usersctp sctp_load_addresses_from_init Out-Of-Bounds Read

usersctp is SCTP library used by a variety of software including WebRTC. There is a vulnerability in the sctp_load_addresses_from_init function of usersctp that can lead to a number of out-of-bound reads. The input to sctp_load_addresses_from_init is verified by calling sctp_arethere_unrecognized_parameters, however there is a difference in how these functions handle parameter bounds. The function sctp_arethere_unrecognized_parameters does not process a parameter that is partially outside of the limit of the chunk, meanwhile, sctp_load_addresses_from_init will continue processing until a parameter that is entirely outside of the chunk occurs. This means that the last parameter of a chunk is not always verified, which can lead to parameters with very short plen values being processed by sctp_load_addresses_from_init. This can lead to out-of-bounds reads whenever the plen is subtracted from the header len.