diff --git a/LICENSE b/LICENSE index bf6a3de1dc14..e290cd10eee5 100644 --- a/LICENSE +++ b/LICENSE @@ -2,5 +2,6 @@ This software is made available under the terms of *either* of the licenses found in LICENSE.APACHE or LICENSE.BSD. Contributions to cryptography are made under the terms of *both* these licenses. -The code used in the OpenSSL locking callback is derived from the same in -Python itself, and is licensed under the terms of the PSF License Agreement. +The code used in the OpenSSL locking callback and OS random engine is derived +from the same in CPython itself, and is licensed under the terms of the PSF +License Agreement. diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst index 791aab3da2ef..6a5ae6f7d749 100644 --- a/docs/hazmat/backends/openssl.rst +++ b/docs/hazmat/backends/openssl.rst @@ -40,6 +40,12 @@ greater. Activates the OS random engine. This will effectively disable OpenSSL's default CSPRNG. + .. method:: osrandom_engine_implementation() + + .. versionadded:: 1.7 + + Returns the implementation of OS random engine. + .. method:: activate_builtin_random() This will activate the default OpenSSL CSPRNG. @@ -81,6 +87,21 @@ details. Linux uses its own PRNG design. ``/dev/urandom`` is a non-blocking source seeded from the same pool as ``/dev/random``. ++------------------------------------------+------------------------------+ +| Windows | ``CryptGenRandom()`` | ++------------------------------------------+------------------------------+ +| Linux >= 3.4.17 with working | ``getrandom(GRND_NONBLOCK)`` | +| ``SYS_getrandom`` syscall | | ++------------------------------------------+------------------------------+ +| OpenBSD >= 5.6 | ``getentropy()`` | ++------------------------------------------+------------------------------+ +| BSD family (including macOS 10.12+) with | ``getentropy()`` | +| ``SYS_getentropy`` in ``sys/syscall.h`` | | ++------------------------------------------+------------------------------+ +| fallback | ``/dev/urandom`` with | +| | cached file descriptor | ++------------------------------------------+------------------------------+ + .. _`OpenSSL`: https://www.openssl.org/ .. _`initializing the RNG`: https://en.wikipedia.org/wiki/OpenSSL#Predictable_private_keys_.28Debian-specific.29 diff --git a/docs/spelling_wordlist.txt b/docs/spelling_wordlist.txt index 186b7eeba834..d57c4d27c115 100644 --- a/docs/spelling_wordlist.txt +++ b/docs/spelling_wordlist.txt @@ -33,6 +33,7 @@ Docstrings El Encodings endian +fallback Fernet fernet FIPS @@ -53,12 +54,14 @@ Mozilla multi namespace namespaces +macOS naïve Nonces nonces online paddings Parallelization +personalization pickleable plaintext pre @@ -75,6 +78,7 @@ serializer Serializers SHA Solaris +syscall Tanja testability tunable diff --git a/src/_cffi_src/build_openssl.py b/src/_cffi_src/build_openssl.py index 56ee5ea6d37d..416e1b391615 100644 --- a/src/_cffi_src/build_openssl.py +++ b/src/_cffi_src/build_openssl.py @@ -68,6 +68,7 @@ def _osx_libraries(build_static): "objects", "ocsp", "opensslv", + "osrandom_engine", "pem", "pkcs12", "rand", diff --git a/src/_cffi_src/openssl/osrandom_engine.py b/src/_cffi_src/openssl/osrandom_engine.py new file mode 100644 index 000000000000..10c5a6083376 --- /dev/null +++ b/src/_cffi_src/openssl/osrandom_engine.py @@ -0,0 +1,29 @@ +# This file is dual licensed under the terms of the Apache License, Version +# 2.0, and the BSD License. See the LICENSE file in the root of this repository +# for complete details. + +from __future__ import absolute_import, division, print_function + +import os + +HERE = os.path.dirname(os.path.abspath(__file__)) + +with open(os.path.join(HERE, "src/osrandom_engine.h")) as f: + INCLUDES = f.read() + +TYPES = """ +static const char *const Cryptography_osrandom_engine_name; +static const char *const Cryptography_osrandom_engine_id; +""" + +FUNCTIONS = """ +int Cryptography_add_osrandom_engine(void); +""" + +MACROS = """ +""" + +with open(os.path.join(HERE, "src/osrandom_engine.c")) as f: + CUSTOMIZATIONS = f.read() + +CONDITIONAL_NAMES = {} diff --git a/src/_cffi_src/openssl/src/osrandom_engine.c b/src/_cffi_src/openssl/src/osrandom_engine.c new file mode 100644 index 000000000000..52f55af88dc6 --- /dev/null +++ b/src/_cffi_src/openssl/src/osrandom_engine.c @@ -0,0 +1,576 @@ +/* osurandom engine + * + * Windows CryptGenRandom() + * macOS >= 10.12 getentropy() + * OpenBSD 5.6+ getentropy() + * other BSD getentropy() if SYS_getentropy is defined + * Linux 3.4.17+ getrandom() with fallback to /dev/urandom + * other /dev/urandom with cached fd + * + * The /dev/urandom, getrandom and getentropy code is derived from Python's + * Python/random.c, written by Antoine Pitrou and Victor Stinner. + * + * Copyright 2001-2016 Python Software Foundation; All Rights Reserved. + */ + +static const char *Cryptography_osrandom_engine_id = "osrandom"; + +/**************************************************************************** + * Windows + */ +#if CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_CRYPTGENRANDOM +static const char *Cryptography_osrandom_engine_name = "osrandom_engine CryptGenRandom()"; +static HCRYPTPROV hCryptProv = 0; + +static int osrandom_init(ENGINE *e) { + if (hCryptProv != 0) { + return 1; + } + if (CryptAcquireContext(&hCryptProv, NULL, NULL, + PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) { + return 1; + } else { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_INIT, + CRYPTOGRAPHY_OSRANDOM_R_CRYPTACQUIRECONTEXT, + __FILE__, __LINE__ + ); + return 0; + } +} + +static int osrandom_rand_bytes(unsigned char *buffer, int size) { + if (hCryptProv == 0) { + return 0; + } + + if (!CryptGenRandom(hCryptProv, (DWORD)size, buffer)) { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES, + CRYPTOGRAPHY_OSRANDOM_R_CRYPTGENRANDOM, + __FILE__, __LINE__ + ); + return 0; + } + return 1; +} + +static int osrandom_finish(ENGINE *e) { + if (CryptReleaseContext(hCryptProv, 0)) { + hCryptProv = 0; + return 1; + } else { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_FINISH, + CRYPTOGRAPHY_OSRANDOM_R_CRYPTRELEASECONTEXT, + __FILE__, __LINE__ + ); + return 0; + } +} + +static int osrandom_rand_status(void) { + return hCryptProv != 0; +} + +static const char *osurandom_get_implementation(void) { + return "CryptGenRandom"; +} + +#endif /* CRYPTOGRAPHY_OSRANDOM_ENGINE_CRYPTGENRANDOM */ + +/**************************************************************************** + * BSD getentropy + */ +#if CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_GETENTROPY +static const char *Cryptography_osrandom_engine_name = "osrandom_engine getentropy()"; + +static int osrandom_init(ENGINE *e) { + return 1; +} + +static int osrandom_rand_bytes(unsigned char *buffer, int size) { + int len, res; + while (size > 0) { + /* OpenBSD and macOS restrict maximum buffer size to 256. */ + len = size > 256 ? 