Re: [PATCH 24/32] vfs: syscall: Add fsopen() to prepare for superblock creation [ver #9]

[David Howells]

Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> >    sfd = fsopen("ext4", FSOPEN_CLOEXEC);
> >    write(sfd, "s /dev/sdb1"); // note I'm ignoring write's length arg
> 
> Imagine some malicious program passes sfd as stdout to a setuid
> program. That program gets persuaded to write "s /etc/shadow".  What
> happens?  Youâre okay as long as *every single fs* gets it right, but thatâs
> asking a lot.

Do note that you must already have CAP_SYS_ADMIN to be able to call fsopen().

David