From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
If nfsd4_check_resp_size() returns an error then we should really be
truncating the reply here, otherwise we may leave extra garbage at the
end of the rpc reply.
Also add a warning to catch any cases where our reply-size estimates may
be wrong in the case of a non-idempotent operation.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 9 +++++++++
fs/nfsd/nfs4xdr.c | 17 ++++++++++++++++-
fs/nfsd/xdr4.h | 2 ++
3 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 747d6a8..db14965 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1859,6 +1859,15 @@ static struct nfsd4_operation nfsd4_ops[] = {
},
};
+void warn_on_nonidempotent_op(struct nfsd4_op *op)
+{
+ if (OPDESC(op)->op_flags & OP_MODIFIES_SOMETHING) {
+ pr_err("unable to encode reply to nonidempotent op %d (%s)\n",
+ op->opnum, nfsd4_op_name(op->opnum));
+ WARN_ON_ONCE(1);
+ }
+}
+
#ifdef NFSD_DEBUG
static const char *nfsd4_op_name(unsigned opnum)
{
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 1879250..24ba652 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3637,6 +3637,7 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
struct nfs4_stateowner *so = resp->cstate.replay_owner;
__be32 *statp;
+ nfsd4_enc encoder;
__be32 *p;
RESERVE_SPACE(8);
@@ -3648,10 +3649,24 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
goto status;
BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
!nfsd4_enc_ops[op->opnum]);
- op->status = nfsd4_enc_ops[op->opnum](resp, op->status, &op->u);
+ encoder = nfsd4_enc_ops[op->opnum];
+ op->status = encoder(resp, op->status, &op->u);
/* nfsd4_check_resp_size guarantees enough room for error status */
if (!op->status)
op->status = nfsd4_check_resp_size(resp, 0);
+ if (op->status == nfserr_resource ||
+ op->status == nfserr_rep_too_big ||
+ op->status == nfserr_rep_too_big_to_cache) {
+ /*
+ * The operation may have already been encoded or
+ * partially encoded. No op returns anything additional
+ * in the case of one of these three errors, so we can
+ * just truncate back to after the status. But it's a
+ * bug if we had to do this on a non-idempotent op:
+ */
+ warn_on_nonidempotent_op(op);
+ resp->xdr.p = statp + 1;
+ }
if (so) {
so->so_replay.rp_status = op->status;
so->so_replay.rp_buflen = (char *)resp->xdr.p
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index f62a055..15ca477 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -536,6 +536,8 @@ static inline bool nfsd4_last_compound_op(struct svc_rqst *rqstp)
return argp->opcnt == resp->opcnt;
}
+void warn_on_nonidempotent_op(struct nfsd4_op *op);
+
#define NFS4_SVC_XDRSIZE sizeof(struct nfsd4_compoundargs)
static inline void
--
1.9.0
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