goto finish;
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t = mfree(t);
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} else if (linkat(fd, "", dfd, fn, AT_EMPTY_PATH) < 0) {
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r = -errno;
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goto finish;
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}
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if (fsync(dfd) < 0) {
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r = -errno;
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goto finish;
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}
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if (ret_data) {
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void *copy;
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copy = memdup(buf.data, sizeof(buf.data));
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if (!copy) {
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r = -ENOMEM;
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goto finish;
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}
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*ret_data = copy;
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}
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if (ret_size)
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*ret_size = sizeof(buf.data);
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r = 0;
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finish:
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if (t && unlinkat(dfd, t, 0) < 0)
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log_debug_errno(errno, "Failed to remove temporary credential key: %m");
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explicit_bzero_safe(&buf, sizeof(buf));
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return r;
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}
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int get_credential_host_secret(CredentialSecretFlags flags, void **ret, size_t *ret_size) {
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_cleanup_free_ char *_dirname = NULL, *_filename = NULL;
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_cleanup_close_ int dfd = -EBADF;
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sd_id128_t machine_id;
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const char *dirname, *filename;
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int r;
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r = sd_id128_get_machine_app_specific(credential_app_id, &machine_id);
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if (r < 0)
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return r;
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const char *e = secure_getenv("SYSTEMD_CREDENTIAL_SECRET");
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if (e) {
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if (!path_is_normalized(e))
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return -EINVAL;
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if (!path_is_absolute(e))
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return -EINVAL;
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r = path_extract_directory(e, &_dirname);
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if (r < 0)
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return r;
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r = path_extract_filename(e, &_filename);
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if (r < 0)
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return r;
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dirname = _dirname;
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filename = _filename;
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} else {
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dirname = "/var/lib/systemd";
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filename = "credential.secret";
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}
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mkdir_parents(dirname, 0755);
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dfd = open_mkdir_at(AT_FDCWD, dirname, O_CLOEXEC, 0755);
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if (dfd < 0)
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return log_debug_errno(dfd, "Failed to create or open directory '%s': %m", dirname);
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if (FLAGS_SET(flags, CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS)) {
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r = fd_is_temporary_fs(dfd);
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if (r < 0)
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return log_debug_errno(r, "Failed to check directory '%s': %m", dirname);
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if (r > 0)
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return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
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"Directory '%s' is on a temporary file system, refusing.", dirname);
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}
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for (unsigned attempt = 0;; attempt++) {
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_cleanup_(erase_and_freep) struct credential_host_secret_format *f = NULL;
