diff --git a/src/prim/prim-unix.c b/src/prim/prim-unix.c index ce24c24a..6b593fd3 100644 --- a/src/prim/prim-unix.c +++ b/src/prim/prim-unix.c @@ -6,7 +6,7 @@ terms of the MIT license. A copy of the license can be found in the file -----------------------------------------------------------------------------*/ #ifndef _DEFAULT_SOURCE -#define _DEFAULT_SOURCE // ensure mmap flags are defined +#define _DEFAULT_SOURCE // ensure mmap flags and syscall are defined #endif #if defined(__sun) @@ -661,3 +661,91 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) { return true; } #endif // !MI_USE_ENVIRON + + +//---------------------------------------------------------------- +// Random +//---------------------------------------------------------------- + +#if defined(__APPLE__) + +#include +#if defined(MAC_OS_X_VERSION_10_10) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_10 +#include +#include +#endif +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + #if defined(MAC_OS_X_VERSION_10_15) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15 + // We prefere CCRandomGenerateBytes as it returns an error code while arc4random_buf + // may fail silently on macOS. See PR #390, and + return (CCRandomGenerateBytes(buf, buf_len) == kCCSuccess); + #else + // fall back on older macOS + arc4random_buf(buf, buf_len); + return true; + #endif +} + +#elif defined(__ANDROID__) || defined(__DragonFly__) || \ + defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || \ + defined(__sun) + +#include +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + arc4random_buf(buf, buf_len); + return true; +} + +#elif defined(__linux__) || defined(__HAIKU__) + +#if defined(__linux__) +#include +#endif +#include +#include +#include +#include +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + // Modern Linux provides `getrandom` but different distributions either use `sys/random.h` or `linux/random.h` + // and for the latter the actual `getrandom` call is not always defined. + // (see ) + // We therefore use a syscall directly and fall back dynamically to /dev/urandom when needed. + #ifdef SYS_getrandom + #ifndef GRND_NONBLOCK + #define GRND_NONBLOCK (1) + #endif + static _Atomic(uintptr_t) no_getrandom; // = 0 + if (mi_atomic_load_acquire(&no_getrandom)==0) { + ssize_t ret = syscall(SYS_getrandom, buf, buf_len, GRND_NONBLOCK); + if (ret >= 0) return (buf_len == (size_t)ret); + if (errno != ENOSYS) return false; + mi_atomic_store_release(&no_getrandom, 1UL); // don't call again, and fall back to /dev/urandom + } + #endif + int flags = O_RDONLY; + #if defined(O_CLOEXEC) + flags |= O_CLOEXEC; + #endif + int fd = open("/dev/urandom", flags, 0); + if (fd < 0) return false; + size_t count = 0; + while(count < buf_len) { + ssize_t ret = read(fd, (char*)buf + count, buf_len - count); + if (ret<=0) { + if (errno!=EAGAIN && errno!=EINTR) break; + } + else { + count += ret; + } + } + close(fd); + return (count==buf_len); +} + +#else + +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + return false; +} + +#endif \ No newline at end of file diff --git a/src/prim/prim-wasi.c b/src/prim/prim-wasi.c index c37b0847..38efece0 100644 --- a/src/prim/prim-wasi.c +++ b/src/prim/prim-wasi.c @@ -233,4 +233,13 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) { if (s == NULL || _mi_strnlen(s,result_size) >= result_size) return false; _mi_strlcpy(result, s, result_size); return true; -} \ No newline at end of file +} + + +//---------------------------------------------------------------- +// Random +//---------------------------------------------------------------- + +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + return false; +} diff --git a/src/prim/prim-windows.c b/src/prim/prim-windows.c index f6f1a9db..3b791de7 100644 --- a/src/prim/prim-windows.c +++ b/src/prim/prim-windows.c @@ -506,3 +506,45 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) { size_t len = GetEnvironmentVariableA(name, result, (DWORD)result_size); return (len > 0 && len < result_size); } + + + +//---------------------------------------------------------------- +// Random +//---------------------------------------------------------------- + +#if defined(MI_USE_RTLGENRANDOM) // || defined(__cplusplus) +// We prefer to use BCryptGenRandom instead of (the unofficial) RtlGenRandom but when using +// dynamic overriding, we observed it can raise an exception when compiled with C++, and +// sometimes deadlocks when also running under the VS debugger. +// In contrast, issue #623 implies that on Windows Server 2019 we need to use BCryptGenRandom. +// To be continued.. +#pragma comment (lib,"advapi32.lib") +#define RtlGenRandom SystemFunction036 +mi_decl_externc BOOLEAN NTAPI RtlGenRandom(PVOID RandomBuffer, ULONG RandomBufferLength); + +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + return (RtlGenRandom(buf, (ULONG)buf_len) != 0); +} + +#else + +#ifndef BCRYPT_USE_SYSTEM_PREFERRED_RNG +#define BCRYPT_USE_SYSTEM_PREFERRED_RNG 0x00000002 +#endif + +typedef LONG (NTAPI *PBCryptGenRandom)(HANDLE, PUCHAR, ULONG, ULONG); +static PBCryptGenRandom pBCryptGenRandom = NULL; + +bool _mi_prim_random_buf(void* buf, size_t buf_len) { + if (pBCryptGenRandom == NULL) { + HINSTANCE hDll = LoadLibrary(TEXT("bcrypt.dll")); + if (hDll != NULL) { + pBCryptGenRandom = (PBCryptGenRandom)(void (*)(void))GetProcAddress(hDll, "BCryptGenRandom"); + } + if (pBCryptGenRandom == NULL) return false; + } + return (pBCryptGenRandom(NULL, (PUCHAR)buf, (ULONG)buf_len, BCRYPT_USE_SYSTEM_PREFERRED_RNG) >= 0); +} + +#endif // MI_USE_RTLGENRANDOM diff --git a/src/prim/prim.h b/src/prim/prim.h index 272fd72f..c067046d 100644 --- a/src/prim/prim.h +++ b/src/prim/prim.h @@ -72,6 +72,10 @@ void _mi_prim_out_stderr( const char* msg ); bool _mi_prim_getenv(const char* name, char* result, size_t result_size); +// Fill a buffer with strong randomness; return `false` on error or if +// there is no strong randomization available. +bool _mi_prim_random_buf(void* buf, size_t buf_len); + //------------------------------------------------------------------- // Thread id // diff --git a/src/random.c b/src/random.c index ad14bf1f..3c8372c8 100644 --- a/src/random.c +++ b/src/random.c @@ -4,14 +4,10 @@ This is free software; you can redistribute it and/or modify it under the terms of the MIT license. A copy of the license can be found in the file "LICENSE" at the root of this distribution. -----------------------------------------------------------------------------*/ -#ifndef _DEFAULT_SOURCE -#define _DEFAULT_SOURCE // for syscall() on Linux -#endif - #include "mimalloc.h" #include "mimalloc-internal.h" - -#include // memset +#include "prim/prim.h" // _mi_prim_random_buf +#include // memset /* ---------------------------------------------------------------------------- We use our own PRNG to keep predictable performance of random number generation @@ -158,161 +154,13 @@ uintptr_t _mi_random_next(mi_random_ctx_t* ctx) { /* ---------------------------------------------------------------------------- -To initialize a fresh random context we rely on the OS: -- Windows : BCryptGenRandom (or RtlGenRandom) -- macOS : CCRandomGenerateBytes, arc4random_buf -- bsd,wasi : arc4random_buf -- Linux : getrandom,/dev/urandom +To initialize a fresh random context. If we cannot get good randomness, we fall back to weak randomness based on a timer and ASLR. -----------------------------------------------------------------------------*/ -#if defined(_WIN32) - -#include - -#if defined(MI_USE_RTLGENRANDOM) // || defined(__cplusplus) -// We prefer to use BCryptGenRandom instead of (the unofficial) RtlGenRandom but when using -// dynamic overriding, we observed it can raise an exception when compiled with C++, and -// sometimes deadlocks when also running under the VS debugger. -// In contrast, issue #623 implies that on Windows Server 2019 we need to use BCryptGenRandom. -// To be continued.. -#pragma comment (lib,"advapi32.lib") -#define RtlGenRandom SystemFunction036 -#ifdef __cplusplus -extern "C" { -#endif -BOOLEAN NTAPI RtlGenRandom(PVOID RandomBuffer, ULONG RandomBufferLength); -#ifdef __cplusplus -} -#endif -static bool os_random_buf(void* buf, size_t buf_len) { - return (RtlGenRandom(buf, (ULONG)buf_len) != 0); -} -#else - -#ifndef BCRYPT_USE_SYSTEM_PREFERRED_RNG -#define BCRYPT_USE_SYSTEM_PREFERRED_RNG 0x00000002 -#endif - -typedef LONG (NTAPI *PBCryptGenRandom)(HANDLE, PUCHAR, ULONG, ULONG); -static PBCryptGenRandom pBCryptGenRandom = NULL; - -static bool os_random_buf(void* buf, size_t buf_len) { - if (pBCryptGenRandom == NULL) { - HINSTANCE hDll = LoadLibrary(TEXT("bcrypt.dll")); - if (hDll != NULL) { - pBCryptGenRandom = (PBCryptGenRandom)(void (*)(void))GetProcAddress(hDll, "BCryptGenRandom"); - } - } - if (pBCryptGenRandom == NULL) { - return false; - } - else { - return (pBCryptGenRandom(NULL, (PUCHAR)buf, (ULONG)buf_len, BCRYPT_USE_SYSTEM_PREFERRED_RNG) >= 0); - } -} -#endif - -#elif defined(__APPLE__) -#include -#if defined(MAC_OS_X_VERSION_10_10) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_10 -#include -#include -#endif -static bool os_random_buf(void* buf, size_t buf_len) { - #if defined(MAC_OS_X_VERSION_10_15) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15 - // We prefere CCRandomGenerateBytes as it returns an error code while arc4random_buf - // may fail silently on macOS. See PR #390, and - return (CCRandomGenerateBytes(buf, buf_len) == kCCSuccess); - #else - // fall back on older macOS - arc4random_buf(buf, buf_len); - return true; - #endif -} - -#elif defined(__ANDROID__) || defined(__DragonFly__) || \ - defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || \ - defined(__sun) // todo: what to use with __wasi__? -#include -static bool os_random_buf(void* buf, size_t buf_len) { - arc4random_buf(buf, buf_len); - return true; -} -#elif defined(__linux__) || defined(__HAIKU__) -#if defined(__linux__) -#include -#endif -#include -#include -#include -#include -#include -static bool os_random_buf(void* buf, size_t buf_len) { - // Modern Linux provides `getrandom` but different distributions either use `sys/random.h` or `linux/random.h` - // and for the latter the actual `getrandom` call is not always defined. - // (see ) - // We therefore use a syscall directly and fall back dynamically to /dev/urandom when needed. -#ifdef SYS_getrandom - #ifndef GRND_NONBLOCK - #define GRND_NONBLOCK (1) - #endif - static _Atomic(uintptr_t) no_getrandom; // = 0 - if (mi_atomic_load_acquire(&no_getrandom)==0) { - ssize_t ret = syscall(SYS_getrandom, buf, buf_len, GRND_NONBLOCK); - if (ret >= 0) return (buf_len == (size_t)ret); - if (errno != ENOSYS) return false; - mi_atomic_store_release(&no_getrandom, 1UL); // don't call again, and fall back to /dev/urandom - } -#endif - int flags = O_RDONLY; - #if defined(O_CLOEXEC) - flags |= O_CLOEXEC; - #endif - int fd = open("/dev/urandom", flags, 0); - if (fd < 0) return false; - size_t count = 0; - while(count < buf_len) { - ssize_t ret = read(fd, (char*)buf + count, buf_len - count); - if (ret<=0) { - if (errno!=EAGAIN && errno!=EINTR) break; - } - else { - count += ret; - } - } - close(fd); - return (count==buf_len); -} -#else -static bool os_random_buf(void* buf, size_t buf_len) { - return false; -} -#endif - -#if defined(_WIN32) -#include -#elif defined(__APPLE__) -#include -#else -#include -#endif - uintptr_t _mi_os_random_weak(uintptr_t extra_seed) { uintptr_t x = (uintptr_t)&_mi_os_random_weak ^ extra_seed; // ASLR makes the address random - - #if defined(_WIN32) - LARGE_INTEGER pcount; - QueryPerformanceCounter(&pcount); - x ^= (uintptr_t)(pcount.QuadPart); - #elif defined(__APPLE__) - x ^= (uintptr_t)mach_absolute_time(); - #else - struct timespec time; - clock_gettime(CLOCK_MONOTONIC, &time); - x ^= (uintptr_t)time.tv_sec; - x ^= (uintptr_t)time.tv_nsec; - #endif + x ^= _mi_prim_clock_now(); // and do a few randomization steps uintptr_t max = ((x ^ (x >> 17)) & 0x0F) + 1; for (uintptr_t i = 0; i < max; i++) { @@ -324,7 +172,7 @@ uintptr_t _mi_os_random_weak(uintptr_t extra_seed) { static void mi_random_init_ex(mi_random_ctx_t* ctx, bool use_weak) { uint8_t key[32]; - if (use_weak || !os_random_buf(key, sizeof(key))) { + if (use_weak || !_mi_prim_random_buf(key, sizeof(key))) { // if we fail to get random data from the OS, we fall back to a // weak random source based on the current time #if !defined(__wasi__)