Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 1 | #include "Python.h" |
| 2 | #ifdef MS_WINDOWS |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 3 | # include <windows.h> |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 4 | #else |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 5 | # include <fcntl.h> |
| 6 | # ifdef HAVE_SYS_STAT_H |
| 7 | # include <sys/stat.h> |
| 8 | # endif |
Victor Stinner | dddf484 | 2016-06-07 11:21:42 +0200 | [diff] [blame] | 9 | # ifdef HAVE_LINUX_RANDOM_H |
| 10 | # include <linux/random.h> |
| 11 | # endif |
Ned Deily | 7ae4112 | 2016-11-12 16:35:48 -0500 | [diff] [blame^] | 12 | # if defined(HAVE_GETRANDOM) || defined(HAVE_GETENTROPY) |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 13 | # include <sys/random.h> |
Ned Deily | 7ae4112 | 2016-11-12 16:35:48 -0500 | [diff] [blame^] | 14 | # endif |
| 15 | # if !defined(HAVE_GETRANDOM) && defined(HAVE_GETRANDOM_SYSCALL) |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 16 | # include <sys/syscall.h> |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 17 | # endif |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 18 | #endif |
| 19 | |
Benjamin Peterson | 69e9727 | 2012-02-21 11:08:50 -0500 | [diff] [blame] | 20 | #ifdef Py_DEBUG |
| 21 | int _Py_HashSecret_Initialized = 0; |
| 22 | #else |
| 23 | static int _Py_HashSecret_Initialized = 0; |
| 24 | #endif |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 25 | |
| 26 | #ifdef MS_WINDOWS |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 27 | static HCRYPTPROV hCryptProv = 0; |
| 28 | |
| 29 | static int |
| 30 | win32_urandom_init(int raise) |
| 31 | { |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 32 | /* Acquire context */ |
Martin v. Löwis | 3f50bf6 | 2013-01-25 14:06:18 +0100 | [diff] [blame] | 33 | if (!CryptAcquireContext(&hCryptProv, NULL, NULL, |
| 34 | PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 35 | goto error; |
| 36 | |
| 37 | return 0; |
| 38 | |
| 39 | error: |
| 40 | if (raise) |
| 41 | PyErr_SetFromWindowsErr(0); |
| 42 | else |
| 43 | Py_FatalError("Failed to initialize Windows random API (CryptoGen)"); |
| 44 | return -1; |
| 45 | } |
| 46 | |
| 47 | /* Fill buffer with size pseudo-random bytes generated by the Windows CryptoGen |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 48 | API. Return 0 on success, or raise an exception and return -1 on error. */ |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 49 | static int |
| 50 | win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise) |
| 51 | { |
| 52 | Py_ssize_t chunk; |
| 53 | |
| 54 | if (hCryptProv == 0) |
| 55 | { |
| 56 | if (win32_urandom_init(raise) == -1) |
| 57 | return -1; |
| 58 | } |
| 59 | |
| 60 | while (size > 0) |
| 61 | { |
| 62 | chunk = size > INT_MAX ? INT_MAX : size; |
Victor Stinner | 0c08346 | 2013-11-15 23:26:25 +0100 | [diff] [blame] | 63 | if (!CryptGenRandom(hCryptProv, (DWORD)chunk, buffer)) |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 64 | { |
| 65 | /* CryptGenRandom() failed */ |
| 66 | if (raise) |
| 67 | PyErr_SetFromWindowsErr(0); |
| 68 | else |
| 69 | Py_FatalError("Failed to initialized the randomized hash " |
| 70 | "secret using CryptoGen)"); |
| 71 | return -1; |
| 72 | } |
| 73 | buffer += chunk; |
| 74 | size -= chunk; |
| 75 | } |
| 76 | return 0; |
| 77 | } |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 78 | |
Martin Panter | 39b1025 | 2016-06-10 08:07:11 +0000 | [diff] [blame] | 79 | /* Issue #25003: Don't use getentropy() on Solaris (available since |
| 80 | * Solaris 11.3), it is blocking whereas os.urandom() should not block. */ |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 81 | #elif defined(HAVE_GETENTROPY) && !defined(sun) |
| 82 | #define PY_GETENTROPY 1 |
| 83 | |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 84 | /* Fill buffer with size pseudo-random bytes generated by getentropy(). |
| 85 | Return 0 on success, or raise an exception and return -1 on error. |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 86 | |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 87 | If fatal is nonzero, call Py_FatalError() instead of raising an exception |
| 88 | on error. */ |
| 89 | static int |
| 90 | py_getentropy(unsigned char *buffer, Py_ssize_t size, int fatal) |
| 91 | { |
| 92 | while (size > 0) { |
