From: drh <drh@noemail.net>
Date: Mon, 15 Feb 2016 20:41:56 +0000 (+0000)
Subject: Improved entropy gathering for the implementation of winRandomness().
X-Git-Tag: version-3.12.0~189
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8eb3790a8d228d363836c1fcbe790325c747436f;p=thirdparty%2Fsqlite.git

Improved entropy gathering for the implementation of winRandomness().

FossilOrigin-Name: fea3705e7750d276a8c8300b7a82dfae2d5979c0
---

diff --git a/manifest b/manifest
index 4dbb251d56..223eb2086c 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sworking\s-q\sand\s--help\soptions\sto\stestfixture.
-D 2016-02-15T19:38:17.026
+C Improved\sentropy\sgathering\sfor\sthe\simplementation\sof\swinRandomness().
+D 2016-02-15T20:41:56.528
 F Makefile.in 4e90dc1521879022aa9479268a4cd141d1771142
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 30f075dc4f27a07abb76088946b2944178d85347
@@ -333,7 +333,7 @@ F src/os.h 3e57a24e2794a94d3cf2342c6d9a884888cd96bf
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
 F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
 F src/os_unix.c 3a6f20736dfb8a0949cdd66553fdf59f6604be35
-F src/os_win.c 6cce4c3aab5fb5cc6fabf999d785cfccb66ff9d4
+F src/os_win.c ae1f287a5a47e6cc08c0ac8dd0cfa2c67358f73a
 F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
 F src/pager.c 6812f3803951774b56abded396171e1c12b0b003
 F src/pager.h f3eb324a3ff2408b28bab7e81c1c55c13720f865
@@ -1427,7 +1427,7 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh a98af506df552f3b3c0d904f94e4cdc4e1a6d598
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 153f01a821e9844d0a2e418eb83c60f6c7695c8d
-R b996ecd577900723d8e8c822f6ba0fa2
+P 404494e52b6385671ccde1c83b7b868986645536
+R 65a12199f7ba9145cf2ed73477d5bc07
 U drh
-Z 1c21e4bc8961adde657fcb0992c7a61d
+Z f5568a99b7bf2a6087045b1c5b2d107b
diff --git a/manifest.uuid b/manifest.uuid
index 33f1beae3e..85665bc05f 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-404494e52b6385671ccde1c83b7b868986645536
\ No newline at end of file
+fea3705e7750d276a8c8300b7a82dfae2d5979c0
\ No newline at end of file
diff --git a/src/os_win.c b/src/os_win.c
index caa6dea5db..9824ffb1c7 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -5390,65 +5390,82 @@ static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
   #define winDlClose 0
 #endif
 
+/* State information for the randomness gatherer. */
+typedef struct EntropyGatherer EntropyGatherer;
+struct EntropyGatherer {
+  unsigned char *a;   /* Gather entropy into this buffer */
+  int na;             /* Size of a[] in bytes */
+  int i;              /* XOR next input into a[i] */
+  int nXor;           /* Number of XOR operations done */
+};
+
+#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS)
+/* Mix sz bytes of entropy into p. */
+static void xorMemory(EntropyGatherer *p, unsigned char *x, int sz){
+  int j, k;
+  for(j=0, k=p->i; j<sz; j++){
+    p->a[k++] ^= x[j];
+    if( k>=p->na ) k = 0;
+  }
+  p->i = k;
+  p->nXor += sz;
+}
+#endif
 
 /*
 ** Write up to nBuf bytes of randomness into zBuf.
 */
 static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
-  int n = 0;
-  UNUSED_PARAMETER(pVfs);
 #if defined(SQLITE_TEST) || defined(SQLITE_OMIT_RANDOMNESS)
-  n = nBuf;
+  UNUSED_PARAMETER(pVfs);
   memset(zBuf, 0, nBuf);
+  return nBuf;
 #else
-  if( sizeof(SYSTEMTIME)<=nBuf-n ){
+  EntropyGatherer e;
+  UNUSED_PARAMETER(pVfs);
+  memset(zBuf, 0, nBuf);
+  e.a = (unsigned char*)zBuf;
+  e.na = nBuf;
+  e.nXor = 0;
+  e.i = 0;
+  {
     SYSTEMTIME x;
     osGetSystemTime(&x);
-    memcpy(&zBuf[n], &x, sizeof(x));
-    n += sizeof(x);
+    xorMemory(&e, (unsigned char*)&x, sizeof(x));
   }
-  if( sizeof(DWORD)<=nBuf-n ){
+  {
     DWORD pid = osGetCurrentProcessId();
-    memcpy(&zBuf[n], &pid, sizeof(pid));
-    n += sizeof(pid);
+    xorMemory(&e, (unsigned char*)&pid, sizeof(pid));
   }
 #if SQLITE_OS_WINRT
-  if( sizeof(ULONGLONG)<=nBuf-n ){
+  {
     ULONGLONG cnt = osGetTickCount64();
-    memcpy(&zBuf[n], &cnt, sizeof(cnt));
-    n += sizeof(cnt);
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(cnt));
   }
 #else
-  if( sizeof(DWORD)<=nBuf-n ){
+  {
     DWORD cnt = osGetTickCount();
-    memcpy(&zBuf[n], &cnt, sizeof(cnt));
-    n += sizeof(cnt);
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(cnt));
   }
 #endif
-  if( sizeof(LARGE_INTEGER)<=nBuf-n ){
+  {
     LARGE_INTEGER i;
     osQueryPerformanceCounter(&i);
-    memcpy(&zBuf[n], &i, sizeof(i));
-    n += sizeof(i);
+    xorMemory(&e, (unsigned char*)&i, sizeof(i));
   }
 #if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
-  if( sizeof(UUID)<=nBuf-n ){
+  {
     UUID id;
     memset(&id, 0, sizeof(UUID));
     osUuidCreate(&id);
-    memcpy(&zBuf[n], &id, sizeof(UUID));
-    n += sizeof(UUID);
-  }
-  if( sizeof(UUID)<=nBuf-n ){
-    UUID id;
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
     memset(&id, 0, sizeof(UUID));
     osUuidCreateSequential(&id);
-    memcpy(&zBuf[n], &id, sizeof(UUID));
-    n += sizeof(UUID);
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
   }
 #endif
+  return e.nXor>nBuf ? nBuf : e.nXor;
 #endif /* defined(SQLITE_TEST) || defined(SQLITE_ZERO_PRNG_SEED) */
-  return n;
 }