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Windows: Refactor and fix config_reg.c

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We want to be able to reuse registry handling code here from elsewhere.
This commit is contained in:
Asanka C. Herath
2010-11-01 16:45:33 -04:00
parent 25e3b0d70e
commit f190a65aed
1 changed files with 169 additions and 64 deletions
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233
lib/krb5/config_reg.c
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@@ -38,7 +38,7 @@
#define REGPATH "SOFTWARE\\Heimdal"
/**
* Parse a registry value as a configuration value
* Parse a registry value as a string
*
* The following registry value types are handled:
*
@@ -54,102 +54,153 @@
* a separator. No quoting is performed.
*
* Any other value type is rejected.
*
* @param [in]valuename Name of the registry value to be queried
* @param [in]type Type of the value. REG_NONE if unknown
* @param [in]cbdata Size of value. 0 if unknown.
*
* @a type and @a cbdata are only considered valid if both are
* specified.
*
* @retval The registry value string, or NULL if there was an error.
* If NULL is returned, an error message has been set using
* krb5_set_error_message().
*/
static krb5_error_code
parse_reg_value(krb5_context context,
HKEY key, const char * valuename,
DWORD type, DWORD cbdata, krb5_config_section ** parent)
char *
_krb5_parse_reg_value_as_string(krb5_context context,
HKEY key, const char * valuename,
DWORD type, DWORD cb_data)
{
LONG rcode;
DWORD cb;
LONG rcode = ERROR_MORE_DATA;
DWORD cb_alloc;
krb5_config_section *value;
krb5_error_code code = 0;
BYTE static_buffer[16384];
BYTE *pbuffer;
char *ret_string = NULL;
/* Size adjustments */
/* If we know a type and cb_data from a previous call to
* RegEnumValue(), we use it. Otherwise we use the
* static_buffer[] and query directly. We do this to minimize the
* number of queries. */
if (type == REG_NONE || cb_data == 0) {
pbuffer = &static_buffer[0];
cb_alloc = cb_data = sizeof(static_buffer);
rcode = RegQueryValueExA(key, valuename, NULL, &type, pbuffer, &cb_data);
if (rcode == ERROR_SUCCESS &&
((type != REG_SZ &&
type != REG_EXPAND_SZ) || cb_data + 1 <= sizeof(static_buffer)) &&
(type != REG_MULTI_SZ || cb_data + 2 <= sizeof(static_buffer)))
goto have_data;
if (rcode != ERROR_MORE_DATA && rcode != ERROR_SUCCESS)
return NULL;
}
/* Either we don't have the data or we aren't sure of the size
* (due to potentially missing terminating NULs). */
switch (type) {
case REG_DWORD:
if (cbdata != sizeof(DWORD)) {
krb5_set_error_message(context, KRB5_CONFIG_BADFORMAT,
"Unexpected size while reading registry value %s",
valuename);
return KRB5_CONFIG_BADFORMAT;
if (cb_data != sizeof(DWORD)) {
if (context)
krb5_set_error_message(context, 0,
"Unexpected size while reading registry value %s",
valuename);
return NULL;
}
break;
case REG_SZ:
case REG_EXPAND_SZ:
cbdata += sizeof(char); /* Accout for potential missing NUL
* terminator. */
if (rcode == ERROR_SUCCESS && cb_data > 0 && pbuffer[cb_data - 1] == '\0')
goto have_data;
cb_data += sizeof(char); /* Accout for potential missing NUL
* terminator. */
break;
case REG_MULTI_SZ:
cbdata += sizeof(char) * 2;
if (rcode == ERROR_SUCCESS && cb_data > 0 && pbuffer[cb_data - 1] == '\0' &&
(cb_data == 1 || pbuffer[cb_data - 2] == '\0'))
goto have_data;
cb_data += sizeof(char) * 2; /* Potential missing double NUL
* terminator. */
break;
default:
krb5_set_error_message(context, KRB5_CONFIG_BADFORMAT,
"Unexpected type while reading registry value %s",
valuename);
return KRB5_CONFIG_BADFORMAT;
if (context)
krb5_set_error_message(context, 0,
"Unexpected type while reading registry value %s",
valuename);
return NULL;
}
if (cbdata <= sizeof(static_buffer))
if (cb_data <= sizeof(static_buffer))
pbuffer = &static_buffer[0];
else {
pbuffer = malloc(cbdata);
pbuffer = malloc(cb_data);
if (pbuffer == NULL)
return ENOMEM;
return NULL;
}
cb = cbdata;
cb_alloc = cb_data;
rcode = RegQueryValueExA(key, valuename, NULL, NULL, pbuffer, &cb_data);
rcode = RegQueryValueExA(key, valuename, NULL, NULL, pbuffer, &cb);
if (rcode != ERROR_SUCCESS) {
