From patchwork Sun Oct 28 07:18:58 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akinobu Mita X-Patchwork-Id: 194655 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id EFC7A2C008D for ; Sun, 28 Oct 2012 18:21:32 +1100 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TSNA1-0001Ky-QK; Sun, 28 Oct 2012 07:19:53 +0000 Received: from mail-da0-f49.google.com ([209.85.210.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TSN9p-0001J9-O0 for linux-mtd@lists.infradead.org; Sun, 28 Oct 2012 07:19:43 +0000 Received: by mail-da0-f49.google.com with SMTP id q27so1746291daj.36 for ; Sun, 28 Oct 2012 00:19:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer; bh=9m/snZjrB/xmVMydJU5ZQQf2XaiPun75gohlqL4Bm6A=; b=0X0ItOTmADrO9hy2Mxq6E1zfWEHQKJZwt+YeGpr69p5NZaw+BBiPOFk/tmoCxwnqJn Z2HRxKsG5B9ghgVfohpbGnJtMey1+h6Fr0W8jOIn1uY4o11pasq1Wg2cr+TwH05HkOZ/ U6hp9eLyV82+ivbN+pkYZSzk0t8htgkxpl8Ow3U8AVKu52+rAj7UZAc96ezTyG80IwG2 LCmeBRGcyLtD8pAOCA5moQvUUat0qlHXF9SffbbO3CdzGDaV1fC+qRFH2yqi8ioCnpjB 7NiopZYD23TyLcaoAKygAUDiZqIII4Q+kFPg7qWCSj/ipxf04WfO9CCMgvFrgB1ArI1I mVSg== Received: by 10.66.72.134 with SMTP id d6mr74585232pav.13.1351408775698; Sun, 28 Oct 2012 00:19:35 -0700 (PDT) Received: from localhost.localdomain (p1120-ipbf2201hodogaya.kanagawa.ocn.ne.jp. [123.220.186.120]) by mx.google.com with ESMTPS id lb4sm3961166pbc.6.2012.10.28.00.19.33 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 28 Oct 2012 00:19:35 -0700 (PDT) From: Akinobu Mita To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes() Date: Sun, 28 Oct 2012 16:18:58 +0900 Message-Id: <1351408746-8623-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.7.11.7 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (akinobu.mita[at]gmail.com) -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.210.49 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature Cc: Theodore Ts'o , Artem Bityutskiy , Adrian Hunter , Akinobu Mita , linux-mtd@lists.infradead.org, David Woodhouse X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Add functions to get the requested number of pseudo-random bytes. The difference from get_random_bytes() is that it uses pseudo-random numbers generated by random32. It is fast, suitable for generating random bytes for testing, and reproducible if prandom32 interface is used. Signed-off-by: Akinobu Mita Cc: "Theodore Ts'o" Cc: Artem Bityutskiy Cc: Adrian Hunter Cc: David Woodhouse Cc: linux-mtd@lists.infradead.org --- include/linux/random.h | 2 ++ lib/random32.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/include/linux/random.h b/include/linux/random.h index 6330ed4..eedf429b 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -27,8 +27,10 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l u32 random32(void); void srandom32(u32 seed); +void random32_get_bytes(void *buf, int nbytes); u32 prandom32(struct rnd_state *); +void prandom32_get_bytes(struct rnd_state *state, void *buf, int nbytes); /* * Handle minimum values for seeds diff --git a/lib/random32.c b/lib/random32.c index 938bde5..aee87dd 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -61,6 +61,44 @@ u32 prandom32(struct rnd_state *state) EXPORT_SYMBOL(prandom32); /** + * prandom32_get_bytes - get the requested number of pseudo-random bytes + * @state: pointer to state structure holding seeded state. + * @buf: where to copy the pseudo-random bytes to + * @bytes: the requested number of bytes + * + * This is used for pseudo-randomness with no outside seeding. + * For more random results, use random32_get_bytes(). + */ +void prandom32_get_bytes(struct rnd_state *state, void *buf, int bytes) +{ + unsigned char *p = buf; + + for (; bytes > 0 && ((unsigned long)p) % sizeof(u32); bytes--, p++) + *p = prandom32(state); + + for (; bytes > sizeof(u32) - 1; bytes -= sizeof(u32), p += sizeof(u32)) + *(u32 *)p = prandom32(state); + + for (; bytes > 0; bytes--, p++) + *p = prandom32(state); +} +EXPORT_SYMBOL(prandom32_get_bytes); + +/** + * random32_get_bytes - get the requested number of pseudo-random bytes + * @buf: where to copy the pseudo-random bytes to + * @bytes: the requested number of bytes + */ +void random32_get_bytes(void *buf, int bytes) +{ + struct rnd_state *state = &get_cpu_var(net_rand_state); + + prandom32_get_bytes(state, buf, bytes); + put_cpu_var(state); +} +EXPORT_SYMBOL(random32_get_bytes); + +/** * random32 - pseudo random number generator * * A 32 bit pseudo-random number is generated using a fast