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Router: null-check destination node before dereferencing public_key in PKI decode #10226

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nightjoker7 wants to merge 5 commits into from
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Router: null-check destination node before dereferencing public_key in PKI decode #10226

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794b135
Router: null-check destination node before dereferencing public_key i…
nightjoker7 Apr 21, 2026
3d6fd7c
Merge remote-tracking branch 'origin/develop' into fix/router-pki-to-…
nightjoker7 Apr 23, 2026
8cb93f5
Address Copilot TOCTOU review: cache NodeDB lookups in locals
nightjoker7 Apr 23, 2026
21e961b
Apply suggestion from @Copilot
thebentern Apr 23, 2026
f9e3666
Merge branch 'develop' into fix/router-pki-to-null-deref
thebentern Apr 23, 2026
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17 changes: 11 additions & 6 deletions src/mesh/Router.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -449,14 +449,19 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
bool decrypted = false;
ChannelIndex chIndex = 0;
#if !(MESHTASTIC_EXCLUDE_PKI)
// Attempt PKI decryption first
if (p->channel == 0 && isToUs(p) && p->to > 0 && !isBroadcast(p->to) && nodeDB->getMeshNode(p->from) != nullptr &&
nodeDB->getMeshNode(p->from)->user.public_key.size > 0 && nodeDB->getMeshNode(p->to)->user.public_key.size > 0 &&
// Attempt PKI decryption first. Cache the NodeDB lookups in local pointers to avoid
// (a) repeat linear scans over numMeshNodes and (b) the TOCTOU hazard where a node could
// be evicted between two calls of getMeshNode() by a concurrent task.
meshtastic_NodeInfoLite *fromNode = (p->channel == 0 && isToUs(p) && p->to > 0 && !isBroadcast(p->to))
? nodeDB->getMeshNode(p->from)
: nullptr;
meshtastic_NodeInfoLite *toNode = nullptr;
if (fromNode != nullptr && fromNode->user.public_key.size > 0 &&
(toNode = nodeDB->getMeshNode(p->to)) != nullptr && toNode->user.public_key.size > 0 &&
rawSize > MESHTASTIC_PKC_OVERHEAD) {
LOG_DEBUG("Attempt PKI decryption");

if (crypto->decryptCurve25519(p->from, nodeDB->getMeshNode(p->from)->user.public_key, p->id, rawSize, p->encrypted.bytes,
bytes)) {
if (crypto->decryptCurve25519(p->from, fromNode->user.public_key, p->id, rawSize, p->encrypted.bytes, bytes)) {
LOG_INFO("PKI Decryption worked!");

meshtastic_Data decodedtmp;
Expand All @@ -467,7 +472,7 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
decrypted = true;
LOG_INFO("Packet decrypted using PKI!");
p->pki_encrypted = true;
memcpy(&p->public_key.bytes, nodeDB->getMeshNode(p->from)->user.public_key.bytes, 32);
memcpy(&p->public_key.bytes, fromNode->user.public_key.bytes, 32);
p->public_key.size = 32;
p->decoded = decodedtmp;
p->which_payload_variant = meshtastic_MeshPacket_decoded_tag; // change type to decoded
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