[PATCH net 0/2] nfc: llcp: fix OOB reads and integer bugs in TLV parsers

Muhammad Bilal <[email protected]> Mon, 18 May 2026 21:19:35 -0400
Newsgroups dev.linux.lists.oe-linux-nfc,org.kernel.vger.linux-kernel,org.kernel.vger.netdev,org.kernel.vger.stable
Message-ID <[email protected]>
This series fixes memory safety bugs in the NFC LLCP TLV parsing code,
reachable from a remote NFC peer via crafted LLCP frames.

Patch 1 fixes nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv():
  - u8 offset wraps to zero after 255 (widened to u16)
  - OOB read of TLV header on truncated buffer
  - OOB read of value field via attacker-controlled length byte

Patch 2 fixes nfc_llcp_recv_snl():
  - OOB read of TLV header when tlv_len - offset == 1
  - OOB read of SDREQ value via attacker-controlled length
  - SIZE_MAX underflow when length == 0 in service_name_len,
    bypassing the sn_len == 0 guard in nfc_llcp_sock_from_sn()

Previously reported to [email protected] on 2026-05-15. Willy Tarreau
advised posting to public lists as NFC is currently orphaned.

Muhammad Bilal (2):
  nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers
  nfc: llcp: add missing bounds checks in nfc_llcp_recv_snl()

 net/nfc/llcp_commands.c | 28 ++++++++++++++++++++++++++--
 net/nfc/llcp_core.c     | 23 +++++++++++++++++++++--
 2 files changed, 47 insertions(+), 4 deletions(-)

-- 
2.54.0