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_cleanup_close_ int fd = -EBADF;
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size_t l = 0;
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ssize_t n = 0;
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struct stat st;
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if (attempt >= 3) /* Somebody is playing games with us */
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return log_debug_errno(SYNTHETIC_ERRNO(EIO),
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"All attempts to create secret store in %s failed.", dirname);
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fd = openat(dfd, filename, O_CLOEXEC|O_RDONLY|O_NOCTTY|O_NOFOLLOW);
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if (fd < 0) {
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if (errno != ENOENT || !FLAGS_SET(flags, CREDENTIAL_SECRET_GENERATE))
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return log_debug_errno(errno,
|
||
"Failed to open %s/%s: %m", dirname, filename);
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||
|
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|
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r = make_credential_host_secret(dfd, machine_id, flags, dirname, filename, ret, ret_size);
|
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if (r == -EEXIST) {
|
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log_debug_errno(r, "Credential secret %s/%s appeared while we were creating it, rereading.",
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dirname, filename);
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continue;
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}
|
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if (r < 0)
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return log_debug_errno(r, "Failed to create credential secret %s/%s: %m",
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dirname, filename);
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return 0;
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}
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if (fstat(fd, &st) < 0)
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return log_debug_errno(errno, "Failed to stat %s/%s: %m", dirname, filename);
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|
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r = stat_verify_regular(&st);
|
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if (r < 0)
|
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return log_debug_errno(r, "%s/%s is not a regular file: %m", dirname, filename);
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if (st.st_nlink == 0) /* Deleted by now, try again */
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continue;
|
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if (st.st_nlink > 1)
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/* Our deletion check won't work if hardlinked somewhere else */
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return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
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"%s/%s has too many links, refusing.",
|
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dirname, filename);
|
||
if ((st.st_mode & 07777) != 0400)
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/* Don't use file if not 0400 access mode */
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return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
|
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"%s/%s has permissive access mode, refusing.",
|
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dirname, filename);
|
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l = st.st_size;
|
||
if (l < offsetof(struct credential_host_secret_format, data) + 1)
|
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return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
|
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"%s/%s is too small, refusing.", dirname, filename);
|
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if (l > 16*1024*1024)
|
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return log_debug_errno(SYNTHETIC_ERRNO(E2BIG),
|
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"%s/%s is too big, refusing.", dirname, filename);
|
||
|
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f = malloc(l+1);
|
||
if (!f)
|
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return log_oom_debug();
|
||
|
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n = read(fd, f, l+1);
|
||
if (n < 0)
|
||
return log_debug_errno(errno,
|
||
"Failed to read %s/%s: %m", dirname, filename);
|
||
if ((size_t) n != l) /* What? The size changed? */
|
||
return log_debug_errno(SYNTHETIC_ERRNO(EIO),
|
||
"Failed to read %s/%s: %m", dirname, filename);
|
||
|
||
if (sd_id128_equal(machine_id, f->machine_id)) {
|
||
size_t sz;
|
||
|
||
warn_not_encrypted(fd, flags, dirname, filename);
|
||
|
||
sz = l - offsetof(struct credential_host_secret_format, data);
|
||
assert(sz > 0);
|
||
|
||
if (ret) {
|
||
void *copy;
|
||
|
||
assert(sz <= sizeof(f->data)); /* Ensure we don't read past f->data bounds */
|
||
|
||
copy = memdup(f->data, sz);
|
||
if (!copy)
|
||
return log_oom_debug();
|
||
|
||
*ret = copy;
|
||
}
|
||
|
||
if (ret_size)
|
||
*ret_size = sz;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Hmm, this secret is from somewhere else. Let's delete the file. Let's first acquire a lock
