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Sanitise user input in SSID and PSK values #93

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Merged
jubeormk1 merged 1 commit into from
Apr 4, 2026
Merged

Sanitise user input in SSID and PSK values #93

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37 changes: 27 additions & 10 deletions src/serve.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,10 @@ fn key_signature_ok(a: &ServPubkeyAuth<'_, '_>) -> bool {
a.real()
}

fn is_valid_wifi_credential(s: &str) -> bool {
!s.is_empty() && s.bytes().all(|b| b.is_ascii_graphic())
}

pub async fn connection_loop(
serv: &SSHServer<'_>,
chan_pipe: &Channel<NoopRawMutex, SessionType, 1>,
Expand Down Expand Up @@ -230,16 +234,24 @@ pub async fn connection_loop(
);
a.fail()?;
} else {
let mut s = String::<32>::new();
if s.push_str(a.value()?).is_ok() {
config_guard.wifi_ssid = s;
debug!("Set wifi SSID from ENV");
a.succeed()?;
config_changed = true;
needs_reset = true;
} else {
warn!("SSH_STAMP_WIFI_SSID too long");
let value = a.value()?;
if !is_valid_wifi_credential(value) {
warn!(
"SSH_STAMP_WIFI_SSID contains invalid characters (null bytes or non-printable ASCII)"
);
a.fail()?;
} else {
let mut s = String::<32>::new();
if s.push_str(value).is_ok() {
config_guard.wifi_ssid = s;
debug!("Set wifi SSID from ENV");
a.succeed()?;
config_changed = true;
needs_reset = true;
} else {
warn!("SSH_STAMP_WIFI_SSID too long");
a.fail()?;
}
}
}
}
Expand All @@ -252,7 +264,12 @@ pub async fn connection_loop(
a.fail()?;
} else {
let value = a.value()?;
if value.len() < 8 {
if !is_valid_wifi_credential(value) {
warn!(
"SSH_STAMP_WIFI_PSK contains invalid characters (null bytes or non-printable ASCII)"
);
a.fail()?;
} else if value.len() < 8 {
warn!("SSH_STAMP_WIFI_PSK too short (min 8 characters)");
a.fail()?;
} else if value.len() > 63 {
Expand Down
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