From: "Cyril B." <cbay@alwaysdata.com>
To: Zhou Chengming <zhouchengming1@huawei.com>
Cc: jpoimboe@redhat.com, sjenning@redhat.com, jkosina@suse.cz,
vojtech@suse.cz, live-patching@vger.kernel.org,
linux-kernel@vger.kernel.org, guohanjun@huawei.com,
huawei.libin@huawei.com, xiexiuqi@huawei.com
Subject: Re: [PATCH] livepatch: x86: bugfix about kASLR
Date: Wed, 04 Nov 2015 13:27:33 +0100 [thread overview]
Message-ID: <5639F9B5.6090608@alwaysdata.com> (raw)
In-Reply-To: <1446629532-32111-1-git-send-email-zhouchengming1@huawei.com>
Zhou Chengming wrote:
> When enable KASLR, func->old_addr will be set to zero
> and livepatch will find the right old address.
> But for reloc, livepatch just verify it using reloc->val
> (old addr from user), so verify failed and report
> "kernel mismatch" error.
>
> Reported-by: Cyril B.<cbay@alwaysdata.com>
> Signed-off-by: Zhou Chengming<zhouchengming1@huawei.com>
> ---
> kernel/livepatch/core.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 53196e2..c8885c6 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -311,7 +311,12 @@ static int klp_write_object_relocations(struct module *pmod,
> return -EINVAL;
>
> for (reloc = obj->relocs; reloc->name; reloc++) {
> - if (!klp_is_module(obj)) {
> +
> +#if defined(CONFIG_RANDOMIZE_BASE)
> + /* KASLR is enabled, disregard old_addr from user */
> + reloc->val = 0;
> +#endif
> + if (reloc->val&& !klp_is_module(obj)) {
> ret = klp_verify_vmlinux_symbol(reloc->name,
> reloc->val);
> if (ret)
I still get the 'symbol not found in symbol table' error with that patch
(on top of Linux 4.3).
Cyril
prev parent reply other threads:[~2015-11-04 16:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-04 9:32 [PATCH] livepatch: x86: bugfix about kASLR Zhou Chengming
2015-11-04 9:44 ` Jiri Kosina
2015-11-04 10:05 ` zhouchengming
2015-11-04 12:27 ` Cyril B. [this message]
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