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Message-ID: <33eba9f60af54f1585ba82af73be4eb2@AcuMS.aculab.com>
Date: Thu, 14 May 2020 10:12:34 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Kees Cook' <keescook@...omium.org>, Stephen Smalley
<stephen.smalley.work@...il.com>
CC: Mickaël Salaün <mic@...ikod.net>, linux-kernel
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Subject: RE: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec
through O_MAYEXEC
From: Kees Cook
> Sent: 14 May 2020 04:05
> On Wed, May 13, 2020 at 04:27:39PM -0700, Kees Cook wrote:
> > Like, couldn't just the entire thing just be:
> >
> > diff --git a/fs/namei.c b/fs/namei.c
> > index a320371899cf..0ab18e19f5da 100644
> > --- a/fs/namei.c
> > +++ b/fs/namei.c
> > @@ -2849,6 +2849,13 @@ static int may_open(const struct path *path, int acc_mode, int flag)
> > break;
> > }
> >
> > + if (unlikely(mask & MAY_OPENEXEC)) {
> > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_MOUNT &&
> > + path_noexec(path))
> > + return -EACCES;
> > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_FILE)
> > + acc_mode |= MAY_EXEC;
> > + }
> > error = inode_permission(inode, MAY_OPEN | acc_mode);
> > if (error)
> > return error;
> >
>
> FYI, I've confirmed this now. Effectively with patch 2 dropped, patch 3
> reduced to this plus the Kconfig and sysctl changes, the self tests
> pass.
>
> I think this makes things much cleaner and correct.
And a summary of that would be right for the 0/n patch email.
David
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