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authorXin Long <lucien.xin@gmail.com>2017-07-26 16:24:59 +0800
committerDavid S. Miller <davem@davemloft.net>2017-07-27 00:03:12 -0700
commit6b84202c946cd3da3a8daa92c682510e9ed80321 (patch)
tree017fb69be1e7083df03315af8a40b5c42709ff0b
parente90ce2fc27cad7e7b1e72b9e66201a7a4c124c2b (diff)
sctp: fix the check for _sctp_walk_params and _sctp_walk_errors
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@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/sctp/sctp.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 980807d7506f..45fd4c6056b5 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -469,7 +469,7 @@ _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
#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(struct sctp_paramhdr);\
@@ -481,7 +481,7 @@ _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
#define _sctp_walk_errors(err, chunk_hdr, end)\
for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
sizeof(struct sctp_chunkhdr));\
- ((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); \