From patchwork Mon Dec 12 03:48:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 9470027 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A4504607D4 for ; Mon, 12 Dec 2016 03:48:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 99D1C283F7 for ; Mon, 12 Dec 2016 03:48:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8E7C32840F; Mon, 12 Dec 2016 03:48:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, URI_HEX autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id D021C283F7 for ; Mon, 12 Dec 2016 03:48:51 +0000 (UTC) Received: (qmail 24199 invoked by uid 550); 12 Dec 2016 03:48:49 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 24170 invoked from network); 12 Dec 2016 03:48:47 -0000 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=from:to:cc :subject:date:message-id:in-reply-to:references; s=mail; bh=jFZf xGPQ6/JQ+dkrSpee1poTBfI=; b=rA4JCI0hvVDjc75qOfqqHNcs2RTptREb+U8q p8FvI+QOh2ksHqEwKW5+NfZcWsPIe9M5PUytWzMM9Y40IDB6l9WU+PgtLE8kgiJx 9BmkaTwIJ04CM8ZIGL2fr9aA3akoH5z2M3xBPC01bOd401pGgxVy4f0oImFl0mR+ 0YsRFeaVF81+0yvV+YfUORSPwoLjwrcghRVFj6GiEM2p+GR5sWG531HasuRddV3y 1S5y9nc5VwR9BFkWVxRGVdjAzK7/7K2hRQaa/vrqX0jfUQ2S96qD454fI2uLJNqm bede9qQzSlTlm2l4GjVvjBDsbiLElkwSS2WeDkqPUsqYxOD9bA== From: "Jason A. Donenfeld" To: kernel-hardening@lists.openwall.com, LKML , linux-crypto@vger.kernel.org, Linus Torvalds , George Spelvin , Scott Bauer , ak@linux.intel.com, Andy Lutomirski , Greg KH Cc: "Jason A. Donenfeld" , Jean-Philippe Aumasson , "Daniel J . Bernstein" Date: Mon, 12 Dec 2016 04:48:17 +0100 Message-Id: <20161212034817.1773-1-Jason@zx2c4.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20161211204345.GA1558@kroah.com> References: <20161211204345.GA1558@kroah.com> Subject: [kernel-hardening] [PATCH v2] siphash: add cryptographically secure hashtable function X-Virus-Scanned: ClamAV using ClamSMTP SipHash is a 64-bit keyed hash function that is actually a cryptographically secure PRF, like HMAC. Except SipHash is super fast, and is meant to be used as a hashtable keyed lookup function. SipHash isn't just some new trendy hash function. It's been around for a while, and there really isn't anything that comes remotely close to being useful in the way SipHash is. With that said, why do we need this? There are a variety of attacks known as "hashtable poisoning" in which an attacker forms some data such that the hash of that data will be the same, and then preceeds to fill up all entries of a hashbucket. This is a realistic and well-known denial-of-service vector. Linux developers already seem to be aware that this is an issue, and various places that use hash tables in, say, a network context, use a non-cryptographically secure function (usually jhash) and then try to twiddle with the key on a time basis (or in many cases just do nothing and hope that nobody notices). While this is an admirable attempt at solving the problem, it doesn't actually fix it. SipHash fixes it. (It fixes it in such a sound way that you could even build a stream cipher out of SipHash that would resist the modern cryptanalysis.) There are a modicum of places in the kernel that are vulnerable to hashtable poisoning attacks, either via userspace vectors or network vectors, and there's not a reliable mechanism inside the kernel at the moment to fix it. The first step toward fixing these issues is actually getting a secure primitive into the kernel for developers to use. Then we can, bit by bit, port things over to it as deemed appropriate. Dozens of languages are already using this internally for their hash tables. Some of the BSDs already use this in their kernels. SipHash is a widely known high-speed solution to a widely known problem, and it's time we catch-up. Signed-off-by: Jason A. Donenfeld Cc: Jean-Philippe Aumasson Cc: Daniel J. Bernstein --- include/linux/siphash.h | 20 +++++++++ lib/Makefile | 5 ++- lib/siphash.c | 72 ++++++++++++++++++++++++++++++ lib/test_siphash.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 211 insertions(+), 2 deletions(-) create mode 100644 include/linux/siphash.h create mode 100644 lib/siphash.c create mode 100644 lib/test_siphash.c diff --git a/include/linux/siphash.h b/include/linux/siphash.h new file mode 100644 index 000000000000..6623b3090645 --- /dev/null +++ b/include/linux/siphash.h @@ -0,0 +1,20 @@ +/* Copyright (C) 2016 Jason A. Donenfeld + * + * This file is provided under a dual BSD/GPLv2 license. + * + * SipHash: a fast short-input PRF + * https://131002.net/siphash/ + */ + +#ifndef _LINUX_SIPHASH_H +#define _LINUX_SIPHASH_H + +#include + +enum siphash_lengths { + SIPHASH24_KEY_LEN = 16 +}; + +u64 siphash24(const u8 *data, size_t len, const u8 key[SIPHASH24_KEY_LEN]); + +#endif /* _LINUX_SIPHASH_H */ diff --git a/lib/Makefile b/lib/Makefile index 50144a3aeebd..71d398b04a74 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -22,7 +22,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ sha1.o chacha20.o md5.o irq_regs.o argv_split.o \ flex_proportions.o ratelimit.o show_mem.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ - earlycpio.o seq_buf.o nmi_backtrace.o nodemask.o win_minmax.o + earlycpio.o seq_buf.o siphash.o \ + nmi_backtrace.o nodemask.o win_minmax.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o @@ -44,7 +45,7 @@ obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o obj-y += kstrtox.o obj-$(CONFIG_TEST_BPF) += test_bpf.o obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o -obj-$(CONFIG_TEST_HASH) += test_hash.o +obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o obj-$(CONFIG_TEST_KASAN) += test_kasan.o obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o obj-$(CONFIG_TEST_LKM) += test_module.o diff --git a/lib/siphash.c b/lib/siphash.c new file mode 100644 index 000000000000..e78dc36d19b9 --- /dev/null +++ b/lib/siphash.c @@ -0,0 +1,72 @@ +/* Copyright (C) 2015-2016 Jason A. Donenfeld + * Copyright (C) 2012-2014 Jean-Philippe Aumasson + * Copyright (C) 2012-2014 Daniel J. Bernstein + * + * This file is provided under a dual BSD/GPLv2 license. + * + * SipHash: a fast short-input PRF + * https://131002.net/siphash/ + */ + +#include +#include + +static inline u64 le64_to_cpuvp(const void *p) +{ + return le64_to_cpup(p); +} + +#define SIPROUND \ + do { \ + v0 += v1; v1 = rol64(v1, 13); v1 ^= v0; v0 = rol64(v0, 