Live-Patching Archive on lore.kernel.org
 help / color / Atom feed
From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Miroslav Benes <mbenes@suse.cz>
Cc: Kristen Carlson Accardi <kristen@linux.intel.com>,
	Kees Cook <keescook@chromium.org>,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	arjan@linux.intel.com, x86@kernel.org,
	linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com,
	live-patching@vger.kernel.org, Hongjiu Lu <hongjiu.lu@intel.com>,
	joe.lawrence@redhat.com
Subject: Re: [PATCH v4 00/10] Function Granular KASLR
Date: Fri, 28 Aug 2020 14:24:13 -0500
Message-ID: <20200828192413.p6rctr42xtuh2c2e@treble> (raw)
In-Reply-To: <alpine.LSU.2.21.2008281216031.29208@pobox.suse.cz>

On Fri, Aug 28, 2020 at 12:21:13PM +0200, Miroslav Benes wrote:
> > Hi there! I was trying to find a super easy way to address this, so I
> > thought the best thing would be if there were a compiler or linker
> > switch to just eliminate any duplicate symbols at compile time for
> > vmlinux. I filed this question on the binutils bugzilla looking to see
> > if there were existing flags that might do this, but H.J. Lu went ahead
> > and created a new one "-z unique", that seems to do what we would need
> > it to do. 
> > 
> > https://sourceware.org/bugzilla/show_bug.cgi?id=26391
> > 
> > When I use this option, it renames any duplicate symbols with an
> > extension - for example duplicatefunc.1 or duplicatefunc.2. You could
> > either match on the full unique name of the specific binary you are
> > trying to patch, or you match the base name and use the extension to
> > determine original position. Do you think this solution would work?
> 
> Yes, I think so (thanks, Joe, for testing!).
> 
> It looks cleaner to me than the options above, but it may just be a matter 
> of taste. Anyway, I'd go with full name matching, because -z unique-symbol 
> would allow us to remove sympos altogether, which is appealing.
> 
> > If
> > so, I can modify livepatch to refuse to patch on duplicated symbols if
> > CONFIG_FG_KASLR and when this option is merged into the tool chain I
> > can add it to KBUILD_LDFLAGS when CONFIG_FG_KASLR and livepatching
> > should work in all cases. 
> 
> Ok.
> 
> Josh, Petr, would this work for you too?

Sounds good to me.  Kristen, thanks for finding a solution!

-- 
Josh


  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200717170008.5949-1-kristen@linux.intel.com>
2020-07-22  9:27 ` Miroslav Benes
2020-07-22 14:39   ` Kees Cook
2020-07-22 14:51     ` Joe Lawrence
2020-07-22 14:56       ` Joe Lawrence
2020-07-22 18:24         ` Kristen Carlson Accardi
2020-07-22 16:07     ` Josh Poimboeuf
2020-07-22 19:42       ` Kees Cook
2020-07-22 19:56         ` Kristen Carlson Accardi
2020-07-22 21:33           ` Josh Poimboeuf
2020-08-21 23:02             ` Kristen Carlson Accardi
2020-08-25 16:16               ` Joe Lawrence
2020-08-28 10:21               ` Miroslav Benes
2020-08-28 19:24                 ` Josh Poimboeuf [this message]
2020-08-03 11:39   ` Evgenii Shatokhin
2020-08-03 17:45     ` Kees Cook
2020-08-03 18:17       ` Joe Lawrence
2020-08-03 19:38         ` Frank Ch. Eigler
2020-08-03 20:11           ` Kees Cook
2020-08-03 21:12             ` Frank Ch. Eigler
2020-08-03 21:41               ` Kees Cook
2020-08-04  0:48                 ` Frank Ch. Eigler
2020-08-04 17:04         ` Jessica Yu
2020-08-04 18:23 ` Joe Lawrence
2020-08-07 16:38   ` Kristen Carlson Accardi
2020-08-07 17:20     ` Kees Cook
2020-08-10 16:10       ` Kristen Carlson Accardi
2020-08-12 17:18   ` Kristen Carlson Accardi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200828192413.p6rctr42xtuh2c2e@treble \
    --to=jpoimboe@redhat.com \
    --cc=arjan@linux.intel.com \
    --cc=bp@alien8.de \
    --cc=hongjiu.lu@intel.com \
    --cc=joe.lawrence@redhat.com \
    --cc=keescook@chromium.org \
    --cc=kernel-hardening@lists.openwall.com \
    --cc=kristen@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=live-patching@vger.kernel.org \
    --cc=mbenes@suse.cz \
    --cc=mingo@redhat.com \
    --cc=rick.p.edgecombe@intel.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Live-Patching Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/live-patching/0 live-patching/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 live-patching live-patching/ https://lore.kernel.org/live-patching \
		live-patching@vger.kernel.org
	public-inbox-index live-patching

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.live-patching


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git