From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71327194C78; Mon, 20 Jan 2025 21:10:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737407448; cv=none; b=Tkc4tMkHWUzC0yY7/6INYw/PAPIu2A3vB4iqmN/pwoDj50jorKc7oQ6tg+n6577zxBWTk2t85EIjImlVNW8WTRmOzN3hPwltrdeNpGcNqenNr2fb/HC6oKSB74OCb1eZ8XkawSx6ie7MlC24d19FWD6qG50jtq0vM3RBYsPWAxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737407448; c=relaxed/simple; bh=yUlmELXOb4rfYZ4Rmz94aC92qm8PbhGPnzsTDq1BxQY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HvC7fuTT0N+HzhMI4Hju8h0UNUgRx/+7a8S4UDnE6gLrguvsLxafJd/BH8KG/9j7pOGhdShr6g0tQjf+4vkbHwXl3d05jM/9pmpB+3Ueg4/wTCkjxHNd2F4m79IEFf75YIGXJku6hnJJwB43BaVj9iA16Ri5fL5vHI+ruglKTZQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j6mRKFVc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j6mRKFVc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCAA9C4CEDD; Mon, 20 Jan 2025 21:10:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737407447; bh=yUlmELXOb4rfYZ4Rmz94aC92qm8PbhGPnzsTDq1BxQY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=j6mRKFVcVuZylWvDsguiBjATm8aeu65LaE9Ejl4pa0nFvhY6xWUcD9kdxndpB2ami yYwOM4fxGc3Y3wufXBSkdzcqTGgRX1ypSM9Ah4vfBLoeNEB7GdzrlEUq2ddfw72xR9 i8y6ObkCQof8LkOAMDB3n6cD/Qd87KajGJNSPa+oFnvOb6FPeuOFq2SD2cAcoN8TnF 2Mb8oBZ4n/IYphNTGIWZV4+iXxC6c0nAyWn0u8W+pNaL0Uanln+1vDpgpNNaYS6gC5 ut94XJEiSp/f9MegijO1wPZSV8D8zjzff8COp3kEZv/xrS7kG+vMUZaJuFLxu3Reai Ff5BWow/3NiFg== Date: Mon, 20 Jan 2025 13:10:44 -0800 From: Kees Cook To: Mel Gorman Cc: Daniel Micay , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] mm: security: Move hardened usercopy under 'Kernel hardening options' Message-ID: <202501201309.73DA8439B@keescook> References: <20250117130337.4716-1-mgorman@techsingularity.net> <20250117130337.4716-2-mgorman@techsingularity.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250117130337.4716-2-mgorman@techsingularity.net> On Fri, Jan 17, 2025 at 01:03:35PM +0000, Mel Gorman wrote: > There is a submenu for 'Kernel hardening options' under "Security". > Move HARDENED_USERCOPY under the hardening options as it is clearly > related. > > Signed-off-by: Mel Gorman > --- > security/Kconfig | 12 ------------ > security/Kconfig.hardening | 16 ++++++++++++++++ > 2 files changed, 16 insertions(+), 12 deletions(-) > > diff --git a/security/Kconfig b/security/Kconfig > index 28e685f53bd1..fe7346dc4bc3 100644 > --- a/security/Kconfig > +++ b/security/Kconfig > @@ -159,18 +159,6 @@ config LSM_MMAP_MIN_ADDR > this low address space will need the permission specific to the > systems running LSM. > > -config HARDENED_USERCOPY > - bool "Harden memory copies between kernel and userspace" > - imply STRICT_DEVMEM > - help > - This option checks for obviously wrong memory regions when > - copying memory to/from the kernel (via copy_to_user() and > - copy_from_user() functions) by rejecting memory ranges that > - are larger than the specified heap object, span multiple > - separately allocated pages, are not on the process stack, > - or are part of the kernel text. This prevents entire classes > - of heap overflow exploits and similar kernel memory exposures. > - > config FORTIFY_SOURCE > bool "Harden common str/mem functions against buffer overflows" > depends on ARCH_HAS_FORTIFY_SOURCE > diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening > index c9d5ca3d8d08..00e6e2ed0c43 100644 > --- a/security/Kconfig.hardening > +++ b/security/Kconfig.hardening > @@ -279,6 +279,22 @@ config ZERO_CALL_USED_REGS > > endmenu > > +menu "String manipulation" I think "string" means different things to different people. I'd prefer "Bounds checking" or "Spatial safety" if it's going to be a separate menu section. > + > +config HARDENED_USERCOPY > + bool "Harden memory copies between kernel and userspace" > + imply STRICT_DEVMEM > + help > + This option checks for obviously wrong memory regions when > + copying memory to/from the kernel (via copy_to_user() and > + copy_from_user() functions) by rejecting memory ranges that > + are larger than the specified heap object, span multiple > + separately allocated pages, are not on the process stack, > + or are part of the kernel text. This prevents entire classes > + of heap overflow exploits and similar kernel memory exposures. > + > +endmenu > + > menu "Hardening of kernel data structures" Otherwise, looks good. -- Kees Cook