| 93 | Py_ssize_t len = Py_MIN(size, 256); |
Victor Stinner | 9aa1331 | 2015-03-30 11:18:30 +0200 | [diff] [blame] | 94 | int res; |
| 95 | |
| 96 | if (!fatal) { |
| 97 | Py_BEGIN_ALLOW_THREADS |
| 98 | res = getentropy(buffer, len); |
| 99 | Py_END_ALLOW_THREADS |
| 100 | |
| 101 | if (res < 0) { |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 102 | PyErr_SetFromErrno(PyExc_OSError); |
| 103 | return -1; |
| 104 | } |
| 105 | } |
Victor Stinner | 9aa1331 | 2015-03-30 11:18:30 +0200 | [diff] [blame] | 106 | else { |
| 107 | res = getentropy(buffer, len); |
| 108 | if (res < 0) |
| 109 | Py_FatalError("getentropy() failed"); |
| 110 | } |
| 111 | |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 112 | buffer += len; |
| 113 | size -= len; |
| 114 | } |
| 115 | return 0; |
| 116 | } |
| 117 | |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 118 | #else |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 119 | |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 120 | #if defined(HAVE_GETRANDOM) || defined(HAVE_GETRANDOM_SYSCALL) |
| 121 | #define PY_GETRANDOM 1 |
| 122 | |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 123 | /* Call getrandom() |
| 124 | - Return 1 on success |
Victor Stinner | 6d8bc46 | 2016-09-20 22:46:02 +0200 | [diff] [blame] | 125 | - Return 0 if getrandom() syscall is not available (failed with ENOSYS or |
| 126 | EPERM) or if getrandom(GRND_NONBLOCK) failed with EAGAIN (system urandom |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 127 | not initialized yet) and raise=0. |
| 128 | - Raise an exception (if raise is non-zero) and return -1 on error: |
| 129 | getrandom() failed with EINTR and the Python signal handler raised an |
| 130 | exception, or getrandom() failed with a different error. */ |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 131 | static int |
| 132 | py_getrandom(void *buffer, Py_ssize_t size, int raise) |
| 133 | { |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 134 | /* Is getrandom() supported by the running kernel? Set to 0 if getrandom() |
Victor Stinner | 6d8bc46 | 2016-09-20 22:46:02 +0200 | [diff] [blame] | 135 | failed with ENOSYS or EPERM. Need Linux kernel 3.17 or newer, or Solaris |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 136 | 11.3 or newer */ |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 137 | static int getrandom_works = 1; |
Victor Stinner | dddf484 | 2016-06-07 11:21:42 +0200 | [diff] [blame] | 138 | |
| 139 | /* getrandom() on Linux will block if called before the kernel has |
| 140 | * initialized the urandom entropy pool. This will cause Python |
| 141 | * to hang on startup if called very early in the boot process - |
| 142 | * see https://bugs.python.org/issue26839. To avoid this, use the |
| 143 | * GRND_NONBLOCK flag. */ |
| 144 | const int flags = GRND_NONBLOCK; |
Victor Stinner | ec721f3 | 2016-06-16 23:53:47 +0200 | [diff] [blame] | 145 | long n; |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 146 | |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 147 | if (!getrandom_works) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 148 | return 0; |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 149 | } |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 150 | |
| 151 | while (0 < size) { |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 152 | #ifdef sun |
| 153 | /* Issue #26735: On Solaris, getrandom() is limited to returning up |
| 154 | to 1024 bytes */ |
| 155 | n = Py_MIN(size, 1024); |
| 156 | #else |
Victor Stinner | ec721f3 | 2016-06-16 23:53:47 +0200 | [diff] [blame] | 157 | n = Py_MIN(size, LONG_MAX); |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 158 | #endif |
Victor Stinner | 79b74ae | 2015-03-30 11:16:40 +0200 | [diff] [blame] | 159 | |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 160 | errno = 0; |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 161 | #ifdef HAVE_GETRANDOM |
| 162 | if (raise) { |
| 163 | Py_BEGIN_ALLOW_THREADS |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 164 | n = getrandom(buffer, n, flags); |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 165 | Py_END_ALLOW_THREADS |
| 166 | } |
| 167 | else { |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 168 | n = getrandom(buffer, n, flags); |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 169 | } |