|
||
* to ensure we are the only ones accessing the file while we delete it. */
|
||
|
||
if (flock(fd, LOCK_EX) < 0)
|
||
return log_debug_errno(errno,
|
||
"Failed to flock %s/%s: %m", dirname, filename);
|
||
|
||
/* Before we delete it check that the file is still linked into the file system */
|
||
if (fstat(fd, &st) < 0)
|
||
return log_debug_errno(errno, "Failed to stat %s/%s: %m", dirname, filename);
|
||
if (st.st_nlink == 0) /* Already deleted by now? */
|
||
continue;
|
||
if (st.st_nlink != 1) /* Safety check, someone is playing games with us */
|
||
return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
|
||
"%s/%s unexpectedly has too many links.",
|
||
dirname, filename);
|
||
if (unlinkat(dfd, filename, 0) < 0)
|
||
return log_debug_errno(errno, "Failed to unlink %s/%s: %m", dirname, filename);
|
||
|
||
/* And now try again */
|
||
}
|
||
}
|
||
|
||
/* Construction is like this:
|
||
*
|
||
* A symmetric encryption key is derived from:
|
||
*
|
||
* 1. Either the "host" key (a key stored in /var/lib/credential.secret)
|
||
*
|
||
* 2. A key generated by letting the TPM2 calculate an HMAC hash of some nonce we pass to it, keyed
|
||
* by a key derived from its internal seed key.
|
||
*
|
||
* 3. The concatenation of the above.
|
||
*
|
||
* 4. Or a fixed "empty" key. This will not provide confidentiality or authenticity, of course, but is
|
||
* useful to encode credentials for the initrd on TPM-less systems, where we simply have no better
|
||
* concept to bind things to. Note that decryption of a key set up like this will be refused on
|
||
* systems that have a TPM and have SecureBoot enabled.
|
||
*
|
||
* The above is hashed with SHA256 which is then used as encryption key for AES256-GCM. The encrypted
|
||
* credential is a short (unencrypted) header describing which of the three keys to use, the IV to use for
|
||
* AES256-GCM and some more meta information (sizes of certain objects) that is strictly speaking redundant,
|
||
* but kinda nice to have since we can have a more generic parser. If the TPM2 key is used this is followed
|
||
* by another (unencrypted) header, with information about the TPM2 policy used (specifically: the PCR mask
|
||
* to bind against, and a hash of the resulting policy — the latter being redundant, but speeding up things a
|
||
* bit, since we can more quickly refuse PCR state), followed by a sealed/exported TPM2 HMAC key. This is
|
||
* then followed by the encrypted data, which begins with a metadata header (which contains validity
|
||
* timestamps as well as the credential name), followed by the actual credential payload. The file ends in
|
||
* the AES256-GCM tag. To make things simple, the AES256-GCM AAD covers the main and the TPM2 header in
|
||
* full. This means the whole file is either protected by AAD, or is ciphertext, or is the tag. No
|
||
* unprotected data is included.
|
||
*/
|
||
|
||
struct _packed_ encrypted_credential_header {
|
||
sd_id128_t id;
|
||
le32_t key_size;
|
||
le32_t block_size;
|
||
le32_t iv_size;
|
||
le32_t tag_size;
|
||
uint8_t iv[];
|
||
/* Followed by NUL bytes until next 8 byte boundary */
|
||
};
|
||
|
||
struct _packed_ tpm2_credential_header {
|
||
le64_t pcr_mask; /* Note that the spec for PC Clients only mandates 24 PCRs, and that's what systems
|
||
* generally have. But keep the door open for more. */
|
||
le16_t pcr_bank; /* For now, either TPM2_ALG_SHA256 or TPM2_ALG_SHA1 */
|
||
le16_t primary_alg; /* Primary key algorithm (either TPM2_ALG_RSA or TPM2_ALG_ECC for now) */
|
||
le32_t blob_size;
|
||
le32_t policy_hash_size;
|
||
uint8_t policy_hash_and_blob[];
|
||
/* Followed by NUL bytes until next 8 byte boundary */
|
||
};
|
||
|
||
struct _packed_ tpm2_public_key_credential_header {
|
||
le64_t pcr_mask; /* PCRs used for the public key PCR policy (usually just PCR 11, i.e. the unified kernel) */
|
||
le32_t size; /* Size of DER public key */
|
||
uint8_t data[]; /* DER public key */
|
||
/* Followed by NUL bytes until next 8 byte boundary */
|
||
};
|
||
|
||
struct _packed_ metadata_credential_header {
|
||
le64_t timestamp;
|
||
le64_t not_after;
|
||
le32_t name_size;
|
||
char name[];
|
||
/* Followed by NUL bytes until next 8 byte boundary */
|
||
};
|
||
|
||
/* Some generic limit for parts of the encrypted credential for which we don't know the right size ahead of
|
||
* time, but where we are really sure it won't be larger than this. Should be larger than any possible IV,
|
||
* padding, tag size and so on. This is purely used for early filtering out of invalid sizes. */
|
||
#define CREDENTIAL_FIELD_SIZE_MAX (16U*1024U)
|
||
|
||
static int sha256_hash_host_and_tpm2_key(
|
||
const void *host_key,
|
||
size_t host_key_size,
|
||
const void *tpm2_key,
|
||
size_t tpm2_key_size,
|
||
uint8_t ret[static SHA256_DIGEST_LENGTH]) {
|
||
|
||
_cleanup_(EVP_MD_CTX_freep) EVP_MD_CTX *md = NULL;
|
||
unsigned l;
|
||
|
||
assert(host_key_size == 0 || host_key);
|
||
assert(tpm2_key_size == 0 || tpm2_key);
|
||
assert(ret);
|
||
|
||
/* Combines the host key and the TPM2 HMAC hash into a SHA256 hash value we'll use as symmetric encryption key. */
|
||
|
||
md = EVP_MD_CTX_new();
|
||
if (!md)
|
||
return log_oom();
|
||
|
||
if (EVP_DigestInit_ex(md, EVP_sha256(), NULL) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initial SHA256 context.");
|
||
|
||
if (host_key && EVP_DigestUpdate(md, host_key, host_key_size) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to hash host key.");
