Patch "sctp: fix an array overflow when all ext chunks are set" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
sctp-fix-an-array-overflow-when-all-ext-chunks-are-set.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Xin Long <[email protected]>
Date: Fri, 14 Jul 2017 22:07:33 +0800
Subject: sctp: fix an array overflow when all ext chunks are set

From: Xin Long <[email protected]>

[ Upstream commit 10b3bf54406bb7f4e78da9bb2a485c5c986678ad ]

Marcelo noticed an array overflow caused by commit c28445c3cb07 ("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.

---
 net/sctp/sm_make_chunk.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -228,7 +228,7 @@ struct sctp_chunk *sctp_make_init(const
 	sctp_adaptation_ind_param_t aiparam;
 	sctp_supported_ext_param_t ext_param;
 	int num_ext = 0;
-	__u8 extensions[3];
+	__u8 extensions[4];
 	sctp_paramhdr_t *auth_chunks = NULL,
 			*auth_hmacs = NULL;
 

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

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/sctp-fix-the-check-for-_sctp_walk_params-and-_sctp_walk_errors.patch queue-4.12/dccp-fix-a-memleak-that-dccp_ipv6-doesn-t-put-reqsk-properly.patch queue-4.12/dccp-fix-a-memleak-that-dccp_ipv4-doesn-t-put-reqsk-properly.patch queue-4.12/dccp-fix-a-memleak-for-dccp_feat_init-err-process.patch queue-4.12/sctp-fix-an-array-overflow-when-all-ext-chunks-are-set.patch