In the Linux kernel, the following vulnerability has been resolved:
sctp: validate stream count in sctp_process_strreset_inreq()
When processing a RESET_IN_REQUEST from a peer,
sctp_process_strreset_inreq() derives the stream count from the
parameter length but does not check whether the resulting
RESET_OUT_REQUEST would exceed SCTP_MAX_CHUNK_LEN.
The OUT request header (sctp_strreset_outreq, 16 bytes) is 8 bytes
larger than the IN request header (sctp_strreset_inreq, 8 bytes).
Generally, the IP payload is bounded to 65535 bytes, so the stream
list cannot be large enough to trigger the overflow. However, on
interfaces with MTU > 65535 (e.g., loopback with IPv6 jumbograms), a
stream list that fits within the incoming IN parameter can cause a
__u16 overflow in sctp_make_strreset_req() when computing the OUT
request size, leading to an undersized skb allocation and a kernel
BUG:
net/core/skbuff.c:207 skb_panic
net/core/skbuff.c:2625 skb_put
net/sctp/sm_make_chunk.c:1535 sctp_addto_chunk
net/sctp/sm_make_chunk.c:3695 sctp_make_strreset_req
net/sctp/stream.c:655 sctp_process_strreset_inreq
The local setsockopt path validates the generated reset request size.
However, for an incoming-only reset, it accounts for the smaller IN
request even though the peer must generate an OUT request with the same
stream list. Such a request cannot be completed successfully by the
peer.
Reject peer IN requests whose corresponding OUT request would exceed
SCTP_MAX_CHUNK_LEN. Also tighten the local check so it does not send an
IN request that would require an oversized OUT request from the peer.
