git.distorted.org.uk Git - u/mdw/putty/blob - windows/winnoise.c

   1 /*
   2  * Noise generation for PuTTY's cryptographic random number
   3  * generator.
   4  */
   5
   6 #include <stdio.h>
   7
   8 #include "putty.h"
   9 #include "ssh.h"
  10 #include "storage.h"
  11
  12 #include <wincrypt.h>
  13
  14 DECL_WINDOWS_FUNCTION(static, BOOL, CryptAcquireContextA,
  15                       (HCRYPTPROV *, LPCTSTR, LPCTSTR, DWORD, DWORD));
  16 DECL_WINDOWS_FUNCTION(static, BOOL, CryptGenRandom,
  17                       (HCRYPTPROV, DWORD, BYTE *));
  18 DECL_WINDOWS_FUNCTION(static, BOOL, CryptReleaseContext,
  19                       (HCRYPTPROV, DWORD));
  20 static HMODULE wincrypt_module = NULL;
  21
  22 /*
  23  * This function is called once, at PuTTY startup.
  24  */
  25
  26 void noise_get_heavy(void (*func) (void *, int))
  27 {
  28     HANDLE srch;
  29     WIN32_FIND_DATA finddata;
  30     DWORD pid;
  31     HCRYPTPROV crypt_provider;
  32     char winpath[MAX_PATH + 3];
  33
  34     GetWindowsDirectory(winpath, sizeof(winpath));
  35     strcat(winpath, "\\*");
  36     srch = FindFirstFile(winpath, &finddata);
  37     if (srch != INVALID_HANDLE_VALUE) {
  38         do {
  39             func(&finddata, sizeof(finddata));
  40         } while (FindNextFile(srch, &finddata));
  41         FindClose(srch);
  42     }
  43
  44     pid = GetCurrentProcessId();
  45     func(&pid, sizeof(pid));
  46
  47     if (!wincrypt_module) {
  48         wincrypt_module = load_system32_dll("advapi32.dll");
  49         GET_WINDOWS_FUNCTION(wincrypt_module, CryptAcquireContextA);
  50         GET_WINDOWS_FUNCTION(wincrypt_module, CryptGenRandom);
  51         GET_WINDOWS_FUNCTION(wincrypt_module, CryptReleaseContext);
  52     }
  53
  54     if (wincrypt_module && p_CryptAcquireContextA &&
  55         p_CryptGenRandom && p_CryptReleaseContext &&
  56         p_CryptAcquireContextA(&crypt_provider, NULL, NULL, PROV_RSA_FULL,
  57                                CRYPT_VERIFYCONTEXT)) {
  58         BYTE buf[32];
  59         if (p_CryptGenRandom(crypt_provider, 32, buf)) {
  60             func(buf, sizeof(buf));
  61         }
  62         p_CryptReleaseContext(crypt_provider, 0);
  63     }
  64
  65     read_random_seed(func);
  66     /* Update the seed immediately, in case another instance uses it. */
  67     random_save_seed();
  68 }
  69
  70 void random_save_seed(void)
  71 {
  72     int len;
  73     void *data;
  74
  75     if (random_active) {
  76         random_get_savedata(&data, &len);
  77         write_random_seed(data, len);
  78         sfree(data);
  79     }
  80 }
  81
  82 /*
  83  * This function is called every time the random pool needs
  84  * stirring, and will acquire the system time in all available
  85  * forms.
  86  */
  87 void noise_get_light(void (*func) (void *, int))
  88 {
  89     SYSTEMTIME systime;
  90     DWORD adjust[2];
  91     BOOL rubbish;
  92
  93     GetSystemTime(&systime);
  94     func(&systime, sizeof(systime));
  95
  96     GetSystemTimeAdjustment(&adjust[0], &adjust[1], &rubbish);
  97     func(&adjust, sizeof(adjust));
  98 }
  99
 100 /*
 101  * This function is called on a timer, and it will monitor
 102  * frequently changing quantities such as the state of physical and
 103  * virtual memory, the state of the process's message queue, which
 104  * window is in the foreground, which owns the clipboard, etc.
 105  */
 106 void noise_regular(void)
 107 {
 108     HWND w;
 109     DWORD z;
 110     POINT pt;
 111     MEMORYSTATUS memstat;
 112     FILETIME times[4];
 113
 114     w = GetForegroundWindow();
 115     random_add_noise(&w, sizeof(w));
 116     w = GetCapture();
 117     random_add_noise(&w, sizeof(w));
 118     w = GetClipboardOwner();
 119     random_add_noise(&w, sizeof(w));
 120     z = GetQueueStatus(QS_ALLEVENTS);
 121     random_add_noise(&z, sizeof(z));
 122
 123     GetCursorPos(&pt);
 124     random_add_noise(&pt, sizeof(pt));
 125
 126     GlobalMemoryStatus(&memstat);
 127     random_add_noise(&memstat, sizeof(memstat));
 128
 129     GetThreadTimes(GetCurrentThread(), times, times + 1, times + 2,
 130                    times + 3);
 131     random_add_noise(&times, sizeof(times));
 132     GetProcessTimes(GetCurrentProcess(), times, times + 1, times + 2,
 133                     times + 3);
 134     random_add_noise(&times, sizeof(times));
 135 }
 136
 137 /*
 138  * This function is called on every keypress or mouse move, and
 139  * will add the current Windows time and performance monitor
 140  * counter to the noise pool. It gets the scan code or mouse
 141  * position passed in.
 142  */
 143 void noise_ultralight(unsigned long data)
 144 {
 145     DWORD wintime;
 146     LARGE_INTEGER perftime;
 147
 148     random_add_noise(&data, sizeof(DWORD));
 149
 150     wintime = GetTickCount();
 151     random_add_noise(&wintime, sizeof(DWORD));
 152
 153     if (QueryPerformanceCounter(&perftime))
 154         random_add_noise(&perftime, sizeof(perftime));
 155 }