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Escape untrusted strings in LNURL-auth logs #1184

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Merged
tnull merged 2 commits into from
Oct 22, 2026
Merged

Escape untrusted strings in LNURL-auth logs #1184

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7e70dfb
Escape untrusted strings in LNURL-auth logs
benthecarman Oct 20, 2026
7c21597
Log only the domain when starting LNURL-auth
benthecarman Oct 20, 2026
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19 changes: 15 additions & 4 deletions src/lnurl_auth.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ use bitcoin::hashes::{sha256, Hash, HashEngine, Hmac, HmacEngine};
use bitcoin::secp256k1::{All, Message, Secp256k1, SecretKey};
use bitreq::Client;
use lightning::util::logger::Logger as LdkLogger;
use lightning_types::string::PrintableString;
use serde::{Deserialize, Serialize};

use crate::logger::{log_debug, log_error, Logger};
Expand Down Expand Up @@ -86,8 +87,6 @@ impl LnurlAuth {
Error::InvalidLnurl
})?;

log_debug!(self.logger, "Starting LNURL-auth process for URL: {lnurl_auth_url}");

// Parse the URL to extract domain and parameters
let url = bitreq::Url::parse(&lnurl_auth_url).map_err(|e| {
log_error!(self.logger, "Invalid LNURL-auth URL: {e}");
Expand All @@ -96,6 +95,10 @@ impl LnurlAuth {

let domain = url.base_url();

// Only log the domain, the full URL carries the k1 challenge and potentially other
// credentials.
log_debug!(self.logger, "Starting LNURL-auth process for domain: {domain}");

// Enforce HTTPS for non-localhost URLs per LNURL spec.
let is_localhost = domain == "localhost" || domain == "127.0.0.1" || domain == "[::1]";
if url.scheme() != "https" && !is_localhost {
Expand All @@ -112,7 +115,11 @@ impl LnurlAuth {
})?;

if tag != "login" {
log_error!(self.logger, "Invalid tag parameter in LNURL-auth URL: {tag}");
log_error!(
self.logger,
"Invalid tag parameter in LNURL-auth URL: {}",
PrintableString(tag)
);
return Err(Error::InvalidLnurl);
}

Expand Down Expand Up @@ -158,7 +165,11 @@ impl LnurlAuth {
Ok(())
} else {
let reason = response.reason.unwrap_or_else(|| "Unknown error".to_string());
log_error!(self.logger, "LNURL-auth authentication failed: {reason}");
log_error!(
self.logger,
"LNURL-auth authentication failed: {}",
PrintableString(&reason)
);
Err(Error::LnurlAuthFailed)
}
}
Expand Down
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