256 : size; + res = getentropy(buffer, len); + if (res < 0) { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES, + CRYPTOGRAPHY_OSRANDOM_R_GETENTROPY_FAILED, + __FILE__, __LINE__ + ); + return 0; + } + buffer += len; + size -= len; + } + return 1; +} + +static int osrandom_finish(ENGINE *e) { + return 1; +} + +static int osrandom_rand_status(void) { + return 1; +} + +static const char *osurandom_get_implementation(void) { + return "getentropy"; +} +#endif /* CRYPTOGRAPHY_OSRANDOM_ENGINE_GETENTROPY */ + +/**************************************************************************** + * /dev/urandom helpers for all non-BSD Unix platforms + */ +#ifdef CRYPTOGRAPHY_OSRANDOM_NEEDS_DEV_URANDOM + +static struct { + int fd; + dev_t st_dev; + ino_t st_ino; +} urandom_cache = { -1 }; + +/* return -1 on error */ +static int dev_urandom_fd(void) { + int fd, n, flags; + struct stat st; + + /* Check that fd still points to the correct device */ + if (urandom_cache.fd >= 0) { + if (fstat(urandom_cache.fd, &st) + || st.st_dev != urandom_cache.st_dev + || st.st_ino != urandom_cache.st_ino) { + /* Somebody replaced our FD. Invalidate our cache but don't + * close the fd. */ + urandom_cache.fd = -1; + } + } + if (urandom_cache.fd < 0) { + fd = open("/dev/urandom", O_RDONLY); + if (fd < 0) { + goto error; + } + if (fstat(fd, &st)) { + goto error; + } + /* set CLOEXEC flag */ + flags = fcntl(fd, F_GETFD); + if (flags == -1) { + goto error; + } else if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) { + goto error; + } + /* Another thread initialized the fd */ + if (urandom_cache.fd >= 0) { + do { + n = close(fd); + } while (n < 0 && errno == EINTR); + return urandom_cache.fd; + } + urandom_cache.st_dev = st.st_dev; + urandom_cache.st_ino = st.st_ino; + urandom_cache.fd = fd; + } + return urandom_cache.fd; + + error: + if (fd != -1) { + do { + n = close(fd); + } while (n < 0 && errno == EINTR); + } + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_FD, + CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_OPEN_FAILED, + __FILE__, __LINE__ + ); + return -1; +} + +static int dev_urandom_read(unsigned char *buffer, int size) { + int fd; + ssize_t n; + + fd = dev_urandom_fd(); + if (fd < 0) { + return 0; + } + + while (size > 0) { + do { + n = read(fd, buffer, (size_t)size); + } while (n < 0 && errno == EINTR); + + if (n <= 0) { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_READ, + CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_READ_FAILED, + __FILE__, __LINE__ + ); + return 0; + } + buffer += n; + size -= n; + } + return 1; +} + +static void dev_urandom_close(void) { + if (urandom_cache.fd >= 0) { + int fd, n; + struct stat st; + + if (fstat(urandom_cache.fd, &st) + && st.st_dev == urandom_cache.st_dev + && st.st_ino == urandom_cache.st_ino) { + fd = urandom_cache.fd; + urandom_cache.fd = -1; + do { + n = close(fd); + } while (n < 0 && errno == EINTR); + } + } +} +#endif /* CRYPTOGRAPHY_OSRANDOM_NEEDS_DEV_URANDOM */ + +/**************************************************************************** + * Linux getrandom engine with fallback to dev_urandom + */ + +#if CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_GETRANDOM +static const char *Cryptography_osrandom_engine_name = "osrandom_engine getrandom()"; + +static int getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_NOT_INIT; + +static int osrandom_init(ENGINE *e) { + /* We try to detect working getrandom until we succeed. */ + if (getrandom_works != CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS) { + long n; + char dest[1]; + n = syscall(SYS_getrandom, dest, sizeof(dest), GRND_NONBLOCK); + if (n == sizeof(dest)) { + getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS; + } else { + int e = errno; + switch(e) { + case ENOSYS: + /* Fallback: Kernel does not support the syscall. */ + getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK; + break; + case EPERM: + /* Fallback: seccomp prevents syscall */ + getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK; + break; + case EAGAIN: + /* Failure: Kernel CRPNG has not been seeded yet */ + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_INIT, + CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_EAGAIN, + __FILE__, __LINE__ + ); + getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED; + break; + default: + /* EINTR cannot occur for buflen < 256. */ + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_INIT, + CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_UNEXPECTED, + "errno", e + ); + getrandom_works = CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED; + break; + } + } + } + + /* fallback to dev urandom */ + if (getrandom_works == CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK) { + int fd = dev_urandom_fd(); + if (fd < 0) { + return 0; + } + } + return 1; +} + +static int osrandom_rand_bytes(unsigned char *buffer, int size) { + long n; + + switch(getrandom_works) { + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED: + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES, + CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED, + __FILE__, __LINE__ + ); + return 0; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_NOT_INIT: + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES, + CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_NOT_INIT, + __FILE__, __LINE__ + ); + return 0; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK: + return dev_urandom_read(buffer, size); + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS: + while (size > 0) { + do { + n = syscall(SYS_getrandom, buffer, size, GRND_NONBLOCK); + } while (n < 0 && errno == EINTR); + + if (n <= 0) { + ERR_Cryptography_OSRandom_error( + CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES, + CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_FAILED, + __FILE__, __LINE__ + ); + return 0; + } + buffer += n; + size -= n; + } + return 1; + } + return 0; /* unreachable */ +} + +static int osrandom_finish(ENGINE *e) { + dev_urandom_close(); + return 1; +} + +static int osrandom_rand_status(void) { + switch(getrandom_works) { + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED: + return 0; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_NOT_INIT: + return 0; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK: + return urandom_cache.fd >= 0; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS: + return 1; + } + return 0; /* unreachable */ +} + +static const char *osurandom_get_implementation(void) { + switch(getrandom_works) { + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED: + return ""; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_NOT_INIT: + return ""; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK: + return "/dev/urandom"; + case CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS: + return "getrandom"; + } + return ""; /* unreachable */ +} +#endif /* CRYPTOGRAPHY_OSRANDOM_ENGINE_GETRANDOM */ + +/**************************************************************************** + * dev_urandom engine for all remaining platforms + */ + +#if CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_DEV_URANDOM +static const char *Cryptography_osrandom_engine_name = "osrandom_engine /dev/urandom"; + +static int osrandom_init(ENGINE *e) { + int fd = dev_urandom_fd(); + if (fd < 0) { + return 0; + } + return 1; +} + +static int osrandom_rand_bytes(unsigned char *buffer, int size) { + return dev_urandom_read(buffer, size); +} + +static int osrandom_finish(ENGINE *e) { + dev_urandom_close(); + return 1; +} + +static int osrandom_rand_status(void) { + return urandom_cache.fd >= 0; +} + +static const char *osurandom_get_implementation(void) { + return "/dev/urandom"; +} +#endif /* CRYPTOGRAPHY_OSRANDOM_ENGINE_DEV_URANDOM */ + +/**************************************************************************** + * ENGINE boiler plate + */ + +/* This replicates the behavior of the OpenSSL FIPS