| 170 | #else |
| 171 | /* On Linux, use the syscall() function because the GNU libc doesn't |
| 172 | * expose the Linux getrandom() syscall yet. See: |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 173 | * https://sourceware.org/bugzilla/show_bug.cgi?id=17252 */ |
Victor Stinner | 79b74ae | 2015-03-30 11:16:40 +0200 | [diff] [blame] | 174 | if (raise) { |
| 175 | Py_BEGIN_ALLOW_THREADS |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 176 | n = syscall(SYS_getrandom, buffer, n, flags); |
Victor Stinner | 79b74ae | 2015-03-30 11:16:40 +0200 | [diff] [blame] | 177 | Py_END_ALLOW_THREADS |
| 178 | } |
| 179 | else { |
Victor Stinner | 9d24271 | 2016-04-12 22:28:49 +0200 | [diff] [blame] | 180 | n = syscall(SYS_getrandom, buffer, n, flags); |
Victor Stinner | 79b74ae | 2015-03-30 11:16:40 +0200 | [diff] [blame] | 181 | } |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 182 | #endif |
Victor Stinner | 79b74ae | 2015-03-30 11:16:40 +0200 | [diff] [blame] | 183 | |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 184 | if (n < 0) { |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 185 | /* ENOSYS: getrandom() syscall not supported by the kernel (but |
Victor Stinner | 6d8bc46 | 2016-09-20 22:46:02 +0200 | [diff] [blame] | 186 | * maybe supported by the host which built Python). EPERM: |
| 187 | * getrandom() syscall blocked by SECCOMP or something else. */ |
| 188 | if (errno == ENOSYS || errno == EPERM) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 189 | getrandom_works = 0; |
| 190 | return 0; |
| 191 | } |
Victor Stinner | dddf484 | 2016-06-07 11:21:42 +0200 | [diff] [blame] | 192 | if (errno == EAGAIN) { |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 193 | /* getrandom(GRND_NONBLOCK) fails with EAGAIN if the system |
| 194 | urandom is not initialiazed yet. In this case, fall back on |
| 195 | reading from /dev/urandom. |
| 196 | |
| 197 | Note: In this case the data read will not be random so |
| 198 | should not be used for cryptographic purposes. Retaining |
| 199 | the existing semantics for practical purposes. */ |
Victor Stinner | dddf484 | 2016-06-07 11:21:42 +0200 | [diff] [blame] | 200 | getrandom_works = 0; |
| 201 | return 0; |
| 202 | } |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 203 | |
| 204 | if (errno == EINTR) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 205 | if (PyErr_CheckSignals()) { |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 206 | if (!raise) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 207 | Py_FatalError("getrandom() interrupted by a signal"); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 208 | } |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 209 | return -1; |
| 210 | } |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 211 | |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 212 | /* retry getrandom() */ |
| 213 | continue; |
| 214 | } |
| 215 | |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 216 | if (raise) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 217 | PyErr_SetFromErrno(PyExc_OSError); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 218 | } |
| 219 | else { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 220 | Py_FatalError("getrandom() failed"); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 221 | } |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 222 | return -1; |
| 223 | } |
| 224 | |
| 225 | buffer += n; |
| 226 | size -= n; |
| 227 | } |
| 228 | return 1; |
| 229 | } |
| 230 | #endif |
| 231 | |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 232 | static struct { |
| 233 | int fd; |
| 234 | dev_t st_dev; |
| 235 | ino_t st_ino; |
| 236 | } urandom_cache = { -1 }; |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 237 | |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 238 | |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 239 | /* Read 'size' random bytes from py_getrandom(). Fall back on reading from |
| 240 | /dev/urandom if getrandom() is not available. |
| 241 | |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 242 | Call Py_FatalError() on error. */ |
| 243 | static void |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 244 | dev_urandom_noraise(unsigned char *buffer, Py_ssize_t size) |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 245 | { |
| 246 | int fd; |
