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putty-source/windows/storage.c
Simon Tatham dc7ba12253 Permit configuring RSA signature types in certificates. 
As distinct from the type of signature generated by the SSH server
itself from the host key, this lets you exclude (and by default does
exclude) the old "ssh-rsa" SHA-1 signature type from the signature of
the CA on the certificate.
2022-05-02 11:17:58 +01:00

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/*
* storage.c: Windows-specific implementation of the interface
* defined in storage.h.
*/
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <assert.h>
#include "putty.h"
#include "storage.h"
#include <shlobj.h>
#ifndef CSIDL_APPDATA
#define CSIDL_APPDATA 0x001a
#endif
#ifndef CSIDL_LOCAL_APPDATA
#define CSIDL_LOCAL_APPDATA 0x001c
#endif
static const char *const reg_jumplist_key = PUTTY_REG_POS "\\Jumplist";
static const char *const reg_jumplist_value = "Recent sessions";
static const char *const puttystr = PUTTY_REG_POS "\\Sessions";
static const char *const host_ca_key = PUTTY_REG_POS "\\SshHostCAs";
static bool tried_shgetfolderpath = false;
static HMODULE shell32_module = NULL;
DECL_WINDOWS_FUNCTION(static, HRESULT, SHGetFolderPathA,
(HWND, int, HANDLE, DWORD, LPSTR));
struct settings_w {
HKEY sesskey;
};
settings_w *open_settings_w(const char *sessionname, char **errmsg)
{
*errmsg = NULL;
if (!sessionname || !*sessionname)
sessionname = "Default Settings";
strbuf *sb = strbuf_new();
escape_registry_key(sessionname, sb);
HKEY sesskey = open_regkey(true, HKEY_CURRENT_USER, puttystr, sb->s);
if (!sesskey) {
*errmsg = dupprintf("Unable to create registry key\n"
"HKEY_CURRENT_USER\\%s\\%s", puttystr, sb->s);
strbuf_free(sb);
return NULL;
}
strbuf_free(sb);
settings_w *toret = snew(settings_w);
toret->sesskey = sesskey;
return toret;
}
void write_setting_s(settings_w *handle, const char *key, const char *value)
{
if (handle)
put_reg_sz(handle->sesskey, key, value);
}
void write_setting_i(settings_w *handle, const char *key, int value)
{
if (handle)
put_reg_dword(handle->sesskey, key, value);
}
void close_settings_w(settings_w *handle)
{
close_regkey(handle->sesskey);
sfree(handle);
}
struct settings_r {
HKEY sesskey;
};
settings_r *open_settings_r(const char *sessionname)
{
if (!sessionname || !*sessionname)
sessionname = "Default Settings";
strbuf *sb = strbuf_new();
escape_registry_key(sessionname, sb);
HKEY sesskey = open_regkey(false, HKEY_CURRENT_USER, puttystr, sb->s);
strbuf_free(sb);
if (!sesskey)
return NULL;
settings_r *toret = snew(settings_r);
toret->sesskey = sesskey;
return toret;
}
char *read_setting_s(settings_r *handle, const char *key)
{
if (!handle)
return NULL;
return get_reg_sz(handle->sesskey, key);
}
int read_setting_i(settings_r *handle, const char *key, int defvalue)
{
DWORD val;
if (!handle || !get_reg_dword(handle->sesskey, key, &val))
return defvalue;
else
return val;
}
FontSpec *read_setting_fontspec(settings_r *handle, const char *name)
{
char *settingname;
char *fontname;
FontSpec *ret;
int isbold, height, charset;
fontname = read_setting_s(handle, name);
if (!fontname)
return NULL;
settingname = dupcat(name, "IsBold");
isbold = read_setting_i(handle, settingname, -1);
sfree(settingname);
if (isbold == -1) {
sfree(fontname);
return NULL;
}
settingname = dupcat(name, "CharSet");
charset = read_setting_i(handle, settingname, -1);
sfree(settingname);
if (charset == -1) {
sfree(fontname);
return NULL;
}
settingname = dupcat(name, "Height");
height = read_setting_i(handle, settingname, INT_MIN);
sfree(settingname);
if (height == INT_MIN) {
sfree(fontname);
return NULL;
}
