diff options
Diffstat (limited to 'Python/random.c')
| -rw-r--r-- | Python/random.c | 209 |
1 files changed, 129 insertions, 80 deletions
diff --git a/Python/random.c b/Python/random.c index 337be86087..af3d0bd0d5 100644 --- a/Python/random.c +++ b/Python/random.c @@ -3,6 +3,9 @@ #include <windows.h> #else #include <fcntl.h> +#ifdef HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif #endif #ifdef Py_DEBUG @@ -12,43 +15,14 @@ static int _Py_HashSecret_Initialized = 0; #endif #ifdef MS_WINDOWS -typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTA)(HCRYPTPROV *phProv,\ - LPCSTR pszContainer, LPCSTR pszProvider, DWORD dwProvType,\ - DWORD dwFlags ); -typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV hProv, DWORD dwLen,\ - BYTE *pbBuffer ); - -static CRYPTGENRANDOM pCryptGenRandom = NULL; -/* This handle is never explicitly released. Instead, the operating - system will release it when the process terminates. */ static HCRYPTPROV hCryptProv = 0; static int win32_urandom_init(int raise) { - HINSTANCE hAdvAPI32 = NULL; - CRYPTACQUIRECONTEXTA pCryptAcquireContext = NULL; - - /* Obtain handle to the DLL containing CryptoAPI. This should not fail. */ - hAdvAPI32 = GetModuleHandle("advapi32.dll"); - if(hAdvAPI32 == NULL) - goto error; - - /* Obtain pointers to the CryptoAPI functions. This will fail on some early - versions of Win95. */ - pCryptAcquireContext = (CRYPTACQUIRECONTEXTA)GetProcAddress( - hAdvAPI32, "CryptAcquireContextA"); - if (pCryptAcquireContext == NULL) - goto error; - - pCryptGenRandom = (CRYPTGENRANDOM)GetProcAddress(hAdvAPI32, - "CryptGenRandom"); - if (pCryptGenRandom == NULL) - goto error; - /* Acquire context */ - if (! pCryptAcquireContext(&hCryptProv, NULL, NULL, - PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) + if (!CryptAcquireContext(&hCryptProv, NULL, NULL, + PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) goto error; return 0; @@ -62,7 +36,7 @@ error: } /* Fill buffer with size pseudo-random bytes generated by the Windows CryptoGen - API. Return 0 on success, or -1 on error. */ + API. Return 0 on success, or raise an exception and return -1 on error. */ static int win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise) { @@ -77,7 +51,7 @@ win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise) while (size > 0) { chunk = size > INT_MAX ? INT_MAX : size; - if (!pCryptGenRandom(hCryptProv, chunk, buffer)) + if (!CryptGenRandom(hCryptProv, (DWORD)chunk, buffer)) { /* CryptGenRandom() failed */ if (raise) @@ -92,43 +66,64 @@ win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise) } return 0; } -#endif /* MS_WINDOWS */ +/* Issue #25003: Don' use getentropy() on Solaris (available since + * Solaris 11.3), it is blocking whereas os.urandom() should not block. */ +#elif defined(HAVE_GETENTROPY) && !defined(sun) +#define PY_GETENTROPY 1 + +/* Fill buffer with size pseudo-random bytes generated by getentropy(). + Return 0 on success, or raise an exception and return -1 on error. -#ifdef __VMS -/* Use openssl random routine */ -#include <openssl/rand.h> + If fatal is nonzero, call Py_FatalError() instead of raising an exception + on error. */ static int -vms_urandom(unsigned char *buffer, Py_ssize_t size, int raise) +py_getentropy(unsigned char *buffer, Py_ssize_t size, int fatal) { - if (RAND_pseudo_bytes(buffer, size) < 0) { - if (raise) { - PyErr_Format(PyExc_ValueError, - "RAND_pseudo_bytes"); - } else { - Py_FatalError("Failed to initialize the randomized hash " - "secret using RAND_pseudo_bytes"); + while (size > 0) { + Py_ssize_t len = Py_MIN(size, 256); + int res; + + if (!fatal) { + Py_BEGIN_ALLOW_THREADS + res = getentropy(buffer, len); + Py_END_ALLOW_THREADS + + if (res < 0) { + PyErr_SetFromErrno(PyExc_OSError); + return -1; + } } - return -1; + else { + res = getentropy(buffer, len); + if (res < 0) + Py_FatalError("getentropy() failed"); + } + + buffer += len; + size -= len; } return 0; } -#endif /* __VMS */ - -#if !defined(MS_WINDOWS) && !defined(__VMS) +#else +static struct { + int fd; + dev_t st_dev; + ino_t st_ino; +} urandom_cache = { -1 }; /* Read size bytes from /dev/urandom into buffer. Call Py_FatalError() on error. */ static void -dev_urandom_noraise(char *buffer, Py_ssize_t size) +dev_urandom_noraise(unsigned char *buffer, Py_ssize_t size) { int fd; Py_ssize_t