| 247 | Py_ssize_t n; |
| 248 | |
| 249 | assert (0 < size); |
| 250 | |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 251 | #ifdef PY_GETRANDOM |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 252 | if (py_getrandom(buffer, size, 0) == 1) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 253 | return; |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 254 | } |
Victor Stinner | 6d8bc46 | 2016-09-20 22:46:02 +0200 | [diff] [blame] | 255 | /* getrandom() failed with ENOSYS or EPERM, |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 256 | fall back on reading /dev/urandom */ |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 257 | #endif |
| 258 | |
Victor Stinner | c7cd12d | 2015-03-19 23:24:45 +0100 | [diff] [blame] | 259 | fd = _Py_open_noraise("/dev/urandom", O_RDONLY); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 260 | if (fd < 0) { |
Victor Stinner | c7cd12d | 2015-03-19 23:24:45 +0100 | [diff] [blame] | 261 | Py_FatalError("Failed to open /dev/urandom"); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 262 | } |
Victor Stinner | c7cd12d | 2015-03-19 23:24:45 +0100 | [diff] [blame] | 263 | |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 264 | while (0 < size) |
| 265 | { |
| 266 | do { |
| 267 | n = read(fd, buffer, (size_t)size); |
| 268 | } while (n < 0 && errno == EINTR); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 269 | |
| 270 | if (n <= 0) { |
| 271 | /* read() failed or returned 0 bytes */ |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 272 | Py_FatalError("Failed to read bytes from /dev/urandom"); |
| 273 | break; |
| 274 | } |
| 275 | buffer += n; |
Victor Stinner | c72828b | 2016-06-14 16:35:49 +0200 | [diff] [blame] | 276 | size -= n; |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 277 | } |
| 278 | close(fd); |
| 279 | } |
| 280 | |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 281 | /* Read 'size' random bytes from py_getrandom(). Fall back on reading from |
| 282 | /dev/urandom if getrandom() is not available. |
| 283 | |
| 284 | Return 0 on success. Raise an exception and return -1 on error. */ |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 285 | static int |
| 286 | dev_urandom_python(char *buffer, Py_ssize_t size) |
| 287 | { |
| 288 | int fd; |
| 289 | Py_ssize_t n; |
Steve Dower | f2f373f | 2015-02-21 08:44:05 -0800 | [diff] [blame] | 290 | struct _Py_stat_struct st; |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 291 | #ifdef PY_GETRANDOM |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 292 | int res; |
| 293 | #endif |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 294 | |
| 295 | if (size <= 0) |
| 296 | return 0; |
| 297 | |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 298 | #ifdef PY_GETRANDOM |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 299 | res = py_getrandom(buffer, size, 1); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 300 | if (res < 0) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 301 | return -1; |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 302 | } |
| 303 | if (res == 1) { |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 304 | return 0; |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 305 | } |
Victor Stinner | 6d8bc46 | 2016-09-20 22:46:02 +0200 | [diff] [blame] | 306 | /* getrandom() failed with ENOSYS or EPERM, |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 307 | fall back on reading /dev/urandom */ |
Victor Stinner | 59f7fb2 | 2015-03-18 14:39:33 +0100 | [diff] [blame] | 308 | #endif |
| 309 | |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 310 | if (urandom_cache.fd >= 0) { |
| 311 | /* Does the fd point to the same thing as before? (issue #21207) */ |
Victor Stinner | e134a7f | 2015-03-30 10:09:31 +0200 | [diff] [blame] | 312 | if (_Py_fstat_noraise(urandom_cache.fd, &st) |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 313 | || st.st_dev != urandom_cache.st_dev |
| 314 | || st.st_ino != urandom_cache.st_ino) { |
| 315 | /* Something changed: forget the cached fd (but don't close it, |
| 316 | since it probably points to something important for some |
| 317 | third-party code). */ |
| 318 | urandom_cache.fd = -1; |
| 319 | } |
| 320 | } |
| 321 | if (urandom_cache.fd >= 0) |
