Replace the open-coded decode logic for PMAP_GETPORT/RPCB_GETADDR with
an xdr_stream-based implementation, similar to what NFSv4 uses, to
protect against buffer overflows. The new implementation also checks
that the incoming port number is reasonable.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/rpcb_clnt.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index fe183af..88de754 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -454,7 +454,7 @@ int rpcb_getport_sync(struct sockaddr_in *sin, u32 prog, u32 vers, int prot)
struct rpc_message msg = {
.rpc_proc = &rpcb_procedures2[RPCBPROC_GETPORT],
.rpc_argp = &map,
- .rpc_resp = &map.r_port,
+ .rpc_resp = &map,
};
struct rpc_clnt *rpcb_clnt;
int status;
@@ -484,7 +484,7 @@ static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbi
struct rpc_message msg = {
.rpc_proc = proc,
.rpc_argp = map,
- .rpc_resp = &map->r_port,
+ .rpc_resp = map,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = rpcb_clnt,
@@ -727,6 +727,31 @@ static int rpcb_decode_getport(struct rpc_rqst *req, __be32 *p,
return 0;
}
+static int rpcb_dec_getport(struct rpc_rqst *req, __be32 *p,
+ struct rpcbind_args *rpcb)
+{
+ struct rpc_task *task = req->rq_task;
+ struct xdr_stream xdr;
+ unsigned long port;
+
+ xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
+
+ rpcb->r_port = 0;
+
+ p = xdr_inline_decode(&xdr, sizeof(__be32));
+ if (unlikely(p == NULL))
+ return -EIO;
+
+ port = ntohl(*p);
+ dprintk("RPC: %5u PMAP_%s result: %lu\n", task->tk_pid,
+ task->tk_msg.rpc_proc->p_name, port);
+ if (unlikely(port > USHORT_MAX))
+ return -EIO;
+
+ rpcb->r_port = port;
+ return 0;
+}
+
static int rpcb_decode_set(struct rpc_rqst *req, __be32 *p,
unsigned int *boolp)
{
@@ -871,11 +896,60 @@ out_err:
return -EIO;
}
+static int rpcb_dec_getaddr(struct rpc_rqst *req, __be32 *p,
+ struct rpcbind_args *rpcb)
+{
+ struct sockaddr_storage address;
+ struct sockaddr *sap = (struct sockaddr *)&address;
+ struct rpc_task *task = req->rq_task;
+ struct xdr_stream xdr;
+ u32 len;
+
+ rpcb->r_port = 0;
+
+ xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
+
+ p = xdr_inline_decode(&xdr, sizeof(__be32));
+ if (unlikely(p == NULL))
+ goto out_fail;
+ len = ntohl(*p);
+
+ /*
+ * If the returned universal address is a null string,
+ * the requested RPC service was not registered.
+ */
+ if (len == 0) {
+ dprintk("RPC: %5u RPCB reply: program not registered\n",
+ task->tk_pid);
+ return 0;
+ }
+
+ if (unlikely(len > RPCBIND_MAXUADDRLEN))
+ goto out_fail;
+
+ p = xdr_inline_decode(&xdr, len);
+ if (unlikely(p == NULL))
+ goto out_fail;
+ dprintk("RPC: %5u RPCB_%s reply: %s\n", task->tk_pid,
+ task->tk_msg.rpc_proc->p_name, (char *)p);
+
+ if (rpc_uaddr2sockaddr((char *)p, len, sap, sizeof(address)) == 0)
+ goto out_fail;
+ rpcb->r_port = rpc_get_port(sap);
+
+ return 0;
+
+out_fail:
+ dprintk("RPC: %5u malformed RPCB_%s reply\n",
+ task->tk_pid, task->tk_msg.rpc_proc->p_name);
+ return -EIO;
+}
+
#define PROC(proc, argtype, restype) \
[RPCBPROC_##proc] = { \
.p_proc = RPCBPROC_##proc, \
.p_encode = (kxdrproc_t) rpcb_enc_##argtype, \
- .p_decode = (kxdrproc_t) rpcb_decode_##restype, \
+ .p_decode = (kxdrproc_t) rpcb_dec_##restype, \
.p_arglen = RPCB_##argtype##args_sz, \
.p_replen = RPCB_##restype##res_sz, \
.p_statidx = RPCBPROC_##proc, \
--
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