Re: Commit 13c164b1a186 - regression for LSMs/SELinux?
Linus Torvalds <[email protected]>
| Newsgroups | org.kernel.vger.autofs,org.kernel.vger.linux-security-module,org.kernel.vger.selinux |
|---|---|
| Message-ID | <CAHk-=wgTz9h-WCtkEcByebaqv3arZWuUQ7TzfHejo10=bztZeA@mail.gmail.com> |
On Mon, Sep 21, 2020 at 9:09 AM Christoph Hellwig <[email protected]> wrote: > > So we obviously should not break existing user space and need to fix > this ASAP. The trivial "fix" would be to export __kernel_write again > and switch autofs to use it. The other option would be a FMODE flag > to bypass security checks, only to be set if the callers ensures > they've been valided (i.e. in autofs_prepare_pipe). > > Any opinions? I'd much rather do the former than add a new dynamic flag that we then have to worry about somebody being able to set thanks to a bug. Static behavior is a lot easier to verify and document (ie just a comment in the code explaining why autofs cannot use the regular kernel_write()). There's no chance of that static behavior then leaking to other call sites. Linus