ret = fontspec_new(fontname, isbold, height, charset);
sfree(fontname);
return ret;
}
void write_setting_fontspec(settings_w *handle,
const char *name, FontSpec *font)
{
char *settingname;
write_setting_s(handle, name, font->name);
settingname = dupcat(name, "IsBold");
write_setting_i(handle, settingname, font->isbold);
sfree(settingname);
settingname = dupcat(name, "CharSet");
write_setting_i(handle, settingname, font->charset);
sfree(settingname);
settingname = dupcat(name, "Height");
write_setting_i(handle, settingname, font->height);
sfree(settingname);
}
Filename *read_setting_filename(settings_r *handle, const char *name)
{
char *tmp = read_setting_s(handle, name);
if (tmp) {
Filename *ret = filename_from_str(tmp);
sfree(tmp);
return ret;
} else
return NULL;
}
void write_setting_filename(settings_w *handle,
const char *name, Filename *result)
{
write_setting_s(handle, name, result->path);
}
void close_settings_r(settings_r *handle)
{
if (handle) {
close_regkey(handle->sesskey);
sfree(handle);
}
}
void del_settings(const char *sessionname)
{
HKEY rkey = open_regkey(false, HKEY_CURRENT_USER, puttystr);
if (!rkey)
return;
strbuf *sb = strbuf_new();
escape_registry_key(sessionname, sb);
del_regkey(rkey, sb->s);
strbuf_free(sb);
close_regkey(rkey);
remove_session_from_jumplist(sessionname);
}
struct settings_e {
HKEY key;
int i;
};
settings_e *enum_settings_start(void)
{
HKEY key = open_regkey(false, HKEY_CURRENT_USER, puttystr);
if (!key)
return NULL;
settings_e *ret = snew(settings_e);
if (ret) {
ret->key = key;
ret->i = 0;
}
return ret;
}
bool enum_settings_next(settings_e *e, strbuf *sb)
{
char *name = enum_regkey(e->key, e->i);
if (!name)
return false;
unescape_registry_key(name, sb);
sfree(name);
e->i++;
return true;
}
void enum_settings_finish(settings_e *e)
{
close_regkey(e->key);
sfree(e);
}
static void hostkey_regname(strbuf *sb, const char *hostname,
int port, const char *keytype)
{
put_fmt(sb, "%s@%d:", keytype, port);
escape_registry_key(hostname, sb);
}
int check_stored_host_key(const char *hostname, int port,
const char *keytype, const char *key)
{
/*
* Read a saved key in from the registry and see what it says.
*/
strbuf *regname = strbuf_new();
hostkey_regname(regname, hostname, port, keytype);
HKEY rkey = open_regkey(false, HKEY_CURRENT_USER,
PUTTY_REG_POS "\\SshHostKeys");
if (!rkey) {
strbuf_free(regname);
return 1; /* key does not exist in registry */
}
char *otherstr = get_reg_sz(rkey, regname->s);
if (!otherstr && !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->s + 1 + strcspn(regname->s, ":");
char *oldstyle = get_reg_sz(rkey, justhost);
if (oldstyle) {
/*
* 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.
*/
strbuf *new = strbuf_new();
const char *q = oldstyle;
int i, j;
for (i = 0; i < 2; i++) {
int ndigits, nwords;
put_datapl(new, PTRLEN_LITERAL("0x"));
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 = ndigits; j-- > 0 ;)
put_byte(new, q[j ^ 3]);
q += nwords * 4;
if (*q) {
q++; /* eat the slash */
put_byte(new, ','); /* add a comma */
}
}
/*
* 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(new->s, key)) {
put_reg_sz(rkey, regname->s, new->s);
otherstr = strbuf_to_str(new);
} else {
strbuf_free(new);
}
}
sfree(oldstyle);
}
close_regkey(rkey);
int compare = otherstr ? strcmp(otherstr, key) : -1;
sfree(otherstr);
strbuf_free(regname);
if (!otherstr)
return 1; /* key does not exist in registry */
else if (compare)
return 2; /* key is different in registry */
else
return 0; /* key matched OK in registry */
}
bool have_ssh_host_key(const char *hostname, int port,
const char *keytype)
{
/*
* If we have a host key, check_stored_host_key will return 0 or 2.
