NFSD: If port value written to /proc/fs/nfsd/portlist is invalid, return EINVAL

Make sure port value read from user space by write_ports is valid before
passing it to svc_find_xprt().  If it wasn't, the writer would get ENOENT
instead of EINVAL.

Noticed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 3d93b2064ce5..5a936c14f6ff 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -938,6 +938,8 @@ static ssize_t __write_ports(struct file *file, char *buf, size_t size)
                 char transport[16];
                 int port;
                 if (sscanf(buf, "%15s %4d", transport, &port) == 2) {
+                        if (port < 1 || port > 65535)
+                                return -EINVAL;
                         err = nfsd_create_serv();
                         if (!err) {
                                 err = svc_create_xprt(nfsd_serv,
@@ -960,7 +962,7 @@ static ssize_t __write_ports(struct file *file, char *buf, size_t size)
                 char transport[16];
                 int port;
                 if (sscanf(&buf[1], "%15s %4d", transport, &port) == 2) {
-                        if (port == 0)
+                        if (port < 1 || port > 65535)
                                 return -EINVAL;
                         if (nfsd_serv) {
                                 xprt = svc_find_xprt(nfsd_serv, transport,