From: Greg KH <greg@kroah.com>
To: kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@amacapital.net>,
"H. Peter Anvin" <hpa@zytor.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Mathias Krause <minipli@googlemail.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Arnd Bergmann <arnd@arndb.de>,
PaX Team <pageexec@freemail.hu>, Emese Revfy <re.emese@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [kernel-hardening] [PATCH v2 1/4] init: create cmdline param to disable readonly
Date: Wed, 25 Nov 2015 16:44:02 -0800 [thread overview]
Message-ID: <20151126004402.GA30235@kroah.com> (raw)
In-Reply-To: <1448494286-16029-2-git-send-email-keescook@chromium.org>
On Wed, Nov 25, 2015 at 03:31:23PM -0800, Kees Cook wrote:
> It may be useful to debug writes to the readonly sections of memory,
> so provide a cmdline "rodata=off" to allow for this.
>
> Suggested-by: H. Peter Anvin <hpa@zytor.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Documentation/kernel-parameters.txt | 4 ++++
> init/main.c | 31 +++++++++++++++++++++++++++----
> 2 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 742f69d18fc8..21cf76dbba90 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -3409,6 +3409,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>
> ro [KNL] Mount root device read-only on boot
>
> + rodata= [KNL]
> + on Mark read-only kernel memory as read-only (default).
> + off Leave read-only kernel memory writable for debugging.
> +
> root= [KNL] Root filesystem
> See name_to_dev_t comment in init/do_mounts.c.
>
> diff --git a/init/main.c b/init/main.c
> index 9e64d7097f1a..06200d2fbf08 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -93,9 +93,6 @@ static int kernel_init(void *);
> extern void init_IRQ(void);
> extern void fork_init(void);
> extern void radix_tree_init(void);
> -#ifndef CONFIG_DEBUG_RODATA
> -static inline void mark_rodata_ro(void) { }
> -#endif
>
> /*
> * Debug helper: via this flag we know that we are in 'early bootup code'
> @@ -929,6 +926,32 @@ static int try_to_run_init_process(const char *init_filename)
>
> static noinline void __init kernel_init_freeable(void);
>
> +#ifdef CONFIG_DEBUG_RODATA
> +bool disable_mark_readonly;
> +static int __init set_debug_rodata(char *str)
> +{
> + if (!str)
> + return -EINVAL;
> + if (!strncmp(str, "on", 2))
> + disable_mark_readonly = false;
> + else if (!strncmp(str, "off", 3))
> + disable_mark_readonly = true;
strtobool()?
next prev parent reply other threads:[~2015-11-26 0:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 23:31 [kernel-hardening] [PATCH v2 0/4] introduce post-init read-only memory Kees Cook
2015-11-25 23:31 ` [kernel-hardening] [PATCH v2 1/4] init: create cmdline param to disable readonly Kees Cook
2015-11-26 0:37 ` [kernel-hardening] " PaX Team
2015-11-26 0:44 ` Greg KH [this message]
2015-11-26 7:51 ` Ingo Molnar
2015-11-30 21:52 ` Kees Cook
2015-11-30 22:24 ` Russell King - ARM Linux
2015-11-30 22:34 ` Kees Cook
2015-12-01 7:24 ` Ingo Molnar
2015-12-01 7:19 ` Heiko Carstens
2015-11-25 23:31 ` [kernel-hardening] [PATCH v2 2/4] introduce post-init read-only memory Kees Cook
2015-11-26 0:15 ` [kernel-hardening] " PaX Team
2015-11-30 22:24 ` H. Peter Anvin
2015-12-09 19:35 ` Kees Cook
2015-11-25 23:31 ` [kernel-hardening] [PATCH v2 3/4] lkdtm: verify that __ro_after_init works correctly Kees Cook
2015-11-25 23:31 ` [kernel-hardening] [PATCH v2 4/4] x86, vdso: mark vDSO read-only after init Kees Cook
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