|
||
|
||
if (tpm2_key && EVP_DigestUpdate(md, tpm2_key, tpm2_key_size) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to hash TPM2 key.");
|
||
|
||
assert(EVP_MD_CTX_size(md) == SHA256_DIGEST_LENGTH);
|
||
|
||
if (EVP_DigestFinal_ex(md, ret, &l) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finalize SHA256 hash.");
|
||
|
||
assert(l == SHA256_DIGEST_LENGTH);
|
||
return 0;
|
||
}
|
||
|
||
int encrypt_credential_and_warn(
|
||
sd_id128_t with_key,
|
||
const char *name,
|
||
usec_t timestamp,
|
||
usec_t not_after,
|
||
const char *tpm2_device,
|
||
uint32_t tpm2_hash_pcr_mask,
|
||
const char *tpm2_pubkey_path,
|
||
uint32_t tpm2_pubkey_pcr_mask,
|
||
const void *input,
|
||
size_t input_size,
|
||
void **ret,
|
||
size_t *ret_size) {
|
||
|
||
_cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
|
||
_cleanup_(erase_and_freep) void *host_key = NULL, *tpm2_key = NULL;
|
||
size_t host_key_size = 0, tpm2_key_size = 0, tpm2_blob_size = 0, tpm2_policy_hash_size = 0, output_size, p, ml;
|
||
_cleanup_free_ void *tpm2_blob = NULL, *tpm2_policy_hash = NULL, *iv = NULL, *output = NULL;
|
||
_cleanup_free_ struct metadata_credential_header *m = NULL;
|
||
uint16_t tpm2_pcr_bank = 0, tpm2_primary_alg = 0;
|
||
struct encrypted_credential_header *h;
|
||
int ksz, bsz, ivsz, tsz, added, r;
|
||
_cleanup_free_ void *pubkey = NULL;
|
||
size_t pubkey_size = 0;
|
||
uint8_t md[SHA256_DIGEST_LENGTH];
|
||
const EVP_CIPHER *cc;
|
||
sd_id128_t id;
|
||
|
||
assert(input || input_size == 0);
|
||
assert(ret);
|
||
assert(ret_size);
|
||
|
||
if (!sd_id128_in_set(with_key,
|
||
_CRED_AUTO,
|
||
_CRED_AUTO_INITRD,
|
||
CRED_AES256_GCM_BY_HOST,
|
||
CRED_AES256_GCM_BY_TPM2_HMAC,
|
||
CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK,
|
||
CRED_AES256_GCM_BY_TPM2_ABSENT))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid key type: " SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(with_key));
|
||
|
||
if (name && !credential_name_valid(name))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid credential name: %s", name);
|
||
|
||
if (not_after != USEC_INFINITY && timestamp != USEC_INFINITY && not_after < timestamp)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Credential is invalidated before it is valid (" USEC_FMT " < " USEC_FMT ").", not_after, timestamp);
|
||
|
||
if (DEBUG_LOGGING) {
|
||
char buf[FORMAT_TIMESTAMP_MAX];
|
||
|
||
if (name)
|
||
log_debug("Including credential name '%s' in encrypted credential.", name);
|
||
if (timestamp != USEC_INFINITY)
|
||
log_debug("Including timestamp '%s' in encrypted credential.", format_timestamp(buf, sizeof(buf), timestamp));
|
||
if (not_after != USEC_INFINITY)
|
||
log_debug("Including not-after timestamp '%s' in encrypted credential.", format_timestamp(buf, sizeof(buf), not_after));
|
||
}
|
||
|
||
if (sd_id128_in_set(with_key,
|
||
_CRED_AUTO,
|
||
CRED_AES256_GCM_BY_HOST,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK)) {
|
||
|
||
r = get_credential_host_secret(
|
||
CREDENTIAL_SECRET_GENERATE|
|
||
CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED|
|
||
(sd_id128_equal(with_key, _CRED_AUTO) ? CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS : 0),
|
||
&host_key,
|
||
&host_key_size);
|
||
if (r == -ENOMEDIUM && sd_id128_equal(with_key, _CRED_AUTO))
|
||
log_debug_errno(r, "Credential host secret location on temporary file system, not using.");
|
||
else if (r < 0)
|
||
return log_error_errno(r, "Failed to determine local credential host secret: %m");
|
||
}
|
||
|
||
#if HAVE_TPM2
|
||
bool try_tpm2;
|
||
if (sd_id128_equal(with_key, _CRED_AUTO)) {
|
||
/* If automatic mode is selected and we are running in a container, let's not try TPM2. OTOH
|
||
* if user picks TPM2 explicitly, let's always honour the request and try. */
|
||
|
||
r = detect_container();
|
||
if (r < 0)
|
||
log_debug_errno(r, "Failed to determine whether we are running in a container, ignoring: %m");
|
||
else if (r > 0)
|
||
log_debug("Running in container, not attempting to use TPM2.");
|
||
|
||
try_tpm2 = r <= 0;
|
||
} else if (sd_id128_equal(with_key, _CRED_AUTO_INITRD)) {
|
||
/* If automatic mode for initrds is selected, we'll use the TPM2 key if the firmware does it,
|
||
* otherwise we'll use a fixed key */
|
||
|
||
try_tpm2 = efi_has_tpm2();
|
||
if (!try_tpm2)
|
||
log_debug("Firmware lacks TPM2 support, not attempting to use TPM2.");
|
||
} else
|
||
try_tpm2 = sd_id128_in_set(with_key,
|
||
CRED_AES256_GCM_BY_TPM2_HMAC,
|
||
CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK);
|
||
|
||
if (try_tpm2) {
|
||
if (sd_id128_in_set(with_key,
|
||
_CRED_AUTO,
|
||
_CRED_AUTO_INITRD,
|
||
CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK,
|
||
CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK)) {
|
||
|
||
/* Load public key for PCR policies, if one is specified, or explicitly requested */
|
||
|
||
r = tpm2_load_pcr_public_key(tpm2_pubkey_path, &pubkey, &pubkey_size);
|
||
if (r < 0) {
|
||
if (tpm2_pubkey_path || r != -ENOENT || !sd_id128_in_set(with_key, _CRED_AUTO, _CRED_AUTO_INITRD))
|
||
return log_error_errno(r, "Failed read TPM PCR public key: %m");
|
||
|
||
log_debug_errno(r, "Failed to read TPM2 PCR public key, proceeding without: %m");
|
||
}
|
||
}
|
||
|
||
if (!pubkey)
|
||
tpm2_pubkey_pcr_mask = 0;
|
||
|
||
r = tpm2_seal(tpm2_device,
|
||
tpm2_hash_pcr_mask,
|
||
pubkey, pubkey_size,
|
||
tpm2_pubkey_pcr_mask,
|
||
/* pin= */ NULL,
|
||
&tpm2_key, &tpm2_key_size,
