From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16A46C3A59D for ; Thu, 22 Aug 2019 07:16:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4683233A0 for ; Thu, 22 Aug 2019 07:16:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jyOzhTFh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731373AbfHVHQq (ORCPT ); Thu, 22 Aug 2019 03:16:46 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:39367 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731295AbfHVHQq (ORCPT ); Thu, 22 Aug 2019 03:16:46 -0400 Received: by mail-pf1-f194.google.com with SMTP id f17so3308883pfn.6 for ; Thu, 22 Aug 2019 00:16:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=u1M0h1fse5fWcD6TExQsXpSrhJTc/UmTdvcIiT+sTi4=; b=jyOzhTFhEpT0F8vv04j2INavdeUrerCYnwz08j2DyPbn/ksQ1D/zzsYav4RTqZ3jvh met3GnRNZPdjm/iarcVQbwLySgdKIjkUnfqolpTzUJziFzR3D7wTvFDDsydcFGYVPwws I6sGoA3MwMa88O6C9ba2arRlSpOy3xm2L2HbA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=u1M0h1fse5fWcD6TExQsXpSrhJTc/UmTdvcIiT+sTi4=; b=MoCAalKK95TXAJCKynNMuzHdGbJLFy1G2UnNOF4Z7iNeH1tTBrxIqoEcQLhHQuy5DO 4il+ExIufa78ngazoS6GxhGiRtKJHM4wHjlwJspFoZsP2yQcI+dh2snZpAEvD3slupP4 aeqPeclb4D/SBcARr27spYnHj7oINeJU10xJONGSYOJ0xB5pTrB43VV0Fmy3xD5iWN8R Ec7iC1v0PnvCWA3U3f+HMIOBOB0fayOJVi34eRgzwk5f9VSNJ3zMAebfIVxaCsqDa2Gt Flj7uGRagCPvkMkF+dUK1yW2OYz8Qpf6pLJ6n3x1Tkf2myMGqQ7TsofWUoHX88Z+QXpP dCKg== X-Gm-Message-State: APjAAAV2MQH5CnBnK3EM8DW6ZQHdip9TNDLQuaK0MPghwffh6BTVo/3e bxtoRVuicH1rO27Kbvb8a0xfIQ== X-Google-Smtp-Source: APXvYqywLFIAaNaYsXu1OfGGVmmvmZGXRzd+bHimaWcDa4BRxGcbhjI6qIAuKVbwffys+v10Uq3gKA== X-Received: by 2002:a63:ed55:: with SMTP id m21mr32583711pgk.343.1566458205158; Thu, 22 Aug 2019 00:16:45 -0700 (PDT) Received: from hsinyi-z840.tpe.corp.google.com ([2401:fa00:1:10:b852:bd51:9305:4261]) by smtp.gmail.com with ESMTPSA id w26sm30233450pfq.100.2019.08.22.00.16.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 22 Aug 2019 00:16:44 -0700 (PDT) From: Hsin-Yi Wang To: linux-arm-kernel@lists.infradead.org, "Theodore Y . Ts'o" Cc: Russell King , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , "Paul E . McKenney" , Kate Stewart , "David S . Miller" , Viresh Kumar , Marek Szyprowski , Arnd Bergmann , Marc Zyngier , Julien Thierry , Greg Kroah-Hartman , Wei Li , Anders Roxell , Rob Herring , Aaro Koskinen , Daniel Thompson , Tim Chen , Rik van Riel , Waiman Long , Marcelo Tosatti , Peter Zijlstra , Armijn Hemel , Grzegorz Halat , Len Brown , Shaokun Zhang , Mike Rapoport , Kees Cook , Stephen Boyd , Guenter Roeck , Andrew Morton , Mathieu Desnoyers , Alexey Dobriyan , Yury Norov , Josh Poimboeuf , Jiri Kosina , Mukesh Ojha , linux-kernel@vger.kernel.org Subject: [PATCH v9 2/3] fdt: add support for rng-seed Date: Thu, 22 Aug 2019 15:15:22 +0800 Message-Id: <20190822071522.143986-3-hsinyi@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190822071522.143986-1-hsinyi@chromium.org> References: <20190822071522.143986-1-hsinyi@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introducing a chosen node, rng-seed, which is an entropy that can be passed to kernel called very early to increase initial device randomness. Bootloader should provide this entropy and the value is read from /chosen/rng-seed in DT. Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(), since early_init_dt_scan_chosen() would modify fdt to erase rng-seed. Add a new interface add_bootloader_randomness() for rng-seed use case. Depends on whether the seed is trustworthy, rng seed would be passed to add_hwgenerator_randomness(). Otherwise it would be passed to add_device_randomness(). Decision is controlled by kernel config RANDOM_TRUST_BOOTLOADER. Signed-off-by: Hsin-Yi Wang Reviewed-by: Stephen Boyd Reviewed-by: Rob Herring --- Change from v8: * Add a new interface add_bootloader_randomness * Add a new kernel config --- drivers/char/Kconfig | 10 ++++++++++ drivers/char/random.c | 15 +++++++++++++++ drivers/of/fdt.c | 14 ++++++++++++-- include/linux/random.h | 1 + 4 files changed, 38 insertions(+), 2 deletions(-) diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 96156c729a31..5974a5906fd0 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -551,3 +551,13 @@ config RANDOM_TRUST_CPU has not installed a hidden back door to compromise the CPU's random number generation facilities. This can also be configured at boot with "random.trust_cpu=on/off". + +config RANDOM_TRUST_BOOTLOADER + bool "Trust the bootloader to initialize Linux's CRNG" + default n + help + Bootloader could provide rng-seed set in /chosen/rng-seed in DT to help + increase initial device randomness. Assume the entropy provided is + trustworthy, it would be regarded as true hardware RNGs and update the + entropy estimate. Otherwise it would be regarded as device input that + could help mix the entropy pool, but won't be added to actual entropy. \ No newline at end of file diff --git a/drivers/char/random.c b/drivers/char/random.c index 5d5ea4ce1442..29d3ff3de1e1 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2445,3 +2445,18 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, credit_entropy_bits(poolp, entropy); } EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); + +/* Handle random seed passed by bootloader. + * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise + * it would be regarded as device data. + * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER. + */ +void add_bootloader_randomness(const void *buf, unsigned int size) +{ +#ifdef CONFIG_RANDOM_TRUST_BOOTLOADER + add_hwgenerator_randomness(buf, size, size * 8); +#else + add_device_randomness(buf, size); +#endif +} +EXPORT_SYMBOL_GPL(add_bootloader_randomness); \ No newline at end of file diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 9cdf14b9aaab..7d97ab6d0e31 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -24,6 +24,7 @@ #include #include #include +#include #include /* for COMMAND_LINE_SIZE */ #include @@ -1044,6 +1045,7 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, { int l; const char *p; + const void *rng_seed; pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname); @@ -1078,6 +1080,14 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, pr_debug("Command line is: %s\n", (char*)data); + rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); + if (rng_seed && l > 0) { + add_bootloader_randomness(rng_seed, l); + + /* try to clear seed so it won't be found. */ + fdt_nop_property(initial_boot_params, node, "rng-seed"); + } + /* break now */ return 1; } @@ -1166,8 +1176,6 @@ bool __init early_init_dt_verify(void *params) /* Setup flat device-tree pointer */ initial_boot_params = params; - of_fdt_crc32 = crc32_be(~0, initial_boot_params, - fdt_totalsize(initial_boot_params)); return true; } @@ -1197,6 +1205,8 @@ bool __init early_init_dt_scan(void *params) return false; early_init_dt_scan_nodes(); + of_fdt_crc32 = crc32_be(~0, initial_boot_params, + fdt_totalsize(initial_boot_params)); return true; } diff --git a/include/linux/random.h b/include/linux/random.h index 1f7dced2bba6..f189c927fdea 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -19,6 +19,7 @@ struct random_ready_callback { }; extern void add_device_randomness(const void *, unsigned int); +extern void add_bootloader_randomness(const void *, unsigned int); #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) static inline void add_latent_entropy(void) -- 2.20.1