efi_signature_parse_sigdb() is a helper function will be used to parse signature database variable and instantiate a signature store structure in later patches.
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- include/efi_loader.h | 3 + lib/efi_loader/efi_signature.c | 226 +++++++++++++++++++++++++++++++++ 2 files changed, 229 insertions(+)
diff --git a/include/efi_loader.h b/include/efi_loader.h index 3ca68f9bbb6e..3b3618e0be24 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -720,6 +720,9 @@ bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, efi_status_t efi_image_region_add(struct efi_image_regions *regs, const void *start, const void *end, int nocheck); + +void efi_sigstore_free(struct efi_signature_store *sigstore); +struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name); #endif /* CONFIG_EFI_SECURE_BOOT */
#else /* CONFIG_IS_ENABLED(EFI_LOADER) */ diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c index 823d3311e010..98302e1ab3d3 100644 --- a/lib/efi_loader/efi_signature.c +++ b/lib/efi_loader/efi_signature.c @@ -581,4 +581,230 @@ efi_status_t efi_image_region_add(struct efi_image_regions *regs,
return EFI_SUCCESS; } + +/** + * efi_sigstore_free - free signature store + * @sigstore: Pointer to signature store structure + * + * Feee all the memories held in signature store and itself, + * which were allocated by efi_sigstore_parse_sigdb(). + */ +void efi_sigstore_free(struct efi_signature_store *sigstore) +{ + struct efi_signature_store *sigstore_next; + struct efi_sig_data *sig_data, *sig_data_next; + + while (sigstore) { + sigstore_next = sigstore->next; + + sig_data = sigstore->sig_data_list; + while (sig_data) { + sig_data_next = sig_data->next; + free(sig_data->data); + free(sig_data); + sig_data = sig_data_next; + } + + free(sigstore); + sigstore = sigstore_next; + } +} + +/** + * efi_sigstore_parse_siglist - parse a signature list + * @name: Pointer to signature list + * + * Parse signature list and instantiate a signature store structure. + * Signature database is a simple concatenation of one or more + * signature list(s). + * + * Return: Pointer to signature store on success, NULL on error + */ +static struct efi_signature_store * +efi_sigstore_parse_siglist(struct efi_signature_list *esl) +{ + struct efi_signature_store *siglist = NULL; + struct efi_sig_data *sig_data, *sig_data_next; + struct efi_signature_data *esd; + size_t left; + + /* + * UEFI specification defines certificate types: + * for non-signed images, + * EFI_CERT_SHA256_GUID + * EFI_CERT_RSA2048_GUID + * EFI_CERT_RSA2048_SHA256_GUID + * EFI_CERT_SHA1_GUID + * EFI_CERT_RSA2048_SHA_GUID + * EFI_CERT_SHA224_GUID + * EFI_CERT_SHA384_GUID + * EFI_CERT_SHA512_GUID + * + * for signed images, + * EFI_CERT_X509_GUID + * NOTE: Each certificate will normally be in a separate + * EFI_SIGNATURE_LIST as the size may vary depending on + * its algo's. + * + * for timestamp revocation of certificate, + * EFI_CERT_X509_SHA512_GUID + * EFI_CERT_X509_SHA256_GUID + * EFI_CERT_X509_SHA384_GUID + */ + + if (esl->signature_list_size + <= (sizeof(*esl) + esl->signature_header_size)) { + debug("Siglist in wrong format\n"); + return NULL; + } + + /* Create a head */ + siglist = calloc(sizeof(*siglist), 1); + if (!siglist) { + debug("Out of memory\n"); + goto err; + } + memcpy(&siglist->sig_type, &esl->signature_type, sizeof(efi_guid_t)); + + /* Go through the list */ + sig_data_next = NULL; + left = esl->signature_list_size + - (sizeof(*esl) + esl->signature_header_size); + esd = (struct efi_signature_data *) + ((u8 *)esl + sizeof(*esl) + esl->signature_header_size); + + while ((left > 0) && left >= esl->signature_size) { + /* Signature must exist if there is remaining data. */ + if (left < esl->signature_size) { + debug("Certificate is too small\n"); + goto err; + } + + sig_data = calloc(esl->signature_size + - sizeof(esd->signature_owner), 1); + if (!sig_data) { + debug("Out of memory\n"); + goto err; + } + + /* Append signature data */ + memcpy(&sig_data->owner, &esd->signature_owner, + sizeof(efi_guid_t)); + sig_data->size = esl->signature_size + - sizeof(esd->signature_owner); + sig_data->data = malloc(sig_data->size); + if (!sig_data->data) { + debug("Out of memory\n"); + goto err; + } + memcpy(sig_data->data, esd->signature_data, sig_data->size); + + sig_data->next = sig_data_next; + sig_data_next = sig_data; + + /* Next */ + esd = (struct efi_signature_data *) + ((u8 *)esd + esl->signature_size); + left -= esl->signature_size; + } + siglist->sig_data_list = sig_data_next; + + return siglist; + +err: + efi_sigstore_free(siglist); + + return NULL; +} + +/** + * efi_sigstore_parse_sigdb - parse a signature database variable + * @name: Variable's name + * + * Read in a value of signature database variable pointed to by + * @name, parse it and instantiate a signature store structure. + * + * Return: Pointer to signature store on success, NULL on error + */ +struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name) +{ + struct efi_signature_store *sigstore = NULL, *siglist; + struct efi_signature_list *esl; + const efi_guid_t *vendor; + void *db; + efi_uintn_t db_size; + efi_status_t ret; + + if (!u16_strcmp(name, L"PK") || !u16_strcmp(name, L"KEK")) { + vendor = &efi_global_variable_guid; + } else if (!u16_strcmp(name, L"db") || !u16_strcmp(name, L"dbx")) { + vendor = &efi_guid_image_security_database; + } else { + debug("unknown signature database, %ls\n", name); + return NULL; + } + + /* retrieve variable data */ + db_size = 0; + ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, NULL)); + if (ret == EFI_NOT_FOUND) { + debug("variable, %ls, not found\n", name); + sigstore = calloc(sizeof(*sigstore), 1); + return sigstore; + } else if (ret != EFI_BUFFER_TOO_SMALL) { + debug("Getting variable, %ls, failed\n", name); + return NULL; + } + + db = malloc(db_size); + if (!db) { + debug("Out of memory\n"); + return NULL; + } + + ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, db)); + if (ret != EFI_SUCCESS) { + debug("Getting variable, %ls, failed\n", name); + goto err; + } + + /* Parse siglist list */ + esl = db; + while (db_size > 0) { + /* List must exist if there is remaining data. */ + if (db_size < sizeof(*esl)) { + debug("variable, %ls, in wrong format\n", name); + goto err; + } + + if (db_size < esl->signature_list_size) { + debug("variable, %ls, in wrong format\n", name); + goto err; + } + + /* Parse a single siglist. */ + siglist = efi_sigstore_parse_siglist(esl); + if (!siglist) { + debug("Parsing signature list of %ls failed\n", name); + goto err; + } + + /* Append siglist */ + siglist->next = sigstore; + sigstore = siglist; + + /* Next */ + db_size -= esl->signature_list_size; + esl = (void *)esl + esl->signature_list_size; + } + free(db); + + return sigstore; + +err: + efi_sigstore_free(sigstore); + free(db); + + return NULL; +} #endif /* CONFIG_EFI_SECURE_BOOT */