|
||
&tpm2_blob, &tpm2_blob_size,
|
||
&tpm2_policy_hash, &tpm2_policy_hash_size,
|
||
&tpm2_pcr_bank,
|
||
&tpm2_primary_alg);
|
||
if (r < 0) {
|
||
if (sd_id128_equal(with_key, _CRED_AUTO_INITRD))
|
||
log_warning("Firmware reported a TPM2 being present and used, but we didn't manage to talk to it. Credential will be refused if SecureBoot is enabled.");
|
||
else if (!sd_id128_equal(with_key, _CRED_AUTO))
|
||
return r;
|
||
|
||
log_notice_errno(r, "TPM2 sealing didn't work, continuing without TPM2: %m");
|
||
}
|
||
|
||
assert(tpm2_blob_size <= CREDENTIAL_FIELD_SIZE_MAX);
|
||
assert(tpm2_policy_hash_size <= CREDENTIAL_FIELD_SIZE_MAX);
|
||
}
|
||
#endif
|
||
|
||
if (sd_id128_in_set(with_key, _CRED_AUTO, _CRED_AUTO_INITRD)) {
|
||
/* Let's settle the key type in auto mode now. */
|
||
|
||
if (host_key && tpm2_key)
|
||
id = pubkey ? CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK : CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC;
|
||
else if (tpm2_key)
|
||
id = pubkey ? CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK : CRED_AES256_GCM_BY_TPM2_HMAC;
|
||
else if (host_key)
|
||
id = CRED_AES256_GCM_BY_HOST;
|
||
else if (sd_id128_equal(with_key, _CRED_AUTO_INITRD))
|
||
id = CRED_AES256_GCM_BY_TPM2_ABSENT;
|
||
else
|
||
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
|
||
"TPM2 not available and host key located on temporary file system, no encryption key available.");
|
||
} else
|
||
id = with_key;
|
||
|
||
if (sd_id128_equal(id, CRED_AES256_GCM_BY_TPM2_ABSENT))
|
||
log_warning("Using a null key for encryption and signing. Confidentiality or authenticity will not be provided.");
|
||
|
||
/* Let's now take the host key and the TPM2 key and hash it together, to use as encryption key for the data */
|
||
r = sha256_hash_host_and_tpm2_key(host_key, host_key_size, tpm2_key, tpm2_key_size, md);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
assert_se(cc = EVP_aes_256_gcm());
|
||
|
||
ksz = EVP_CIPHER_key_length(cc);
|
||
assert(ksz == sizeof(md));
|
||
|
||
bsz = EVP_CIPHER_block_size(cc);
|
||
assert(bsz > 0);
|
||
assert((size_t) bsz <= CREDENTIAL_FIELD_SIZE_MAX);
|
||
|
||
ivsz = EVP_CIPHER_iv_length(cc);
|
||
if (ivsz > 0) {
|
||
assert((size_t) ivsz <= CREDENTIAL_FIELD_SIZE_MAX);
|
||
|
||
iv = malloc(ivsz);
|
||
if (!iv)
|
||
return log_oom();
|
||
|
||
r = crypto_random_bytes(iv, ivsz);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to acquired randomized IV: %m");
|
||
}
|
||
|
||
tsz = 16; /* FIXME: On OpenSSL 3 there is EVP_CIPHER_CTX_get_tag_length(), until then let's hardcode this */
|
||
|
||
context = EVP_CIPHER_CTX_new();
|
||
if (!context)
|
||
return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to allocate encryption object: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_EncryptInit_ex(context, cc, NULL, md, iv) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize encryption context: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
/* Just an upper estimate */
|
||
output_size =
|
||
ALIGN8(offsetof(struct encrypted_credential_header, iv) + ivsz) +
|
||
ALIGN8(tpm2_key ? offsetof(struct tpm2_credential_header, policy_hash_and_blob) + tpm2_blob_size + tpm2_policy_hash_size : 0) +
|
||
ALIGN8(pubkey ? offsetof(struct tpm2_public_key_credential_header, data) + pubkey_size : 0) +
|
||
ALIGN8(offsetof(struct metadata_credential_header, name) + strlen_ptr(name)) +
|
||
input_size + 2U * (size_t) bsz +
|
||
tsz;
|
||
|
||
output = malloc0(output_size);
|
||
if (!output)
|
||
return log_oom();
|
||
|
||
h = (struct encrypted_credential_header*) output;
|
||
h->id = id;
|
||
h->block_size = htole32(bsz);
|
||
h->key_size = htole32(ksz);
|
||
h->tag_size = htole32(tsz);
|
||
h->iv_size = htole32(ivsz);
|
||
memcpy(h->iv, iv, ivsz);
|
||
|
||
p = ALIGN8(offsetof(struct encrypted_credential_header, iv) + ivsz);
|
||
|
||
if (tpm2_key) {
|
||
struct tpm2_credential_header *t;
|
||
|
||
t = (struct tpm2_credential_header*) ((uint8_t*) output + p);
|
||
t->pcr_mask = htole64(tpm2_hash_pcr_mask);
|
||
t->pcr_bank = htole16(tpm2_pcr_bank);
|
||
t->primary_alg = htole16(tpm2_primary_alg);
|
||
t->blob_size = htole32(tpm2_blob_size);
|
||
t->policy_hash_size = htole32(tpm2_policy_hash_size);
|
||
memcpy(t->policy_hash_and_blob, tpm2_blob, tpm2_blob_size);
|
||
memcpy(t->policy_hash_and_blob + tpm2_blob_size, tpm2_policy_hash, tpm2_policy_hash_size);
|
||
|
||
p += ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) + tpm2_blob_size + tpm2_policy_hash_size);
|
||
}
|
||
|
||
if (pubkey) {
|
||
struct tpm2_public_key_credential_header *z;
|
||
|
||
z = (struct tpm2_public_key_credential_header*) ((uint8_t*) output + p);
|
||
z->pcr_mask = htole64(tpm2_pubkey_pcr_mask);
|
||
z->size = htole32(pubkey_size);
|
||
memcpy(z->data, pubkey, pubkey_size);
|
||
|
||
p += ALIGN8(offsetof(struct tpm2_public_key_credential_header, data) + pubkey_size);
|
||
}
|
||
|
||
/* Pass the encrypted + TPM2 header as AAD */
|
||
if (EVP_EncryptUpdate(context, NULL, &added, output, p) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to write AAD data: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
/* Now construct the metadata header */
|
||
ml = strlen_ptr(name);
|
||
m = malloc0(ALIGN8(offsetof(struct metadata_credential_header, name) + ml));
|
||
if (!m)
|
||
return log_oom();
|
||
|
||
m->timestamp = htole64(timestamp);
|
||
m->not_after = htole64(not_after);
|
||
m->name_size = htole32(ml);
|
||
memcpy_safe(m->name, name, ml);
|
||
|
