path: root/fs/nfs/callback_xdr.c
diff options
authorBenjamin Coddington <bcodding@redhat.com>2015-11-20 09:55:30 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-11-23 22:03:15 -0500
commit38b7631fbe42e6e247e9fc9879f961b14a687e3b (patch)
treeedcf8b437182b980a936bc11a46a292c31173c7f /fs/nfs/callback_xdr.c
parentnfs4: start callback_ident at idr 1 (diff)
nfs4: limit callback decoding to received bytes
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 <bcodding@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/callback_xdr.c')
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 646cdac73488..beac58b0e09c 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -78,7 +78,8 @@ static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
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;
@@ -889,6 +890,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
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,
@@ -900,7 +902,8 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
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);