From patchwork Tue Oct 25 00:43:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 13018380 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A8FF6C38A2D for ; Tue, 25 Oct 2022 00:49:10 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1on83F-0004wm-0R; Mon, 24 Oct 2022 20:44:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1on83C-0004w4-U6 for qemu-devel@nongnu.org; Mon, 24 Oct 2022 20:44:14 -0400 Received: from dfw.source.kernel.org ([139.178.84.217]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1on839-0005HB-Kr for qemu-devel@nongnu.org; Mon, 24 Oct 2022 20:44:14 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DC337616E4; Tue, 25 Oct 2022 00:44:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EA3AC433C1; Tue, 25 Oct 2022 00:44:09 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Ot3qJxyU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1666658648; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hd5sLN7e5NHAIrDa5FhRY1Hjf03Wbgh/dmRxMOuwntI=; b=Ot3qJxyUpfRWqTMi08pSBV8U91yuoP9ZVSoJ9cR8uiJpWf9uVxExcnytMiuMFTLOitOn6S KOVKEjcZINg48m69kMqpqDX7OpZJWxDM/qXVDE4vVxivADZj3BpyT/tnCOb94qgY8xiR2H fX0ItvBm1SvadL9v/WR9pvv0qSZ9lnA= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 5d290634 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 25 Oct 2022 00:44:08 +0000 (UTC) From: "Jason A. Donenfeld" To: peter.maydell@linaro.org, pbonzini@redhat.com, qemu-devel@nongnu.org, richard.henderson@linaro.org Cc: "Jason A. Donenfeld" , Aleksandar Rikalo , Paul Burton , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Subject: [PATCH v4 09/11] mips/malta: pass RNG seed via env var and re-randomize on reboot Date: Tue, 25 Oct 2022 02:43:25 +0200 Message-Id: <20221025004327.568476-10-Jason@zx2c4.com> In-Reply-To: <20221025004327.568476-1-Jason@zx2c4.com> References: <20221025004327.568476-1-Jason@zx2c4.com> MIME-Version: 1.0 Received-SPF: pass client-ip=139.178.84.217; envelope-from=SRS0=a4uw=22=zx2c4.com=Jason@kernel.org; helo=dfw.source.kernel.org X-Spam_score_int: -67 X-Spam_score: -6.8 X-Spam_bar: ------ X-Spam_report: (-6.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org As of the kernel commit linked below, Linux ingests an RNG seed passed as part of the environment block by the bootloader or firmware. This mechanism works across all different environment block types, generically, which pass some block via the second firmware argument. On malta, this has been tested to work when passed as an argument from U-Boot's linux_env_set. As is the case on most other architectures (such as boston), when booting with `-kernel`, QEMU, acting as the bootloader, should pass the RNG seed, so that the machine has good entropy for Linux to consume. So this commit implements that quite simply by using the guest random API, which is what is used on nearly all other archs too. It also reinitializes the seed on reboot, so that it is always fresh. Link: https://git.kernel.org/torvalds/c/056a68cea01 Cc: Aleksandar Rikalo Cc: Paul Burton Cc: Philippe Mathieu-Daudé Signed-off-by: Jason A. Donenfeld --- hw/mips/malta.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/hw/mips/malta.c b/hw/mips/malta.c index 0e932988e0..d337de920c 100644 --- a/hw/mips/malta.c +++ b/hw/mips/malta.c @@ -26,6 +26,7 @@ #include "qemu/units.h" #include "qemu/bitops.h" #include "qemu/datadir.h" +#include "qemu/guest-random.h" #include "hw/clock.h" #include "hw/southbridge/piix.h" #include "hw/isa/superio.h" @@ -1017,6 +1018,17 @@ static void G_GNUC_PRINTF(3, 4) prom_set(uint32_t *prom_buf, int index, va_end(ap); } +static void reinitialize_rng_seed(void *opaque) +{ + char *rng_seed_hex = opaque; + uint8_t rng_seed[32]; + + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); + for (size_t i = 0; i < sizeof(rng_seed); ++i) { + sprintf(rng_seed_hex + i * 2, "%02x", rng_seed[i]); + } +} + /* Kernel */ static uint64_t load_kernel(void) { @@ -1028,6 +1040,8 @@ static uint64_t load_kernel(void) long prom_size; int prom_index = 0; uint64_t (*xlate_to_kseg0) (void *opaque, uint64_t addr); + uint8_t rng_seed[32]; + char rng_seed_hex[sizeof(rng_seed) * 2 + 1]; #if TARGET_BIG_ENDIAN big_endian = 1; @@ -1115,9 +1129,20 @@ static uint64_t load_kernel(void) prom_set(prom_buf, prom_index++, "modetty0"); prom_set(prom_buf, prom_index++, "38400n8r"); + + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); + for (size_t i = 0; i < sizeof(rng_seed); ++i) { + sprintf(rng_seed_hex + i * 2, "%02x", rng_seed[i]); + } + prom_set(prom_buf, prom_index++, "rngseed"); + prom_set(prom_buf, prom_index++, "%s", rng_seed_hex); + prom_set(prom_buf, prom_index++, NULL); rom_add_blob_fixed("prom", prom_buf, prom_size, ENVP_PADDR); + qemu_register_reset_nosnapshotload(reinitialize_rng_seed, + memmem(rom_ptr(ENVP_PADDR, prom_size), prom_size, + rng_seed_hex, sizeof(rng_seed_hex))); g_free(prom_buf); return kernel_entry;