get_net_ns_by_fd() oopses if proc_ns_fget() returns an error

BTW, looking through the code related to struct net lifetime rules has
caught something else:

struct net *get_net_ns_by_fd(int fd)
{
        ...
        file = proc_ns_fget(fd);
        if (!file)
                goto out;

        ei = PROC_I(file->f_dentry->d_inode);

while in proc_ns_fget() we have two return ERR_PTR(...) and not a single
path that would return NULL.  The other caller of proc_ns_fget() treats
ERR_PTR() correctly...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 6c6b86d..e41e511 100644 (file)
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -310,19 +310,17 @@ struct net *get_net_ns_by_fd(int fd)
        struct file *file;
        struct net *net;
 
-       net = ERR_PTR(-EINVAL);
        file = proc_ns_fget(fd);
-       if (!file)
-               goto out;
+       if (IS_ERR(file))
+               return ERR_CAST(file);
 
        ei = PROC_I(file->f_dentry->d_inode);
-       if (ei->ns_ops != &netns_operations)
-               goto out;
+       if (ei->ns_ops == &netns_operations)
+               net = get_net(ei->ns);
+       else
+               net = ERR_PTR(-EINVAL);
 
-       net = get_net(ei->ns);
-out:
-       if (file)
-               fput(file);
+       fput(file);
        return net;
 }