n; assert (0 < size); - fd = open("/dev/urandom", O_RDONLY); + fd = _Py_open("/dev/urandom", O_RDONLY); if (fd < 0) Py_FatalError("Failed to open /dev/urandom"); @@ -156,22 +151,56 @@ dev_urandom_python(char *buffer, Py_ssize_t size) { int fd; Py_ssize_t n; + struct stat st; if (size <= 0) return 0; - Py_BEGIN_ALLOW_THREADS - fd = open("/dev/urandom", O_RDONLY); - Py_END_ALLOW_THREADS - if (fd < 0) - { - if (errno == ENOENT || errno == ENXIO || - errno == ENODEV || errno == EACCES) - PyErr_SetString(PyExc_NotImplementedError, - "/dev/urandom (or equivalent) not found"); - else - PyErr_SetFromErrno(PyExc_OSError); - return -1; + if (urandom_cache.fd >= 0) { + /* Does the fd point to the same thing as before? (issue #21207) */ + if (fstat(urandom_cache.fd, &st) + || st.st_dev != urandom_cache.st_dev + || st.st_ino != urandom_cache.st_ino) { + /* Something changed: forget the cached fd (but don't close it, + since it probably points to something important for some + third-party code). */ + urandom_cache.fd = -1; + } + } + if (urandom_cache.fd >= 0) + fd = urandom_cache.fd; + else { + Py_BEGIN_ALLOW_THREADS + fd = _Py_open("/dev/urandom", O_RDONLY); + Py_END_ALLOW_THREADS + if (fd < 0) + { + if (errno == ENOENT || errno == ENXIO || + errno == ENODEV || errno == EACCES) + PyErr_SetString(PyExc_NotImplementedError, + "/dev/urandom (or equivalent) not found"); + else + PyErr_SetFromErrno(PyExc_OSError); + return -1; + } + if (urandom_cache.fd >= 0) { + /* urandom_fd was initialized by another thread while we were + not holding the GIL, keep it. */ + close(fd); + fd = urandom_cache.fd; + } + else { + if (fstat(fd, &st)) { + PyErr_SetFromErrno(PyExc_OSError); + close(fd); + return -1; + } + else { + urandom_cache.fd = fd; + urandom_cache.st_dev = st.st_dev; + urandom_cache.st_ino = st.st_ino; + } + } } Py_BEGIN_ALLOW_THREADS @@ -195,13 +224,21 @@ dev_urandom_python(char *buffer, Py_ssize_t size) PyErr_Format(PyExc_RuntimeError, "Failed to read %zi bytes from /dev/urandom", size); - close(fd); return -1; } - close(fd); return 0; } -#endif /* !defined(MS_WINDOWS) && !defined(__VMS) */ + +static void +dev_urandom_close(void) +{ + if (urandom_cache.fd >= 0) { + close(urandom_cache.fd); + urandom_cache.fd = -1; + } +} + +#endif /* HAVE_GETENTROPY */ /* Fill buffer with pseudo-random bytes generated by a linear congruent generator (LCG): @@ -225,7 +262,7 @@ lcg_urandom(unsigned int x0, unsigned char *buffer, size_t size) } /* Fill buffer with size pseudo-random bytes from the operating system random - number generator (RNG). It is suitable for for most cryptographic purposes + number generator (RNG). It is suitable for most cryptographic purposes except long living private keys for asymmetric encryption. Return 0 on success, raise an exception and return -1 on error. */ @@ -242,12 +279,10 @@ _PyOS_URandom(void *buffer, Py_ssize_t size) #ifdef MS_WINDOWS return win32_urandom((unsigned char *)buffer, size, 1); +#elif defined(PY_GETENTROPY) + return py_getentropy(buffer, size, 0); #else -# ifdef __VMS - return vms_urandom((unsigned char *)buffer, size, 1); -# else return dev_urandom_python((char*)buffer, size); -# endif #endif } @@ -255,8 +290,9 @@ void _PyRandom_Init(void) { char *env; - void *secret = &_Py_HashSecret; + unsigned char *secret = (unsigned char *)&_Py_HashSecret.uc; Py_ssize_t secret_size = sizeof(_Py_HashSecret_t); + assert(secret_size == sizeof(_Py_HashSecret.uc)); if (_Py_HashSecret_Initialized) return; @@ -284,18 +320,31 @@ _PyRandom_Init(void) memset(secret, 0, secret_size); } else { - lcg_urandom(seed, (unsigned char*)secret, secret_size); + lcg_urandom(seed, secret, secret_size); } } else { #ifdef MS_WINDOWS - (void)win32_urandom((unsigned char *)secret, secret_size, 0); -#else /* #ifdef MS_WINDOWS */ -# ifdef __VMS - vms_urandom((unsigned char *)secret, secret_size, 0); -# else - dev_urandom_noraise((char*)secret, secret_size); -# endif + (void)win32_urandom(secret, secret_size, 0); +#elif defined(PY_GETENTROPY) + (void)py_getentropy(secret, secret_size, 1); +#else + dev_urandom_noraise(secret, secret_size); #endif } } + +void +_PyRandom_Fini(void) +{ +#ifdef MS_WINDOWS + if (hCryptProv) { + CryptReleaseContext(hCryptProv, 0); + hCryptProv = 0; + } +#elif defined(PY_GETENTROPY) + /* nothing to clean */ +#else + dev_urandom_close(); +#endif +} |