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93fb65af61
putty-source/windows/storage.c
Simon Tatham 93fb65af61 Fix translation of legacy registry RSA key format. 
A user points out that in commit 6143a50ed2, when I converted all
use of the registry to functions that return a newly allocated buffer
instead of allocating a buffer themselves beforehand, I overlooked
that one use of the old idiom was reusing the preallocated buffer as
work space.

I _hope_ nobody still needs this code - the 'old-style' host key cache
format it handles was replaced in 2000. If anyone has a PuTTY host key
cache entry that's survived 22 years without either having to be
reinitialised on a new system or changed when the machine's host key
was upgraded, they're doing better than I am!

But if it's still here, it should still work, obviously. Replaced the
reused buffer with a strbuf, which is more robust anyway.
2022-04-27 16:33:23 +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);
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 = snew(host_ca);
memset(hca, 0, sizeof(*hca));
hca->name = dupstr(name);
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);
}
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);
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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