1 files changed, 106 insertions, 44 deletions

diff --git a/lib/scudo/scudo_utils.cpp b/lib/scudo/scudo_utils.cpp
index 9e6a3512e..2d66865b9 100644
--- a/lib/scudo/scudo_utils.cpp
+++ b/lib/scudo/scudo_utils.cpp
@@ -17,6 +17,7 @@
 #include <fcntl.h>
 #include <stdarg.h>
 #include <unistd.h>
+#include <cpuid.h>
 
 #include <cstring>
 
@@ -28,7 +29,7 @@ namespace __sanitizer {
 extern int VSNPrintf(char *buff, int buff_length, const char *format,
                      va_list args);
 
-} // namespace __sanitizer
+}  // namespace __sanitizer
 
 namespace __scudo {
 
@@ -44,60 +45,61 @@ void NORETURN dieWithMessage(const char *Format, ...) {
   Die();
 }
 
+#if defined(__x86_64__) || defined(__i386__)
+// i386 and x86_64 specific code to detect CRC32 hardware support via CPUID.
+// CRC32 requires the SSE 4.2 instruction set.
 typedef struct {
   u32 Eax;
   u32 Ebx;
   u32 Ecx;
   u32 Edx;
-} CPUIDInfo;
+} CPUIDRegs;
 
-static void getCPUID(CPUIDInfo *info, u32 leaf, u32 subleaf)
+static void getCPUID(CPUIDRegs *Regs, u32 Level)
 {
-  asm volatile("cpuid"
-      : "=a" (info->Eax), "=b" (info->Ebx), "=c" (info->Ecx), "=d" (info->Edx)
-      : "a" (leaf), "c" (subleaf)
-  );
+  __get_cpuid(Level, &Regs->Eax, &Regs->Ebx, &Regs->Ecx, &Regs->Edx);
 }
 
-// Returns true is the CPU is a "GenuineIntel" or "AuthenticAMD"
-static bool isSupportedCPU()
-{
-  CPUIDInfo Info;
-
-  getCPUID(&Info, 0, 0);
-  if (memcmp(reinterpret_cast<char *>(&Info.Ebx), "Genu", 4) == 0 &&
-      memcmp(reinterpret_cast<char *>(&Info.Edx), "ineI", 4) == 0 &&
-      memcmp(reinterpret_cast<char *>(&Info.Ecx), "ntel", 4) == 0) {
-      return true;
-  }
-  if (memcmp(reinterpret_cast<char *>(&Info.Ebx), "Auth", 4) == 0 &&
-      memcmp(reinterpret_cast<char *>(&Info.Edx), "enti", 4) == 0 &&
-      memcmp(reinterpret_cast<char *>(&Info.Ecx), "cAMD", 4) == 0) {
-      return true;
+CPUIDRegs getCPUFeatures() {
+  CPUIDRegs VendorRegs = {};
+  getCPUID(&VendorRegs, 0);
+  bool IsIntel =
+      (VendorRegs.Ebx == signature_INTEL_ebx) &&
+      (VendorRegs.Edx == signature_INTEL_edx) &&
+      (VendorRegs.Ecx == signature_INTEL_ecx);
+  bool IsAMD =
+      (VendorRegs.Ebx == signature_AMD_ebx) &&
+      (VendorRegs.Edx == signature_AMD_edx) &&
+      (VendorRegs.Ecx == signature_AMD_ecx);
+  // Default to an empty feature set if not on a supported CPU.
+  CPUIDRegs FeaturesRegs = {};
+  if (IsIntel || IsAMD) {
+    getCPUID(&FeaturesRegs, 1);
   }
-  return false;
+  return FeaturesRegs;
 }
 
-bool testCPUFeature(CPUFeature feature)
+#ifndef bit_SSE4_2
+#define bit_SSE4_2 bit_SSE42  // clang and gcc have different defines.
+#endif
+
+bool testCPUFeature(CPUFeature Feature)
 {
-  static bool InfoInitialized = false;
-  static CPUIDInfo CPUInfo = {};
-
-  if (InfoInitialized == false) {
-    if (isSupportedCPU() == true)
-      getCPUID(&CPUInfo, 1, 0);
-    else
-      UNIMPLEMENTED();
-    InfoInitialized = true;
-  }
-  switch (feature) {
-    case SSE4_2:
-      return ((CPUInfo.Ecx >> 20) & 0x1) != 0;
+  static CPUIDRegs FeaturesRegs = getCPUFeatures();
+
+  switch (Feature) {
+    case CRC32CPUFeature:  // CRC32 is provided by SSE 4.2.
+      return !!(FeaturesRegs.Ecx & bit_SSE4_2);
     default:
       break;
   }
   return false;
 }
+#else
+bool testCPUFeature(CPUFeature Feature) {
+  return false;
+}
+#endif  // defined(__x86_64__) || defined(__i386__)
 
 // readRetry will attempt to read Count bytes from the Fd specified, and if
 // interrupted will retry to read additional bytes to reach Count.
@@ -117,17 +119,77 @@ static ssize_t readRetry(int Fd, u8 *Buffer, size_t Count) {
   return AmountRead;
 }
 
-// Default constructor for Xorshift128Plus seeds the state with /dev/urandom
-Xorshift128Plus::Xorshift128Plus() {
+static void fillRandom(u8 *Data, ssize_t Size) {
   int Fd = open("/dev/urandom", O_RDONLY);
-  bool Success = readRetry(Fd, reinterpret_cast<u8 *>(&State_0_),
-                           sizeof(State_0_)) == sizeof(State_0_);
-  Success &= readRetry(Fd, reinterpret_cast<u8 *>(&State_1_),
-                           sizeof(State_1_)) == sizeof(State_1_);
+  if (Fd < 0) {
+    dieWithMessage("ERROR: failed to open /dev/urandom.\n");
+  }
+  bool Success = readRetry(Fd, Data, Size) == Size;
   close(Fd);
   if (!Success) {
     dieWithMessage("ERROR: failed to read enough data from /dev/urandom.\n");
   }
 }
 
-} // namespace __scudo
+// Default constructor for Xorshift128Plus seeds the state with /dev/urandom.
+// TODO(kostyak): investigate using getrandom() if available.
+Xorshift128Plus::Xorshift128Plus() {
+  fillRandom(reinterpret_cast<u8 *>(State), sizeof(State));
+}
+
+const static u32 CRC32Table[] = {
+  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+  0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+  0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+  0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+  0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+  0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+  0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+  0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+  0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+  0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+  0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+  0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+  0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+  0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+  0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+  0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+  0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+  0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+  0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+  0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+  0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+  0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+  0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+  0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+  0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+  0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+  0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+  0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+  0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+  0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+  0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+  0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+  0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+u32 computeCRC32(u32 Crc, uptr Data)
+{
+  for (uptr i = 0; i < sizeof(Data); i++) {
+    Crc = CRC32Table[(Crc ^ Data) & 0xff] ^ (Crc >> 8);
+    Data >>= 8;
+  }
+  return Crc;
+}
+
+}  // namespace __scudo