diff options
Diffstat (limited to 'src/cryptsetup/cryptsetup-pkcs11.c')
| -rw-r--r-- | src/cryptsetup/cryptsetup-pkcs11.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/src/cryptsetup/cryptsetup-pkcs11.c b/src/cryptsetup/cryptsetup-pkcs11.c new file mode 100644 index 0000000..f991389 --- /dev/null +++ b/src/cryptsetup/cryptsetup-pkcs11.c @@ -0,0 +1,173 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <fcntl.h> +#include <unistd.h> +#include <sys/stat.h> + +#include <p11-kit/p11-kit.h> +#include <p11-kit/uri.h> + +#include "alloc-util.h" +#include "ask-password-api.h" +#include "cryptsetup-pkcs11.h" +#include "escape.h" +#include "fd-util.h" +#include "fileio.h" +#include "format-util.h" +#include "hexdecoct.h" +#include "json.h" +#include "macro.h" +#include "memory-util.h" +#include "parse-util.h" +#include "pkcs11-util.h" +#include "random-util.h" +#include "stat-util.h" +#include "strv.h" + +int decrypt_pkcs11_key( + const char *volume_name, + const char *friendly_name, + const char *pkcs11_uri, + const char *key_file, /* We either expect key_file and associated parameters to be set (for file keys) … */ + size_t key_file_size, + uint64_t key_file_offset, + const void *key_data, /* … or key_data and key_data_size (for literal keys) */ + size_t key_data_size, + usec_t until, + bool headless, + void **ret_decrypted_key, + size_t *ret_decrypted_key_size) { + + _cleanup_(pkcs11_crypt_device_callback_data_release) pkcs11_crypt_device_callback_data data = { + .friendly_name = friendly_name, + .until = until, + .headless = headless, + }; + int r; + + assert(friendly_name); + assert(pkcs11_uri); + assert(key_file || key_data); + assert(ret_decrypted_key); + assert(ret_decrypted_key_size); + + /* The functions called here log about all errors, except for EAGAIN which means "token not found right now" */ + + if (key_data) { + data.encrypted_key = (void*) key_data; + data.encrypted_key_size = key_data_size; + + data.free_encrypted_key = false; + } else { + _cleanup_free_ char *bindname = NULL; + + /* If we read the key via AF_UNIX, make this client recognizable */ + if (asprintf(&bindname, "@%" PRIx64"/cryptsetup-pkcs11/%s", random_u64(), volume_name) < 0) + return log_oom(); + + r = read_full_file_full( + AT_FDCWD, key_file, + key_file_offset == 0 ? UINT64_MAX : key_file_offset, + key_file_size == 0 ? SIZE_MAX : key_file_size, + READ_FULL_FILE_CONNECT_SOCKET, + bindname, + (char**) &data.encrypted_key, &data.encrypted_key_size); + if (r < 0) + return r; + + data.free_encrypted_key = true; + } + + r = pkcs11_find_token(pkcs11_uri, pkcs11_crypt_device_callback, &data); + if (r < 0) + return r; + + *ret_decrypted_key = TAKE_PTR(data.decrypted_key); + *ret_decrypted_key_size = data.decrypted_key_size; + + return 0; +} + +int find_pkcs11_auto_data( + struct crypt_device *cd, + char **ret_uri, + void **ret_encrypted_key, + size_t *ret_encrypted_key_size, + int *ret_keyslot) { + + _cleanup_free_ char *uri = NULL; + _cleanup_free_ void *key = NULL; + int r, keyslot = -1; + size_t key_size = 0; + + assert(cd); + assert(ret_uri); + assert(ret_encrypted_key); + assert(ret_encrypted_key_size); + assert(ret_keyslot); + + /* Loads PKCS#11 metadata from LUKS2 JSON token headers. */ + + for (int token = 0; token < sym_crypt_token_max(CRYPT_LUKS2); token++) { + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + JsonVariant *w; + int ks; + + r = cryptsetup_get_token_as_json(cd, token, "systemd-pkcs11", &v); + if (IN_SET(r, -ENOENT, -EINVAL, -EMEDIUMTYPE)) + continue; + if (r < 0) + return log_error_errno(r, "Failed to read JSON token data off disk: %m"); + + ks = cryptsetup_get_keyslot_from_token(v); + if (ks < 0) { + /* Handle parsing errors of the keyslots field gracefully, since it's not 'owned' by + * us, but by the LUKS2 spec */ + log_warning_errno(ks, "Failed to extract keyslot index from PKCS#11 JSON data token %i, skipping: %m", token); + continue; + } + + if (uri) + return log_error_errno(SYNTHETIC_ERRNO(ENOTUNIQ), + "Multiple PKCS#11 tokens enrolled, cannot automatically determine token."); + + assert(keyslot < 0); + keyslot = ks; + + w = json_variant_by_key(v, "pkcs11-uri"); + if (!w || !json_variant_is_string(w)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "PKCS#11 token data lacks 'pkcs11-uri' field."); + + uri = strdup(json_variant_string(w)); + if (!uri) + return log_oom(); + + if (!pkcs11_uri_valid(uri)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "PKCS#11 token data contains invalid PKCS#11 URI."); + + w = json_variant_by_key(v, "pkcs11-key"); + if (!w || !json_variant_is_string(w)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "PKCS#11 token data lacks 'pkcs11-key' field."); + + assert(!key); + assert(key_size == 0); + r = unbase64mem(json_variant_string(w), SIZE_MAX, &key, &key_size); + if (r < 0) + return log_error_errno(r, "Failed to decode base64 encoded key."); + } + + if (!uri) + return log_error_errno(SYNTHETIC_ERRNO(ENXIO), + "No valid PKCS#11 token data found."); + + log_info("Automatically discovered security PKCS#11 token '%s' unlocks volume.", uri); + + *ret_uri = TAKE_PTR(uri); + *ret_encrypted_key = TAKE_PTR(key); + *ret_encrypted_key_size = key_size; + *ret_keyslot = keyslot; + return 0; +} |