* If we don't have one, it'll return 1.
*/
return check_stored_host_key(hostname, port, keytype, "") != 1;
}
void store_host_key(const char *hostname, int port,
const char *keytype, const char *key)
{
strbuf *regname = strbuf_new();
hostkey_regname(regname, hostname, port, keytype);
HKEY rkey = open_regkey(true, HKEY_CURRENT_USER,
PUTTY_REG_POS "\\SshHostKeys");
if (rkey) {
put_reg_sz(rkey, regname->s, key);
close_regkey(rkey);
} /* else key does not exist in registry */
strbuf_free(regname);
}
struct host_ca_enum {
HKEY key;
int i;
};
host_ca_enum *enum_host_ca_start(void)
{
host_ca_enum *e;
HKEY key;
if (!(key = open_regkey(false, HKEY_CURRENT_USER, host_ca_key)))
return NULL;
e = snew(host_ca_enum);
e->key = key;
e->i = 0;
return e;
}
bool enum_host_ca_next(host_ca_enum *e, strbuf *sb)
{
char *regbuf = enum_regkey(e->key, e->i);
if (!regbuf)
return false;
unescape_registry_key(regbuf, sb);
sfree(regbuf);
e->i++;
return true;
}
void enum_host_ca_finish(host_ca_enum *e)
{
close_regkey(e->key);
sfree(e);
}
host_ca *host_ca_load(const char *name)
{
strbuf *sb;
const char *s;
sb = strbuf_new();
escape_registry_key(name, sb);
HKEY rkey = open_regkey(false, HKEY_CURRENT_USER, host_ca_key, sb->s);
strbuf_free(sb);
if (!rkey)
return NULL;
host_ca *hca = host_ca_new();
hca->name = dupstr(name);
DWORD val;
if ((s = get_reg_sz(rkey, "PublicKey")) != NULL)
hca->ca_public_key = base64_decode_sb(ptrlen_from_asciz(s));
if ((sb = get_reg_multi_sz(rkey, "MatchHosts")) != NULL) {
BinarySource src[1];
BinarySource_BARE_INIT_PL(src, ptrlen_from_strbuf(sb));
const char *wc;
size_t wcsize = 0;
while (wc = get_asciz(src), !get_err(src)) {
sgrowarray(hca->hostname_wildcards, wcsize,
hca->n_hostname_wildcards);
hca->hostname_wildcards[hca->n_hostname_wildcards++] = dupstr(wc);
}
strbuf_free(sb);
}
if (get_reg_dword(rkey, "PermitRSASHA1", &val))
hca->opts.permit_rsa_sha1 = val;
if (get_reg_dword(rkey, "PermitRSASHA256", &val))
hca->opts.permit_rsa_sha256 = val;
if (get_reg_dword(rkey, "PermitRSASHA512", &val))
hca->opts.permit_rsa_sha512 = val;
close_regkey(rkey);
return hca;
}
char *host_ca_save(host_ca *hca)
{
if (!*hca->name)
return dupstr("CA record must have a name");
strbuf *sb = strbuf_new();
escape_registry_key(hca->name, sb);
HKEY rkey = open_regkey(true, HKEY_CURRENT_USER, host_ca_key, sb->s);
if (!rkey) {
char *err = dupprintf("Unable to create registry key\n"
"HKEY_CURRENT_USER\\%s\\%s", host_ca_key, sb->s);
strbuf_free(sb);
return err;
}
strbuf_free(sb);
strbuf *base64_pubkey = base64_encode_sb(
ptrlen_from_strbuf(hca->ca_public_key), 0);
put_reg_sz(rkey, "PublicKey", base64_pubkey->s);
strbuf_free(base64_pubkey);
strbuf *wcs = strbuf_new();
for (size_t i = 0; i < hca->n_hostname_wildcards; i++)
put_asciz(wcs, hca->hostname_wildcards[i]);
put_reg_multi_sz(rkey, "MatchHosts", wcs);
strbuf_free(wcs);
put_reg_dword(rkey, "PermitRSASHA1", hca->opts.permit_rsa_sha1);
put_reg_dword(rkey, "PermitRSASHA256", hca->opts.permit_rsa_sha256);
put_reg_dword(rkey, "PermitRSASHA512", hca->opts.permit_rsa_sha512);
close_regkey(rkey);
return NULL;
}
char *host_ca_delete(const char *name)
{
HKEY rkey = open_regkey(false, HKEY_CURRENT_USER, host_ca_key);
if (!rkey)
return NULL;
strbuf *sb = strbuf_new();
escape_registry_key(name, sb);
del_regkey(rkey, sb->s);
strbuf_free(sb);
return NULL;
}
/*
* Open (or delete) the random seed file.
