mirror of
https://github.com/microsoft/mimalloc.git
synced 2025-05-05 06:59:32 +03:00
move random initialization to primitives
This commit is contained in:
Daan Leijen
parent
9b110090b2
commit
973268bf1e
5 changed files with 150 additions and 159 deletions
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@ -6,7 +6,7 @@ terms of the MIT license. A copy of the license can be found in the file
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-----------------------------------------------------------------------------*/
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#ifndef _DEFAULT_SOURCE
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#define _DEFAULT_SOURCE // ensure mmap flags are defined
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#define _DEFAULT_SOURCE // ensure mmap flags and syscall are defined
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#endif
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#if defined(__sun)
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@ -661,3 +661,91 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
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return true;
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}
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#endif // !MI_USE_ENVIRON
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//----------------------------------------------------------------
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// Random
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//----------------------------------------------------------------
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#if defined(__APPLE__)
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#include <AvailabilityMacros.h>
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#if defined(MAC_OS_X_VERSION_10_10) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_10
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#include <CommonCrypto/CommonCryptoError.h>
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#include <CommonCrypto/CommonRandom.h>
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#endif
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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#if defined(MAC_OS_X_VERSION_10_15) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15
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// We prefere CCRandomGenerateBytes as it returns an error code while arc4random_buf
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// may fail silently on macOS. See PR #390, and <https://opensource.apple.com/source/Libc/Libc-1439.40.11/gen/FreeBSD/arc4random.c.auto.html>
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return (CCRandomGenerateBytes(buf, buf_len) == kCCSuccess);
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#else
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// fall back on older macOS
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arc4random_buf(buf, buf_len);
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return true;
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#endif
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}
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#elif defined(__ANDROID__) || defined(__DragonFly__) || \
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defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || \
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defined(__sun)
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#include <stdlib.h>
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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arc4random_buf(buf, buf_len);
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return true;
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}
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#elif defined(__linux__) || defined(__HAIKU__)
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#if defined(__linux__)
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#include <sys/syscall.h>
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#endif
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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// Modern Linux provides `getrandom` but different distributions either use `sys/random.h` or `linux/random.h`
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// and for the latter the actual `getrandom` call is not always defined.
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// (see <https://stackoverflow.com/questions/45237324/why-doesnt-getrandom-compile>)
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// We therefore use a syscall directly and fall back dynamically to /dev/urandom when needed.
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#ifdef SYS_getrandom
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#ifndef GRND_NONBLOCK
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#define GRND_NONBLOCK (1)
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#endif
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static _Atomic(uintptr_t) no_getrandom; // = 0
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if (mi_atomic_load_acquire(&no_getrandom)==0) {
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ssize_t ret = syscall(SYS_getrandom, buf, buf_len, GRND_NONBLOCK);
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if (ret >= 0) return (buf_len == (size_t)ret);
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if (errno != ENOSYS) return false;
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mi_atomic_store_release(&no_getrandom, 1UL); // don't call again, and fall back to /dev/urandom
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}
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#endif
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int flags = O_RDONLY;
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#if defined(O_CLOEXEC)
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flags |= O_CLOEXEC;
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#endif
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int fd = open("/dev/urandom", flags, 0);
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if (fd < 0) return false;
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size_t count = 0;
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while(count < buf_len) {
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ssize_t ret = read(fd, (char*)buf + count, buf_len - count);
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if (ret<=0) {
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if (errno!=EAGAIN && errno!=EINTR) break;
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}
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else {
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count += ret;
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}
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}
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close(fd);
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return (count==buf_len);
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}
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#else
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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return false;
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}
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#endif
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@ -233,4 +233,13 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
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if (s == NULL || _mi_strnlen(s,result_size) >= result_size) return false;
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_mi_strlcpy(result, s, result_size);
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return true;
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}
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}
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//----------------------------------------------------------------
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// Random
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//----------------------------------------------------------------
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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return false;
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}
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@ -506,3 +506,45 @@ bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
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size_t len = GetEnvironmentVariableA(name, result, (DWORD)result_size);
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return (len > 0 && len < result_size);
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}
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//----------------------------------------------------------------
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// Random
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//----------------------------------------------------------------
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#if defined(MI_USE_RTLGENRANDOM) // || defined(__cplusplus)
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// We prefer to use BCryptGenRandom instead of (the unofficial) RtlGenRandom but when using
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// dynamic overriding, we observed it can raise an exception when compiled with C++, and
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// sometimes deadlocks when also running under the VS debugger.
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// In contrast, issue #623 implies that on Windows Server 2019 we need to use BCryptGenRandom.
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// To be continued..
