[PATCH 4.14 06/27] sctp: add param size validation for SCTP_PARAM_SET_PRIMARY

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

commit ef6c8d6ccf0c1dccdda092ebe8782777cd7803c9 upstream.

When SCTP handles an INIT chunk, it calls for example:
sctp_sf_do_5_1B_init
  sctp_verify_init
    sctp_verify_param
  sctp_process_init
    sctp_process_param
      handling of SCTP_PARAM_SET_PRIMARY

sctp_verify_init() wasn't doing proper size validation and neither the
later handling, allowing it to work over the chunk itself, possibly being
uninitialized memory.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/sm_make_chunk.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2161,9 +2161,16 @@ static enum sctp_ierror sctp_verify_para
 		break;
 
 	case SCTP_PARAM_SET_PRIMARY:
-		if (net->sctp.addip_enable)
-			break;
-		goto fallthrough;
+		if (!net->sctp.addip_enable)
+			goto fallthrough;
+
+		if (ntohs(param.p->length) < sizeof(struct sctp_addip_param) +
+					     sizeof(struct sctp_paramhdr)) {
+			sctp_process_inv_paramlength(asoc, param.p,
+						     chunk, err_chunk);
+			retval = SCTP_IERROR_ABORT;
+		}
+		break;
 
 	case SCTP_PARAM_HOST_NAME_ADDRESS:
 		/* Tell the peer, we won't support this param.  */