krb5_set_error_message(context, KRB5_CONFIG_BADFORMAT,
"Unexpected error while reading registry value %s",
valuename);
code = KRB5_CONFIG_BADFORMAT;
/* This can potentially be from a race condition. I.e. some
* other process or thread went and modified the registry
* value between the time we queried its size and queried for
* its value. Ideally we would retry the query in a loop. */
if (context)
krb5_set_error_message(context, 0,
"Unexpected error while reading registry value %s",
valuename);
goto done;
}
if (cb > cbdata) {
krb5_set_error_message(context, KRB5_CONFIG_BADFORMAT,
"Unexpected error while reading registry value %s",
valuename);
code = KRB5_CONFIG_BADFORMAT;
if (cb_data > cb_alloc || cb_data == 0) {
if (context)
krb5_set_error_message(context, 0,
"Unexpected size while reading registry value %s",
valuename);
goto done;
}
value = _krb5_config_get_entry(parent, valuename, krb5_config_string);
if (value == NULL) {
code = ENOMEM;
goto done;
}
if (value->u.string != NULL) {
free(value->u.string);
value->u.string = NULL;
}
have_data:
switch (type) {
case REG_DWORD:
{
asprintf(&value->u.string, "%d", *((DWORD *) pbuffer));
}
break;
asprintf(&ret_string, "%d", *((DWORD *) pbuffer));
break;
case REG_SZ:
{
char * str = (char *) pbuffer;
if (str[cb - 1] != '\0')
str[cb] = '\0';
if (str[cb_data - 1] != '\0') {
if (cb_data < cb_alloc)
str[cb_data] = '\0';
else
break;
}
value->u.string = strdup(str);
if (pbuffer != static_buffer) {
ret_string = (char *) pbuffer;
pbuffer = NULL;
} else {
ret_string = strdup(pbuffer);
}
}
break;
@@ -160,15 +211,20 @@ parse_reg_value(krb5_context context,
* ExpandEnvironmentStrings() is
* limited to 32K. */
if (str[cb - 1] != '\0')
str[cb] = '\0';
if (str[cb_data - 1] != '\0') {
if (cb_data < cb_alloc)
str[cb_data] = '\0';
else
break;
}
if (ExpandEnvironmentStrings(str, expsz, sizeof(expsz)/sizeof(expsz[0])) != 0) {
value->u.string = strdup(expsz);
if (ExpandEnvironmentStrings(str, expsz, sizeof(expsz)/sizeof(char)) != 0) {
ret_string = strdup(expsz);
} else {
code = KRB5_CONFIG_BADFORMAT;
krb5_set_error_message(context, KRB5_CONFIG_BADFORMAT,
"Overflow while expanding environment strings for registry value %s", valuename);
if (context)
krb5_set_error_message(context, 0,
"Overflow while expanding environment strings "
"for registry value %s", valuename);
}
}
break;
@@ -178,8 +234,8 @@ parse_reg_value(krb5_context context,
char * str = (char *) pbuffer;
char * iter;
str[cbdata - 1] = '\0';
str[cbdata - 2] = '\0';
str[cb_alloc - 1] = '\0';
str[cb_alloc - 2] = '\0';
for (iter = str; *iter;) {
size_t len = strlen(iter);
@@ -191,15 +247,64 @@ parse_reg_value(krb5_context context,
break;
}
value->u.string = strdup(str);
if (pbuffer != static_buffer) {
ret_string = str;
pbuffer = NULL;
} else {
ret_string = strdup(str);
}
}
break;
default:
if (context)
krb5_set_error_message(context, 0,
"Unexpected type while reading registry value %s",
valuename);
}
done:
if (pbuffer != static_buffer && pbuffer != NULL)
free(pbuffer);
return ret_string;
}
/**
* Parse a registry value as a configuration value
*
* @see parse_reg_value_as_string()
*/
static krb5_error_code
parse_reg_value(krb5_context context,
HKEY key, const char * valuename,
DWORD type, DWORD cbdata, krb5_config_section ** parent)
{
char *reg_string = NULL;
krb5_config_section *value;
krb5_error_code code = 0;
reg_string = _krb5_parse_reg_value_as_string(context, key, valuename, type, cbdata);
if (reg_string == NULL)
return KRB5_CONFIG_BADFORMAT;
value = _krb5_config_get_entry(parent, valuename, krb5_config_string);
if (value == NULL) {
code = ENOMEM;
goto done;
}
if (value->u.string != NULL)
free(value->u.string);
value->u.string = reg_string;
reg_string = NULL;
done:
if (reg_string != NULL)
free(reg_string);
return code;
}
@@ -315,8 +420,8 @@ parse_reg_root(krb5_context context,
* @see parse_reg_value() for details about how each type of value is handled.
*/
krb5_error_code
krb5_load_config_from_registry(krb5_context context,
krb5_config_section ** res)
_krb5_load_config_from_registry(krb5_context context,
krb5_config_section ** res)
{
HKEY key = NULL;
LONG rcode;