common: add bolt12 payer proof support (bolt12-cli)
What the developer wrote
Authored by Vincenzo Palazzo
common: add bolt12 payer proof support (bolt12-cli)
[Adapted for my decode routines --RR]
What changed, and why it matters
This commit adds a new command-line feature to a developer tool (bolt12-cli) that lets users decode and display a new type of BOLT 12 data structure called a 'payer proof.' It also makes a small, safe-looking fix to how text fields are printed so that trailing null bytes are not shown. There is no indication in the commit that this fixes a security vulnerability; it appears to be a normal feature addition.
No security action required. Treat as a routine feature commit. If reviewing further, verify that payer_proof_decode and the new print helpers handle malformed/short arrays safely, but the commit itself does not suggest an active vulnerability.
Security signals we found
New decode path added for payer_proof TLVs, with required-field checks using must_have()
Minor output-sanitization change: trailing NUL trimmed from UTF-8 fields before printf
No memory-management, cryptographic, or network-facing changes observed
No vendor disclosure, CVE, or researcher attribution present in commit
Evidence from the diff
The patch extends devtools/bolt12-cli.c to decode and pretty-print lnp (payer_proof) BOLT12 bech32 strings. It adds helper functions for printing BIP340 signatures, SHA256 arrays, and u64 arrays, and wires up a new streq(hrp, "lnp") branch. It also adjusts print_utf8() to strip a trailing NUL byte from length-delimited TLV UTF-8 fields before printing. The change is additive and localized to a developer/debugging CLI tool; no daemon or wallet code is modified.
Changed components
devtools/bolt12-cli.cInspect captured patch +126 / −3
diff --git a/devtools/bolt12-cli.c b/devtools/bolt12-cli.c
index eca58467..5ce9d806 100644
--- a/devtools/bolt12-cli.c
+++ b/devtools/bolt12-cli.c
@@ -6,6 +6,7 @@
#include <ccan/tal/str/str.h>
#include <common/bech32_util.h>
#include <common/bolt12_merkle.h>
+#include <common/bolt12_proof.h>
#include <common/features.h>
#include <common/iso4217.h>
#include <common/setup.h>
@@ -158,11 +159,17 @@ static bool print_offer_amount(const struct bitcoin_blkid *chains,
return ok;
}
-static bool print_utf8(const char *fieldname, const char *description)
+static bool print_utf8(const char *fieldname, const utf8 *description)
{
- bool valid = utf8_check(description, tal_bytelen(description));
+ size_t len = tal_bytelen(description);
+ bool valid = utf8_check(description, len);
+
+ /* Decoded TLV utf8 fields are length-delimited, not necessarily NUL-terminated. */
+ if (len != 0 && description[len - 1] == '\0')
+ len--;
+
printf("%s: %.*s%s\n", fieldname,
- (int)tal_bytelen(description), description,
+ (int)len, description,
valid ? "" : "(INVALID UTF-8)");
return valid;
}
@@ -358,6 +365,29 @@ static void print_hash(const char *fieldname, const struct sha256 *hash)
fieldname, fmt_sha256(tmpctx, hash));
}
+static void print_bip340sig_field(const char *fieldname,
+ const struct bip340sig *sig)
+{
+ printf("%s: %s\n", fieldname, fmt_bip340sig(tmpctx, sig));
+}
+
+static void print_sha256_array(const char *fieldname,
+ const struct sha256 *hashes)
+{
+ printf("%s:", fieldname);
+ for (size_t i = 0; i < tal_count(hashes); i++)
+ printf(" %s", fmt_sha256(tmpctx, &hashes[i]));
+ printf("\n");
+}
+
+static void print_u64_array(const char *fieldname, const u64 *vals)
+{
+ printf("%s:", fieldname);
+ for (size_t i = 0; i < tal_count(vals); i++)
+ printf(" %"PRIu64, vals[i]);
+ printf("\n");
+}
+
static void print_relative_expiry(u64 *created_at, u32 *relative)
{
/* Ignore if already malformed */
@@ -1085,6 +1115,99 @@ int main(int argc, char *argv[])
invoice->signature);
if (!print_extra_fields(invoice->fields))
well_formed = false;
+ } else if (streq(hrp, "lnp")) {
+ const struct tlv_payer_proof *proof
+ = payer_proof_decode(ctx, argv[2], strlen(argv[2]), &fail);
