From: Antonio Quartulli Date: Sun, 8 Jul 2018 02:45:17 +0000 (+0800) Subject: crypto: always reload tls-auth/crypt key contexts X-Git-Tag: v2.5_beta1~456 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5817b49b4ca39f86eabb092c562b72d46d5509f7;p=thirdparty%2Fopenvpn.git crypto: always reload tls-auth/crypt key contexts In preparation to having tls-auth/crypt keys per connection block, it is important to ensure that such material is always reloaded upon SIGUSR1, no matter if `persist-key` was specified or not. This is required because when moving from one remote to the other the key may change and thus the key context needs to be refreshed. To ensure that the `persist-key` logic will still work as expected, the tls-auth/crypt key is pre-loaded so that the keyfile is not required at runtime. Trac: #720 Cc: Steffan Karger Signed-off-by: Antonio Quartulli Acked-by: Steffan Karger Message-Id: <20180708024517.27108-1-a@unstable.cc> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17237.html Signed-off-by: Gert Doering --- diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c index becfeb93a..0972139f2 100644 --- a/src/openvpn/buffer.c +++ b/src/openvpn/buffer.c @@ -189,6 +189,34 @@ free_buf(struct buffer *buf) CLEAR(*buf); } +static void +free_buf_gc(struct buffer *buf, struct gc_arena *gc) +{ + if (gc) + { + struct gc_entry **e = &gc->list; + + while (*e) + { + /* check if this object is the one we want to delete */ + if ((uint8_t *)(*e + 1) == buf->data) + { + struct gc_entry *to_delete = *e; + + /* remove element from linked list and free it */ + *e = (*e)->next; + free(to_delete); + + break; + } + + e = &(*e)->next; + } + } + + CLEAR(*buf); +} + /* * Return a buffer for write that is a subset of another buffer */ @@ -1332,3 +1360,36 @@ buffer_list_file(const char *fn, int max_line_len) } return bl; } + +struct buffer +buffer_read_from_file(const char *filename, struct gc_arena *gc) +{ + struct buffer ret = { 0 }; + + platform_stat_t file_stat = {0}; + if (platform_stat(filename, &file_stat) < 0) + { + return ret; + } + + FILE *fp = platform_fopen(filename, "r"); + if (!fp) + { + return ret; + } + + const size_t size = file_stat.st_size; + ret = alloc_buf_gc(size + 1, gc); /* space for trailing \0 */ + ssize_t read_size = fread(BPTR(&ret), 1, size, fp); + if (read_size < 0) + { + free_buf_gc(&ret, gc); + goto cleanup; + } + ASSERT(buf_inc_len(&ret, read_size)); + buf_null_terminate(&ret); + +cleanup: + fclose(fp); + return ret; +} diff --git a/src/openvpn/buffer.h b/src/openvpn/buffer.h index d848490ab..6b6025ed9 100644 --- a/src/openvpn/buffer.h +++ b/src/openvpn/buffer.h @@ -1112,4 +1112,16 @@ void buffer_list_aggregate_separator(struct buffer_list *bl, struct buffer_list *buffer_list_file(const char *fn, int max_line_len); +/** + * buffer_read_from_file - copy the content of a file into a buffer + * + * @param file path to the file to read + * @param gc the garbage collector to use when allocating the buffer. It + * is passed to alloc_buf_gc() and therefore can be NULL. + * + * @return the buffer storing the file content or an invalid buffer in case of + * error + */ +struct buffer buffer_read_from_file(const char *filename, struct gc_arena *gc); + #endif /* BUFFER_H */ diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c index b59c1f73d..5381ef2ae 100644 --- a/src/openvpn/crypto.c +++ b/src/openvpn/crypto.c @@ -1224,7 +1224,7 @@ read_key_file(struct key2 *key2, const char *file, const unsigned int flags) { struct gc_arena gc = gc_new(); struct buffer in; - int fd, size; + int size; uint8_t hex_byte[3] = {0, 0, 0}; const char *error_filename = file; @@ -1268,22 +1268,11 @@ read_key_file(struct key2 *key2, const char *file, const unsigned int flags) } else /* 'file' is a filename which refers to a file containing the ascii key */ { - in = alloc_buf_gc(2048, &gc); - fd = platform_open(file, O_RDONLY, 0); - if (fd == -1) - { - msg(M_ERR, "Cannot open key file '%s'", file); - } - size = read(fd, in.data, in.capacity); - if (size < 0) - { + in = buffer_read_from_file(file, &gc); + if (!buf_valid(&in)) msg(M_FATAL, "Read error on key file ('%s')", file); - } - if (size == in.capacity) - { - msg(M_FATAL, "Key file ('%s') can be a maximum of %d bytes", file, (int)in.capacity); - } - close(fd); + + size = in.len; } cp = (unsigned char *)in.data; diff --git a/src/openvpn/init.c b/src/openvpn/init.c index d28d1fd28..805344444 100644 --- a/src/openvpn/init.c +++ b/src/openvpn/init.c @@ -2410,7 +2410,6 @@ key_schedule_free(struct key_schedule *ks, bool free_ssl_ctx) if (tls_ctx_initialised(&ks->ssl_ctx) && free_ssl_ctx) { tls_ctx_free(&ks->ssl_ctx); - free_key_ctx_bi(&ks->tls_wrap_key); } CLEAR(*ks); } @@ -2500,6 +2499,48 @@ do_init_crypto_static(struct context *c, const unsigned int flags) check_replay_consistency(&c->c1.ks.key_type, options->replay); } +/* + * Initialize the tls-auth/crypt key context + */ +static void +do_init_tls_wrap_key(struct context *c) +{ + const struct options *options = &c->options; + + /* TLS handshake authentication (--tls-auth) */ + if (options->tls_auth_file) + { + /* Initialize key_type for tls-auth with auth only */ + CLEAR(c->c1.ks.tls_auth_key_type); + if (!streq(options->authname, "none")) + { + c->c1.ks.tls_auth_key_type.digest = md_kt_get(options->authname); + c->c1.ks.tls_auth_key_type.hmac_length = + md_kt_size(c->c1.ks.tls_auth_key_type.digest); + } + else + { + msg(M_FATAL, "ERROR: tls-auth enabled, but no valid --auth " + "algorithm specified ('%s')", options->authname); + } + + crypto_read_openvpn_key(&c->c1.ks.tls_auth_key_type, + &c->c1.ks.tls_wrap_key, + options->tls_auth_file, + options->tls_auth_file_inline, + options->key_direction, + "Control Channel Authentication", "tls-auth"); + } + + /* TLS handshake encryption+authentication (--tls-crypt) */ + if (options->tls_crypt_file) + { + tls_crypt_init_key(&c->c1.ks.tls_wrap_key, + options->tls_crypt_file, + options->tls_crypt_inline, options->tls_server); + } +} + /* * Initialize the persistent component of OpenVPN's TLS mode, * which is preserved across SIGUSR1 resets. @@ -2549,35 +2590,8 @@ do_init_crypto_tls_c1(struct context *c) /* Initialize PRNG with config-specified digest */ prng_init(options->prng_hash, options->prng_nonce_secret_len); - /* TLS handshake authentication (--tls-auth) */ - if (options->tls_auth_file) - { - /* Initialize key_type for tls-auth with auth only */ - CLEAR(c->c1.ks.tls_auth_key_type); - if (!streq(options->authname, "none")) - { - c->c1.ks.tls_auth_key_type.digest = md_kt_get(options->authname); - c->c1.ks.tls_auth_key_type.hmac_length = - md_kt_size(c->c1.ks.tls_auth_key_type.digest); - } - else - { - msg(M_FATAL, "ERROR: tls-auth enabled, but no valid --auth " - "algorithm specified ('%s')", options->authname); - } - - crypto_read_openvpn_key(&c->c1.ks.tls_auth_key_type, - &c->c1.ks.tls_wrap_key, options->tls_auth_file, - options->tls_auth_file_inline, options->key_direction, - "Control Channel Authentication", "tls-auth"); - } - - /* TLS handshake encryption+authentication (--tls-crypt) */ - if (options->tls_crypt_file) - { - tls_crypt_init_key(&c->c1.ks.tls_wrap_key, options->tls_crypt_file, - options->tls_crypt_inline, options->tls_server); - } + /* initialize tls-auth/crypt key */ + do_init_tls_wrap_key(c); c->c1.ciphername = options->ciphername; c->c1.authname = options->authname; @@ -2599,6 +2613,12 @@ do_init_crypto_tls_c1(struct context *c) c->options.ciphername = c->c1.ciphername; c->options.authname = c->c1.authname; c->options.keysize = c->c1.keysize; + + /* + * tls-auth/crypt key can be configured per connection block, therefore + * we must reload it as it may have changed + */ + do_init_tls_wrap_key(c); } } @@ -3402,6 +3422,13 @@ do_close_tls(struct context *c) static void do_close_free_key_schedule(struct context *c, bool free_ssl_ctx) { + /* + * always free the tls_auth/crypt key. If persist_key is true, the key will + * be reloaded from memory (pre-cached) + */ + free_key_ctx_bi(&c->c1.ks.tls_wrap_key); + CLEAR(c->c1.ks.tls_wrap_key); + if (!