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-rw-r--r--lib/security/gpg.c292
1 files changed, 264 insertions, 28 deletions
diff --git a/lib/security/gpg.c b/lib/security/gpg.c
index a377b55..41d1306 100644
--- a/lib/security/gpg.c
+++ b/lib/security/gpg.c
@@ -60,6 +60,178 @@ struct pb_url * gpg_get_signature_url(void *ctx, struct pb_url *base_file)
return signature_file;
}
+int decrypt_file(const char *filename,
+ FILE *authorized_signatures_handle, const char *keyring_path)
+{
+ int result = 0;
+ int valid = 0;
+ size_t bytes_read = 0;
+ unsigned char buffer[8192];
+
+ if (filename == NULL)
+ return -1;
+
+ gpgme_signature_t verification_signatures;
+ gpgme_verify_result_t verification_result;
+ gpgme_data_t ciphertext_data;
+ gpgme_data_t plaintext_data;
+ gpgme_engine_info_t enginfo;
+ gpgme_ctx_t gpg_context;
+ gpgme_error_t err;
+
+ /* Initialize gpgme */
+ setlocale (LC_ALL, "");
+ gpgme_check_version(NULL);
+ gpgme_set_locale(NULL, LC_CTYPE, setlocale (LC_CTYPE, NULL));
+ err = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: OpenPGP support not available\n", __func__);
+ return -1;
+ }
+ err = gpgme_get_engine_info(&enginfo);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: GPG engine failed to initialize\n", __func__);
+ return -1;
+ }
+ err = gpgme_new(&gpg_context);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: GPG context could not be created\n", __func__);
+ return -1;
+ }
+ err = gpgme_set_protocol(gpg_context, GPGME_PROTOCOL_OpenPGP);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: GPG protocol could not be set\n", __func__);
+ return -1;
+ }
+ if (keyring_path)
+ err = gpgme_ctx_set_engine_info (gpg_context,
+ GPGME_PROTOCOL_OpenPGP,
+ enginfo->file_name, keyring_path);
+ else
+ err = gpgme_ctx_set_engine_info (gpg_context,
+ GPGME_PROTOCOL_OpenPGP,
+ enginfo->file_name, enginfo->home_dir);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: Could not set GPG engine information\n", __func__);
+ return -1;
+ }
+ err = gpgme_data_new(&plaintext_data);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: Could not create GPG plaintext data buffer\n",
+ __func__);
+ return -1;
+ }
+ err = gpgme_data_new_from_file(&ciphertext_data, filename, 1);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: Could not create GPG ciphertext data buffer"
+ " from file '%s'\n", __func__, filename);
+ return -1;
+ }
+
+ /* Decrypt and verify file */
+ err = gpgme_op_decrypt_verify(gpg_context, ciphertext_data,
+ plaintext_data);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: Could not decrypt file\n", __func__);
+ return -1;
+ }
+ verification_result = gpgme_op_verify_result(gpg_context);
+ verification_signatures = verification_result->signatures;
+ while (verification_signatures) {
+ if (verification_signatures->status == GPG_ERR_NO_ERROR) {
+ pb_log("%s: Good signature for key ID '%s' ('%s')\n",
+ __func__,
+ verification_signatures->fpr, filename);
+ /* Verify fingerprint is present in authorized
+ * signatures file
+ */
+ char *auth_sig_line = NULL;
+ size_t auth_sig_len = 0;
+ ssize_t auth_sig_read;
+ rewind(authorized_signatures_handle);
+ while ((auth_sig_read = getline(&auth_sig_line,
+ &auth_sig_len,
+ authorized_signatures_handle)) != -1) {
+ auth_sig_len = strlen(auth_sig_line);
+ while ((auth_sig_line[auth_sig_len-1] == '\n')
+ || (auth_sig_line[auth_sig_len-1] == '\r'))
+ auth_sig_len--;
+ auth_sig_line[auth_sig_len] = 0;
+ if (strcmp(auth_sig_line,
+ verification_signatures->fpr) == 0)
+ valid = 1;
+ }
+ free(auth_sig_line);
+ }
+ else {
+ pb_log("%s: Signature for key ID '%s' ('%s') invalid."
