Improve SSH2 host key abstraction into a generic `signing key'

[sgt/putty] / winstore.c

/*
 * winstore.c: Windows-specific implementation of the interface
 * defined in storage.h.
 */

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "putty.h"
#include "storage.h"

static const char *const puttystr = PUTTY_REG_POS "\\Sessions";

static char seedpath[2*MAX_PATH+10] = "\0";

static char hex[16] = "0123456789ABCDEF";

static void mungestr(char *in, char *out) {
    int candot = 0;

    while (*in) {
	if (*in == ' ' || *in == '\\' || *in == '*' || *in == '?' ||
	    *in == '%' || *in < ' ' || *in > '~' || (*in == '.' && !candot)) {
	    *out++ = '%';
	    *out++ = hex[((unsigned char)*in) >> 4];
	    *out++ = hex[((unsigned char)*in) & 15];
	} else
	    *out++ = *in;
	in++;
	candot = 1;
    }
    *out = '\0';
    return;
}

static void unmungestr(char *in, char *out, int outlen) {
    while (*in) {
	if (*in == '%' && in[1] && in[2]) {
	    int i, j;

	    i = in[1] - '0'; i -= (i > 9 ? 7 : 0);
	    j = in[2] - '0'; j -= (j > 9 ? 7 : 0);

	    *out++ = (i<<4) + j;
            if (!--outlen) return;
	    in += 3;
	} else {
	    *out++ = *in++;
            if (!--outlen) return;
        }
    }
    *out = '\0';
    return;
}

void *open_settings_w(char *sessionname) {
    HKEY subkey1, sesskey;
    int ret;
    char *p;

    p = malloc(3*strlen(sessionname)+1);
    mungestr(sessionname, p);
    
    ret = RegCreateKey(HKEY_CURRENT_USER, puttystr, &subkey1);
    if (ret != ERROR_SUCCESS) {
        free(p);
        return NULL;
    }
    ret = RegCreateKey(subkey1, p, &sesskey);
    free(p);
    RegCloseKey(subkey1);
    if (ret != ERROR_SUCCESS)
        return NULL;
    return (void *)sesskey;
}

void write_setting_s(void *handle, char *key, char *value) {
    if (handle)
        RegSetValueEx((HKEY)handle, key, 0, REG_SZ, value, 1+strlen(value));
}

void write_setting_i(void *handle, char *key, int value) {
    if (handle)
        RegSetValueEx((HKEY)handle, key, 0, REG_DWORD,
                      (CONST BYTE *)&value, sizeof(value));
}

void close_settings_w(void *handle) {
    RegCloseKey((HKEY)handle);
}

void *open_settings_r(char *sessionname) {
    HKEY subkey1, sesskey;
    char *p;

    p = malloc(3*strlen(sessionname)+1);
    mungestr(sessionname, p);

    if (RegOpenKey(HKEY_CURRENT_USER, puttystr, &subkey1) != ERROR_SUCCESS) {
	sesskey = NULL;
    } else {
	if (RegOpenKey(subkey1, p, &sesskey) != ERROR_SUCCESS) {
	    sesskey = NULL;
	}
	RegCloseKey(subkey1);
    }

    free(p);

    return (void *)sesskey;
}

char *read_setting_s(void *handle, char *key, char *buffer, int buflen) {
    DWORD type, size;
    size = buflen;

    if (!handle ||
        RegQueryValueEx((HKEY)handle, key, 0,
                        &type, buffer, &size) != ERROR_SUCCESS ||
	type != REG_SZ)
        return NULL;
    else
        return buffer;
}

int read_setting_i(void *handle, char *key, int defvalue) {
    DWORD type, val, size;
    size = sizeof(val);

    if (!handle ||
	RegQueryValueEx((HKEY)handle, key, 0, &type,
			(BYTE *)&val, &size) != ERROR_SUCCESS ||
	size != sizeof(val) || type != REG_DWORD)
	return defvalue;
    else
	return val;
}

void close_settings_r(void *handle) {
    RegCloseKey((HKEY)handle);
}

void del_settings (char *sessionname) {
    HKEY subkey1;
    char *p;

    if (RegOpenKey(HKEY_CURRENT_USER, puttystr, &subkey1) != ERROR_SUCCESS)
	return;

    p = malloc(3*strlen(sessionname)+1);
    mungestr(sessionname, p);
    RegDeleteKey(subkey1, p);
    free(p);