*/
enum { DEL, OPEN_R, OPEN_W };
static bool try_random_seed(char const *path, int action, HANDLE *ret)
{
if (action == DEL) {
if (!DeleteFile(path) && GetLastError() != ERROR_FILE_NOT_FOUND) {
nonfatal("Unable to delete '%s': %s", path,
win_strerror(GetLastError()));
}
*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 bool try_random_seed_and_free(char *path, int action, HANDLE *hout)
{
bool retd = try_random_seed(path, action, hout);
sfree(path);
return retd;
}
static HANDLE access_random_seed(int action)
{
HANDLE rethandle;
/*
* 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.
*/
{
HKEY rkey = open_regkey(false, HKEY_CURRENT_USER, PUTTY_REG_POS);
if (rkey) {
char *regpath = get_reg_sz(rkey, "RandSeedFile");
close_regkey(rkey);
if (regpath) {
bool success = try_random_seed(regpath, action, &rethandle);
sfree(regpath);
if (success)
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 = load_system32_dll("shell32.dll");
GET_WINDOWS_FUNCTION(shell32_module, SHGetFolderPathA);
tried_shgetfolderpath = true;
}
if (p_SHGetFolderPathA) {
char profile[MAX_PATH + 1];
if (SUCCEEDED(p_SHGetFolderPathA(NULL, CSIDL_LOCAL_APPDATA,
NULL, SHGFP_TYPE_CURRENT, profile)) &&
try_random_seed_and_free(dupcat(profile, "\\PUTTY.RND"),
action, &rethandle))
return rethandle;
if (SUCCEEDED(p_SHGetFolderPathA(NULL, CSIDL_APPDATA,
NULL, SHGFP_TYPE_CURRENT, profile)) &&
try_random_seed_and_free(dupcat(profile, "\\PUTTY.RND"),
action, &rethandle))
return rethandle;
}
/*
* Failing that, try %HOMEDRIVE%%HOMEPATH% as a guess at the
* user's home directory.
*/
{
char drv[MAX_PATH], path[MAX_PATH];
DWORD drvlen = GetEnvironmentVariable("HOMEDRIVE", drv, sizeof(drv));
DWORD pathlen = GetEnvironmentVariable("HOMEPATH", path, sizeof(path));
/* We permit %HOMEDRIVE% to expand to an empty string, but if
* %HOMEPATH% does that, we abort the attempt. Same if either
* variable overflows its buffer. */
if (drvlen == 0)
drv[0] = '\0';
if (drvlen < lenof(drv) && pathlen < lenof(path) && pathlen > 0 &&
try_random_seed_and_free(
dupcat(drv, path, "\\PUTTY.RND"), action, &rethandle))
return rethandle;
}
/*
* And finally, fall back to C:\WINDOWS.
*/
{
char windir[MAX_PATH];
DWORD len = GetWindowsDirectory(windir, sizeof(windir));
if (len < lenof(windir) &&
try_random_seed_and_free(
dupcat(windir, "\\PUTTY.RND"), 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);
}
}
/*
* Internal function supporting the jump list registry code. All the
* functions to add, remove and read the list have substantially
* similar content, so this is a generalisation of all of them which
* transforms the list in the registry by prepending 'add' (if
* non-null), removing 'rem' from what's left (if non-null), and
* returning the resulting concatenated list of strings in 'out' (if
* non-null).