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#pragma comment (lib,"advapi32.lib")
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#define RtlGenRandom SystemFunction036
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mi_decl_externc BOOLEAN NTAPI RtlGenRandom(PVOID RandomBuffer, ULONG RandomBufferLength);
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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return (RtlGenRandom(buf, (ULONG)buf_len) != 0);
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}
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#else
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#ifndef BCRYPT_USE_SYSTEM_PREFERRED_RNG
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#define BCRYPT_USE_SYSTEM_PREFERRED_RNG 0x00000002
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#endif
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typedef LONG (NTAPI *PBCryptGenRandom)(HANDLE, PUCHAR, ULONG, ULONG);
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static PBCryptGenRandom pBCryptGenRandom = NULL;
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bool _mi_prim_random_buf(void* buf, size_t buf_len) {
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if (pBCryptGenRandom == NULL) {
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HINSTANCE hDll = LoadLibrary(TEXT("bcrypt.dll"));
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if (hDll != NULL) {
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pBCryptGenRandom = (PBCryptGenRandom)(void (*)(void))GetProcAddress(hDll, "BCryptGenRandom");
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}
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if (pBCryptGenRandom == NULL) return false;
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}
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return (pBCryptGenRandom(NULL, (PUCHAR)buf, (ULONG)buf_len, BCRYPT_USE_SYSTEM_PREFERRED_RNG) >= 0);
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}
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#endif // MI_USE_RTLGENRANDOM
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@ -72,6 +72,10 @@ void _mi_prim_out_stderr( const char* msg );
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bool _mi_prim_getenv(const char* name, char* result, size_t result_size);
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// Fill a buffer with strong randomness; return `false` on error or if
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// there is no strong randomization available.
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bool _mi_prim_random_buf(void* buf, size_t buf_len);
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//-------------------------------------------------------------------
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// Thread id
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//
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162
src/random.c
162
src/random.c
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@ -4,14 +4,10 @@ This is free software; you can redistribute it and/or modify it under the
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terms of the MIT license. A copy of the license can be found in the file
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"LICENSE" at the root of this distribution.
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-----------------------------------------------------------------------------*/
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#ifndef _DEFAULT_SOURCE
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#define _DEFAULT_SOURCE // for syscall() on Linux
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#endif
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#include "mimalloc.h"
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#include "mimalloc-internal.h"
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#include <string.h> // memset
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#include "prim/prim.h" // _mi_prim_random_buf
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#include <string.h> // memset
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/* ----------------------------------------------------------------------------
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We use our own PRNG to keep predictable performance of random number generation
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@ -158,161 +154,13 @@ uintptr_t _mi_random_next(mi_random_ctx_t* ctx) {
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/* ----------------------------------------------------------------------------
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To initialize a fresh random context we rely on the OS:
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- Windows : BCryptGenRandom (or RtlGenRandom)
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- macOS : CCRandomGenerateBytes, arc4random_buf
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- bsd,wasi : arc4random_buf
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- Linux : getrandom,/dev/urandom
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To initialize a fresh random context.
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If we cannot get good randomness, we fall back to weak randomness based on a timer and ASLR.
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-----------------------------------------------------------------------------*/
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#if defined(_WIN32)
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#include <windows.h>
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#if defined(MI_USE_RTLGENRANDOM) // || defined(__cplusplus)
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// We prefer to use BCryptGenRandom instead of (the unofficial) RtlGenRandom but when using
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// dynamic overriding, we observed it can raise an exception when compiled with C++, and
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// sometimes deadlocks when also running under the VS debugger.
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// In contrast, issue #623 implies that on Windows Server 2019 we need to use BCryptGenRandom.
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// To be continued..
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#pragma comment (lib,"advapi32.lib")
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#define RtlGenRandom SystemFunction036
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#ifdef __cplusplus
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extern "C" {
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#endif
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BOOLEAN NTAPI RtlGenRandom(PVOID RandomBuffer, ULONG RandomBufferLength);
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#ifdef __cplusplus
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}
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#endif
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static bool os_random_buf(void* buf, size_t buf_len) {
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return (RtlGenRandom(buf, (ULONG)buf_len) != 0);
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}
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#else
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#ifndef BCRYPT_USE_SYSTEM_PREFERRED_RNG
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#define BCRYPT_USE_SYSTEM_PREFERRED_RNG 0x00000002
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#endif
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typedef LONG (NTAPI *PBCryptGenRandom)(HANDLE, PUCHAR, ULONG, ULONG);
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static PBCryptGenRandom pBCryptGenRandom = NULL;
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static bool os_random_buf(void* buf, size_t buf_len) {
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if (pBCryptGenRandom == NULL) {
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HINSTANCE hDll = LoadLibrary(TEXT("bcrypt.dll"));
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if (hDll != NULL) {
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pBCryptGenRandom = (PBCryptGenRandom)(void (*)(void))GetProcAddress(hDll, "BCryptGenRandom");
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}
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}
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if (pBCryptGenRandom == NULL) {
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return false;
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}
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else {
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return (pBCryptGenRandom(NULL, (PUCHAR)buf, (ULONG)buf_len, BCRYPT_USE_SYSTEM_PREFERRED_RNG) >= 0);
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}
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}
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#endif
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#elif defined(__APPLE__)
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#include <AvailabilityMacros.h>
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#if defined(MAC_OS_X_VERSION_10_10) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_10
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#include <CommonCrypto/CommonCryptoError.h>
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#include <CommonCrypto/CommonRandom.h>
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#endif
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static bool os_random_buf(void* buf, size_t buf_len) {
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#if defined(MAC_OS_X_VERSION_10_15) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15
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// We prefere CCRandomGenerateBytes as it returns an error code while arc4random_buf
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// may fail silently on macOS. See PR #390, and <https://opensource.apple.com/source/Libc/Libc-1439.40.11/gen/FreeBSD/arc4random.c.auto.html>
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return (CCRandomGenerateBytes(buf, buf_len) == kCCSuccess);
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#else
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// fall back on older macOS
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arc4random_buf(buf, buf_len);
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return true;
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#endif
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}
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#elif defined(__ANDROID__) || defined(__DragonFly__) || \
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defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || \
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defined(__sun) // todo: what to use with __wasi__?
