* [PATCH] 9p: validate PDU length
@ 2018-07-23 15:44 Tomas Bortoli
2018-07-24 3:57 ` Dominique Martinet
2018-07-25 4:11 ` Dominique Martinet
0 siblings, 2 replies; 4+ messages in thread
From: Tomas Bortoli @ 2018-07-23 15:44 UTC (permalink / raw)
To: ericvh, rminnich, lucho
Cc: asmadeus, davem, v9fs-developer, netdev, linux-kernel, syzkaller,
Tomas Bortoli
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.
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com
---
net/9p/client.c | 25 ++++++++++++++++---------
net/9p/trans_fd.c | 5 ++++-
net/9p/trans_rdma.c | 1 +
net/9p/trans_virtio.c | 4 +++-
4 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index 18c5271910dc..92240ccf476b 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -477,20 +477,11 @@ 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)
@@ -498,6 +489,16 @@ 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)
@@ -524,6 +525,12 @@ 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.
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 588bf88c3305..65533c437b7f 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -324,7 +324,9 @@ 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);
@@ -369,6 +371,7 @@ 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;
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 3d414acb7015..2649b2ebf961 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -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;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 05006cbb3361..fc6dc9ca86a4 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -159,8 +159,10 @@ static void req_done(struct virtqueue *vq)
spin_unlock_irqrestore(&chan->lock, flags);
/* Wakeup if anyone waiting for VirtIO ring space. */
wake_up(chan->vc_wq);
- if (len)
+ if (len) {
+ req->rc->size = len;
p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
+ }
}
}
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] 9p: validate PDU length
2018-07-23 15:44 [PATCH] 9p: validate PDU length Tomas Bortoli
@ 2018-07-24 3:57 ` Dominique Martinet
2018-07-25 4:11 ` Dominique Martinet
1 sibling, 0 replies; 4+ messages in thread
From: Dominique Martinet @ 2018-07-24 3:57 UTC (permalink / raw)
To: Tomas Bortoli
Cc: ericvh, rminnich, lucho, davem, v9fs-developer, netdev,
linux-kernel, syzkaller
Tomas Bortoli wrote on Mon, Jul 23, 2018:
> 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.
>
> Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
> Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com
Ok, I've run some more in-depth testing this time and all appear in
order.
Like I said last time, I cannot test the xen transport - if someone can
point me to how to set it up or run some tests semi-regularily it'd be
great.
Meanwhile, code looks good and appears to work, so I'll take this
patch unless someone yells
> ---
> net/9p/client.c | 25 ++++++++++++++++---------
> net/9p/trans_fd.c | 5 ++++-
> net/9p/trans_rdma.c | 1 +
> net/9p/trans_virtio.c | 4 +++-
> 4 files changed, 24 insertions(+), 11 deletions(-)
>
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 18c5271910dc..92240ccf476b 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -477,20 +477,11 @@ 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)
> @@ -498,6 +489,16 @@ 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)
> @@ -524,6 +525,12 @@ 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;
Indentation here looks wrong, I took the liberty of deindenting that
return in my tree.
> + }
> /*
> * dump the response from server
> * This should be after check errors which poplulate pdu_fcall.
> diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
> index 588bf88c3305..65533c437b7f 100644
> --- a/net/9p/trans_fd.c
> +++ b/net/9p/trans_fd.c
> @@ -324,7 +324,9 @@ 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);
> @@ -369,6 +371,7 @@ 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;
> diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
> index 3d414acb7015..2649b2ebf961 100644
> --- a/net/9p/trans_rdma.c
> +++ b/net/9p/trans_rdma.c
> @@ -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;
> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
> index 05006cbb3361..fc6dc9ca86a4 100644
> --- a/net/9p/trans_virtio.c
> +++ b/net/9p/trans_virtio.c
> @@ -159,8 +159,10 @@ static void req_done(struct virtqueue *vq)
> spin_unlock_irqrestore(&chan->lock, flags);
> /* Wakeup if anyone waiting for VirtIO ring space. */
> wake_up(chan->vc_wq);
> - if (len)
> + if (len) {
> + req->rc->size = len;
> p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
> + }
> }
> }
>
--
Dominique Martinet
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] 9p: validate PDU length
2018-07-23 15:44 [PATCH] 9p: validate PDU length Tomas Bortoli
2018-07-24 3:57 ` Dominique Martinet
@ 2018-07-25 4:11 ` Dominique Martinet
2018-07-25 10:50 ` Tomas Bortoli
1 sibling, 1 reply; 4+ messages in thread
From: Dominique Martinet @ 2018-07-25 4:11 UTC (permalink / raw)
To: Tomas Bortoli; +Cc: davem, v9fs-developer, netdev, linux-kernel, syzkaller
Tomas Bortoli wrote on Mon, Jul 23, 2018:
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 18c5271910dc..92240ccf476b 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -524,6 +525,12 @@ 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) {
I was looking at this again, I think it's more appropriate to use
req->rc->capacity at this point like you did in the first version of the
patch.
I had suggested msize in the common p9_parse_header function because
that'd let us accept zc requests where the size in the pdu could be
bigger than capacity, but this isn't the case in p9_check_errors.
If you're ok with this I'll edit your commit directly, this is less work
for me than having to check a new patch.
Thanks,
--
Dominique
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] 9p: validate PDU length
2018-07-25 4:11 ` Dominique Martinet
@ 2018-07-25 10:50 ` Tomas Bortoli
0 siblings, 0 replies; 4+ messages in thread
From: Tomas Bortoli @ 2018-07-25 10:50 UTC (permalink / raw)
To: Dominique Martinet; +Cc: davem, v9fs-developer, netdev, linux-kernel, syzkaller
On 07/25/2018 06:11 AM, Dominique Martinet wrote:
> Tomas Bortoli wrote on Mon, Jul 23, 2018:
>> diff --git a/net/9p/client.c b/net/9p/client.c
>> index 18c5271910dc..92240ccf476b 100644
>> --- a/net/9p/client.c
>> +++ b/net/9p/client.c
>> @@ -524,6 +525,12 @@ 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) {
>
> I was looking at this again, I think it's more appropriate to use
> req->rc->capacity at this point like you did in the first version of the
> patch.
>
> I had suggested msize in the common p9_parse_header function because
> that'd let us accept zc requests where the size in the pdu could be
> bigger than capacity, but this isn't the case in p9_check_errors.
>
> If you're ok with this I'll edit your commit directly, this is less work
> for me than having to check a new patch.
>
> Thanks,
>
Yes sure, just forward me the changes later.
Tomas
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-07-23 15:44 [PATCH] 9p: validate PDU length Tomas Bortoli
2018-07-24 3:57 ` Dominique Martinet
2018-07-25 4:11 ` Dominique Martinet
2018-07-25 10:50 ` Tomas Bortoli
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