Validate advert payload length before parsing #1661
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The ADVERT handler copied pub_key, timestamp, and signature from the payload before checking whether payload_len was large enough to contain them. With a short payload, the memcpy operations read uninitialized data from within the payload buffer. Move the bounds check before any parsing so undersized adverts are rejected immediately. The minimum required is PUB_KEY_SIZE + 4 + SIGNATURE_SIZE (100 bytes).
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Severity: Low
Summary
The ADVERT packet handler copies the public key (32 bytes), timestamp (4 bytes), and signature (64 bytes) from the payload before checking whether
payload_lenis large enough to contain them. With a short payload, the memcpy operations read uninitialized data from within the payload buffer array.The reads stay within the 184-byte
payload[]array so this is not a true out-of-bounds access, but the parsed values (pub_key, timestamp, signature) contain garbage. The bounds check at line 251 catches it before any side-effects occur (no routing, no signature verification passes with garbage), but the ordering is sloppy and could become a real bug if the buffer layout changes.Fix
Move the bounds check before any parsing. Undersized adverts are now rejected immediately with a debug log, before any memcpy operations execute.
Test plan
Heltec_v3_companion_radio_ble