external/yambar
1
0
Fork 1
mirror of https://codeberg.org/dnkl/yambar.git synced 2025-04-20 03:35:41 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

module/network: resurrect SSID

Browse source 
Recent kernels, or possibly updated wireless drivers, no longer
provide the SSID in `NL80211_CMD_NEW_STATION` responses.

For yambar, this meant the SSID was always missing.

This patch fixes this, by also issuing a NL80211_CMD_GET_SCAN
command. The response to this (NL80211_CMD_SCAN_RESULTS) _may_ return
many access points. Pick out the one that we’re associated with, and
inspect its BSS_INFORMATION_ELEMENTS. This is a raw data structure
containing, among other things, the SSID.

I haven’t been able to find any documentation of the format, but could
glean enough from
https://git.kernel.org/pub/scm/linux/kernel/git/jberg/iw.git/tree/scan.c#n2313
to be able to parse out the SSID.

Note that we get a “device or resource busy” error if we try to issue
both the NL80211_CMD_GET_STATION and the NL80211_CMD_GET_SCAN commands
at the same time. Therefore, we issue the GET_SCAN command after
completing the GET_STATION command.

Closes #226
This commit is contained in:
Daniel Eklöf 2022-09-10 13:46:34 +02:00
parent d1a8029e6c
commit 4143099e94
No known key found for this signature in database
GPG key ID: 5BBD4992C116573F
2 changed files with 147 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
CHANGELOG.md
View file

@ -110,6 +110,9 @@
* string: crash when failing to convert string to UTF-32.
* script: only first transaction processed when receiving multiple
transactions in a single batch ([#221][221]).
* network: missing SSID (recent kernels, or possibly wireless drivers,
no longer provide the SSID in the `NL80211_CMD_NEW_STATION`
response) ([#226][226]).
[169]: https://codeberg.org/dnkl/yambar/issues/169
[172]: https://codeberg.org/dnkl/yambar/issues/172
@ -117,6 +120,7 @@
[177]: https://codeberg.org/dnkl/yambar/issues/177
[198]: https://codeberg.org/dnkl/yambar/issues/198
[221]: https://codeberg.org/dnkl/yambar/issues/221
[226]: https://codeberg.org/dnkl/yambar/issues/226
### Security