||
/* And encrypt the metadata header */
|
||
if (EVP_EncryptUpdate(context, (uint8_t*) output + p, &added, (const unsigned char*) m, ALIGN8(offsetof(struct metadata_credential_header, name) + ml)) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt metadata header: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
assert(added >= 0);
|
||
assert((size_t) added <= output_size - p);
|
||
p += added;
|
||
|
||
/* Then encrypt the plaintext */
|
||
if (EVP_EncryptUpdate(context, (uint8_t*) output + p, &added, input, input_size) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt data: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
assert(added >= 0);
|
||
assert((size_t) added <= output_size - p);
|
||
p += added;
|
||
|
||
/* Finalize */
|
||
if (EVP_EncryptFinal_ex(context, (uint8_t*) output + p, &added) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finalize data encryption: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
assert(added >= 0);
|
||
assert((size_t) added <= output_size - p);
|
||
p += added;
|
||
|
||
assert(p <= output_size - tsz);
|
||
|
||
/* Append tag */
|
||
if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_GET_TAG, tsz, (uint8_t*) output + p) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to get tag: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
p += tsz;
|
||
assert(p <= output_size);
|
||
|
||
if (DEBUG_LOGGING && input_size > 0) {
|
||
size_t base64_size;
|
||
|
||
base64_size = DIV_ROUND_UP(p * 4, 3); /* Include base64 size increase in debug output */
|
||
assert(base64_size >= input_size);
|
||
log_debug("Input of %zu bytes grew to output of %zu bytes (+%2zu%%).", input_size, base64_size, base64_size * 100 / input_size - 100);
|
||
}
|
||
|
||
*ret = TAKE_PTR(output);
|
||
*ret_size = p;
|
||
|
||
return 0;
|
||
}
|
||
|
||
int decrypt_credential_and_warn(
|
||
const char *validate_name,
|
||
usec_t validate_timestamp,
|
||
const char *tpm2_device,
|
||
const char *tpm2_signature_path,
|
||
const void *input,
|
||
size_t input_size,
|
||
void **ret,
|
||
size_t *ret_size) {
|
||
|
||
_cleanup_(erase_and_freep) void *host_key = NULL, *tpm2_key = NULL, *plaintext = NULL;
|
||
_cleanup_(json_variant_unrefp) JsonVariant *signature_json = NULL;
|
||
_cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
|
||
size_t host_key_size = 0, tpm2_key_size = 0, plaintext_size, p, hs;
|
||
struct encrypted_credential_header *h;
|
||
struct metadata_credential_header *m;
|
||
uint8_t md[SHA256_DIGEST_LENGTH];
|
||
bool with_tpm2, with_host_key, is_tpm2_absent, with_tpm2_pk;
|
||
const EVP_CIPHER *cc;
|
||
int r, added;
|
||
|
||
assert(input || input_size == 0);
|
||
assert(ret);
|
||
assert(ret_size);
|
||
|
||
h = (struct encrypted_credential_header*) input;
|
||
|
||
/* The ID must fit in, for the current and all future formats */
|
||
if (input_size < sizeof(h->id))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
|
||
|
||
with_host_key = sd_id128_in_set(h->id, CRED_AES256_GCM_BY_HOST, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK);
|
||
with_tpm2_pk = sd_id128_in_set(h->id, CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK);
|
||
with_tpm2 = sd_id128_in_set(h->id, CRED_AES256_GCM_BY_TPM2_HMAC, CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC) || with_tpm2_pk;
|
||
is_tpm2_absent = sd_id128_equal(h->id, CRED_AES256_GCM_BY_TPM2_ABSENT);
|
||
|
||
if (!with_host_key && !with_tpm2 && !is_tpm2_absent)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Unknown encryption format, or corrupted data: %m");
|
||
|
||
if (with_tpm2_pk) {
|
||
r = tpm2_load_pcr_signature(tpm2_signature_path, &signature_json);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
if (is_tpm2_absent) {
|
||
/* So this is a credential encrypted with a zero length key. We support this to cover for the
|
||
* case where neither a host key not a TPM2 are available (specifically: initrd environments
|
||
* where the host key is not yet accessible and no TPM2 chip exists at all), to minimize
|
||
* different codeflow for TPM2 and non-TPM2 codepaths. Of course, credentials encoded this
|
||
* way offer no confidentiality nor authenticity. Because of that it's important we refuse to
|
||
* use them on systems that actually *do* have a TPM2 chip – if we are in SecureBoot
|
||
* mode. Otherwise an attacker could hand us credentials like this and we'd use them thinking
|
||
* they are trusted, even though they are not. */
|
||
|
||
if (efi_has_tpm2()) {
|
||
if (is_efi_secure_boot())
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
|
||
"Credential uses fixed key for fallback use when TPM2 is absent — but TPM2 is present, and SecureBoot is enabled, refusing.");
|
||
|
||
log_warning("Credential uses fixed key for use when TPM2 is absent, but TPM2 is present! Accepting anyway, since SecureBoot is disabled.");
|
||
} else
|
||
log_debug("Credential uses fixed key for use when TPM2 is absent, and TPM2 indeed is absent. Accepting.");
|
||
}
|
||
|
||
/* Now we know the minimum header size */
|
||
if (input_size < offsetof(struct encrypted_credential_header, iv))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
|
||
|
||
/* Verify some basic header values */
|
||
if (le32toh(h->key_size) != sizeof(md))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected key size in header.");
|
||
if (le32toh(h->block_size) <= 0 || le32toh(h->block_size) > CREDENTIAL_FIELD_SIZE_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected block size in header.");
|
||
