This is a note to let you know that I've just added the patch titled
nfs4: limit callback decoding to received bytes
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfs4-limit-callback-decoding-to-received-bytes.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 38b7631fbe42e6e247e9fc9879f961b14a687e3b Mon Sep 17 00:00:00 2001
From: Benjamin Coddington <[email protected]>
Date: Fri, 20 Nov 2015 09:55:30 -0500
Subject: nfs4: limit callback decoding to received bytes
From: Benjamin Coddington <[email protected]>
commit 38b7631fbe42e6e247e9fc9879f961b14a687e3b upstream.
A truncated cb_compound request will cause the client to decode null or
data from a previous callback for nfs4.1 backchannel case, or uninitialized
data for the nfs4.0 case. This is because the path through
svc_process_common() advances the request's iov_base and decrements iov_len
without adjusting the overall xdr_buf's len field. That causes
xdr_init_decode() to set up the xdr_stream with an incorrect length in
nfs4_callback_compound().
Fixing this for the nfs4.1 backchannel case first requires setting the
correct iov_len and page_len based on the length of received data in the
same manner as the nfs4.0 case.
Then the request's xdr_buf length can be adjusted for both cases based upon
the remaining iov_len and page_len.
Signed-off-by: Benjamin Coddington <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/nfs/callback_xdr.c | 7 +++++--
net/sunrpc/backchannel_rqst.c | 8 ++++++++
net/sunrpc/svc.c | 1 +
3 files changed, 14 insertions(+), 2 deletions(-)
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -76,7 +76,8 @@ static __be32 *read_buf(struct xdr_strea
p = xdr_inline_decode(xdr, nbytes);
if (unlikely(p == NULL))
- printk(KERN_WARNING "NFS: NFSv4 callback reply buffer
overflowed!\n");
+ printk(KERN_WARNING "NFS: NFSv4 callback reply buffer
overflowed "
+ "or truncated
request.\n");
return p;
}
@@ -892,6 +893,7 @@ static __be32 nfs4_callback_compound(str
struct cb_compound_hdr_arg hdr_arg = { 0 };
struct cb_compound_hdr_res hdr_res = { NULL };
struct xdr_stream xdr_in, xdr_out;
+ struct xdr_buf *rq_arg = &rqstp->rq_arg;
__be32 *p, status;
struct cb_process_state cps = {
.drc_status = 0,
@@ -903,7 +905,8 @@ static __be32 nfs4_callback_compound(str
dprintk("%s: start\n", __func__);
- xdr_init_decode(&xdr_in, &rqstp->rq_arg,
rqstp->rq_arg.head[0].iov_base);
+ rq_arg->len = rq_arg->head[0].iov_len + rq_arg->page_len;
+ xdr_init_decode(&xdr_in, rq_arg, rq_arg->head[0].iov_base);
p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base +
rqstp->rq_res.head[0].iov_len);
xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -333,12 +333,20 @@ void xprt_complete_bc_request(struct rpc
{
struct rpc_xprt *xprt = req->rq_xprt;
struct svc_serv *bc_serv = xprt->bc_serv;
+ struct xdr_buf *rq_rcv_buf = &req->rq_rcv_buf;
spin_lock(&xprt->bc_pa_lock);
list_del(&req->rq_bc_pa_list);
xprt_dec_alloc_count(xprt, 1);
spin_unlock(&xprt->bc_pa_lock);
+ if (copied <= rq_rcv_buf->head[0].iov_len) {
+ rq_rcv_buf->head[0].iov_len = copied;
+ rq_rcv_buf->page_len = 0;
+ } else {
+ rq_rcv_buf->page_len = copied - rq_rcv_buf->head[0].iov_len;
+ }
+
req->rq_private_buf.len = copied;
set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1366,6 +1366,7 @@ bc_svc_process(struct svc_serv *serv, st
memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
+ rqstp->rq_arg.len = req->rq_private_buf.len;
/* reset result send buffer "put" position */
resv->iov_len = 0;
Patches currently in stable-queue which might be from [email protected] are
queue-4.2/nfs4-start-callback_ident-at-idr-1.patch
queue-4.2/nfs4-limit-callback-decoding-to-received-bytes.patch
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