+
+ if (!proof)
+ errx(ERROR_BAD_DECODE, "Bad payer_proof: %s", fail);
+
+ if (proof->offer_chains)
+ print_offer_chains(proof->offer_chains);
+ if (proof->offer_metadata)
+ print_hex("offer_metadata", proof->offer_metadata);
+ if (proof->offer_amount)
+ well_formed &= print_offer_amount(proof->offer_chains,
+ proof->offer_currency,
+ *proof->offer_amount);
+ if (proof->offer_description)
+ well_formed &= print_utf8("offer_description",
+ proof->offer_description);
+ if (proof->offer_features)
+ print_features("offer_features", proof->offer_features);
+ if (proof->offer_absolute_expiry)
+ print_abstime("offer_absolute_expiry",
+ *proof->offer_absolute_expiry);
+ if (proof->offer_paths)
+ print_blindedpaths("offer_paths", proof->offer_paths, NULL);
+ if (proof->offer_issuer)
+ well_formed &= print_utf8("offer_issuer", proof->offer_issuer);
+ if (proof->offer_quantity_max)
+ print_u64("offer_quantity_max", *proof->offer_quantity_max);
+ if (proof->offer_issuer_id)
+ print_node_id("offer_issuer_id", proof->offer_issuer_id);
+ if (proof->invreq_chain)
+ print_invreq_chain(proof->invreq_chain);
+ if (proof->invreq_amount)
+ print_msat("invreq_amount", *proof->invreq_amount);
+ if (proof->invreq_features)
+ print_features("invreq_features", proof->invreq_features);
+ if (proof->invreq_quantity)
+ print_u64("invreq_quantity", *proof->invreq_quantity);
+ if (must_have(proof, invreq_payer_id))
+ print_node_id("invreq_payer_id", proof->invreq_payer_id);
+ if (proof->invreq_payer_note)
+ well_formed &= print_utf8("invreq_payer_note",
+ proof->invreq_payer_note);
+ if (proof->invreq_paths)
+ print_blindedpaths("invreq_paths", proof->invreq_paths, NULL);
+ if (proof->invreq_bip_353_name)
+ well_formed &= print_bip353_name("invreq_bip_353_name",
+ proof->invreq_bip_353_name->name,
+ proof->invreq_bip_353_name->domain);
+ if (proof->invoice_paths)
+ print_blindedpaths("invoice_paths",
+ proof->invoice_paths,
+ proof->invoice_blindedpay);
+ if (proof->invoice_created_at)
+ print_abstime("invoice_created_at",
+ *proof->invoice_created_at);
+ print_relative_expiry(proof->invoice_created_at,
+ proof->invoice_relative_expiry);
+ if (must_have(proof, invoice_payment_hash))
+ print_hash("invoice_payment_hash",
+ proof->invoice_payment_hash);
+ if (proof->invoice_amount)
+ print_msat("invoice_amount", *proof->invoice_amount);
+ if (proof->invoice_fallbacks)
+ print_fallbacks(proof->invoice_fallbacks);
+ if (proof->invoice_features)
+ print_features("invoice_features", proof->invoice_features);
+ /* BOLT-payer_proof #12:
+ * - MUST reject the payer_proof if:
+ * - `invreq_payer_id`, `invoice_payment_hash`,
+ * `invoice_node_id`, `signature`, `proof_preimage`,
+ * `proof_missing_hashes`, `proof_leaf_hashes` or
+ * `proof_signature` are missing.
+ */
+ if (must_have(proof, invoice_node_id))
+ print_node_id("invoice_node_id", proof->invoice_node_id);
+ if (must_have(proof, signature))
+ print_bip340sig_field("signature", proof->signature);
+ if (must_have(proof, proof_preimage))
+ printf("preimage: %s\n", fmt_preimage(tmpctx, proof->proof_preimage));
+ if (proof->proof_omitted_tlvs)
+ print_u64_array("proof_omitted_tlvs", proof->proof_omitted_tlvs);
+ if (must_have(proof, proof_missing_hashes))
+ print_sha256_array("proof_missing_hashes", proof->proof_missing_hashes);
+ if (must_have(proof, proof_leaf_hashes))
+ print_sha256_array("proof_leaf_hashes", proof->proof_leaf_hashes);
+ if (must_have(proof, proof_signature)) {
+ print_bip340sig_field("proof_signature",
+ proof->proof_signature);
+ }
+ if (!print_extra_fields(proof->fields))
+ well_formed = false;
} else
errx(ERROR_BAD_DECODE, "Unknown prefix %s", hrp);
Why this scored 21/100
Community notes
Notes can correct, qualify, or add evidence to the AI analysis. Every note shown here has been validated by a human moderator.
The AI analysis stands alone for now. Submit a note if you can add evidence or important context.