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9p: validate PDU length

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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: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: 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: Dominique Martinet <dominique.martinet@cea.fr>
This commit is contained in:
Tomas Bortoli 2018-07-23 17:44:04 +02:00 committed by Dominique Martinet
parent 9f476d7c54
commit f984579a01
4 changed files with 24 additions and 11 deletions
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25
net/9p/client.c
View File

@ -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.

5
net/9p/trans_fd.c
View File

@ -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;

1
net/9p/trans_rdma.c
View File

@ -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;

4
net/9p/trans_virtio.c
View File

@ -156,8 +156,10 @@ 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. */