Commit 10b3bf54 authored Jul 14, 2017 by Xin Long Committed by David S. Miller Jul 14, 2017

sctp: fix an array overflow when all ext chunks are set



Marcelo noticed an array overflow caused by commit c28445c3
("sctp: add reconf_enable in asoc ep and netns"), in which sctp
would add SCTP_CID_RECONF into extensions when reconf_enable is
set in sctp_make_init and sctp_make_init_ack.

Then now when all ext chunks are set, 4 ext chunk ids can be put
into extensions array while extensions array size is 3. It would
cause a kernel panic because of this overflow.

This patch is to fix it by defining extensions array size is 4 in
both sctp_make_init and sctp_make_init_ack.

Fixes: c28445c3 ("sctp: add reconf_enable in asoc ep and netns")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 56c0da49

net/sctp/sm_make_chunk.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -228,7 +228,7 @@ struct sctp_chunk sctp_make_init(const struct sctp_association asoc,
		sctp_adaptation_ind_param_t aiparam;
		sctp_supported_ext_param_t ext_param;
		int num_ext = 0;
		__u8 extensions[3];
		__u8 extensions[4];
		struct sctp_paramhdr *auth_chunks = NULL,
		*auth_hmacs = NULL;

		@@ -396,7 +396,7 @@ struct sctp_chunk sctp_make_init_ack(const struct sctp_association asoc,
		sctp_adaptation_ind_param_t aiparam;
		sctp_supported_ext_param_t ext_param;
		int num_ext = 0;
		__u8 extensions[3];
		__u8 extensions[4];
		struct sctp_paramhdr *auth_chunks = NULL,
		*auth_hmacs = NULL,
		*auth_random = NULL;

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