146
modules/network.c
View file

@ -60,6 +60,7 @@ struct private {
uint16_t family_id;
uint32_t get_interface_seq_nr;
uint32_t get_station_seq_nr;
uint32_t get_scan_seq_nr;
} nl80211;
bool get_addresses;
@ -457,6 +458,32 @@ send_nl80211_get_station(struct private *m)
return false;
}
static bool
send_nl80211_get_scan(struct private *m)
{
if (m->nl80211.get_scan_seq_nr > 0) {
LOG_ERR(
"%s: nl80211 get-scan request already in progress", m->iface);
return true;
}
LOG_DBG("%s: sending nl80211 get-scan request", m->iface);
uint32_t seq;
if (read(m->urandom_fd, &seq, sizeof(seq)) != sizeof(seq)) {
LOG_ERRNO("failed to read from /dev/urandom");
return false;
}
if (send_nl80211_request(
m, NL80211_CMD_GET_SCAN, NLM_F_REQUEST | NLM_F_DUMP, seq))
{
m->nl80211.get_scan_seq_nr = seq;
return true;
} else
return false;
}
static bool
find_my_ifindex(struct module *mod, const struct ifinfomsg *msg, size_t len)
{
@ -810,6 +837,7 @@ handle_nl80211_new_interface(struct module *mod, uint16_t type, bool nested,
case NL80211_ATTR_SSID: {
const char *ssid = payload;
LOG_INFO("%s: SSID: %.*s", m->iface, (int)len, ssid);
mtx_lock(&mod->lock);
free(m->ssid);
@ -951,6 +979,102 @@ handle_nl80211_new_station(struct module *mod, uint16_t type, bool nested,
return true;
}
static bool
handle_ies(struct module *mod, const void *_ies, size_t len)
{
struct private *m = mod->private;
const uint8_t *ies = _ies;
while (len >= 2 && len - 2 >= ies[1]) {
switch (ies[0]) {
case 0: { /* SSID */
const char *ssid = (const char *)&ies[2];
const size_t ssid_len = ies[1];
LOG_INFO("%s: SSID: %.*s", m->iface, (int)ssid_len, ssid);
mtx_lock(&mod->lock);
free(m->ssid);
m->ssid = strndup(ssid, ssid_len);
mtx_unlock(&mod->lock);
mod->bar->refresh(mod->bar);
break;
}
}
len -= ies[1] + 2;
ies += ies[1] + 2;
}
return true;
}
struct scan_results_context {
bool associated;
const void *ies;
size_t ies_size;
};
static bool
handle_nl80211_bss(struct module *mod, uint16_t type, bool nested,
const void *payload, size_t len, void *_ctx)
{
struct private *m UNUSED = mod->private;
struct scan_results_context *ctx = _ctx;
switch (type) {
case NL80211_BSS_STATUS: {
const uint32_t status = *(uint32_t *)payload;
if (status == NL80211_BSS_STATUS_ASSOCIATED) {
ctx->associated = true;
if (ctx->ies != NULL) {
/* Deferred handling of BSS_INFORMATION_ELEMENTS */
return handle_ies(mod, ctx->ies, ctx->ies_size);
}
}
break;
}
case NL80211_BSS_INFORMATION_ELEMENTS:
if (ctx->associated)
return handle_ies(mod, payload, len);
else {
/*
* We’re either not associated, or, we haven’t seen the
* BSS_STATUS attribute yet.
*
* Save a pointer to the IES payload, so that we can
* process it later, if we see a
* BSS_STATUS == BSS_STATUS_ASSOCIATED.
*/
ctx->ies = payload;
ctx->ies_size = len;
}
}
return true;
}
static bool
handle_nl80211_scan_results(struct module *mod, uint16_t type, bool nested,
const void *payload, size_t len)
{
struct private *m UNUSED = mod->private;
struct scan_results_context ctx = {0};
switch (type) {
case NL80211_ATTR_BSS:
foreach_nlattr_nested(mod, payload, len, &handle_nl80211_bss, &ctx);
break;
}
return true;
}
/*
* Reads at least one (possibly more) message.
*
@ -1083,6 +1207,11 @@ parse_genl_reply(struct module *mod, const struct nlmsghdr *hdr, size_t len)
/* Current request is now considered complete */
m->nl80211.get_station_seq_nr = 0;
}
else if (hdr->nlmsg_seq == m->nl80211.get_scan_seq_nr) {
/* Current request is now considered complete */
m->nl80211.get_scan_seq_nr = 0;
}
}
else if (hdr->nlmsg_type == GENL_ID_CTRL) {
@ -1101,8 +1230,6 @@ parse_genl_reply(struct module *mod, const struct nlmsghdr *hdr, size_t len)
LOG_DBG("%s: got interface information", m->iface);
foreach_nlattr(
mod, genl, msg_size, &handle_nl80211_new_interface);
LOG_INFO("%s: SSID: %s", m->iface, m->ssid);
}
break;
@ -1148,6 +1275,18 @@ parse_genl_reply(struct module *mod, const struct nlmsghdr *hdr, size_t len)
m->iface, m->signal_strength_dbm,
m->rx_bitrate / 1000 / 1000,
m->tx_bitrate / 1000 / 1000);
/* Can’t issue both get-station and get-scan at the
* same time. So, always run a get-scan when a
* get-station is complete */
send_nl80211_get_scan(m);
break;
case NL80211_CMD_NEW_SCAN_RESULTS:
if (nl80211_is_for_us(mod, genl, msg_size)) {
LOG_DBG("%s: got scan results", m->iface);
foreach_nlattr(mod, genl, msg_size, &handle_nl80211_scan_results);
}
break;
default:
@ -1165,7 +1304,8 @@ parse_genl_reply(struct module *mod, const struct nlmsghdr *hdr, size_t len)
else if (nl_errno == ENOENT)
; /* iface down? */
else
LOG_ERRNO_P(nl_errno, "%s: nl80211 reply", m->iface);
LOG_ERRNO_P(nl_errno, "%s: nl80211 reply (seq-nr: %u)",
m->iface, hdr->nlmsg_seq);
}
else {