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-rw-r--r--src/journal-remote/microhttpd-util.c310
1 files changed, 310 insertions, 0 deletions
diff --git a/src/journal-remote/microhttpd-util.c b/src/journal-remote/microhttpd-util.c
new file mode 100644
index 0000000..d3fb0b8
--- /dev/null
+++ b/src/journal-remote/microhttpd-util.c
@@ -0,0 +1,310 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stddef.h>
+#include <stdio.h>
+
+#if HAVE_GNUTLS
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+#endif
+
+#include "alloc-util.h"
+#include "log.h"
+#include "macro.h"
+#include "microhttpd-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
+ char *f;
+
+ f = strjoina("microhttpd: ", fmt);
+
+ DISABLE_WARNING_FORMAT_NONLITERAL;
+ log_internalv(LOG_INFO, 0, NULL, 0, NULL, f, ap);
+ REENABLE_WARNING;
+}
+
+static int mhd_respond_internal(struct MHD_Connection *connection,
+ enum MHD_RequestTerminationCode code,
+ const char *buffer,
+ size_t size,
+ enum MHD_ResponseMemoryMode mode) {
+ assert(connection);
+
+ _cleanup_(MHD_destroy_responsep) struct MHD_Response *response
+ = MHD_create_response_from_buffer(size, (char*) buffer, mode);
+ if (!response)
+ return MHD_NO;
+
+ log_debug("Queueing response %u: %s", code, buffer);
+ MHD_add_response_header(response, "Content-Type", "text/plain");
+ return MHD_queue_response(connection, code, response);
+}
+
+int mhd_respond(struct MHD_Connection *connection,
+ enum MHD_RequestTerminationCode code,
+ const char *message) {
+
+ const char *fmt;
+
+ fmt = strjoina(message, "\n");
+
+ return mhd_respond_internal(connection, code,
+ fmt, strlen(message) + 1,
+ MHD_RESPMEM_PERSISTENT);
+}
+
+int mhd_respond_oom(struct MHD_Connection *connection) {
+ return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE, "Out of memory.");
+}
+
+int mhd_respondf(struct MHD_Connection *connection,
+ int error,
+ enum MHD_RequestTerminationCode code,
+ const char *format, ...) {
+
+ const char *fmt;
+ char *m;
+ int r;
+ va_list ap;
+
+ assert(connection);
+ assert(format);
+
+ if (error < 0)
+ error = -error;
+ errno = -error;
+ fmt = strjoina(format, "\n");
+ va_start(ap, format);
+ DISABLE_WARNING_FORMAT_NONLITERAL;
+ r = vasprintf(&m, fmt, ap);
+ REENABLE_WARNING;
+ va_end(ap);
+
+ if (r < 0)
+ return respond_oom(connection);
+
+ return mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
+}
+
+#if HAVE_GNUTLS
+
+static struct {
+ const char *const names[4];
+ int level;
+ bool enabled;
+} gnutls_log_map[] = {
+ { {"0"}, LOG_DEBUG },
+ { {"1", "audit"}, LOG_WARNING, true}, /* gnutls session audit */
+ { {"2", "assert"}, LOG_DEBUG }, /* gnutls assert log */
+ { {"3", "hsk", "ext"}, LOG_DEBUG }, /* gnutls handshake log */
+ { {"4", "rec"}, LOG_DEBUG }, /* gnutls record log */
+ { {"5", "dtls"}, LOG_DEBUG }, /* gnutls DTLS log */
+ { {"6", "buf"}, LOG_DEBUG },
+ { {"7", "write", "read"}, LOG_DEBUG },
+ { {"8"}, LOG_DEBUG },
+ { {"9", "enc", "int"}, LOG_DEBUG },
+};
+
+static void log_func_gnutls(int level, const char *message) {
+ assert_se(message);
+
+ if (0 <= level && level < (int) ELEMENTSOF(gnutls_log_map)) {
+ if (gnutls_log_map[level].enabled)
+ log_internal(gnutls_log_map[level].level, 0, NULL, 0, NULL, "gnutls %d/%s: %s", level, gnutls_log_map[level].names[1], message);
+ } else {
+ log_debug("Received GNUTLS message with unknown level %d.", level);
+ log_internal(LOG_DEBUG, 0, NULL, 0, NULL, "gnutls: %s", message);
+ }
+}
+
+static void log_reset_gnutls_level(void) {
+ int i;
+
+ for (i = ELEMENTSOF(gnutls_log_map) - 1; i >= 0; i--)
+ if (gnutls_log_map[i].enabled) {
+ log_debug("Setting gnutls log level to %d", i);
+ gnutls_global_set_log_level(i);
+ break;
+ }
+}
+
+static int log_enable_gnutls_category(const char *cat) {
+ unsigned i;
+
+ if (streq(cat, "all")) {
+ for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
+ gnutls_log_map[i].enabled = true;
+ log_reset_gnutls_level();
+ return 0;
+ } else
+ for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
+ if (strv_contains((char**)gnutls_log_map[i].names, cat)) {
+ gnutls_log_map[i].enabled = true;
