arc4random_linux.h (2502B)
1 /* $OpenBSD: arc4random_linux.h,v 1.10 2016/01/04 02:04:56 bcook Exp $ */ 2 3 /* 4 * Copyright (c) 1996, David Mazieres <dm@uun.org> 5 * Copyright (c) 2008, Damien Miller <djm@openbsd.org> 6 * Copyright (c) 2013, Markus Friedl <markus@openbsd.org> 7 * Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org> 8 * 9 * Permission to use, copy, modify, and distribute this software for any 10 * purpose with or without fee is hereby granted, provided that the above 11 * copyright notice and this permission notice appear in all copies. 12 * 13 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 14 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 15 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 16 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 17 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 18 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 19 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 20 */ 21 22 /* 23 * Stub functions for portability. 24 */ 25 26 #include <sys/mman.h> 27 28 #include <pthread.h> 29 #include <signal.h> 30 31 static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER; 32 #define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx) 33 #define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx) 34 35 #ifdef __GLIBC__ 36 extern void *__dso_handle; 37 extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *); 38 #define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle) 39 #else 40 #define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f)) 41 #endif 42 43 static inline void 44 _getentropy_fail(void) 45 { 46 raise(SIGKILL); 47 } 48 49 static volatile sig_atomic_t _rs_forked; 50 51 static inline void 52 _rs_forkhandler(void) 53 { 54 _rs_forked = 1; 55 } 56 57 static inline void 58 _rs_forkdetect(void) 59 { 60 static pid_t _rs_pid = 0; 61 pid_t pid = getpid(); 62 63 /* XXX unusual calls to clone() can bypass checks */ 64 if (_rs_pid == 0 || _rs_pid == 1 || _rs_pid != pid || _rs_forked) { 65 _rs_pid = pid; 66 _rs_forked = 0; 67 if (rs) 68 memset(rs, 0, sizeof(*rs)); 69 } 70 } 71 72 static inline int 73 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp) 74 { 75 if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE, 76 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) 77 return (-1); 78 79 if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE, 80 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) { 81 munmap(*rsp, sizeof(**rsp)); 82 *rsp = NULL; 83 return (-1); 84 } 85 86 _ARC4_ATFORK(_rs_forkhandler); 87 return (0); 88 }