CyberRota Analysis
AI-GeneratedThe vulnerability arises from the gptp_handle_msg() function, which improperly processes gPTP headers without validating the minimum payload size, allowing an unauthenticated peer to send truncated Ethernet frames that can lead to out-of-bounds memory reads. This can result in the disclosure of sensitive information from previously allocated memory, although it does not affect system availability or allow for remote code execution. Organizations utilizing gPTP on their networks, particularly those using configurations that accept undersized frames, should prioritize addressing this issue to mitigate potential information leakage.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
gptp_handle_msg() in subsys/net/l2/ethernet/gptp/gptp.c dereferenced the gPTP header returned by GPTP_HDR() and switched on hdr->message_type without first checking that the received frame carries at least sizeof(struct gptp_hdr) (34) bytes of payload. The header accessor gptp_get_hdr() deliberately never fails for a short buffer — it returns pkt->frags->data and leaves validation to its callers — so a truncated frame produced a header pointer covering memory beyond the received data. The per-message-type checks that follow do not compensate: GPTP_VALID_LEN() reduces to len > 60 once the Ethernet header has been pulled, which is false for every fixed-size gPTP message, so GPTP_CHECK_LEN() never rejects a truncated SYNC, FOLLOWUP, PDELAY_RESP or SIGNALING message. The defect is reached by an unauthenticated peer on the same link sending an Ethernet frame with ethertype 0x88F7 to the PTP multicast address on an interface configured as a gPTP port, with CONFIG_NET_GPTP enabled. Because conformant Ethernet pads frames to 60 bytes, a payload shorter than 34 bytes generally requires a link that can deliver sub-minimum frames — for example the native_sim TAP driver (drivers/ethernet/eth_native_tap.c), which forwards whatever length the host device supplies, or a MAC configured to accept undersized frames. The short packet is retained (net_pkt_ref() into rcvd_sync_ptr, rcvd_follow_up_ptr, rcvd_pdelay_resp_ptr or rcvd_announce_ptr) and later parsed by the media-dependent and media-independent state machines in subsys/net/l2/ethernet/gptp/gptp_md.c and subsys/net/l2/ethernet/gptp/gptp_mi.c, which read tens of further bytes and copy some of them (the announce priority vector, hdr->port_id) into state that is subsequently transmitted. Under the default fixed-size buffer allocator (CONFIG_NET_BUF_FIXED_DATA_SIZE, 128-byte fragments) the accesses stay inside the allocated fragment and disclose stale recycled buffer contents; under the experimental CONFIG_NET_BUF_VARIABLE_DATA_SIZE allocator, where fragments are heap-allocated at the exact frame length, they are genuine out-of-bounds reads. There is no write and no availability impact.