9p: fix multiple NULL-pointer-dereferences

Added checks to prevent GPFs from raising.

Link: http://lkml.kernel.org/r/20180727110558.5479-1-tomasbortoli@gmail.com
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+1a262da37d3bead15c39@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

4 files changed, 13 insertions, 1 deletions

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 964260265b13..e2ef3c782c53 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -945,7 +945,7 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
         if (err < 0)
                 return err;
 
-        if (valid_ipaddr4(addr) < 0)
+        if (addr == NULL || valid_ipaddr4(addr) < 0)
                 return -EINVAL;
 
         csocket = NULL;
@@ -995,6 +995,9 @@ p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
 
         csocket = NULL;
 
+        if (addr == NULL)
+                return -EINVAL;
+
         if (strlen(addr) >= UNIX_PATH_MAX) {
                 pr_err("%s (%d): address too long: %s\n",
                        __func__, task_pid_nr(current), addr);
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 2649b2ebf961..2ab4574183c9 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -645,6 +645,9 @@ rdma_create_trans(struct p9_client *client, const char *addr, char *args)
         struct rdma_conn_param conn_param;
         struct ib_qp_init_attr qp_attr;
 
+        if (addr == NULL)
+                return -EINVAL;
+
         /* Parse the transport specific mount options */
         err = parse_opts(args, &opts);
         if (err < 0)
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 06dcd3cc6a29..8ca356eb66bb 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -654,6 +654,9 @@ p9_virtio_create(struct p9_client *client, const char *devname, char *args)
         int ret = -ENOENT;
         int found = 0;
 
+        if (devname == NULL)
+                return -EINVAL;
+
         mutex_lock(&virtio_9p_lock);
         list_for_each_entry(chan, &virtio_chan_list, chan_list) {
                 if (!strncmp(devname, chan->tag, chan->tag_len) &&
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 2e2b8bca54f3..c2d54ac76bfd 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -94,6 +94,9 @@ static int p9_xen_create(struct p9_client *client, const char *addr, char *args)
 {
         struct xen_9pfs_front_priv *priv;
 
+        if (addr == NULL)
+                return -EINVAL;
+
         read_lock(&xen_9pfs_lock);
         list_for_each_entry(priv, &xen_9pfs_devs, list) {
                 if (!strcmp(priv->tag, addr)) {