The sctp_getsockopt_hmac_ident function in net/sctp/socket.c in the Stream Control Transmission Protocol (sctp) implementation in the Linux kernel before 2.6.26.4, when the SCTP-AUTH extension is enabled, relies on an untrusted length value to limit copying of data from kernel memory, which allows local users to obtain sensitive information via a crafted SCTP_HMAC_IDENT IOCTL request involving the sctp_getsockopt function.