winstore.c

putty

    ret = RegQueryValueEx(rkey, regname, NULL, &type, otherstr, &readlen);

    if (ret != ERROR_SUCCESS && ret != ERROR_MORE_DATA &&
	!strcmp(keytype, "rsa")) {
	/*
	 * Key didn't exist. If the key type is RSA, we'll try
	 * another trick, which is to look up the _old_ key format
	 * under just the hostname and translate that.
	 */
	char *justhost = regname + 1 + strcspn(regname, ":");
	char *oldstyle = snewn(len + 10, char);	/* safety margin */
	readlen = len;
	ret = RegQueryValueEx(rkey, justhost, NULL, &type,
			      oldstyle, &readlen);

	if (ret == ERROR_SUCCESS && type == REG_SZ) {
	    /*
	     * The old format is two old-style bignums separated by
	     * a slash. An old-style bignum is made of groups of
	     * four hex digits: digits are ordered in sensible
	     * (most to least significant) order within each group,
	     * but groups are ordered in silly (least to most)
	     * order within the bignum. The new format is two
	     * ordinary C-format hex numbers (0xABCDEFG...XYZ, with
	     * A nonzero except in the special case 0x0, which
	     * doesn't appear anyway in RSA keys) separated by a
	     * comma. All hex digits are lowercase in both formats.
	     */
	    char *p = otherstr;
	    char *q = oldstyle;
	    int i, j;

	    for (i = 0; i < 2; i++) {
		int ndigits, nwords;
		*p++ = '0';
		*p++ = 'x';
		ndigits = strcspn(q, "/");	/* find / or end of string */
		nwords = ndigits / 4;
		/* now trim ndigits to remove leading zeros */
		while (q[(ndigits - 1) ^ 3] == '0' && ndigits > 1)
		    ndigits--;
		/* now move digits over to new string */
		for (j = 0; j < ndigits; j++)
		    p[ndigits - 1 - j] = q[j ^ 3];
		p += ndigits;
		q += nwords * 4;
		if (*q) {
		    q++;	       /* eat the slash */
		    *p++ = ',';	       /* add a comma */
		}
		*p = '\0';	       /* terminate the string */
	    }

	    /*
	     * Now _if_ this key matches, we'll enter it in the new
	     * format. If not, we'll assume something odd went
	     * wrong, and hyper-cautiously do nothing.
	     */
	    if (!strcmp(otherstr, key))
		RegSetValueEx(rkey, regname, 0, REG_SZ, otherstr,
			      strlen(otherstr) + 1);
	}
    }

    RegCloseKey(rkey);

    compare = strcmp(otherstr, key);

    sfree(otherstr);
    sfree(regname);

    if (ret == ERROR_MORE_DATA ||
	(ret == ERROR_SUCCESS && type == REG_SZ && compare))
	return 2;		       /* key is different in registry */
    else if (ret != ERROR_SUCCESS || type != REG_SZ)
	return 1;		       /* key does not exist in registry */
    else
	return 0;		       /* key matched OK in registry */
}

void store_host_key(const char *hostname, int port,
		    const char *keytype, const char *key)
{
    char *regname;
    HKEY rkey;

    regname = snewn(3 * (strlen(hostname) + strlen(keytype)) + 15, char);

    hostkey_regname(regname, hostname, port, keytype);

    if (RegCreateKey(HKEY_CURRENT_USER, PUTTY_REG_POS "\\SshHostKeys",
		     &rkey) == ERROR_SUCCESS) {
	RegSetValueEx(rkey, regname, 0, REG_SZ, key, strlen(key) + 1);
	RegCloseKey(rkey);
    } /* else key does not exist in registry */

    sfree(regname);
}

/*
 * Open (or delete) the random seed file.
 */
enum { DEL, OPEN_R, OPEN_W };
static int try_random_seed(char const *path, int action, HANDLE *ret)
{
    if (action == DEL) {
	remove(path);
	*ret = INVALID_HANDLE_VALUE;
	return FALSE;		       /* so we'll do the next ones too */
    }

    *ret = CreateFile(path,
		      action == OPEN_W ? GENERIC_WRITE : GENERIC_READ,
		      action == OPEN_W ? 0 : (FILE_SHARE_READ |
					      FILE_SHARE_WRITE),
		      NULL,
		      action == OPEN_W ? CREATE_ALWAYS : OPEN_EXISTING,
		      action == OPEN_W ? FILE_ATTRIBUTE_NORMAL : 0,
		      NULL);

    return (*ret != INVALID_HANDLE_VALUE);
}

static HANDLE access_random_seed(int action)
{
    HKEY rkey;
    DWORD type, size;
    HANDLE rethandle;
    char seedpath[2 * MAX_PATH + 10] = "\0";

    /*
     * Iterate over a selection of possible random seed paths until
     * we find one that works.
     * 
     * We do this iteration separately for reading and writing,
     * meaning that we will automatically migrate random seed files
     * if a better location becomes available (by reading from the
     * best location in which we actually find one, and then
     * writing to the best location in which we can _create_ one).
     */

    /*
     * First, try the location specified by the user in the
     * Registry, if any.
     */
    size = sizeof(seedpath);
    if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_POS, &rkey) ==
	ERROR_SUCCESS) {
	int ret = RegQueryValueEx(rkey, "RandSeedFile",
				  0, &type, seedpath, &size);
	if (ret != ERROR_SUCCESS || type != REG_SZ)
	    seedpath[0] = '\0';
	RegCloseKey(rkey);

	if (*seedpath && try_random_seed(seedpath, action, &rethandle))
	    return rethandle;
    }

