linux-kernel - Re: [PATCH 08/15] kexec: New syscall kexec_file

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140627115057.GC13337@redhat.com>
Date:	Fri, 27 Jun 2014 07:50:58 -0400
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	kexec@...ts.infradead.org,
	Michael Kerrisk-manpages <mtk.manpages@...il.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Greg Kroah-Hartman <greg@...ah.com>,
	Borislav Petkov <bp@...en8.de>, dyoung@...hat.com,
	chaowang@...hat.com, bhe@...hat.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux API <linux-api@...r.kernel.org>
Subject: Re: [PATCH 08/15] kexec: New syscall kexec_file_load() declaration

On Thu, Jun 26, 2014 at 02:03:17PM -0700, Andy Lutomirski wrote:
> On Thu, Jun 26, 2014 at 1:43 PM, Vivek Goyal <vgoyal@...hat.com> wrote:
> > On Thu, Jun 26, 2014 at 04:33:37PM -0400, Vivek Goyal wrote:
> >> This is the new syscall kexec_file_load() declaration/interface. I have
> >> reserved the syscall number only for x86_64 so far. Other architectures
> >> (including i386) can reserve syscall number when they enable the support
> >> for this new syscall.
> >>
> >> Signed-off-by: Vivek Goyal <vgoyal@...hat.com>
> >> CC: linux-api@...r.kernel.org
> >
> > +.BR KEXEC_FILE_NO_INITRAMFS
> > +Loading initrd/initramfs is optional. Specify this flag if no initramfs
> > +is being loaded. If this flag is set, kernel will ignore the value passed
> > +in
> 
> This seems pointless.  Why not just pass -1 for initrd_fd to indicate
> that no initrd is needed?

I was not sure whether negative fd should be treated as error and system
call should fail or it should be treated as user does not want to load
initrd and system call succeeds.

I was concerned about the cases where application does an fd = open(),
operation fails and fd contains -1. Caller does not check fd and
passed it to kexec system call.

I thought that in such cases we should error out saying initrd fd is
not valid. Instead of continuing and loading kernel without initrd. A
user might be surprised.

This is little defensive programming. But I am open to change it if
the perception is that above is not a valid concern.

Thanks
Vivek
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/