+ " Status: %08x\n", __func__,
+ verification_signatures->fpr, filename,
+ verification_signatures->status);
+ }
+ verification_signatures = verification_signatures->next;
+ }
+
+ gpgme_data_release(ciphertext_data);
+
+ if (valid) {
+ /* Write decrypted file over ciphertext */
+ FILE *plaintext_file_handle = NULL;
+ plaintext_file_handle = fopen(filename, "wb");
+ if (!plaintext_file_handle) {
+ pb_log("%s: Could not create GPG plaintext file '%s'\n",
+ __func__, filename);
+ gpgme_data_release(plaintext_data);
+ gpgme_release(gpg_context);
+ return -1;
+ }
+ gpgme_data_seek(plaintext_data, 0, SEEK_SET);
+ if (err != GPG_ERR_NO_ERROR) {
+ pb_log("%s: Could not seek in GPG plaintext buffer\n",
+ __func__);
+ gpgme_data_release(plaintext_data);
+ gpgme_release(gpg_context);
+ fclose(plaintext_file_handle);
+ return -1;
+ }
+ while ((bytes_read = gpgme_data_read(plaintext_data, buffer,
+ 8192)) > 0) {
+ size_t l2 = fwrite(buffer, 1, bytes_read,
+ plaintext_file_handle);
+ if (l2 < bytes_read) {
+ if (ferror(plaintext_file_handle)) {
+ /* General error */
+ result = -1;
+ pb_log("%s: failed: unknown fault\n",
+ __func__);
+ }
+ else {
+ /* No space on destination device */
+ result = -1;
+ pb_log("%s: failed: temporary storage"
+ " full\n", __func__);
+ }
+ break;
+ }
+ }
+ fclose(plaintext_file_handle);
+ }
+
+ /* Clean up */
+ gpgme_data_release(plaintext_data);
+ gpgme_release(gpg_context);
+
+ if (!valid) {
+ pb_log("%s: Incorrect GPG signature\n", __func__);
+ return -1;
+ }
+
+ pb_log("%s: GPG signature for decrypted file '%s' verified\n",
+ __func__, filename);
+
+ return result;
+}
+
int verify_file_signature(const char *plaintext_filename,
const char *signature_filename, FILE *authorized_signatures_handle,
const char *keyring_path)
@@ -208,10 +380,11 @@ int gpg_validate_boot_files(struct boot_task *boot_task) {
boot_task->local_dtb_signature : NULL;
const char* local_image_signature = (boot_task->verify_signature) ?
boot_task->local_image_signature : NULL;
- const char* local_cmdline_signature = (boot_task->verify_signature) ?
+ const char* local_cmdline_signature =
+ (boot_task->verify_signature || boot_task->decrypt_files) ?
