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| author | Benjamin Coddington <bcodding@redhat.com> | 2015-11-20 17:55:30 +0300 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-11-24 06:03:15 +0300 |
| commit | 38b7631fbe42e6e247e9fc9879f961b14a687e3b (patch) | |
| tree | edcf8b437182b980a936bc11a46a292c31173c7f /fs/nfs/callback_xdr.c | |
| parent | c68a027c05709330fe5b2f50c50d5fa02124b5d8 (diff) | |
| download | linux-38b7631fbe42e6e247e9fc9879f961b14a687e3b.tar.xz | |
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')
| -rw-r--r-- | fs/nfs/callback_xdr.c | 7 |
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); |