From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Jessica Yu <jeyu@kernel.org>
Subject: Re: [PATCH 1/7] livepatch: Apply vmlinux-specific KLP relocations early
Date: Tue, 14 Apr 2020 14:31:50 -0500 [thread overview]
Message-ID: <20200414193150.iqw224itgpedpltm@treble> (raw)
In-Reply-To: <20200414180109.da4v2b4ifpixuzn3@treble>
On Tue, Apr 14, 2020 at 01:01:09PM -0500, Josh Poimboeuf wrote:
> On Tue, Apr 14, 2020 at 07:44:06PM +0200, Peter Zijlstra wrote:
> > On Tue, Apr 14, 2020 at 11:28:37AM -0500, Josh Poimboeuf wrote:
> > > KLP relocations are livepatch-specific relocations which are applied to
> > > 1) vmlinux-specific KLP relocation sections
> > >
> > > .klp.rela.vmlinux.{sec}
> > >
> > > These are relocations (applied to the KLP module) which reference
> > > unexported vmlinux symbols.
> > >
> > > 2) module-specific KLP relocation sections
> > >
> > > .klp.rela.{module}.{sec}:
> > >
> > > These are relocations (applied to the KLP module) which reference
> > > unexported or exported module symbols.
> >
> > Is there something that disallows a module from being called 'vmlinux' ?
> > If not, we might want to enforce this somewhere.
>
> I'm pretty sure we don't have a check for that anywhere, though the KLP
> module would almost certainly fail during the module load when it
> couldn't find the vmlinux.ko symbols it needed.
>
> It wouldn't hurt to add a check somewhere though. Maybe in
> klp_module_coming() since the restriction only applies to
> CONFIG_LIVEPATCH...
From: Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH] livepatch: Disallow vmlinux.ko
This is purely a theoretical issue, but if there were a module named
vmlinux.ko, the livepatch relocation code wouldn't be able to
distinguish between vmlinux-specific and vmlinux.o-specific KLP
relocations.
If CONFIG_LIVEPATCH is enabled, don't allow a module named vmlinux.ko.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
kernel/livepatch/core.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 3a88639b3326..3ff886b911ae 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -1169,6 +1169,11 @@ int klp_module_coming(struct module *mod)
if (WARN_ON(mod->state != MODULE_STATE_COMING))
return -EINVAL;
+ if (!strcmp(mod->name, "vmlinux")) {
+ pr_err("vmlinux.ko: invalid module name");
+ return -EINVAL;
+ }
+
mutex_lock(&klp_mutex);
/*
* Each module has to know that klp_module_coming()
--
2.21.1
next prev parent reply other threads:[~2020-04-14 19:32 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 16:28 [PATCH 0/7] livepatch,module: Remove .klp.arch and module_disable_ro() Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 1/7] livepatch: Apply vmlinux-specific KLP relocations early Josh Poimboeuf
2020-04-14 17:44 ` Peter Zijlstra
2020-04-14 18:01 ` Josh Poimboeuf
2020-04-14 19:31 ` Josh Poimboeuf [this message]
2020-04-15 14:30 ` Miroslav Benes
2020-04-15 16:29 ` Josh Poimboeuf
2020-04-15 14:34 ` Miroslav Benes
2020-04-15 16:30 ` Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 2/7] livepatch: Remove .klp.arch Josh Poimboeuf
2020-04-15 15:18 ` Jessica Yu
2020-04-14 16:28 ` [PATCH 3/7] livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 4/7] s390/module: Use s390_kernel_write() for relocations Josh Poimboeuf
2020-04-16 8:56 ` Miroslav Benes
2020-04-16 12:06 ` Josh Poimboeuf
2020-04-16 13:16 ` Josh Poimboeuf
2020-04-17 1:37 ` Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 5/7] x86/module: Use text_poke() " Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 6/7] livepatch: Remove module_disable_ro() usage Josh Poimboeuf
2020-04-15 15:02 ` Jessica Yu
2020-04-15 16:33 ` Josh Poimboeuf
2020-04-16 9:28 ` Miroslav Benes
2020-04-16 12:10 ` Josh Poimboeuf
2020-04-14 16:28 ` [PATCH 7/7] module: Remove module_disable_ro() Josh Poimboeuf
2020-04-14 18:27 ` [PATCH 0/7] livepatch,module: Remove .klp.arch and module_disable_ro() Peter Zijlstra
2020-04-14 19:08 ` Josh Poimboeuf
2020-04-15 14:24 ` Peter Zijlstra
2020-04-15 16:17 ` Josh Poimboeuf
2020-04-16 15:31 ` Jessica Yu
2020-04-16 15:45 ` Josh Poimboeuf
2020-04-17 8:27 ` Miroslav Benes
2020-04-17 8:50 ` Jessica Yu
2020-04-16 9:45 ` Miroslav Benes
2020-04-16 12:20 ` Josh Poimboeuf
2020-04-17 9:08 ` Miroslav Benes
2020-04-15 0:57 ` Joe Lawrence
2020-04-15 1:31 ` Josh Poimboeuf
2020-04-15 1:37 ` Joe Lawrence
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