32); \ + v2 += v3; v3 = rol64(v3, 16); v3 ^= v2; \ + v0 += v3; v3 = rol64(v3, 21); v3 ^= v0; \ + v2 += v1; v1 = rol64(v1, 17); v1 ^= v2; v2 = rol64(v2, 32); \ + } while(0) + +u64 siphash24(const u8 *data, size_t len, const u8 key[SIPHASH24_KEY_LEN]) +{ + u64 v0 = 0x736f6d6570736575ULL; + u64 v1 = 0x646f72616e646f6dULL; + u64 v2 = 0x6c7967656e657261ULL; + u64 v3 = 0x7465646279746573ULL; + u64 b = ((u64)len) << 56; + u64 k0 = le64_to_cpuvp(key); + u64 k1 = le64_to_cpuvp(key + sizeof(u64)); + u64 m; + const u8 *end = data + len - (len % sizeof(u64)); + const u8 left = len & (sizeof(u64) - 1); + v3 ^= k1; + v2 ^= k0; + v1 ^= k1; + v0 ^= k0; + for (; data != end; data += sizeof(u64)) { + m = le64_to_cpuvp(data); + v3 ^= m; + SIPROUND; + SIPROUND; + v0 ^= m; + } + switch (left) { + case 7: b |= ((u64)data[6]) << 48; + case 6: b |= ((u64)data[5]) << 40; + case 5: b |= ((u64)data[4]) << 32; + case 4: b |= ((u64)data[3]) << 24; + case 3: b |= ((u64)data[2]) << 16; + case 2: b |= ((u64)data[1]) << 8; + case 1: b |= ((u64)data[0]); break; + case 0: break; + } + v3 ^= b; + SIPROUND; + SIPROUND; + v0 ^= b; + v2 ^= 0xff; + SIPROUND; + SIPROUND; + SIPROUND; + SIPROUND; + b = (v0 ^ v1) ^ (v2 ^ v3); + return (__force u64)cpu_to_le64(b); +} +EXPORT_SYMBOL(siphash24); diff --git a/lib/test_siphash.c b/lib/test_siphash.c new file mode 100644 index 000000000000..45b5435540e9 --- /dev/null +++ b/lib/test_siphash.c @@ -0,0 +1,116 @@ +/* Test cases for siphash.c + * + * Copyright (C) 2015-2016 Jason A. Donenfeld + * + * This file is provided under a dual BSD/GPLv2 license. + * + * SipHash: a fast short-input PRF + * https://131002.net/siphash/ + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +static const u8 test_vectors[64][8] = { + { 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72 }, + { 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74 }, + { 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d }, + { 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85 }, + { 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf }, + { 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18 }, + { 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb }, + { 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab }, + { 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93 }, + { 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e }, + { 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a }, + { 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4 }, + { 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75 }, + { 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14 }, + { 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7 }, + { 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1 }, + { 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f }, + { 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69 }, + { 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b }, + { 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb }, + { 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe }, + { 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0 }, + { 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93 }, + { 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8 }, + { 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8 }, + { 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc }, + { 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17 }, + { 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f }, + { 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde }, + { 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6 }, + { 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad }, + { 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32 }, + { 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71 }, + { 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7 }, + { 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12 }, + { 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15 }, + { 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31 }, + { 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02 }, + { 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca }, + { 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a }, + { 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e }, + { 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad }, + { 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18 }, + { 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4 }, + { 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9 }, + { 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9 }, + { 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb }, + { 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0 }, + { 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6 }, + { 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7 }, + { 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee }, + { 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1 }, + { 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a }, + { 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81 }, + { 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f }, + { 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24 }, + { 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7 }, + { 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea }, + { 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60 }, + { 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66 }, + { 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c }, + { 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f }, + { 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5 }, + { 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95 } +}; + +static int __init siphash_test_init(void) +{ + u8 in[64], k[16], i; + u64 out; + int ret = 0; + + for (i = 0; i < 16; ++i) + k[i] = i; + + for (i = 0; i < 64; ++i) { + in[i] = i; + out = siphash24(in, i, k); + if (memcmp(&out, test_vectors[i], 8)) { + pr_info("self-test %u: FAIL\n", i + 1); + ret = -EINVAL; + } + } + if (!ret) + pr_info("self-tests: pass\n"); + return ret; +} + +static void __exit siphash_test_exit(void) +{ +} + +module_init(siphash_test_init); +module_exit(siphash_test_exit); + +MODULE_AUTHOR("Jason A. Donenfeld "); +MODULE_LICENSE("Dual BSD/GPL");