From: Arne Schwabe Date: Thu, 7 May 2020 13:25:34 +0000 (+0200) Subject: Do not write extra 0 byte for --gen-key with auth-token/tls-crypt-v2 X-Git-Tag: v2.5_beta1~137 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=14a57be4609fc23e4775072948bf722f21f25099;p=thirdparty%2Fopenvpn.git Do not write extra 0 byte for --gen-key with auth-token/tls-crypt-v2 Change crypto_pem_encode to not put a nul-terminated terminated string into the buffer. This was useful for printf but should not be written into the file. Instead do not assume that the buffer is null terminated and print only the number of bytes in the buffer. Also fix a similar case in printing static key where the 0 byte was never added to the buffer Patch V2: make pem_encode behave more like other similar functions in OpenVPN and do not null terminate. Patch V3: also make the mbed TLS variant of pem_decode behave like other similar functions in OpeNVPN and accept a not null-terminated buffer. Patch V4: The newly introduced unit test test_tls_crypt_v2_write_client_key_file_metadata was added after the V3 version of the patch and now misses the strlen with memcmp replacment that were added to test_tls_crypt_v2_write_client_key_file. Also add the modifictions to this function. Unconditionally allocate buffer in mbed TLS path as requested by Steffan. Signed-off-by: Arne Schwabe Acked-by: Steffan Karger Message-Id: <20200507132534.6380-1-arne@rfc2549.org> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg19852.html Signed-off-by: Gert Doering --- diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c index f1a52d8c7..2388027c5 100644 --- a/src/openvpn/crypto.c +++ b/src/openvpn/crypto.c @@ -1491,7 +1491,7 @@ write_key_file(const int nkeys, const char *filename) /* write key file to stdout if no filename given */ if (!filename || strcmp(filename, "")==0) { - printf("%s\n", BPTR(&out)); + printf("%.*s\n", BLEN(&out), BPTR(&out)); } /* write key file, now formatted in out, to file */ else if (!buffer_write_file(filename, &out)) @@ -1900,7 +1900,7 @@ write_pem_key_file(const char *filename, const char *pem_name) if (!filename || strcmp(filename, "")==0) { - printf("%s\n", BPTR(&server_key_pem)); + printf("%.*s", BLEN(&server_key_pem), BPTR(&server_key_pem)); } else if (!buffer_write_file(filename, &server_key_pem)) { diff --git a/src/openvpn/crypto_mbedtls.c b/src/openvpn/crypto_mbedtls.c index 35072b736..c8dcddc88 100644 --- a/src/openvpn/crypto_mbedtls.c +++ b/src/openvpn/crypto_mbedtls.c @@ -239,10 +239,12 @@ crypto_pem_encode(const char *name, struct buffer *dst, return false; } + /* We set the size buf to out_len-1 to NOT include the 0 byte that + * mbedtls_pem_write_buffer in its length calculation */ *dst = alloc_buf_gc(out_len, gc); if (!mbed_ok(mbedtls_pem_write_buffer(header, footer, BPTR(src), BLEN(src), BPTR(dst), BCAP(dst), &out_len)) - || !buf_inc_len(dst, out_len)) + || !buf_inc_len(dst, out_len-1)) { CLEAR(*dst); return false; @@ -259,11 +261,6 @@ crypto_pem_decode(const char *name, struct buffer *dst, char header[1000+1] = { 0 }; char footer[1000+1] = { 0 }; - if (*(BLAST(src)) != '\0') - { - msg(M_WARN, "PEM decode error: source buffer not null-terminated"); - return false; - } if (!openvpn_snprintf(header, sizeof(header), "-----BEGIN %s-----", name)) { return false; @@ -273,9 +270,16 @@ crypto_pem_decode(const char *name, struct buffer *dst, return false; } + /* mbed TLS requires the src to be null-terminated */ + /* allocate a new buffer to avoid modifying the src buffer */ + struct gc_arena gc = gc_new(); + struct buffer input = alloc_buf_gc(BLEN(src) + 1, &gc); + buf_copy(&input, src); + buf_null_terminate(&input); + size_t use_len = 0; mbedtls_pem_context ctx = { 0 }; - bool ret = mbed_ok(mbedtls_pem_read_buffer(&ctx, header, footer, BPTR(src), + bool ret = mbed_ok(mbedtls_pem_read_buffer(&ctx, header, footer, BPTR(&input), NULL, 0, &use_len)); if (ret && !buf_write(dst, ctx.buf, ctx.buflen)) { @@ -284,6 +288,7 @@ crypto_pem_decode(const char *name, struct buffer *dst, } mbedtls_pem_free(&ctx); + gc_free(&gc); return ret; } diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c index 9e7ea0fff..a5b2c45a4 100644 --- a/src/openvpn/crypto_openssl.c +++ b/src/openvpn/crypto_openssl.c @@ -400,9 +400,8 @@ crypto_pem_encode(const char *name, struct buffer *dst, BUF_MEM *bptr; BIO_get_mem_ptr(bio, &bptr); - *dst = alloc_buf_gc(bptr->length + 1, gc); + *dst = alloc_buf_gc(bptr->length, gc); ASSERT(buf_write(dst, bptr->data, bptr->length)); - buf_null_terminate(dst); ret = true; cleanup: diff --git a/src/openvpn/tls_crypt.c b/src/openvpn/tls_crypt.c index a3894d66e..7b5016d38 100644 --- a/src/openvpn/tls_crypt.c +++ b/src/openvpn/tls_crypt.c @@ -702,7 +702,7 @@ tls_crypt_v2_write_client_key_file(const char *filename, if (!filename || streq(filename, "")) { - printf("%s\n", BPTR(&client_key_pem)); + printf("%.*s\n", BLEN(&client_key_pem), BPTR(&client_key_pem)); client_file = (const char *)BPTR(&client_key_pem); client_inline = true; } diff --git a/tests/unit_tests/openvpn/test_tls_crypt.c b/tests/unit_tests/openvpn/test_tls_crypt.c index 2a146f840..218772e8b 100644 --- a/tests/unit_tests/openvpn/test_tls_crypt.c +++ b/tests/unit_tests/openvpn/test_tls_crypt.c @@ -548,7 +548,8 @@ test_tls_crypt_v2_write_server_key_file(void **state) const char *filename = "testfilename.key"; expect_string(__wrap_buffer_write_file, filename, filename); - expect_string(__wrap_buffer_write_file, pem, test_server_key); + expect_memory(__wrap_buffer_write_file, pem, test_server_key, + strlen(test_server_key)); will_return(__wrap_buffer_write_file, true); tls_crypt_v2_write_server_key_file(filename); @@ -561,7 +562,8 @@ test_tls_crypt_v2_write_client_key_file(void **state) /* Test writing the client key */ expect_string(__wrap_buffer_write_file, filename, filename); - expect_string(__wrap_buffer_write_file, pem, test_client_key); + expect_memory(__wrap_buffer_write_file, pem, test_client_key, + strlen(test_client_key)); will_return(__wrap_buffer_write_file, true); /* Key generation re-reads the created file as a sanity check */ @@ -579,7 +581,8 @@ test_tls_crypt_v2_write_client_key_file_metadata(void **state) /* Test writing the client key */ expect_string(__wrap_buffer_write_file, filename, filename); - expect_string(__wrap_buffer_write_file, pem, test_client_key_metadata); + expect_memory(__wrap_buffer_write_file, pem, test_client_key_metadata, + strlen(test_client_key_metadata)); will_return(__wrap_buffer_write_file, true); /* Key generation re-reads the created file as a sanity check */