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#include <stdlib.h>
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static bool os_random_buf(void* buf, size_t buf_len) {
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arc4random_buf(buf, buf_len);
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return true;
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}
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#elif defined(__linux__) || defined(__HAIKU__)
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#if defined(__linux__)
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#include <sys/syscall.h>
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#endif
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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static bool os_random_buf(void* buf, size_t buf_len) {
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// Modern Linux provides `getrandom` but different distributions either use `sys/random.h` or `linux/random.h`
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// and for the latter the actual `getrandom` call is not always defined.
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// (see <https://stackoverflow.com/questions/45237324/why-doesnt-getrandom-compile>)
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// We therefore use a syscall directly and fall back dynamically to /dev/urandom when needed.
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#ifdef SYS_getrandom
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#ifndef GRND_NONBLOCK
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#define GRND_NONBLOCK (1)
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#endif
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static _Atomic(uintptr_t) no_getrandom; // = 0
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if (mi_atomic_load_acquire(&no_getrandom)==0) {
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ssize_t ret = syscall(SYS_getrandom, buf, buf_len, GRND_NONBLOCK);
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if (ret >= 0) return (buf_len == (size_t)ret);
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if (errno != ENOSYS) return false;
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mi_atomic_store_release(&no_getrandom, 1UL); // don't call again, and fall back to /dev/urandom
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}
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#endif
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int flags = O_RDONLY;
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#if defined(O_CLOEXEC)
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flags |= O_CLOEXEC;
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#endif
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int fd = open("/dev/urandom", flags, 0);
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if (fd < 0) return false;
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size_t count = 0;
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while(count < buf_len) {
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ssize_t ret = read(fd, (char*)buf + count, buf_len - count);
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if (ret<=0) {
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if (errno!=EAGAIN && errno!=EINTR) break;
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}
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else {
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count += ret;
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}
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}
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close(fd);
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return (count==buf_len);
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}
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#else
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static bool os_random_buf(void* buf, size_t buf_len) {
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return false;
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}
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#endif
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#if defined(_WIN32)
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#include <windows.h>
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#elif defined(__APPLE__)
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#include <mach/mach_time.h>
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#else
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#include <time.h>
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#endif
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uintptr_t _mi_os_random_weak(uintptr_t extra_seed) {
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uintptr_t x = (uintptr_t)&_mi_os_random_weak ^ extra_seed; // ASLR makes the address random
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#if defined(_WIN32)
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LARGE_INTEGER pcount;
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QueryPerformanceCounter(&pcount);
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x ^= (uintptr_t)(pcount.QuadPart);
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#elif defined(__APPLE__)
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x ^= (uintptr_t)mach_absolute_time();
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#else
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struct timespec time;
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clock_gettime(CLOCK_MONOTONIC, &time);
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x ^= (uintptr_t)time.tv_sec;
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x ^= (uintptr_t)time.tv_nsec;
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#endif
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x ^= _mi_prim_clock_now();
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// and do a few randomization steps
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uintptr_t max = ((x ^ (x >> 17)) & 0x0F) + 1;
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for (uintptr_t i = 0; i < max; i++) {
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@ -324,7 +172,7 @@ uintptr_t _mi_os_random_weak(uintptr_t extra_seed) {
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static void mi_random_init_ex(mi_random_ctx_t* ctx, bool use_weak) {
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uint8_t key[32];
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if (use_weak || !os_random_buf(key, sizeof(key))) {
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if (use_weak || !_mi_prim_random_buf(key, sizeof(key))) {
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// if we fail to get random data from the OS, we fall back to a
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// weak random source based on the current time
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#if !defined(__wasi__)
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