chiark / gitweb /
microhttpd-util: avoid double free on error
[elogind.git] / src / journal / microhttpd-util.c
index 5675af4..f693e0f 100644 (file)
@@ -3,6 +3,7 @@
 /***
   This file is part of systemd.
 
+  Copyright 2012 Lennart Poettering
   Copyright 2012 Zbigniew JÄ™drzejewski-Szmek
 
   systemd is free software; you can redistribute it and/or modify it
 
 #include <stddef.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "microhttpd-util.h"
 #include "log.h"
 #include "macro.h"
 #include "util.h"
 
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat-nonliteral"
-_printf_(2,0)
+#ifdef HAVE_GNUTLS
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+#endif
+
 void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
-        _cleanup_free_ char *f;
-        if (asprintf(&f, "microhttpd: %s", fmt) <= 0) {
-                log_oom();
-                return;
-        }
+        char *f;
+
+        f = strappenda("microhttpd: ", fmt);
+
+        DISABLE_WARNING_FORMAT_NONLITERAL;
         log_metav(LOG_INFO, NULL, 0, NULL, f, ap);
+        REENABLE_WARNING;
+}
+
+
+static int mhd_respond_internal(struct MHD_Connection *connection,
+                                enum MHD_RequestTerminationCode code,
+                                char *buffer,
+                                size_t size,
+                                enum MHD_ResponseMemoryMode mode) {
+        struct MHD_Response *response;
+        int r;
+
+        assert(connection);
+
+        response = MHD_create_response_from_buffer(size, buffer, mode);
+        if (!response)
+                return MHD_NO;
+
+        log_debug("Queing response %u: %s", code, buffer);
+        MHD_add_response_header(response, "Content-Type", "text/plain");
+        r = MHD_queue_response(connection, code, response);
+        MHD_destroy_response(response);
+
+        return r;
+}
+
+int mhd_respond(struct MHD_Connection *connection,
+                enum MHD_RequestTerminationCode code,
+                const char *message) {
+
+        return mhd_respond_internal(connection, code,
+                                    (char*) message, strlen(message),
+                                    MHD_RESPMEM_PERSISTENT);
+}
+
+int mhd_respond_oom(struct MHD_Connection *connection) {
+        return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE,  "Out of memory.\n");
+}
+
+int mhd_respondf(struct MHD_Connection *connection,
+                 enum MHD_RequestTerminationCode code,
+                 const char *format, ...) {
+
+        char *m;
+        int r;
+        va_list ap;
+
+        assert(connection);
+        assert(format);
+
+        va_start(ap, format);
+        r = vasprintf(&m, format, ap);
+        va_end(ap);
+
+        if (r < 0)
+                return respond_oom(connection);
+
+        return mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
+}
+
+#ifdef HAVE_GNUTLS
+
+static int log_level_map[] = {
+        LOG_DEBUG,
+        LOG_WARNING, /* gnutls session audit */
+        LOG_DEBUG,   /* gnutls debug log */
+        LOG_WARNING, /* gnutls assert log */
+        LOG_INFO,    /* gnutls handshake log */
+        LOG_DEBUG,   /* gnutls record log */
+        LOG_DEBUG,   /* gnutls dtls log */
+        LOG_DEBUG,
+        LOG_DEBUG,
+        LOG_DEBUG,
+        LOG_DEBUG,   /* gnutls hard log */
+        LOG_DEBUG,   /* gnutls read log */
+        LOG_DEBUG,   /* gnutls write log */
+        LOG_DEBUG,   /* gnutls io log */
+        LOG_DEBUG,   /* gnutls buffers log */
+};
+
+void log_func_gnutls(int level, const char *message) {
+        int ourlevel;
+
+        assert_se(message);
+
+        if (0 <= level && level < (int) ELEMENTSOF(log_level_map))
+                ourlevel = log_level_map[level];
+        else
+                level = LOG_DEBUG;
+
+        log_meta(ourlevel, NULL, 0, NULL, "gnutls: %s", message);
+}
+
+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) {
+                log_error("gnutls_certificate_verify_peers2 failed: %s", strerror(-r));
+                return r;
+        }
+
+        type = gnutls_certificate_type_get(session);
+        r = gnutls_certificate_verification_status_print(status, type, &out, 0);
+        if (r < 0) {
+                log_error("gnutls_certificate_verification_status_print failed: %s", strerror(-r));
+                return r;
+        }
+
+        log_info("Certificate status: %s", 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) {
+                log_error("Failed to retrieve certificate chain");
+                return -EINVAL;
+        }
+
+        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;
+}
+
+int check_permissions(struct MHD_Connection *connection, int *code) {
+        const union MHD_ConnectionInfo *ci;
+        gnutls_session_t session;
+        gnutls_x509_crt_t client_cert;
+        char _cleanup_free_ *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_info("Connection from %s", 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) {
+        return -EPERM;
 }
-#pragma GCC diagnostic pop
+#endif