    /*
     * Next, try the user's local Application Data directory,
     * followed by their non-local one. This is found using the
     * SHGetFolderPath function, which won't be present on all
     * versions of Windows.
     */
    if (!tried_shgetfolderpath) {
	/* This is likely only to bear fruit on systems with IE5+
	 * installed, or WinMe/2K+. There is some faffing with
	 * SHFOLDER.DLL we could do to try to find an equivalent
	 * on older versions of Windows if we cared enough.
	 * However, the invocation below requires IE5+ anyway,
	 * so stuff that. */
	shell32_module = LoadLibrary("SHELL32.DLL");
	if (shell32_module) {
	    p_SHGetFolderPath = (p_SHGetFolderPath_t)
		GetProcAddress(shell32_module, "SHGetFolderPathA");
	}
    }
    if (p_SHGetFolderPath) {
	if (SUCCEEDED(p_SHGetFolderPath(NULL, CSIDL_LOCAL_APPDATA,
					NULL, SHGFP_TYPE_CURRENT, seedpath))) {
	    strcat(seedpath, "\\PUTTY.RND");
	    if (try_random_seed(seedpath, action, &rethandle))
		return rethandle;
	}

	if (SUCCEEDED(p_SHGetFolderPath(NULL, CSIDL_APPDATA,
					NULL, SHGFP_TYPE_CURRENT, seedpath))) {
	    strcat(seedpath, "\\PUTTY.RND");
	    if (try_random_seed(seedpath, action, &rethandle))
		return rethandle;
	}
    }

    /*
     * Failing that, try %HOMEDRIVE%%HOMEPATH% as a guess at the
     * user's home directory.
     */
    {
	int len, ret;

	len =
	    GetEnvironmentVariable("HOMEDRIVE", seedpath,
				   sizeof(seedpath));
	ret =
	    GetEnvironmentVariable("HOMEPATH", seedpath + len,
				   sizeof(seedpath) - len);
	if (ret != 0) {
	    strcat(seedpath, "\\PUTTY.RND");
	    if (try_random_seed(seedpath, action, &rethandle))
		return rethandle;
	}
    }

    /*
     * And finally, fall back to C:\WINDOWS.
     */
    GetWindowsDirectory(seedpath, sizeof(seedpath));
    strcat(seedpath, "\\PUTTY.RND");
    if (try_random_seed(seedpath, action, &rethandle))
	return rethandle;

    /*
     * If even that failed, give up.
     */
    return INVALID_HANDLE_VALUE;
}

void read_random_seed(noise_consumer_t consumer)
{
    HANDLE seedf = access_random_seed(OPEN_R);

    if (seedf != INVALID_HANDLE_VALUE) {
	while (1) {
	    char buf[1024];
	    DWORD len;

	    if (ReadFile(seedf, buf, sizeof(buf), &len, NULL) && len)
		consumer(buf, len);
	    else
		break;
	}
	CloseHandle(seedf);
    }
}

void write_random_seed(void *data, int len)
{
    HANDLE seedf = access_random_seed(OPEN_W);

    if (seedf != INVALID_HANDLE_VALUE) {
	DWORD lenwritten;

	WriteFile(seedf, data, len, &lenwritten, NULL);
	CloseHandle(seedf);
    }
}

/*
 * Recursively delete a registry key and everything under it.
 */
static void registry_recursive_remove(HKEY key)
{
    DWORD i;
    char name[MAX_PATH + 1];
    HKEY subkey;

    i = 0;
    while (RegEnumKey(key, i, name, sizeof(name)) == ERROR_SUCCESS) {
	if (RegOpenKey(key, name, &subkey) == ERROR_SUCCESS) {
	    registry_recursive_remove(subkey);
	    RegCloseKey(subkey);
	}
	RegDeleteKey(key, name);
    }
}

void cleanup_all(void)
{
    HKEY key;
    int ret;
    char name[MAX_PATH + 1];

    /* ------------------------------------------------------------
     * Wipe out the random seed file, in all of its possible
     * locations.
     */
    access_random_seed(DEL);

    /* ------------------------------------------------------------
     * Destroy all registry information associated with PuTTY.
     */

    /*
     * Open the main PuTTY registry key and remove everything in it.
     */
    if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_POS, &key) ==
	ERROR_SUCCESS) {
	registry_recursive_remove(key);
	RegCloseKey(key);
    }
    /*
     * Now open the parent key and remove the PuTTY main key. Once
     * we've done that, see if the parent key has any other
     * children.
     */
    if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_PARENT,
		   &key) == ERROR_SUCCESS) {
	RegDeleteKey(key, PUTTY_REG_PARENT_CHILD);
	ret = RegEnumKey(key, 0, name, sizeof(name));
	RegCloseKey(key);
	/*
	 * If the parent key had no other children, we must delete
	 * it in its turn. That means opening the _grandparent_
	 * key.
	 */
	if (ret != ERROR_SUCCESS) {
	    if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_GPARENT,
			   &key) == ERROR_SUCCESS) {
		RegDeleteKey(key, PUTTY_REG_GPARENT_CHILD);
		RegCloseKey(key);
	    }
	}
    }
    /*
     * Now we're done.
     */
}