RNG, which returns a + -1 in the event that there is an error when calling RAND_pseudo_bytes. */ +static int osrandom_pseudo_rand_bytes(unsigned char *buffer, int size) { + int res = osrandom_rand_bytes(buffer, size); + if (res == 0) { + return -1; + } else { + return res; + } +} + +static RAND_METHOD osrandom_rand = { + NULL, + osrandom_rand_bytes, + NULL, + NULL, + osrandom_pseudo_rand_bytes, + osrandom_rand_status, +}; + +static const ENGINE_CMD_DEFN osrandom_cmd_defns[] = { + {CRYPTOGRAPHY_OSRANDOM_GET_IMPLEMENTATION, + "get_implementation", + "Get CPRNG implementation.", + ENGINE_CMD_FLAG_NO_INPUT}, + {0, NULL, NULL, 0} +}; + +static int osrandom_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void)) { + const char *name; + size_t len; + + switch (cmd) { + case CRYPTOGRAPHY_OSRANDOM_GET_IMPLEMENTATION: + /* i: buffer size, p: char* buffer */ + name = osurandom_get_implementation(); + len = strlen(name); + if ((p == NULL) && (i == 0)) { + /* return required buffer len */ + return len; + } + if ((p == NULL) || i < 0 || ((size_t)i <= len)) { + /* no buffer or buffer too small */ + ENGINEerr(ENGINE_F_ENGINE_CTRL, ENGINE_R_INVALID_ARGUMENT); + return 0; + } + strncpy((char *)p, name, len); + return len; + default: + ENGINEerr(ENGINE_F_ENGINE_CTRL, ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED); + return 0; + } +} + +/* error reporting */ +#define ERR_FUNC(func) ERR_PACK(0, func, 0) +#define ERR_REASON(reason) ERR_PACK(0, 0, reason) + +static ERR_STRING_DATA CRYPTOGRAPHY_OSRANDOM_lib_name[] = { + {0, "osrandom_engine"}, + {0, NULL} +}; + +static ERR_STRING_DATA CRYPTOGRAPHY_OSRANDOM_str_funcs[] = { + {ERR_FUNC(CRYPTOGRAPHY_OSRANDOM_F_INIT), + "osrandom_init"}, + {ERR_FUNC(CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES), + "osrandom_rand_bytes"}, + {ERR_FUNC(CRYPTOGRAPHY_OSRANDOM_F_FINISH), + "osrandom_finish"}, + {ERR_FUNC(CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_FD), + "dev_urandom_fd"}, + {ERR_FUNC(CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_READ), + "dev_urandom_read"}, + {0, NULL} +}; + +static ERR_STRING_DATA CRYPTOGRAPHY_OSRANDOM_str_reasons[] = { + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_CRYPTACQUIRECONTEXT), + "CryptAcquireContext() failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_CRYPTGENRANDOM), + "CryptGenRandom() failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_CRYPTRELEASECONTEXT), + "CryptReleaseContext() failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETENTROPY_FAILED), + "getentropy() failed"}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_OPEN_FAILED), + "open('/dev/urandom') failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_READ_FAILED), + "Reading from /dev/urandom fd failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED), + "getrandom() initialization failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_EAGAIN), + "getrandom() initialization failed with EAGAIN. Most likely Kernel " + "CPRNG is not seeded yet."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_UNEXPECTED), + "getrandom() initialization failed with unexpected errno."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_FAILED), + "getrandom() syscall failed."}, + {ERR_REASON(CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_NOT_INIT), + "getrandom() engine was not properly initialized."