    RegCloseKey(subkey1);
}

struct enumsettings {
    HKEY key;
    int i;
};

void *enum_settings_start(void) {
    struct enumsettings *ret;
    HKEY key;

    if (RegCreateKey(HKEY_CURRENT_USER, puttystr, &key) != ERROR_SUCCESS)
        return NULL;

    ret = malloc(sizeof(*ret));
    if (ret) {
        ret->key = key;
        ret->i = 0;
    }

    return ret;
}

char *enum_settings_next(void *handle, char *buffer, int buflen) {
    struct enumsettings *e = (struct enumsettings *)handle;
    char *otherbuf;
    otherbuf = malloc(3*buflen);
    if (otherbuf && RegEnumKey(e->key, e->i++, otherbuf,
                               3*buflen) == ERROR_SUCCESS) {
        unmungestr(otherbuf, buffer, buflen);
        free(otherbuf);
        return buffer;
    } else
        return NULL;

}

void enum_settings_finish(void *handle) {
    struct enumsettings *e = (struct enumsettings *)handle;
    RegCloseKey(e->key);
    free(e);
}

static void hostkey_regname(char *buffer, char *hostname,
                            int port, char *keytype) {
    int len;
    strcpy(buffer, keytype);
    strcat(buffer, "@");
    len = strlen(buffer);
    len += sprintf(buffer+len, "%d:", port);
    mungestr(hostname, buffer + strlen(buffer));
}

int verify_host_key(char *hostname, int port, char *keytype, char *key) {
    char *otherstr, *regname;
    int len;
    HKEY rkey;
    DWORD readlen;
    DWORD type;
    int ret, compare;

    len = 1 + strlen(key);

    /*
     * Now read a saved key in from the registry and see what it
     * says.
     */
    otherstr = smalloc(len);
    regname = smalloc(3*(strlen(hostname)+strlen(keytype))+15);

    hostkey_regname(regname, hostname, port, keytype);

    if (RegCreateKey(HKEY_CURRENT_USER, PUTTY_REG_POS "\\SshHostKeys",
		     &rkey) != ERROR_SUCCESS)
        return 1;                      /* key does not exist in registry */

    readlen = len;
    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 = smalloc(len + 10);   /* 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(char *hostname, int port, char *keytype, char *key) {
    char *regname;
    HKEY rkey;

    regname = smalloc(3*(strlen(hostname)+strlen(keytype))+15);

    hostkey_regname(regname, hostname, port, keytype);

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

/*
 * Find the random seed file path and store it in `seedpath'.
 */
static void get_seedpath(void) {
    HKEY rkey;
    DWORD type, size;

    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);
    } else
	seedpath[0] = '\0';

    if (!seedpath[0]) {
	int len, ret;

	len = GetEnvironmentVariable("HOMEDRIVE", seedpath, sizeof(seedpath));
	ret = GetEnvironmentVariable("HOMEPATH", seedpath+len,
				      sizeof(seedpath)-len);
	if (ret == 0) {		       /* probably win95; store in \WINDOWS */
	    GetWindowsDirectory(seedpath, sizeof(seedpath));
	    len = strlen(seedpath);
	} else
	    len += ret;
	strcpy(seedpath+len, "\\PUTTY.RND");
    }
}

void read_random_seed(noise_consumer_t consumer) {
    HANDLE seedf;

    if (!seedpath[0])
	get_seedpath();

    seedf = CreateFile(seedpath, GENERIC_READ,
		       FILE_SHARE_READ | FILE_SHARE_WRITE,
		       NULL, OPEN_EXISTING, 0, NULL);

    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;

    if (!seedpath[0])
	get_seedpath();

    seedf = CreateFile(seedpath, GENERIC_WRITE, 0,
		       NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

    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.
     */
    if (!seedpath[0])
	get_seedpath();
    remove(seedpath);

    /* ------------------------------------------------------------
     * 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.
     */
}