| 322 | fd = urandom_cache.fd; |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 323 | else { |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 324 | fd = _Py_open("/dev/urandom", O_RDONLY); |
Victor Stinner | a555cfc | 2015-03-18 00:22:14 +0100 | [diff] [blame] | 325 | if (fd < 0) { |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 326 | if (errno == ENOENT || errno == ENXIO || |
| 327 | errno == ENODEV || errno == EACCES) |
| 328 | PyErr_SetString(PyExc_NotImplementedError, |
| 329 | "/dev/urandom (or equivalent) not found"); |
Victor Stinner | a555cfc | 2015-03-18 00:22:14 +0100 | [diff] [blame] | 330 | /* otherwise, keep the OSError exception raised by _Py_open() */ |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 331 | return -1; |
| 332 | } |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 333 | if (urandom_cache.fd >= 0) { |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 334 | /* urandom_fd was initialized by another thread while we were |
| 335 | not holding the GIL, keep it. */ |
| 336 | close(fd); |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 337 | fd = urandom_cache.fd; |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 338 | } |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 339 | else { |
Steve Dower | f2f373f | 2015-02-21 08:44:05 -0800 | [diff] [blame] | 340 | if (_Py_fstat(fd, &st)) { |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 341 | close(fd); |
| 342 | return -1; |
| 343 | } |
| 344 | else { |
| 345 | urandom_cache.fd = fd; |
| 346 | urandom_cache.st_dev = st.st_dev; |
| 347 | urandom_cache.st_ino = st.st_ino; |
| 348 | } |
| 349 | } |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 350 | } |
| 351 | |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 352 | do { |
Victor Stinner | c9382eb | 2015-03-19 23:36:33 +0100 | [diff] [blame] | 353 | n = _Py_read(fd, buffer, (size_t)size); |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 354 | if (n == -1) { |
Victor Stinner | c9382eb | 2015-03-19 23:36:33 +0100 | [diff] [blame] | 355 | return -1; |
Victor Stinner | af59732 | 2016-09-20 22:26:18 +0200 | [diff] [blame] | 356 | } |
Victor Stinner | c9382eb | 2015-03-19 23:36:33 +0100 | [diff] [blame] | 357 | if (n == 0) { |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 358 | PyErr_Format(PyExc_RuntimeError, |
Victor Stinner | c9382eb | 2015-03-19 23:36:33 +0100 | [diff] [blame] | 359 | "Failed to read %zi bytes from /dev/urandom", |
| 360 | size); |
| 361 | return -1; |
| 362 | } |
| 363 | |
| 364 | buffer += n; |
| 365 | size -= n; |
| 366 | } while (0 < size); |
| 367 | |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 368 | return 0; |
| 369 | } |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 370 | |
| 371 | static void |
| 372 | dev_urandom_close(void) |
| 373 | { |
Antoine Pitrou | e472aea | 2014-04-26 14:33:03 +0200 | [diff] [blame] | 374 | if (urandom_cache.fd >= 0) { |
| 375 | close(urandom_cache.fd); |
| 376 | urandom_cache.fd = -1; |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 377 | } |
| 378 | } |
| 379 | |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 380 | #endif |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 381 | |
| 382 | /* Fill buffer with pseudo-random bytes generated by a linear congruent |
| 383 | generator (LCG): |
| 384 | |
| 385 | x(n+1) = (x(n) * 214013 + 2531011) % 2^32 |
| 386 | |
| 387 | Use bits 23..16 of x(n) to generate a byte. */ |
| 388 | static void |
| 389 | lcg_urandom(unsigned int x0, unsigned char *buffer, size_t size) |
| 390 | { |
| 391 | size_t index; |
| 392 | unsigned int x; |
| 393 | |
| 394 | x = x0; |
| 395 | for (index=0; index < size; index++) { |
| 396 | x *= 214013; |
| 397 | x += 2531011; |
| 398 | /* modulo 2 ^ (8 * sizeof(int)) */ |
| 399 | buffer[index] = (x >> 16) & 0xff; |
| 400 | } |
| 401 | } |
| 402 | |
Georg Brandl | c6a2c9b | 2013-10-06 18:43:19 +0200 | [diff] [blame] | 403 | /* Fill buffer with size pseudo-random bytes from the operating system random |
Serhiy Storchaka | 56a6d85 | 2014-12-01 18:28:43 +0200 | [diff] [blame] | 404 | number generator (RNG). It is suitable for most cryptographic purposes |
Georg Brandl | c6a2c9b | 2013-10-06 18:43:19 +0200 | [diff] [blame] | 405 | except long living private keys for asymmetric encryption. |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 406 | |
| 407 | Return 0 on success, raise an exception and return -1 on error. */ |
| 408 | int |
