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wifi_drv: handle invalid config_rom and psk 

* Only attach the config_rom dataspace if it is valid.
* Check if PSK has a valid length.

Issue #1439.
This commit is contained in:
Josef Söntgen 2015-03-06 14:24:06 +01:00 committed by Christian Helmuth
parent d443c136ed
commit f94176af3f
1 changed files with 147 additions and 49 deletions
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196
repos/dde_linux/src/drivers/wifi/main.cc
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@ -35,24 +35,68 @@ static Genode::Lock &wpa_startup_lock()
}
static int update_conf(char **p, Genode::size_t *len, char const *ssid,
bool encryption = false, char const *psk = 0)
namespace {
template <Genode::size_t CAPACITY>
class Buffer
{
private:
char _data[CAPACITY] { 0 };
Genode::size_t _length { 0 };
public:
void reset() { _data[0] = 0; _length = 0; }
char const *data() const { return _data; }
Genode::size_t length() const { return _length; }
void append(char const *format, ...)
{
va_list list;
va_start(list, format);
Genode::String_console sc(_data + _length, CAPACITY - _length);
sc.vprintf(format, list);
va_end(list);
_length += sc.len();
}
};
} /* anonymous namespace */
/**
* Generate wpa_supplicant.conf file
*/
static int generate_wpa_supplicant_conf(char const **p, Genode::size_t *len, char const *ssid,
char const *bssid, bool protection = false, char const *psk = 0)
{
char const *ssid_fmt = "network={\n\tssid=\"%s\"\n\tkey_mgmt=%s\n";
char const *psk_fmt = "psk=\"%s\"\n";
char const *end_fmt = "}\n";
static char const *start_fmt = "network={\n";
static char const *ssid_fmt = "\tssid=\"%s\"\n";
static char const *bssid_fmt = "\tbssid=%s\n";
static char const *prot_fmt = "\tkey_mgmt=%s\n";
static char const *psk_fmt = "\tpsk=\"%s\"\n";
static char const *end_fmt = "}\n";
static char buf[4096];
Genode::size_t n = Genode::snprintf(buf, sizeof(buf), ssid_fmt, ssid,
encryption ? "WPA-PSK" : "NONE");
if (encryption) {
n += Genode::snprintf(buf + n, sizeof(buf) - n, psk_fmt, psk);
}
static Buffer<256> buffer;
buffer.reset();
n += Genode::snprintf(buf + n, sizeof(buf) - n, end_fmt);
buffer.append(start_fmt);
*p = buf;
*len = n;
if (ssid)
buffer.append(ssid_fmt, ssid);
if (bssid)
buffer.append(bssid_fmt, bssid);
if (protection)
buffer.append(psk_fmt, psk);
buffer.append(prot_fmt, protection ? "WPA-PSK" : "NONE");
buffer.append(end_fmt);
*p = buffer.data();
*len = buffer.length();
return 0;
}
@ -60,55 +104,109 @@ static int update_conf(char **p, Genode::size_t *len, char const *ssid,
struct Wlan_configration
{
Genode::Attached_rom_dataspace config_rom { "wlan_configuration" };
Genode::Attached_rom_dataspace config_rom { "wlan_configuration" };
Genode::Signal_rpc_member<Wlan_configration> dispatcher;
Genode::Lock update_lock;
void _update_conf()
char const *buffer;
Genode::size_t size;
/**
* Write configuration buffer to conf file to activate the new configuration.
*/
void _activate_configuration()
{
config_rom.update();
Genode::size_t size = config_rom.size();
char *file_buffer;
Genode::size_t buffer_length;
Genode::Xml_node node(config_rom.local_addr<char>(), size);
/**
* Since <selected_accesspoint/> is empty we generate a dummy
* configuration to fool wpa_supplicant to keep it scanning for
* the non exisiting network.
*/
if (!node.has_attribute("ssid")) {
update_conf(&file_buffer, &buffer_length, "dummyssid");
} else {
char ssid[32+1] = { 0 };
node.attribute("ssid").value(ssid, sizeof(ssid));
bool use_protection = node.has_attribute("protection");
char psk[63+1] = { 0 };
if (use_protection && node.has_attribute("psk"))
node.attribute("psk").value(psk, sizeof(psk));
if (update_conf(&file_buffer, &buffer_length, ssid,
use_protection, psk) != 0)
return;
}
if (wpa_write_conf(file_buffer, buffer_length) == 0) {
if (wpa_write_conf(buffer, size) == 0) {
PINF("reload wpa_supplicant configuration");
wpa_conf_reload();
}
}
void _handle_update(unsigned) { _update_conf(); }
/**
* Write dummy configuration buffer to conf file to activate the new
* configuration.
*/
void _active_dummy_configuration()
{
generate_wpa_supplicant_conf(&buffer, &size, "dummyssid", "00:00:00:00:00:00");
_activate_configuration();
}
/**
* Update the conf file used by the wpa_supplicant.
*/
void _update_configuration()
{
Genode::Lock::Guard guard(update_lock);
config_rom.update();
/**
* We generate a dummy configuration because there is no valid
* configuration yet to fool wpa_supplicant to keep it scanning
* for the non exisiting network.
*/
if (!config_rom.is_valid()) {
_active_dummy_configuration();
return;
}
Genode::Xml_node node(config_rom.local_addr<char>(), config_rom.size());
/**
* Since <selected_accesspoint/> is empty we also generate a dummy
* configuration.
*/
bool use_ssid = node.has_attribute("ssid");
bool use_bssid = node.has_attribute("bssid");
if (!use_ssid && !use_bssid) {
_active_dummy_configuration();
return;
}
/**
* Try to generate a valid configuration.
*/
enum { MAX_SSID_LENGTH = 32,
BSSID_LENGTH = 12 + 5,
MIN_PSK_LENGTH = 8,
MAX_PSK_LENGTH = 63 };
char ssid[MAX_SSID_LENGTH + 1] = { 0 };
if (use_ssid)
node.attribute("ssid").value(ssid, sizeof(ssid));
char bssid[BSSID_LENGTH + 1] = { 0 };
if (use_bssid)
node.attribute("bssid").value(bssid, sizeof(bssid));
bool use_protection = node.has_attribute("protection");
char psk[MAX_PSK_LENGTH + 1] = { 0 };
if (use_protection && node.has_attribute("psk"))
node.attribute("psk").value(psk, sizeof(psk));
/* psk must be between 8 and 63 characters long */
if (Genode::strlen(psk) < MIN_PSK_LENGTH) {
_active_dummy_configuration();
return;
}
if (generate_wpa_supplicant_conf(&buffer, &size,
use_ssid ? ssid : 0,
use_bssid ? bssid : 0,
use_protection, psk) == 0)
_activate_configuration();
}
void _handle_update(unsigned) { _update_configuration(); }
Wlan_configration(Server::Entrypoint &ep)
:
dispatcher(ep, *this, &Wlan_configration::_handle_update)
{
config_rom.sigh(dispatcher);
_update_conf();
_update_configuration();
}
};