boot_task->local_cmdline_signature : NULL;
- if (!boot_task->verify_signature)
+ if ((!boot_task->verify_signature) && (!boot_task->decrypt_files))
return result;
/* Load authorized signatures file */
@@ -283,38 +456,71 @@ int gpg_validate_boot_files(struct boot_task *boot_task) {
fflush(cmdline_handle);
}
- /* Check signatures */
- if (verify_file_signature(kernel_filename,
- local_image_signature,
- authorized_signatures_handle, "/etc/gpg"))
- result = KEXEC_LOAD_SIGNATURE_FAILURE;
- if (verify_file_signature(cmdline_template,
- local_cmdline_signature,
- authorized_signatures_handle, "/etc/gpg"))
- result = KEXEC_LOAD_SIGNATURE_FAILURE;
- if (boot_task->local_initrd_signature)
- if (verify_file_signature(initrd_filename,
- local_initrd_signature,
- authorized_signatures_handle, "/etc/gpg"))
- result = KEXEC_LOAD_SIGNATURE_FAILURE;
- if (boot_task->local_dtb_signature)
- if (verify_file_signature(dtb_filename,
- local_dtb_signature,
- authorized_signatures_handle, "/etc/gpg"))
+ if (boot_task->verify_signature) {
+ /* Check signatures */
+ if (verify_file_signature(kernel_filename,
+ local_image_signature,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ if (verify_file_signature(cmdline_template,
+ local_cmdline_signature,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+
+ if (boot_task->local_initrd_signature)
+ if (verify_file_signature(initrd_filename,
+ local_initrd_signature,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ result = KEXEC_LOAD_SIGNATURE_FAILURE;
+ if (boot_task->local_dtb_signature)
+ if (verify_file_signature(dtb_filename,
+ local_dtb_signature,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ result = KEXEC_LOAD_SIGNATURE_FAILURE;
+
+ /* Clean up */
+ if (cmdline_handle) {
+ fclose(cmdline_handle);
+ unlink(cmdline_template);
+ }
+ fclose(authorized_signatures_handle);
+ } else if (boot_task->decrypt_files) {
+ /* Decrypt files */
+ if (decrypt_file(kernel_filename,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ result = KEXEC_LOAD_DECRYPTION_FALURE;
+ if (verify_file_signature(cmdline_template,
+ local_cmdline_signature,
+ authorized_signatures_handle,
+ "/etc/gpg"))
result = KEXEC_LOAD_SIGNATURE_FAILURE;
+ if (boot_task->local_initrd)
+ if (decrypt_file(initrd_filename,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ result = KEXEC_LOAD_DECRYPTION_FALURE;
+ if (boot_task->local_dtb)
+ if (decrypt_file(dtb_filename,
+ authorized_signatures_handle,
+ "/etc/gpg"))
+ result = KEXEC_LOAD_DECRYPTION_FALURE;
- /* Clean up */
- if (cmdline_handle) {
- fclose(cmdline_handle);
- unlink(cmdline_template);
+ /* Clean up */
+ if (cmdline_handle) {
+ fclose(cmdline_handle);
+ unlink(cmdline_template);
+ }
+ fclose(authorized_signatures_handle);
}
- fclose(authorized_signatures_handle);
return result;
}
void gpg_validate_boot_files_cleanup(struct boot_task *boot_task) {
- if (boot_task->verify_signature) {
+ if ((boot_task->verify_signature) || (boot_task->decrypt_files)) {
unlink(boot_task->local_image_override);
if (boot_task->local_initrd_override)
unlink(boot_task->local_initrd_override);
@@ -330,8 +536,38 @@ void gpg_validate_boot_files_cleanup(struct boot_task *boot_task) {
}
int lockdown_status() {
+ /* assume most restrictive lockdown type */
+ int ret = PB_LOCKDOWN_SIGN;
+
if (access(LOCKDOWN_FILE, F_OK) == -1)
return PB_LOCKDOWN_NONE;
- else
- return PB_LOCKDOWN_SIGN;
+
+ /* determine lockdown type */
+ FILE *authorized_signatures_handle = NULL;
+ authorized_signatures_handle = fopen(LOCKDOWN_FILE, "r");
+ if (!authorized_signatures_handle)
+ return ret;
+
+ char *auth_sig_line = NULL;
+ size_t auth_sig_len = 0;
+ ssize_t auth_sig_read;
+ rewind(authorized_signatures_handle);
+ if ((auth_sig_read = getline(&auth_sig_line,
+ &auth_sig_len,
+ authorized_signatures_handle)) != -1) {
+ auth_sig_len = strlen(auth_sig_line);
+ while ((auth_sig_line[auth_sig_len-1] == '\n')
+ || (auth_sig_line[auth_sig_len-1] == '\r'))
+ auth_sig_len--;
+ auth_sig_line[auth_sig_len] = 0;
+ if (strcmp(auth_sig_line, "ENCRYPTED") == 0) {
+ /* first line indicates encrypted files
+ * expected. enable decryption.
+ */
+ ret = PB_LOCKDOWN_DECRYPT;
+ }
+ }
+ free(auth_sig_line);
+
+ return ret;
} \ No newline at end of file
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