*/
static int transform_jumplist_registry
(const char *add, const char *rem, char **out)
{
HKEY rkey = open_regkey(true, HKEY_CURRENT_USER, reg_jumplist_key);
if (!rkey)
return JUMPLISTREG_ERROR_KEYOPENCREATE_FAILURE;
/* Get current list of saved sessions in the registry. */
strbuf *oldlist = get_reg_multi_sz(rkey, reg_jumplist_value);
if (!oldlist) {
/* Start again with the empty list. */
oldlist = strbuf_new();
put_data(oldlist, "\0\0", 2);
}
/*
* Modify the list, if we're modifying.
*/
bool write_failure = false;
if (add || rem) {
BinarySource src[1];
BinarySource_BARE_INIT_PL(src, ptrlen_from_strbuf(oldlist));
strbuf *newlist = strbuf_new();
/* First add the new item to the beginning of the list. */
if (add)
put_asciz(newlist, add);
/* Now add the existing list, taking care to leave out the removed
* item, if it was already in the existing list. */
while (true) {
const char *olditem = get_asciz(src);
if (get_err(src))
break;
if (!rem || strcmp(olditem, rem) != 0) {
/* Check if this is a valid session, otherwise don't add. */
settings_r *psettings_tmp = open_settings_r(olditem);
if (psettings_tmp != NULL) {
close_settings_r(psettings_tmp);
put_asciz(newlist, olditem);
}
}
}
/* Save the new list to the registry. */
write_failure = !put_reg_multi_sz(rkey, reg_jumplist_value, newlist);
strbuf_free(oldlist);
oldlist = newlist;
}
close_regkey(rkey);
if (out && !write_failure)
*out = strbuf_to_str(oldlist);
else
strbuf_free(oldlist);
if (write_failure)
return JUMPLISTREG_ERROR_VALUEWRITE_FAILURE;
else
return JUMPLISTREG_OK;
}
/* Adds a new entry to the jumplist entries in the registry. */
int add_to_jumplist_registry(const char *item)
{
return transform_jumplist_registry(item, item, NULL);
}
/* Removes an item from the jumplist entries in the registry. */
int remove_from_jumplist_registry(const char *item)
{
return transform_jumplist_registry(NULL, item, NULL);
}
/* Returns the jumplist entries from the registry. Caller must free
* the returned pointer. */
char *get_jumplist_registry_entries (void)
{
char *list_value;
if (transform_jumplist_registry(NULL,NULL,&list_value) != JUMPLISTREG_OK) {
list_value = snewn(2, char);
*list_value = '\0';
*(list_value + 1) = '\0';
}
return list_value;
}
/*
* Recursively delete a registry key and everything under it.
*/
static void registry_recursive_remove(HKEY key)
{
char *name;
DWORD i = 0;
while ((name = enum_regkey(key, i)) != NULL) {
HKEY subkey = open_regkey(false, key, name);
if (subkey) {
registry_recursive_remove(subkey);
close_regkey(subkey);
}
del_regkey(key, name);
sfree(name);
}
}
void cleanup_all(void)
{
/* ------------------------------------------------------------
* Wipe out the random seed file, in all of its possible
* locations.
*/
access_random_seed(DEL);
/* ------------------------------------------------------------
* Ask Windows to delete any jump list information associated
* with this installation of PuTTY.
*/
clear_jumplist();
/* ------------------------------------------------------------
* Destroy all registry information associated with PuTTY.
*/
/*
* Open the main PuTTY registry key and remove everything in it.
*/
HKEY key = open_regkey(false, HKEY_CURRENT_USER, PUTTY_REG_POS);
if (key) {
registry_recursive_remove(key);
close_regkey(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 ((key = open_regkey(false, HKEY_CURRENT_USER,
PUTTY_REG_PARENT)) != NULL) {
del_regkey(key, PUTTY_REG_PARENT_CHILD);
char *name = enum_regkey(key, 0);
close_regkey(key);
/*
* If the parent key had no other children, we must delete
* it in its turn. That means opening the _grandparent_
* key.
*/
if (name) {
sfree(name);
} else {
if ((key = open_regkey(false, HKEY_CURRENT_USER,
PUTTY_REG_GPARENT)) != NULL) {
del_regkey(key, PUTTY_REG_GPARENT_CHILD);
close_regkey(key);
}
}
}
/*
* Now we're done.
*/
}
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