if (le32toh(h->iv_size) > CREDENTIAL_FIELD_SIZE_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "IV size too large.");
|
||
if (le32toh(h->tag_size) != 16) /* FIXME: On OpenSSL 3, let's verify via EVP_CIPHER_CTX_get_tag_length() */
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected tag size in header.");
|
||
|
||
/* Ensure we have space for the full header now (we don't know the size of the name hence this is a
|
||
* lower limit only) */
|
||
if (input_size <
|
||
ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size)) +
|
||
ALIGN8(with_tpm2 ? offsetof(struct tpm2_credential_header, policy_hash_and_blob) : 0) +
|
||
ALIGN8(with_tpm2_pk ? offsetof(struct tpm2_public_key_credential_header, data) : 0) +
|
||
ALIGN8(offsetof(struct metadata_credential_header, name)) +
|
||
le32toh(h->tag_size))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
|
||
|
||
p = ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size));
|
||
|
||
if (with_tpm2) {
|
||
#if HAVE_TPM2
|
||
struct tpm2_credential_header* t = (struct tpm2_credential_header*) ((uint8_t*) input + p);
|
||
struct tpm2_public_key_credential_header *z = NULL;
|
||
|
||
if (!TPM2_PCR_MASK_VALID(t->pcr_mask))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 PCR mask out of range.");
|
||
if (!tpm2_pcr_bank_to_string(le16toh(t->pcr_bank)))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 PCR bank invalid or not supported");
|
||
if (!tpm2_primary_alg_to_string(le16toh(t->primary_alg)))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 primary key algorithm invalid or not supported.");
|
||
if (le32toh(t->blob_size) > CREDENTIAL_FIELD_SIZE_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected TPM2 blob size.");
|
||
if (le32toh(t->policy_hash_size) > CREDENTIAL_FIELD_SIZE_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected TPM2 policy hash size.");
|
||
|
||
/* Ensure we have space for the full TPM2 header now (still don't know the name, and its size
|
||
* though, hence still just a lower limit test only) */
|
||
if (input_size <
|
||
ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size)) +
|
||
ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) + le32toh(t->blob_size) + le32toh(t->policy_hash_size)) +
|
||
ALIGN8(with_tpm2_pk ? offsetof(struct tpm2_public_key_credential_header, data) : 0) +
|
||
ALIGN8(offsetof(struct metadata_credential_header, name)) +
|
||
le32toh(h->tag_size))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
|
||
|
||
p += ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) +
|
||
le32toh(t->blob_size) +
|
||
le32toh(t->policy_hash_size));
|
||
|
||
if (with_tpm2_pk) {
|
||
z = (struct tpm2_public_key_credential_header*) ((uint8_t*) input + p);
|
||
|
||
if (!TPM2_PCR_MASK_VALID(le64toh(z->pcr_mask)) || le64toh(z->pcr_mask) == 0)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "TPM2 PCR mask out of range.");
|
||
if (le32toh(z->size) > PUBLIC_KEY_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected public key size.");
|
||
|
||
if (input_size <
|
||
ALIGN8(offsetof(struct encrypted_credential_header, iv) + le32toh(h->iv_size)) +
|
||
ALIGN8(offsetof(struct tpm2_credential_header, policy_hash_and_blob) + le32toh(t->blob_size) + le32toh(t->policy_hash_size)) +
|
||
ALIGN8(offsetof(struct tpm2_public_key_credential_header, data) + le32toh(z->size)) +
|
||
ALIGN8(offsetof(struct metadata_credential_header, name)) +
|
||
le32toh(h->tag_size))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Encrypted file too short.");
|
||
|
||
p += ALIGN8(offsetof(struct tpm2_public_key_credential_header, data) +
|
||
le32toh(z->size));
|
||
}
|
||
|
||
r = tpm2_unseal(tpm2_device,
|
||
le64toh(t->pcr_mask),
|
||
le16toh(t->pcr_bank),
|
||
z ? z->data : NULL,
|
||
z ? le32toh(z->size) : 0,
|
||
z ? le64toh(z->pcr_mask) : 0,
|
||
signature_json,
|
||
/* pin= */ NULL,
|
||
le16toh(t->primary_alg),
|
||
t->policy_hash_and_blob,
|
||
le32toh(t->blob_size),
|
||
t->policy_hash_and_blob + le32toh(t->blob_size),
|
||
le32toh(t->policy_hash_size),
|
||
&tpm2_key,
|
||
&tpm2_key_size);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
#else
|
||
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Credential requires TPM2 support, but TPM2 support not available.");
|
||
#endif
|
||
}
|
||
|
||
if (with_host_key) {
|
||
r = get_credential_host_secret(
|
||
0,
|
||
&host_key,
|
||
&host_key_size);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine local credential key: %m");
|
||
}
|
||
|
||
if (is_tpm2_absent)
|
||
log_warning("Warning: using a null key for decryption and authentication. Confidentiality or authenticity are not provided.");
|
||
|
||
sha256_hash_host_and_tpm2_key(host_key, host_key_size, tpm2_key, tpm2_key_size, md);
|
||
|
||
assert_se(cc = EVP_aes_256_gcm());
|
||
|
||
/* Make sure cipher expectations match the header */
|
||
if (EVP_CIPHER_key_length(cc) != (int) le32toh(h->key_size))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected key size in header.");
|
||
if (EVP_CIPHER_block_size(cc) != (int) le32toh(h->block_size))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Unexpected block size in header.");
|
||
|
||
context = EVP_CIPHER_CTX_new();
|
||
if (!context)
|
||
