sctp: account stream padding length for reconf chunk

sctp_make_strreset_req() makes repeated calls to sctp_addto_chunk()
which will automatically account for padding on each call. inreq and
outreq are already 4 bytes aligned, but the payload is not and doing
SCTP_PAD4(a + b) (which _sctp_make_chunk() did implicitly here) is
different from SCTP_PAD4(a) + SCTP_PAD4(b) and not enough. It led to
possible attempt to use more buffer than it was allocated and triggered

Cc: Vlad Yasevich <>
Cc: Neil Horman <>
Cc: Greg KH <>
Fixes: cc16f00f6529 ("sctp: add support for generating stream reconf ssn reset request chunk")
Reported-by: Eiichi Tsukata <>
Signed-off-by: Eiichi Tsukata <>
Signed-off-by: Marcelo Ricardo Leitner <>
Signed-off-by: Marcelo Ricardo Leitner <>
Reviewed-by: Xin Long <>
Signed-off-by: Jakub Kicinski <>
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index b8fa8f1..c7503fd 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3697,7 +3697,7 @@
 	outlen = (sizeof(outreq) + stream_len) * out;
 	inlen = (sizeof(inreq) + stream_len) * in;
-	retval = sctp_make_reconf(asoc, outlen + inlen);
+	retval = sctp_make_reconf(asoc, SCTP_PAD4(outlen) + SCTP_PAD4(inlen));
 	if (!retval)
 		return NULL;