1 files changed, 142 insertions, 0 deletions
diff --git a/windows/noise.c b/windows/noise.c
new file mode 100644
index 00000000..65c4c92d
--- /dev/null
+++ b/windows/noise.c
@@ -0,0 +1,142 @@
+/*
+ * Noise generation for PuTTY's cryptographic random number
+ * generator.
+ */
+
+#include <stdio.h>
+
+#include "putty.h"
+#include "ssh.h"
+#include "storage.h"
+
+#include <wincrypt.h>
+
+DECL_WINDOWS_FUNCTION(static, BOOL, CryptAcquireContextA,
+                      (HCRYPTPROV *, LPCTSTR, LPCTSTR, DWORD, DWORD));
+DECL_WINDOWS_FUNCTION(static, BOOL, CryptGenRandom,
+                      (HCRYPTPROV, DWORD, BYTE *));
+DECL_WINDOWS_FUNCTION(static, BOOL, CryptReleaseContext,
+                      (HCRYPTPROV, DWORD));
+static HMODULE wincrypt_module = NULL;
+
+bool win_read_random(void *buf, unsigned wanted)
+{
+    bool toret = false;
+    HCRYPTPROV crypt_provider;
+
+    if (!wincrypt_module) {
+        wincrypt_module = load_system32_dll("advapi32.dll");
+        GET_WINDOWS_FUNCTION(wincrypt_module, CryptAcquireContextA);
+        GET_WINDOWS_FUNCTION(wincrypt_module, CryptGenRandom);
+        GET_WINDOWS_FUNCTION(wincrypt_module, CryptReleaseContext);
+    }
+
+    if (wincrypt_module && p_CryptAcquireContextA &&
+        p_CryptGenRandom && p_CryptReleaseContext &&
+        p_CryptAcquireContextA(&crypt_provider, NULL, NULL, PROV_RSA_FULL,
+                               CRYPT_VERIFYCONTEXT)) {
+        toret = p_CryptGenRandom(crypt_provider, wanted, buf);
+        p_CryptReleaseContext(crypt_provider, 0);
+    }
+
+    return toret;
+}
+
+/*
+ * This function is called once, at PuTTY startup.
+ */
+
+void noise_get_heavy(void (*func) (void *, int))
+{
+    HANDLE srch;
+    WIN32_FIND_DATA finddata;
+    DWORD pid;
+    char winpath[MAX_PATH + 3];
+    BYTE buf[32];
+
+    GetWindowsDirectory(winpath, sizeof(winpath));
+    strcat(winpath, "\\*");
+    srch = FindFirstFile(winpath, &finddata);
+    if (srch != INVALID_HANDLE_VALUE) {
+        do {
+            func(&finddata, sizeof(finddata));
+        } while (FindNextFile(srch, &finddata));
+        FindClose(srch);
+    }
+
+    pid = GetCurrentProcessId();
+    func(&pid, sizeof(pid));
+
+    if (win_read_random(buf, sizeof(buf))) {
+        func(buf, sizeof(buf));
+        smemclr(buf, sizeof(buf));
+    }
+
+    read_random_seed(func);
+}
+
+/*
+ * This function is called on a timer, and it will monitor
+ * frequently changing quantities such as the state of physical and
+ * virtual memory, the state of the process's message queue, which
+ * window is in the foreground, which owns the clipboard, etc.
+ */
+void noise_regular(void)
+{
+    HWND w;
+    DWORD z;
+    POINT pt;
+    MEMORYSTATUS memstat;
+    FILETIME times[4];
+
+    w = GetForegroundWindow();
+    random_add_noise(NOISE_SOURCE_FGWINDOW, &w, sizeof(w));
+    w = GetCapture();
+    random_add_noise(NOISE_SOURCE_CAPTURE, &w, sizeof(w));
+    w = GetClipboardOwner();
+    random_add_noise(NOISE_SOURCE_CLIPBOARD, &w, sizeof(w));
+    z = GetQueueStatus(QS_ALLEVENTS);
+    random_add_noise(NOISE_SOURCE_QUEUE, &z, sizeof(z));
+
+    GetCursorPos(&pt);
+    random_add_noise(NOISE_SOURCE_CURSORPOS, &pt, sizeof(pt));
+
+    GlobalMemoryStatus(&memstat);
+    random_add_noise(NOISE_SOURCE_MEMINFO, &memstat, sizeof(memstat));
+
+    GetThreadTimes(GetCurrentThread(), times, times + 1, times + 2,
+                   times + 3);
+    random_add_noise(NOISE_SOURCE_THREADTIME, &times, sizeof(times));
+    GetProcessTimes(GetCurrentProcess(), times, times + 1, times + 2,
+                    times + 3);
+    random_add_noise(NOISE_SOURCE_PROCTIME, &times, sizeof(times));
+}
+
+/*
+ * This function is called on every keypress or mouse move, and
+ * will add the current Windows time and performance monitor
+ * counter to the noise pool. It gets the scan code or mouse
+ * position passed in.
+ */
+void noise_ultralight(NoiseSourceId id, unsigned long data)
+{
+    DWORD wintime;
+    LARGE_INTEGER perftime;
+
+    random_add_noise(id, &data, sizeof(DWORD));
+
+    wintime = GetTickCount();
+    random_add_noise(NOISE_SOURCE_TIME, &wintime, sizeof(DWORD));
+
+    if (QueryPerformanceCounter(&perftime))
+        random_add_noise(NOISE_SOURCE_PERFCOUNT, &perftime, sizeof(perftime));
+}
+
+uint64_t prng_reseed_time_ms(void)
+{
+    FILETIME ft;
+    GetSystemTimeAsFileTime(&ft);
+    uint64_t value = ft.dwHighDateTime;
+    value = (value << 32) + ft.dwLowDateTime;
+    return value / 10000;              /* 1 millisecond / 100ns */
+}