| 409 | _PyOS_URandom(void *buffer, Py_ssize_t size) |
| 410 | { |
| 411 | if (size < 0) { |
| 412 | PyErr_Format(PyExc_ValueError, |
| 413 | "negative argument not allowed"); |
| 414 | return -1; |
| 415 | } |
| 416 | if (size == 0) |
| 417 | return 0; |
| 418 | |
| 419 | #ifdef MS_WINDOWS |
| 420 | return win32_urandom((unsigned char *)buffer, size, 1); |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 421 | #elif defined(PY_GETENTROPY) |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 422 | return py_getentropy(buffer, size, 0); |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 423 | #else |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 424 | return dev_urandom_python((char*)buffer, size); |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 425 | #endif |
| 426 | } |
| 427 | |
| 428 | void |
| 429 | _PyRandom_Init(void) |
| 430 | { |
| 431 | char *env; |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 432 | unsigned char *secret = (unsigned char *)&_Py_HashSecret.uc; |
Benjamin Peterson | 69e9727 | 2012-02-21 11:08:50 -0500 | [diff] [blame] | 433 | Py_ssize_t secret_size = sizeof(_Py_HashSecret_t); |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 434 | assert(secret_size == sizeof(_Py_HashSecret.uc)); |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 435 | |
Benjamin Peterson | 69e9727 | 2012-02-21 11:08:50 -0500 | [diff] [blame] | 436 | if (_Py_HashSecret_Initialized) |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 437 | return; |
Benjamin Peterson | 69e9727 | 2012-02-21 11:08:50 -0500 | [diff] [blame] | 438 | _Py_HashSecret_Initialized = 1; |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 439 | |
| 440 | /* |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 441 | Hash randomization is enabled. Generate a per-process secret, |
| 442 | using PYTHONHASHSEED if provided. |
| 443 | */ |
| 444 | |
| 445 | env = Py_GETENV("PYTHONHASHSEED"); |
Georg Brandl | 12897d7 | 2012-02-20 23:49:29 +0100 | [diff] [blame] | 446 | if (env && *env != '\0' && strcmp(env, "random") != 0) { |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 447 | char *endptr = env; |
| 448 | unsigned long seed; |
| 449 | seed = strtoul(env, &endptr, 10); |
| 450 | if (*endptr != '\0' |
| 451 | || seed > 4294967295UL |
| 452 | || (errno == ERANGE && seed == ULONG_MAX)) |
| 453 | { |
| 454 | Py_FatalError("PYTHONHASHSEED must be \"random\" or an integer " |
| 455 | "in range [0; 4294967295]"); |
| 456 | } |
| 457 | if (seed == 0) { |
| 458 | /* disable the randomized hash */ |
| 459 | memset(secret, 0, secret_size); |
| 460 | } |
| 461 | else { |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 462 | lcg_urandom(seed, secret, secret_size); |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 463 | } |
| 464 | } |
| 465 | else { |
| 466 | #ifdef MS_WINDOWS |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 467 | (void)win32_urandom(secret, secret_size, 0); |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 468 | #elif defined(PY_GETENTROPY) |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 469 | (void)py_getentropy(secret, secret_size, 1); |
Christian Heimes | af01f66 | 2013-12-21 16:19:10 +0100 | [diff] [blame] | 470 | #else |
Christian Heimes | 985ecdc | 2013-11-20 11:46:18 +0100 | [diff] [blame] | 471 | dev_urandom_noraise(secret, secret_size); |
Georg Brandl | 2daf6ae | 2012-02-20 19:54:16 +0100 | [diff] [blame] | 472 | #endif |
| 473 | } |
| 474 | } |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 475 | |
| 476 | void |
| 477 | _PyRandom_Fini(void) |
| 478 | { |
Victor Stinner | d50c3f3 | 2014-05-02 22:06:44 +0200 | [diff] [blame] | 479 | #ifdef MS_WINDOWS |
| 480 | if (hCryptProv) { |
Tim Golden | b8ac3e1 | 2014-05-06 13:29:45 +0100 | [diff] [blame] | 481 | CryptReleaseContext(hCryptProv, 0); |
Victor Stinner | d50c3f3 | 2014-05-02 22:06:44 +0200 | [diff] [blame] | 482 | hCryptProv = 0; |
| 483 | } |
Victor Stinner | bae2d62 | 2015-10-01 09:47:30 +0200 | [diff] [blame] | 484 | #elif defined(PY_GETENTROPY) |
Victor Stinner | 4d6a3d6 | 2014-12-21 01:16:38 +0100 | [diff] [blame] | 485 | /* nothing to clean */ |
Victor Stinner | d50c3f3 | 2014-05-02 22:06:44 +0200 | [diff] [blame] | 486 | #else |
Antoine Pitrou | 4879a96 | 2013-08-31 00:26:02 +0200 | [diff] [blame] | 487 | dev_urandom_close(); |
| 488 | #endif |
| 489 | } |