return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to allocate decryption object: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_DecryptInit_ex(context, cc, NULL, NULL, NULL) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize decryption context: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_SET_IVLEN, le32toh(h->iv_size), NULL) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set IV size on decryption context: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_DecryptInit_ex(context, NULL, NULL, md, h->iv) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set IV and key: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_DecryptUpdate(context, NULL, &added, input, p) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to write AAD data: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
plaintext = malloc(input_size - p - le32toh(h->tag_size));
|
||
if (!plaintext)
|
||
return -ENOMEM;
|
||
|
||
if (EVP_DecryptUpdate(
|
||
context,
|
||
plaintext,
|
||
&added,
|
||
(uint8_t*) input + p,
|
||
input_size - p - le32toh(h->tag_size)) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to decrypt data: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
assert(added >= 0);
|
||
assert((size_t) added <= input_size - p - le32toh(h->tag_size));
|
||
plaintext_size = added;
|
||
|
||
if (EVP_CIPHER_CTX_ctrl(context, EVP_CTRL_GCM_SET_TAG, le32toh(h->tag_size), (uint8_t*) input + input_size - le32toh(h->tag_size)) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set tag: %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
if (EVP_DecryptFinal_ex(context, (uint8_t*) plaintext + plaintext_size, &added) != 1)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Decryption failed (incorrect key?): %s",
|
||
ERR_error_string(ERR_get_error(), NULL));
|
||
|
||
plaintext_size += added;
|
||
|
||
if (plaintext_size < ALIGN8(offsetof(struct metadata_credential_header, name)))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Metadata header incomplete.");
|
||
|
||
m = plaintext;
|
||
|
||
if (le64toh(m->timestamp) != USEC_INFINITY &&
|
||
le64toh(m->not_after) != USEC_INFINITY &&
|
||
le64toh(m->timestamp) >= le64toh(m->not_after))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Timestamps of credential are not in order, refusing.");
|
||
|
||
if (le32toh(m->name_size) > CREDENTIAL_NAME_MAX)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name too long, refusing.");
|
||
|
||
hs = ALIGN8(offsetof(struct metadata_credential_header, name) + le32toh(m->name_size));
|
||
if (plaintext_size < hs)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Metadata header incomplete.");
|
||
|
||
if (le32toh(m->name_size) > 0) {
|
||
_cleanup_free_ char *embedded_name = NULL;
|
||
|
||
if (memchr(m->name, 0, le32toh(m->name_size)))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name contains NUL byte, refusing.");
|
||
|
||
embedded_name = memdup_suffix0(m->name, le32toh(m->name_size));
|
||
if (!embedded_name)
|
||
return log_oom();
|
||
|
||
if (!credential_name_valid(embedded_name))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Embedded credential name is not valid, refusing.");
|
||
|
||
if (validate_name && !streq(embedded_name, validate_name)) {
|
||
|
||
r = getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NAME");
|
||
if (r < 0 && r != -ENXIO)
|
||
log_debug_errno(r, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NAME: %m");
|
||
if (r != 0)
|
||
return log_error_errno(SYNTHETIC_ERRNO(EREMOTE), "Embedded credential name '%s' does not match filename '%s', refusing.", embedded_name, validate_name);
|
||
|
||
log_debug("Embedded credential name '%s' does not match expected name '%s', but configured to use credential anyway.", embedded_name, validate_name);
|
||
}
|
||
}
|
||
|
||
if (validate_timestamp != USEC_INFINITY) {
|
||
if (le64toh(m->timestamp) != USEC_INFINITY && le64toh(m->timestamp) > validate_timestamp)
|
||
log_debug("Credential timestamp is from the future, assuming clock skew.");
|
||
|
||
if (le64toh(m->not_after) != USEC_INFINITY && le64toh(m->not_after) < validate_timestamp) {
|
||
|
||
r = getenv_bool_secure("SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER");
|
||
if (r < 0 && r != -ENXIO)
|
||
log_debug_errno(r, "Failed to parse $SYSTEMD_CREDENTIAL_VALIDATE_NOT_AFTER: %m");
|
||
if (r != 0)
|
||
return log_error_errno(SYNTHETIC_ERRNO(ESTALE), "Credential's time passed, refusing to use.");
|
||
|
||
log_debug("Credential not-after timestamp has passed, but configured to use credential anyway.");
|
||
}
|
||
}
|
||
|
||
if (ret) {
|
||
char *without_metadata;
|
||
|
||
without_metadata = memdup((uint8_t*) plaintext + hs, plaintext_size - hs);
|
||
if (!without_metadata)
|
||
return log_oom();
|
||
|
||
*ret = without_metadata;
|
||
}
|
||
|
||
if (ret_size)
|
||
*ret_size = plaintext_size - hs;
|
||
|
||
return 0;
|
||
}
|
||
|
||
#else
|
||
|
||
int get_credential_host_secret(CredentialSecretFlags flags, void **ret, size_t *ret_size) {
|
||
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
|
||
}
|
||
|
||
int encrypt_credential_and_warn(sd_id128_t with_key, const char *name, usec_t timestamp, usec_t not_after, const char *tpm2_device, uint32_t tpm2_hash_pcr_mask, const char *tpm2_pubkey_path, uint32_t tpm2_pubkey_pcr_mask, const void *input, size_t input_size, void **ret, size_t *ret_size) {
|
||
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
|
||
}
|
||
|
||
int decrypt_credential_and_warn(const char *validate_name, usec_t validate_timestamp, const char *tpm2_device, const char *tpm2_signature_path, const void *input, size_t input_size, void **ret, size_t *ret_size) {
|
||
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Support for encrypted credentials not available.");
|
||
}
|
||
|
||
#endif
|