[PATCH 4.19 08/34] sctp: add param size validation for SCTP_PARAM_SET_PRIMARY

Greg Kroah-Hartman
2021-09-24T12:51:46Z

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
@@ -2172,9 +2172,16 @@ 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. */