This is a note to let you know that I've just added the patch titled
sctp: fix the check for _sctp_walk_params and _sctp_walk_errors
to the 3.18-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-the-check-for-_sctp_walk_params-and-_sctp_walk_errors.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Aug 8 16:54:20 PDT 2017
From: Xin Long <lucien.xin@xxxxxxxxx>
Date: Wed, 26 Jul 2017 16:24:59 +0800
Subject: sctp: fix the check for _sctp_walk_params and _sctp_walk_errors
From: Xin Long <lucien.xin@xxxxxxxxx>
[ Upstream commit 6b84202c946cd3da3a8daa92c682510e9ed80321 ]
Commit b1f5bfc27a19 ("sctp: don't dereference ptr before leaving
_sctp_walk_{params, errors}()") tried to fix the issue that it
may overstep the chunk end for _sctp_walk_{params, errors} with
'chunk_end > offset(length) + sizeof(length)'.
But it introduced a side effect: When processing INIT, it verifies
the chunks with 'param.v == chunk_end' after iterating all params
by sctp_walk_params(). With the check 'chunk_end > offset(length)
+ sizeof(length)', it would return when the last param is not yet
accessed. Because the last param usually is fwdtsn supported param
whose size is 4 and 'chunk_end == offset(length) + sizeof(length)'
This is a badly issue even causing sctp couldn't process 4-shakes.
Client would always get abort when connecting to server, due to
the failure of INIT chunk verification on server.
The patch is to use 'chunk_end <= offset(length) + sizeof(length)'
instead of 'chunk_end < offset(length) + sizeof(length)' for both
_sctp_walk_params and _sctp_walk_errors.
Fixes: b1f5bfc27a19 ("sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()")
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/sctp/sctp.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -441,7 +441,7 @@ _sctp_walk_params((pos), (chunk), ntohs(
#define _sctp_walk_params(pos, chunk, end, member)\
for (pos.v = chunk->member;\
- (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <\
+ (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
(void *)chunk + end) &&\
pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
@@ -453,7 +453,7 @@ _sctp_walk_errors((err), (chunk_hdr), nt
#define _sctp_walk_errors(err, chunk_hdr, end)\
for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
sizeof(sctp_chunkhdr_t));\
- ((void *)err + offsetof(sctp_errhdr_t, length) + sizeof(err->length) <\
+ ((void *)err + offsetof(sctp_errhdr_t, length) + sizeof(err->length) <=\
(void *)chunk_hdr + end) &&\
(void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
ntohs(err->length) >= sizeof(sctp_errhdr_t); \
Patches currently in stable-queue which might be from lucien.xin@xxxxxxxxx are
queue-3.18/sctp-fix-the-check-for-_sctp_walk_params-and-_sctp_walk_errors.patch
queue-3.18/dccp-fix-a-memleak-for-dccp_feat_init-err-process.patch