SUNRPC: Use struct xdr_stream when decoding RPC Reply header

Modernize and harden the code path that parses an RPC Reply
message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 23 insertions, 19 deletions

diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 1d5b7ed9c6f7..5ea84a96f96e 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -160,29 +160,32 @@ unx_refresh(struct rpc_task *task)
         return 0;
 }
 
-static __be32 *
-unx_validate(struct rpc_task *task, __be32 *p)
+static int
+unx_validate(struct rpc_task *task, struct xdr_stream *xdr)
 {
-        rpc_authflavor_t        flavor;
-        u32                     size;
-
-        flavor = ntohl(*p++);
-        if (flavor != RPC_AUTH_NULL &&
-            flavor != RPC_AUTH_UNIX &&
-            flavor != RPC_AUTH_SHORT) {
-                printk("RPC: bad verf flavor: %u\n", flavor);
-                return ERR_PTR(-EIO);
-        }
+        __be32 *p;
+        u32 size;
 
-        size = ntohl(*p++);
-        if (size > RPC_MAX_AUTH_SIZE) {
-                printk("RPC: giant verf size: %u\n", size);
-                return ERR_PTR(-EIO);
+        p = xdr_inline_decode(xdr, 2 * sizeof(*p));
+        if (!p)
+                return -EIO;
+        switch (*p++) {
+        case rpc_auth_null:
+        case rpc_auth_unix:
+        case rpc_auth_short:
+                break;
+        default:
+                return -EIO;
         }
-        task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
-        p += (size >> 2);
+        size = be32_to_cpup(p);
+        if (size > RPC_MAX_AUTH_SIZE)
+                return -EIO;
+        p = xdr_inline_decode(xdr, size);
+        if (!p)
+                return -EIO;
 
-        return p;
+        task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
+        return 0;
 }
 
 int __init rpc_init_authunix(void)
@@ -223,4 +226,5 @@ const struct rpc_credops unix_credops = {
         .crwrap_req     = rpcauth_wrap_req_encode,
         .crrefresh      = unx_refresh,
         .crvalidate     = unx_validate,
+        .crunwrap_resp  = rpcauth_unwrap_resp_decode,
 };