}, + {0, NULL} +}; + +static int Cryptography_OSRandom_lib_error_code = 0; + +static void ERR_load_Cryptography_OSRandom_strings(void) +{ + if (Cryptography_OSRandom_lib_error_code == 0) { + Cryptography_OSRandom_lib_error_code = ERR_get_next_error_library(); + ERR_load_strings(Cryptography_OSRandom_lib_error_code, + CRYPTOGRAPHY_OSRANDOM_lib_name); + ERR_load_strings(Cryptography_OSRandom_lib_error_code, + CRYPTOGRAPHY_OSRANDOM_str_funcs); + ERR_load_strings(Cryptography_OSRandom_lib_error_code, + CRYPTOGRAPHY_OSRANDOM_str_reasons); + } +} + +static void ERR_Cryptography_OSRandom_error(int function, int reason, + char *file, int line) +{ + ERR_PUT_error(Cryptography_OSRandom_lib_error_code, function, reason, + file, line); +} + +/* Returns 1 if successfully added, 2 if engine has previously been added, + and 0 for error. */ +int Cryptography_add_osrandom_engine(void) { + ENGINE *e; + + ERR_load_Cryptography_OSRandom_strings(); + + e = ENGINE_by_id(Cryptography_osrandom_engine_id); + if (e != NULL) { + ENGINE_free(e); + return 2; + } else { + ERR_clear_error(); + } + + e = ENGINE_new(); + if (e == NULL) { + return 0; + } + if(!ENGINE_set_id(e, Cryptography_osrandom_engine_id) || + !ENGINE_set_name(e, Cryptography_osrandom_engine_name) || + !ENGINE_set_RAND(e, &osrandom_rand) || + !ENGINE_set_init_function(e, osrandom_init) || + !ENGINE_set_finish_function(e, osrandom_finish) || + !ENGINE_set_cmd_defns(e, osrandom_cmd_defns) || + !ENGINE_set_ctrl_function(e, osrandom_ctrl)) { + ENGINE_free(e); + return 0; + } + if (!ENGINE_add(e)) { + ENGINE_free(e); + return 0; + } + if (!ENGINE_free(e)) { + return 0; + } + + return 1; +} diff --git a/src/_cffi_src/openssl/src/osrandom_engine.h b/src/_cffi_src/openssl/src/osrandom_engine.h new file mode 100644 index 000000000000..d28ebf391943 --- /dev/null +++ b/src/_cffi_src/openssl/src/osrandom_engine.h @@ -0,0 +1,88 @@ +#ifdef _WIN32 + #include +#else + #include + #include + /* for defined(BSD) */ + #include + + #ifdef BSD + /* for SYS_getentropy */ + #include + #endif + + #ifdef __APPLE__ + #include + #endif + + #ifdef __linux__ + /* for SYS_getrandom */ + #include + #ifndef GRND_NONBLOCK + #define GRND_NONBLOCK 0x0001 + #endif /* GRND_NONBLOCK */ + #endif /* __linux__ */ +#endif /* _WIN32 */ + +#define CRYPTOGRAPHY_OSRANDOM_ENGINE_CRYPTGENRANDOM 1 +#define CRYPTOGRAPHY_OSRANDOM_ENGINE_GETENTROPY 2 +#define CRYPTOGRAPHY_OSRANDOM_ENGINE_GETRANDOM 3 +#define CRYPTOGRAPHY_OSRANDOM_ENGINE_DEV_URANDOM 4 + +#ifndef CRYPTOGRAPHY_OSRANDOM_ENGINE + #if defined(_WIN32) + /* Windows */ + #define CRYPTOGRAPHY_OSRANDOM_ENGINE CRYPTOGRAPHY_OSRANDOM_ENGINE_CRYPTGENRANDOM + #elif defined(BSD) && defined(SYS_getentropy) + /* OpenBSD 5.6+ or macOS 10.12+ */ + #define CRYPTOGRAPHY_OSRANDOM_ENGINE CRYPTOGRAPHY_OSRANDOM_ENGINE_GETENTROPY + #elif defined(__linux__) && defined(SYS_getrandom) + /* Linux 3.4.17+ */ + #define CRYPTOGRAPHY_OSRANDOM_ENGINE CRYPTOGRAPHY_OSRANDOM_ENGINE_GETRANDOM + #else + /* Keep this as last entry, fall back to /dev/urandom */ + #define CRYPTOGRAPHY_OSRANDOM_ENGINE CRYPTOGRAPHY_OSRANDOM_ENGINE_DEV_URANDOM + #endif +#endif /* CRYPTOGRAPHY_OSRANDOM_ENGINE */ + +/* Fallbacks need /dev/urandom helper functions. */ +#if CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_GETRANDOM || \ + CRYPTOGRAPHY_OSRANDOM_ENGINE == CRYPTOGRAPHY_OSRANDOM_ENGINE_DEV_URANDOM + #define CRYPTOGRAPHY_OSRANDOM_NEEDS_DEV_URANDOM 1 +#endif + +enum { + CRYPTOGRAPHY_OSRANDOM_GETRANDOM_INIT_FAILED = -2, + CRYPTOGRAPHY_OSRANDOM_GETRANDOM_NOT_INIT, + CRYPTOGRAPHY_OSRANDOM_GETRANDOM_FALLBACK, + CRYPTOGRAPHY_OSRANDOM_GETRANDOM_WORKS +}; + +/* engine ctrl */ +#define CRYPTOGRAPHY_OSRANDOM_GET_IMPLEMENTATION ENGINE_CMD_BASE + +/* error reporting */ +static void ERR_load_Cryptography_OSRandom_strings(void); +static void ERR_Cryptography_OSRandom_error(int function, int reason, + char *file, int line); + +#define CRYPTOGRAPHY_OSRANDOM_F_INIT 100 +#define CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES 101 +#define CRYPTOGRAPHY_OSRANDOM_F_FINISH 102 +#define CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_FD 300 +#define CRYPTOGRAPHY_OSRANDOM_F_DEV_URANDOM_READ 301 + +#define CRYPTOGRAPHY_OSRANDOM_R_CRYPTACQUIRECONTEXT 100 +#define CRYPTOGRAPHY_OSRANDOM_R_CRYPTGENRANDOM 101 +#define CRYPTOGRAPHY_OSRANDOM_R_CRYPTRELEASECONTEXT 102 + +#define CRYPTOGRAPHY_OSRANDOM_R_GETENTROPY_FAILED 200 + +#define CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_OPEN_FAILED 300 +#define CRYPTOGRAPHY_OSRANDOM_R_DEV_URANDOM_READ_FAILED 301 + +#define CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED 400 +#define CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_EAGAIN 401 +#define CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_INIT_FAILED_UNEXPECTED 402 +#define CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_FAILED 403 +#define CRYPTOGRAPHY_OSRANDOM_R_GETRANDOM_NOT_INIT 404 diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py index 1c01e83dff58..71063c1920eb 100644 --- a/src/cryptography/hazmat/backends/openssl/backend.py +++ b/src/cryptography/hazmat/backends/openssl/backend.py @@ -7,6 +7,7 @@ import base64 import calendar import collections +import contextlib import itertools import sys from contextlib import contextmanager @@ -157,9 +158,8 @@ def activate_builtin_random(self): res = self._lib.ENGINE_finish(e) self.openssl_assert(res == 1) - def activate_osrandom_engine(self): - # Unregister and free the current engine. - self.activate_builtin_random() + @contextlib.contextmanager + def _get_osurandom_engine(self): # Fetches an engine by id and returns it. This creates a structural # reference. e = self._lib.ENGINE_by_id(self._binding._osrandom_engine_id) @@ -167,18 +167,36 @@ def activate_osrandom_engine(self): # Initialize the engine for use. This adds a functional reference. res = self._lib.ENGINE_init(e) self.openssl_assert(res == 1) - # Set the engine as the default RAND provider. - res = self._lib.ENGINE_set_default_RAND(e) - self.openssl_assert(res == 1) - # Decrement the structural ref incremented by ENGINE_by_id. - res = self._lib.ENGINE_free(e) - self.openssl_assert(res == 1) - # Decrement the functional ref incremented by ENGINE_init. - res = self._lib.ENGINE_finish(e) - self.openssl_assert(res == 1) + + try: + yield e + finally: + # Decrement the structural ref incremented by ENGINE_by_id. + res = self._lib.ENGINE_free(e) + self.openssl_assert(res == 1) + # Decrement the functional ref incremented by ENGINE_init. + res = self._lib.ENGINE_finish(e) + self.openssl_assert(res == 1) + + def activate_osrandom_engine(self): + # Unregister and free the current engine. + self.activate_builtin_random() + with self._get_osurandom_engine() as e: + # Set the engine as the default RAND provider. + res = self._lib.ENGINE_set_default_RAND(e) + self.openssl_assert(res == 1) # Reset the RNG to use the new engine. self._lib.RAND_cleanup() + def osrandom_engine_implementation(self): + buf = self._ffi.new("char[]", 64) + with self._get_osurandom_engine() as e: + res = self._lib.ENGINE_ctrl_cmd(e, b"get_implementation", + len(buf), buf, + self._ffi.NULL, 0) + self.openssl_assert(res > 0) + return self._ffi.string(buf).decode('ascii') + def openssl_version_text(self): """ Friendly string name of the loaded OpenSSL library. This is not diff --git a/src/cryptography/hazmat/bindings/openssl/binding.py b/src/cryptography/hazmat/bindings/openssl/binding.py index 19151b0e158d..39750abcd9af 100644 --- a/src/cryptography/hazmat/bindings/openssl/binding.py +++ b/src/cryptography/hazmat/bindings/openssl/binding.py @@ -82,21 +82,6 @@ def wrapper(func): return wrapper -@ffi_callback("int (*)(unsigned char *, int)", - name="Cryptography_rand_bytes", - error=-1) -def _osrandom_rand_bytes(buf, size): - signed = ffi.cast("char *", buf) - result = os.urandom(size) - signed[0:size] = result - return 1 - - -@ffi_callback("int (*)(void)", name="Cryptography_rand_status") -def _osrandom_rand_status(): - return 1 - - def build_conditional_library(lib, conditional_names): conditional_lib = types.ModuleType("lib") excluded_names = set() @@ -121,42 +106,16 @@ class Binding(object): _init_lock = threading.Lock() _lock_init_lock = threading.Lock() - _osrandom_engine_id = ffi.new("const char[]", b"osrandom") - _osrandom_engine_name = ffi.new("const char[]", b"osrandom_engine") - _osrandom_method = ffi.new( - "RAND_METHOD *", - dict(bytes=_osrandom_rand_bytes, - pseudorand=_osrandom_rand_bytes, - status=_osrandom_rand_status) - ) - def __init__(self): self._ensure_ffi_initialized() @classmethod def _register_osrandom_engine(cls): _openssl_assert(cls.lib, cls.lib.ERR_peek_error() == 0) - - engine = cls.lib.ENGINE_new() - _openssl_assert(cls.lib, engine != cls.ffi.NULL) - try: - result = cls.lib.ENGINE_set_id(engine, cls._osrandom_engine_id) - _openssl_assert(cls.lib, result == 1) - result = cls.lib.ENGINE_set_name(engine, cls._osrandom_engine_name) - _openssl_assert(cls.lib, result == 1) - result = cls.lib.ENGINE_set_RAND(engine, cls._osrandom_method) - _openssl_assert(cls.lib, result == 1) - result = cls.lib.ENGINE_add(engine) - if result != 1: - errors = _consume_errors(cls.lib) - _openssl_assert( - cls.lib, - errors[0].reason == cls.lib.ENGINE_R_CONFLICTING_ENGINE_ID - ) - - finally: - result = cls.lib.ENGINE_free(engine) - _openssl_assert(cls.lib, result == 1) + cls._osrandom_engine_id = cls.lib.Cryptography_osrandom_engine_id + cls._osrandom_engine_name = cls.lib.Cryptography_osrandom_engine_name + result = cls.lib.Cryptography_add_osrandom_engine() + _openssl_assert(cls.lib, result in (1, 2)) @classmethod def _ensure_ffi_initialized(cls): diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py index db3c19b831f9..47c46065eb99 100644 --- a/tests/hazmat/backends/test_openssl.py +++ b/tests/hazmat/backends/test_openssl.py @@ -11,6 +11,8 @@ import sys import textwrap +from pkg_resources import parse_version + import pytest from cryptography import utils, x509 @@ -173,19 +175,6 @@ def test_bn_to_int(self): bn = backend._int_to_bn(0) assert backend._bn_to_int(bn) == 0 - def test_actual_osrandom_bytes(self, monkeypatch): - skip_if_libre_ssl(backend.openssl_version_text()) - sample_data = (b"\x01\x02\x03\x04" * 4) - length = len(sample_data) - - def notrandom(size): - assert size == length - return sample_data - monkeypatch.setattr(os, "urandom", notrandom) - buf = backend._ffi.new("unsigned char[]", length) - backend._lib.RAND_bytes(buf, length) - assert backend._ffi.buffer(buf)[0:length] == sample_data - class TestOpenSSLRandomEngine(object): def setup(self): @@ -282,6 +271,23 @@ def test_activate_builtin_random_already_active(self): e = backend._lib.ENGINE_get_default_RAND() assert e == backend._ffi.NULL + def test_osrandom_engine_implementation(self): + name = backend.osrandom_engine_implementation() + assert name in ['/dev/urandom', 'CryptGenRandom', 'getentropy', + 'getrandom'] + if sys.platform.startswith('linux'): + assert name in ['getrandom', '/dev/urandom'] + if sys.platform == 'darwin': + # macOS 10.12+ supports getentropy + if parse_version(os.uname()[2]) >= parse_version("16.0"): + assert name == 'getentropy' + else: + assert name == '/dev/urandom' + if 'bsd' in sys.platform: + assert name in ['getentropy', '/dev/urandom'] + if sys.platform == 'win32': + assert name == 'CryptGenRandom' + def test_activate_osrandom_already_default(self): e = backend._lib.ENGINE_get_default_RAND() name = backend._lib.ENGINE_get_name(e)