Mercurial > cpython-lru_cache-weakref
diff Modules/_ssl.c @ 85314:39c9dbed3aa1 3.3
Issue #18747: Use a parent atfork handler instead of a child atfork handler.
fork() is suppose to be async-signal safe but the handler calls unsafe functions. A parent handler mitigates the issue.
| author | Christian Heimes <christian@cheimes.de> |
|---|---|
| date | Thu, 22 Aug 2013 13:19:48 +0200 |
| parents | 8e1194c39bed |
| children | 8b962e831ff0 25e05147d662 |
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--- a/Modules/_ssl.c Wed Aug 21 21:10:31 2013 -0400 +++ b/Modules/_ssl.c Thu Aug 22 13:19:48 2013 +0200 @@ -2585,23 +2585,25 @@ /* Seed OpenSSL's PRNG at fork(), http://bugs.python.org/issue18747 * - * The child handler seeds the PRNG from pseudo-random data like pid, the - * current time (nanoseconds, miliseconds or seconds) and an uninitialized - * array. The array contains stack variables that are impossible to predict + * The parent handler seeds the PRNG from pseudo-random data like pid, the + * current time (miliseconds or seconds) and an uninitialized arry. + * The array contains stack variables that are impossible to predict * on most systems, e.g. function return address (subject to ASLR), the * stack protection canary and automatic variables. * The code is inspired by Apache's ssl_rand_seed() function. * * Note: * The code uses pthread_atfork() until Python has a proper atfork API. The - * handlers are not removed from the child process. + * handlers are not removed from the child process. A parent handler is used + * instead of a child handler because fork() is suppose to be async-signal + * safe but the handler calls unsafe functions. */ #if defined(HAVE_PTHREAD_ATFORK) && defined(WITH_THREAD) #define PYSSL_RAND_ATFORK 1 static void -PySSL_RAND_atfork_child(void) +PySSL_RAND_atfork_parent(void) { struct { char stack[128]; /* uninitialized (!) stack data, 128 is an @@ -2615,11 +2617,6 @@ #endif seed.pid = getpid(); _PyTime_gettimeofday(&(seed.tp)); - -#if 0 - fprintf(stderr, "PySSL_RAND_atfork_child() seeds %i bytes in pid %i\n", - (int)sizeof(seed), seed.pid); -#endif RAND_add((unsigned char *)&seed, sizeof(seed), 0.0); } @@ -2633,8 +2630,8 @@ return 0; retval = pthread_atfork(NULL, /* prepare */ - NULL, /* parent */ - PySSL_RAND_atfork_child); /* child */ + PySSL_RAND_atfork_parent, /* parent */ + NULL); /* child */ if (retval != 0) { PyErr_SetFromErrno(PyExc_OSError); return -1;
