Re: [PATCH 2/2] acct: block access to kernel internal filesystems

On Tue, Feb 11, 2025 at 06:16:00PM +0100, Christian Brauner wrote:

There's no point in allowing anything kernel internal nor procfs or sysfs.

• /* Exclude kernel kernel internal filesystems. */
• if (file_inode(file)->i_sb->s_flags & (SB_NOUSER | SB_KERNMOUNT)) {

• kfree(acct);
  

• filp_close(file, NULL);
  

• return -EINVAL;
  

• }
• /* Exclude procfs and sysfs. */
• if (file_inode(file)->i_sb->s_iflags & SB_I_USERNS_VISIBLE) {

• kfree(acct);
  

• filp_close(file, NULL);
  

• return -EINVAL;
  

• }

That looks like a really weird way to test it, especially the second part...