(c->sig->signal_received == SIGUSR1 && c->options.persist_key)) { key_schedule_free(&c->c1.ks, free_ssl_ctx); diff --git a/src/openvpn/options.c b/src/openvpn/options.c index b89f4ba23..78b941fe0 100644 --- a/src/openvpn/options.c +++ b/src/openvpn/options.c @@ -3020,6 +3020,32 @@ options_postprocess_mutate(struct options *o) options_postprocess_mutate_ce(o, o->connection_list->array[i]); } + /* pre-cache tls-auth/crypt key file if persist-key was specified */ + if (o->persist_key) + { + if (o->tls_auth_file && !o->tls_auth_file_inline) + { + struct buffer in = buffer_read_from_file(o->tls_auth_file, &o->gc); + if (!buf_valid(&in)) + msg(M_FATAL, "Cannot pre-load tls-auth keyfile (%s)", + o->tls_auth_file); + + o->tls_auth_file = INLINE_FILE_TAG; + o->tls_auth_file_inline = (char *)in.data; + } + + if (o->tls_crypt_file && !o->tls_crypt_inline) + { + struct buffer in = buffer_read_from_file(o->tls_crypt_file, &o->gc); + if (!buf_valid(&in)) + msg(M_FATAL, "Cannot pre-load tls-crypt keyfile (%s)", + o->tls_auth_file); + + o->tls_crypt_file = INLINE_FILE_TAG; + o->tls_crypt_inline = (char *)in.data; + } + } + if (o->tls_server) { /* Check that DH file is specified, or explicitly disabled */ diff --git a/tests/unit_tests/openvpn/Makefile.am b/tests/unit_tests/openvpn/Makefile.am index 1ff626158..0f7f86b9a 100644 --- a/tests/unit_tests/openvpn/Makefile.am +++ b/tests/unit_tests/openvpn/Makefile.am @@ -28,7 +28,6 @@ buffer_testdriver_CFLAGS = @TEST_CFLAGS@ -I$(openvpn_srcdir) -I$(compat_srcdir) buffer_testdriver_LDFLAGS = @TEST_LDFLAGS@ -L$(openvpn_srcdir) -Wl,--wrap=parse_line buffer_testdriver_SOURCES = test_buffer.c mock_msg.c \ mock_get_random.c \ - $(openvpn_srcdir)/buffer.c \ $(openvpn_srcdir)/platform.c crypto_testdriver_CFLAGS = @TEST_CFLAGS@ \ diff --git a/tests/unit_tests/openvpn/test_buffer.c b/tests/unit_tests/openvpn/test_buffer.c index d083b78f9..7c9a9e2f2 100644 --- a/tests/unit_tests/openvpn/test_buffer.c +++ b/tests/unit_tests/openvpn/test_buffer.c @@ -33,6 +33,7 @@ #include #include "buffer.h" +#include "buffer.c" static void test_buffer_strprefix(void **state) @@ -197,6 +198,48 @@ test_buffer_list_aggregate_separator_emptybuffers(void **state) assert_int_equal(BLEN(buf), 0); } +static void +test_buffer_free_gc_one(void **state) +{ + struct gc_arena gc = gc_new(); + struct buffer buf = alloc_buf_gc(1024, &gc); + + assert_ptr_equal(gc.list + 1, buf.data); + free_buf_gc(&buf, &gc); + assert_null(gc.list); + + gc_free(&gc); +} + +static void +test_buffer_free_gc_two(void **state) +{ + struct gc_arena gc = gc_new(); + struct buffer buf1 = alloc_buf_gc(1024, &gc); + struct buffer buf2 = alloc_buf_gc(1024, &gc); + struct buffer buf3 = alloc_buf_gc(1024, &gc); + + struct gc_entry *e; + + e = gc.list; + + assert_ptr_equal(e + 1, buf3.data); + assert_ptr_equal(e->next + 1, buf2.data); + assert_ptr_equal(e->next->next + 1, buf1.data); + + free_buf_gc(&buf2, &gc); + + assert_non_null(gc.list); + + while (e) + { + assert_ptr_not_equal(e + 1, buf2.data); + e = e->next; + } + + gc_free(&gc); +} + int main(void) { @@ -226,6 +269,8 @@ main(void) cmocka_unit_test_setup_teardown(test_buffer_list_aggregate_separator_emptybuffers, test_buffer_list_setup, test_buffer_list_teardown), + cmocka_unit_test(test_buffer_free_gc_one), + cmocka_unit_test(test_buffer_free_gc_two), }; return cmocka_run_group_tests_name("buffer", tests, NULL, NULL);