Commit f984579a authored by Tomas Bortoli's avatar Tomas Bortoli Committed by Dominique Martinet
Browse files

9p: validate PDU length 

This commit adds length check for the PDU size.
The size contained in the header has to match the actual size,
except for TCP (trans_fd.c) where actual length is not known ahead
and the header's length will be checked only against the validity
range.

Link: http://lkml.kernel.org/r/20180723154404.2406-1-tomasbortoli@gmail.com


Signed-off-by: default avatarTomas Bortoli <tomasbortoli@gmail.com>
Reported-by: default avatar <syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com>
To: Eric Van Hensbergen <ericvh@gmail.com>
To: Ron Minnich <rminnich@sandia.gov>
To: Latchesar Ionkov <lucho@ionkov.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: default avatarDominique Martinet <dominique.martinet@cea.fr>
parent 9f476d7c

net/9p/client.c

+16 −9
Original line number Diff line number Diff line
@@ -469,20 +469,11 @@ p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag, 
	int err;



	pdu->offset = 0;

	if (pdu->size == 0)

		pdu->size = 7;



	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);

	if (err)

		goto rewind_and_exit;



	pdu->size = r_size;

	pdu->id = r_type;

	pdu->tag = r_tag;



	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",

		 pdu->size, pdu->id, pdu->tag);



	if (type)

		*type = r_type;

	if (tag)
@@ -490,6 +481,16 @@ p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag, 
	if (size)

		*size = r_size;



	if (pdu->size != r_size || r_size < 7) {

		err = -EINVAL;

		goto rewind_and_exit;

	}



	pdu->id = r_type;

	pdu->tag = r_tag;



	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",

		 pdu->size, pdu->id, pdu->tag);



rewind_and_exit:

	if (rewind)
@@ -516,6 +517,12 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req) 
	int ecode;



	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);

	if (req->rc->size >= c->msize) {

		p9_debug(P9_DEBUG_ERROR,

			 "requested packet size too big: %d\n",

			 req->rc->size);

		return -EIO;

	}

	/*

	 * dump the response from server

	 * This should be after check errors which poplulate pdu_fcall.

net/9p/trans_fd.c

+4 −1
Original line number Diff line number Diff line
@@ -325,7 +325,9 @@ static void p9_read_work(struct work_struct *work) 
	if ((!m->req) && (m->rc.offset == m->rc.capacity)) {

		p9_debug(P9_DEBUG_TRANS, "got new header\n");



		err = p9_parse_header(&m->rc, NULL, NULL, NULL, 0);

		/* Header size */

		m->rc.size = 7;

		err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0);

		if (err) {

			p9_debug(P9_DEBUG_ERROR,

				 "error parsing header: %d\n", err);
@@ -370,6 +372,7 @@ static void p9_read_work(struct work_struct *work) 
	 */

	if ((m->req) && (m->rc.offset == m->rc.capacity)) {

		p9_debug(P9_DEBUG_TRANS, "got new packet\n");

		m->req->rc->size = m->rc.offset;

		spin_lock(&m->client->lock);

		if (m->req->status != REQ_STATUS_ERROR)

			status = REQ_STATUS_RCVD;

net/9p/trans_rdma.c

+1 −0
Original line number Diff line number Diff line
@@ -320,6 +320,7 @@ recv_done(struct ib_cq *cq, struct ib_wc *wc) 
	if (wc->status != IB_WC_SUCCESS)

		goto err_out;



	c->rc->size = wc->byte_len;

	err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);

	if (err)

		goto err_out;

net/9p/trans_virtio.c

+3 −1
Original line number Diff line number Diff line
@@ -156,9 +156,11 @@ static void req_done(struct virtqueue *vq) 
			need_wakeup = true;

		}



		if (len)

		if (len) {

			req->rc->size = len;

			p9_client_cb(chan->client, req, REQ_STATUS_RCVD);

		}

	}

	spin_unlock_irqrestore(&chan->lock, flags);

	/* Wakeup if anyone waiting for VirtIO ring space. */

	if (need_wakeup)

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