+ log_reset_gnutls_level();
+ return 0;
+ }
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No such log category: %s", cat);
+}
+
+int setup_gnutls_logger(char **categories) {
+ char **cat;
+ int r;
+
+ gnutls_global_set_log_function(log_func_gnutls);
+
+ if (categories) {
+ STRV_FOREACH(cat, categories) {
+ r = log_enable_gnutls_category(*cat);
+ if (r < 0)
+ return r;
+ }
+ } else
+ log_reset_gnutls_level();
+
+ return 0;
+}
+
+static int verify_cert_authorized(gnutls_session_t session) {
+ unsigned status;
+ gnutls_certificate_type_t type;
+ gnutls_datum_t out;
+ int r;
+
+ r = gnutls_certificate_verify_peers2(session, &status);
+ if (r < 0)
+ return log_error_errno(r, "gnutls_certificate_verify_peers2 failed: %m");
+
+ type = gnutls_certificate_type_get(session);
+ r = gnutls_certificate_verification_status_print(status, type, &out, 0);
+ if (r < 0)
+ return log_error_errno(r, "gnutls_certificate_verification_status_print failed: %m");
+
+ log_debug("Certificate status: %s", out.data);
+ gnutls_free(out.data);
+
+ return status == 0 ? 0 : -EPERM;
+}
+
+static int get_client_cert(gnutls_session_t session, gnutls_x509_crt_t *client_cert) {
+ const gnutls_datum_t *pcert;
+ unsigned listsize;
+ gnutls_x509_crt_t cert;
+ int r;
+
+ assert(session);
+ assert(client_cert);
+
+ pcert = gnutls_certificate_get_peers(session, &listsize);
+ if (!pcert || !listsize)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "Failed to retrieve certificate chain");
+
+ r = gnutls_x509_crt_init(&cert);
+ if (r < 0) {
+ log_error("Failed to initialize client certificate");
+ return r;
+ }
+
+ /* Note that by passing values between 0 and listsize here, you
+ can get access to the CA's certs */
+ r = gnutls_x509_crt_import(cert, &pcert[0], GNUTLS_X509_FMT_DER);
+ if (r < 0) {
+ log_error("Failed to import client certificate");
+ gnutls_x509_crt_deinit(cert);
+ return r;
+ }
+
+ *client_cert = cert;
+ return 0;
+}
+
+static int get_auth_dn(gnutls_x509_crt_t client_cert, char **buf) {
+ size_t len = 0;
+ int r;
+
+ assert(buf);
+ assert(*buf == NULL);
+
+ r = gnutls_x509_crt_get_dn(client_cert, NULL, &len);
+ if (r != GNUTLS_E_SHORT_MEMORY_BUFFER) {
+ log_error("gnutls_x509_crt_get_dn failed");
+ return r;
+ }
+
+ *buf = malloc(len);
+ if (!*buf)
+ return log_oom();
+
+ gnutls_x509_crt_get_dn(client_cert, *buf, &len);
+ return 0;
+}
+
+static void gnutls_x509_crt_deinitp(gnutls_x509_crt_t *p) {
+ gnutls_x509_crt_deinit(*p);
+}
+
+int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
+ const union MHD_ConnectionInfo *ci;
+ gnutls_session_t session;
+ _cleanup_(gnutls_x509_crt_deinitp) gnutls_x509_crt_t client_cert = NULL;
+ _cleanup_free_ char *buf = NULL;
+ int r;
+
+ assert(connection);
+ assert(code);
+
+ *code = 0;
+
+ ci = MHD_get_connection_info(connection,
+ MHD_CONNECTION_INFO_GNUTLS_SESSION);
+ if (!ci) {
+ log_error("MHD_get_connection_info failed: session is unencrypted");
+ *code = mhd_respond(connection, MHD_HTTP_FORBIDDEN,
+ "Encrypted connection is required");
+ return -EPERM;
+ }
+ session = ci->tls_session;
+ assert(session);
+
+ r = get_client_cert(session, &client_cert);
+ if (r < 0) {
+ *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+ "Authorization through certificate is required");
+ return -EPERM;
+ }
+
+ r = get_auth_dn(client_cert, &buf);
+ if (r < 0) {
+ *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+ "Failed to determine distinguished name from certificate");
+ return -EPERM;
+ }
+
+ log_debug("Connection from %s", buf);
+
+ if (hostname)
+ *hostname = TAKE_PTR(buf);
+
+ r = verify_cert_authorized(session);
+ if (r < 0) {
+ log_warning("Client is not authorized");
+ *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+ "Client certificate not signed by recognized authority");
+ }
+ return r;
+}
+
+#else
+int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
+ return -EPERM;
+}
+
+int setup_gnutls_logger(char **categories) {
+ if (categories)
+ log_notice("Ignoring specified gnutls logging categories — gnutls not available.");
+ return 0;
+}
+#endif
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