SUNRPC: Fix use of copy_to_user() in gss_pipe_upcall()
The gss_pipe_upcall() function expects the copy_to_user() function to
return a negative error value if the call fails, but copy_to_user()
returns an unsigned long number of bytes that couldn't be copied.
Can rpc_pipefs actually retry a partially completed upcall read? If
not, then gss_pipe_upcall() should punt any partial read, just like the
upcall logic in net/sunrpc/cache.c.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 1f2d85e..6dac387 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -472,16 +472,15 @@
char __user *dst, size_t buflen)
{
char *data = (char *)msg->data + msg->copied;
- ssize_t mlen = msg->len;
- ssize_t left;
+ size_t mlen = min(msg->len, buflen);
+ unsigned long left;
- if (mlen > buflen)
- mlen = buflen;
left = copy_to_user(dst, data, mlen);
- if (left < 0) {
- msg->errno = left;
- return left;
+ if (left == mlen) {
+ msg->errno = -EFAULT;
+ return -EFAULT;
}
+
mlen -= left;
msg->copied += mlen;
msg->errno = 0;