proc: fix type confusion in pde_set_flags()

Commit 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc
files") missed a key part in the definition of proc_dir_entry:

union {
	const struct proc_ops *proc_ops;
	const struct file_operations *proc_dir_ops;
};

So dereference of ->proc_ops assumes it is a proc_ops structure results in
type confusion and make NULL check for 'proc_ops' not work for proc dir.

Add !S_ISDIR(dp->mode) test before calling pde_set_flags() to fix it.

Link: https://lkml.kernel.org/r/20250904135715.3972782-1-wangzijie1@honor.com
Fixes: 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc files")
Signed-off-by: wangzijie <wangzijie1@honor.com>
Reported-by: Brad Spengler <spender@grsecurity.net>
Closes: https://lore.kernel.org/all/20250903065758.3678537-1-wangzijie1@honor.com/
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index bd0c099cfdd2a5c9e0d44028d79a24808c2006d5..1762811122735f9402bb3f87c3bc41ebebe8ca4d 100644 (file)
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -393,7 +393,8 @@ struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
        if (proc_alloc_inum(&dp->low_ino))
                goto out_free_entry;
 
-       pde_set_flags(dp);
+       if (!S_ISDIR(dp->mode))
+               pde_set_flags(dp);
 
        write_lock(&proc_subdir_lock);
        dp->parent = dir;