CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's NFC LLCP implementation, where the system fails to validate the length of incoming Protocol Data Units (PDUs) before parsing, potentially leading to out-of-bounds reads. This flaw can be exploited by nearby NFC devices without authentication, allowing attackers to read beyond allocated memory and potentially disrupt system operations. Organizations using Linux systems with NFC capabilities should prioritize addressing this vulnerability to mitigate risks associated with unauthorized access and data integrity issues.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: reject PDUs shorter than the LLCP header Every LLCP PDU begins with a two-byte header (DSAP/SSAP + PTYPE), but the receive path never checked that a frame is at least LLCP_HEADER_SIZE bytes before parsing it. nfc_llcp_rx_skb() reads the header via nfc_llcp_ptype()/nfc_llcp_dsap()/ nfc_llcp_ssap(), which dereference pdu->data[0] and pdu->data[1], and a CONNECT or CC PDU then computes tlv_array_len = skb->len - LLCP_HEADER_SIZE; as a size_t and hands it to the TLV walk. When the frame is shorter than the header the subtraction wraps to a huge value and the walk runs far past the buffer, an out-of-bounds read. A nearby NFC device can reach this without authentication; LLCP link activation happens automatically after NFC-DEP. Guard the common receive choke point __nfc_llcp_recv(), shared by both the target (nfc_llcp_data_received()) and initiator (nfc_llcp_recv()) paths, so a short skb is dropped before the rx_work worker parses it. Use pskb_may_pull() rather than a skb->len test so the two header bytes are guaranteed to sit in the skb linear area even for a non-linear skb, matching how the sibling NCI and HCI receive paths validate their headers. Reproduced with a KFENCE out-of-bounds read via /dev/virtual_nci on linux-next. Found by 0sec automated security-research tooling (https://0sec.ai).