From: "George Spelvin" <linux@sciencehorizons.net> To: linux@sciencehorizons.net, tytso@mit.edu Cc: ak@linux.intel.com, davem@davemloft.net, David.Laight@aculab.com, djb@cr.yp.to, ebiggers3@gmail.com, hannes@stressinduktion.org, Jason@zx2c4.com, jeanphilippe.aumasson@gmail.com, kernel-hardening@lists.openwall.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, luto@amacapital.net, netdev@vger.kernel.org, tom@herbertland.com, torvalds@linux-foundation.org, vegard.nossum@gmail.com Subject: Re: [PATCH v5 1/4] siphash: add cryptographically secure PRF Date: 16 Dec 2016 17:13:52 -0500 [thread overview] Message-ID: <20161216221352.26899.qmail@ns.sciencehorizons.net> (raw) In-Reply-To: <20161216204358.nlwifgcqnu6pitxs@thunk.org> > What should we do with get_random_int() and get_random_long()? In > some cases it's being used in performance sensitive areas, and where > anti-DoS protection might be enough. In others, maybe not so much. This is tricky. The entire get_random_int() structure is an abuse of the hash function and will need to be thoroughly rethought to convert it to SipHash. Remember, SipHash's security goals are very different from MD5, so there's no obvious way to do the conversion. (It's *documented* as "not cryptographically secure", but we know where that goes.) > If we rekeyed the secret used by get_random_int() and > get_random_long() frequently (say, every minute or every 5 minutes), > would that be sufficient for current and future users of these > interfaces? Remembering that on "real" machines it's full SipHash, then I'd say that 64-bit security + rekeying seems reasonable. The question is, the idea has recently been floated to make hsiphash = SipHash-1-3 on 64-bit machines. Is *that* okay? The annoying thing about the currently proposed patch is that the *only* chaining is the returned value. What I'd *like* to do is the same pattern as we do with md5, and remember v[0..3] between invocations. But there's no partial SipHash primitive; we only get one word back. Even *chaining += ret = siphash_3u64(...) would be an improvement. Although we could do something like c0 = chaining[0]; chaining[0] = c1 = chaining[1]; ret = hsiphash(c0, c1, ...) chaining[1] = c0 + ret;
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From: "George Spelvin" <linux@sciencehorizons.net> To: linux@sciencehorizons.net, tytso@mit.edu Cc: ak@linux.intel.com, davem@davemloft.net, David.Laight@aculab.com, djb@cr.yp.to, ebiggers3@gmail.com, hannes@stressinduktion.org, Jason@zx2c4.com, jeanphilippe.aumasson@gmail.com, kernel-hardening@lists.openwall.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, luto@amacapital.net, netdev@vger.kernel.org, tom@herbertland.com, torvalds@linux-foundation.org, vegard.nossum@gmail.com Subject: [kernel-hardening] Re: [PATCH v5 1/4] siphash: add cryptographically secure PRF Date: 16 Dec 2016 17:13:52 -0500 [thread overview] Message-ID: <20161216221352.26899.qmail@ns.sciencehorizons.net> (raw) In-Reply-To: <20161216204358.nlwifgcqnu6pitxs@thunk.org> > What should we do with get_random_int() and get_random_long()? In > some cases it's being used in performance sensitive areas, and where > anti-DoS protection might be enough. In others, maybe not so much. This is tricky. The entire get_random_int() structure is an abuse of the hash function and will need to be thoroughly rethought to convert it to SipHash. Remember, SipHash's security goals are very different from MD5, so there's no obvious way to do the conversion. (It's *documented* as "not cryptographically secure", but we know where that goes.) > If we rekeyed the secret used by get_random_int() and > get_random_long() frequently (say, every minute or every 5 minutes), > would that be sufficient for current and future users of these > interfaces? Remembering that on "real" machines it's full SipHash, then I'd say that 64-bit security + rekeying seems reasonable. The question is, the idea has recently been floated to make hsiphash = SipHash-1-3 on 64-bit machines. Is *that* okay? The annoying thing about the currently proposed patch is that the *only* chaining is the returned value. What I'd *like* to do is the same pattern as we do with md5, and remember v[0..3] between invocations. But there's no partial SipHash primitive; we only get one word back. Even *chaining += ret = siphash_3u64(...) would be an improvement. Although we could do something like c0 = chaining[0]; chaining[0] = c1 = chaining[1]; ret = hsiphash(c0, c1, ...) chaining[1] = c0 + ret;
next prev parent reply other threads:[~2016-12-16 22:13 UTC|newest] Thread overview: 182+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-12-15 20:29 [PATCH v5 0/4] The SipHash Patchset Jason A. Donenfeld 2016-12-15 20:29 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-15 20:30 ` [PATCH v5 1/4] siphash: add cryptographically secure PRF Jason A. Donenfeld 2016-12-15 20:30 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-15 22:42 ` George Spelvin 2016-12-15 22:42 ` [kernel-hardening] " George Spelvin 2016-12-15 23:00 ` Jean-Philippe Aumasson 2016-12-15 23:00 ` [kernel-hardening] " Jean-Philippe Aumasson 2016-12-15 23:28 ` George Spelvin 2016-12-15 23:28 ` [kernel-hardening] " George Spelvin 2016-12-16 17:06 ` David Laight 2016-12-16 17:06 ` [kernel-hardening] " David Laight 2016-12-16 17:06 ` David Laight 2016-12-16 17:09 ` Jason A. Donenfeld 2016-12-16 17:09 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 17:09 ` Jason A. Donenfeld 2016-12-16 3:46 ` George Spelvin 2016-12-16 3:46 ` [kernel-hardening] " George Spelvin 2016-12-16 8:08 ` Jean-Philippe Aumasson 2016-12-16 8:08 ` [kernel-hardening] " Jean-Philippe Aumasson 2016-12-16 12:39 ` Jason A. Donenfeld 2016-12-16 12:39 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 13:22 ` Jean-Philippe Aumasson 2016-12-16 13:22 ` [kernel-hardening] " Jean-Philippe Aumasson 2016-12-16 15:51 ` Jason A. Donenfeld 2016-12-16 15:51 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 17:36 ` George Spelvin 2016-12-16 17:36 ` [kernel-hardening] " George Spelvin 2016-12-16 18:00 ` Jason A. Donenfeld 2016-12-16 18:00 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 20:17 ` George Spelvin 2016-12-16 20:17 ` [kernel-hardening] " George Spelvin 2016-12-16 20:43 ` Theodore Ts'o 2016-12-16 20:43 ` [kernel-hardening] " Theodore Ts'o 2016-12-16 22:13 ` George Spelvin [this message] 2016-12-16 22:13 ` George Spelvin 2016-12-16 22:15 ` Andy Lutomirski 2016-12-16 22:15 ` [kernel-hardening] " Andy Lutomirski 2016-12-16 22:15 ` Andy Lutomirski 2016-12-16 22:18 ` Jason A. Donenfeld 2016-12-16 22:18 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 23:44 ` George Spelvin 2016-12-16 23:44 ` [kernel-hardening] " George Spelvin 2016-12-17 1:39 ` Jason A. Donenfeld 2016-12-17 1:39 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-17 2:15 ` George Spelvin 2016-12-17 2:15 ` [kernel-hardening] " George Spelvin 2016-12-17 15:41 ` Theodore Ts'o 2016-12-17 15:41 ` [kernel-hardening] " Theodore Ts'o 2016-12-17 16:14 ` Jeffrey Walton 2016-12-17 16:14 ` [kernel-hardening] " Jeffrey Walton 2016-12-19 17:21 ` Jason A. Donenfeld 2016-12-17 12:42 ` George Spelvin 2016-12-17 12:42 ` [kernel-hardening] " George Spelvin 2016-12-16 20:39 ` Jason A. Donenfeld 2016-12-16 20:39 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 19:47 ` Tom Herbert 2016-12-16 19:47 ` [kernel-hardening] " Tom Herbert 2016-12-16 20:41 ` George Spelvin 2016-12-16 20:41 ` [kernel-hardening] " George Spelvin 2016-12-16 20:57 ` Tom Herbert 2016-12-16 20:57 ` [kernel-hardening] " Tom Herbert 2016-12-16 20:44 ` Daniel Micay 2016-12-16 20:44 ` [kernel-hardening] " Daniel Micay 2016-12-16 21:09 ` Jason A. Donenfeld 2016-12-17 15:21 ` George Spelvin 2016-12-17 15:21 ` [kernel-hardening] " George Spelvin 2016-12-19 14:14 ` David Laight 2016-12-19 14:14 ` [kernel-hardening] " David Laight 2016-12-19 14:14 ` David Laight 2016-12-19 18:10 ` George Spelvin 2016-12-19 18:10 ` [kernel-hardening] " George Spelvin 2016-12-19 20:18 ` Jean-Philippe Aumasson 2016-12-19 20:18 ` [kernel-hardening] " Jean-Philippe Aumasson 2016-12-16 2:14 ` kbuild test robot 2016-12-16 2:14 ` [kernel-hardening] " kbuild test robot 2016-12-17 14:55 ` Jeffrey Walton 2016-12-17 14:55 ` [kernel-hardening] " Jeffrey Walton 2016-12-19 17:08 ` Jason A. Donenfeld 2016-12-19 17:08 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-19 17:19 ` Jean-Philippe Aumasson 2016-12-19 17:19 ` [kernel-hardening] " Jean-Philippe Aumasson 2016-12-15 20:30 ` [PATCH v5 2/4] siphash: add Nu{32,64} helpers Jason A. Donenfeld 2016-12-15 20:30 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 10:39 ` David Laight 2016-12-16 10:39 ` [kernel-hardening] " David Laight 2016-12-16 10:39 ` David Laight 2016-12-16 15:44 ` George Spelvin 2016-12-16 15:44 ` [kernel-hardening] " George Spelvin 2016-12-15 20:30 ` [PATCH v5 3/4] secure_seq: use SipHash in place of MD5 Jason A. Donenfeld 2016-12-15 20:30 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 9:59 ` David Laight 2016-12-16 9:59 ` [kernel-hardening] " David Laight 2016-12-16 9:59 ` David Laight 2016-12-16 15:57 ` Jason A. Donenfeld 2016-12-16 15:57 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 15:57 ` Jason A. Donenfeld 2016-12-15 20:30 ` [PATCH v5 4/4] random: " Jason A. Donenfeld 2016-12-15 20:30 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 3:03 ` [PATCH v6 0/5] The SipHash Patchset Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 3:03 ` [PATCH v6 1/5] siphash: add cryptographically secure PRF Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 3:03 ` [PATCH v6 2/5] secure_seq: use SipHash in place of MD5 Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 3:03 ` [PATCH v6 3/5] random: " Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 21:31 ` Andy Lutomirski 2016-12-16 21:31 ` [kernel-hardening] " Andy Lutomirski 2016-12-16 21:31 ` Andy Lutomirski 2016-12-16 3:03 ` [PATCH v6 4/5] md5: remove from lib and only live in crypto Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-16 3:03 ` [PATCH v6 5/5] syncookies: use SipHash in place of SHA1 Jason A. Donenfeld 2016-12-16 3:03 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 0/6] The SipHash Patchset Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 1/6] siphash: add cryptographically secure PRF Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 1:40 ` Stephen Hemminger 2016-12-22 1:40 ` [kernel-hardening] " Stephen Hemminger 2016-12-21 23:02 ` [PATCH v7 2/6] secure_seq: use SipHash in place of MD5 Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 3/6] random: " Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:13 ` Jason A. Donenfeld 2016-12-21 23:13 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:42 ` Andy Lutomirski 2016-12-21 23:42 ` [kernel-hardening] " Andy Lutomirski 2016-12-21 23:42 ` Andy Lutomirski 2016-12-22 2:07 ` Hannes Frederic Sowa 2016-12-22 2:07 ` [kernel-hardening] " Hannes Frederic Sowa 2016-12-22 2:07 ` Hannes Frederic Sowa 2016-12-22 2:09 ` Andy Lutomirski 2016-12-22 2:09 ` [kernel-hardening] " Andy Lutomirski 2016-12-22 2:09 ` Andy Lutomirski 2016-12-22 2:49 ` Jason A. Donenfeld 2016-12-22 2:49 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 2:49 ` Jason A. Donenfeld 2016-12-22 3:12 ` Jason A. Donenfeld 2016-12-22 3:12 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 3:12 ` Jason A. Donenfeld 2016-12-22 5:41 ` Theodore Ts'o 2016-12-22 5:41 ` [kernel-hardening] " Theodore Ts'o 2016-12-22 6:03 ` Jason A. Donenfeld 2016-12-22 15:58 ` Theodore Ts'o 2016-12-22 15:58 ` [kernel-hardening] " Theodore Ts'o 2016-12-22 16:16 ` Jason A. Donenfeld 2016-12-22 16:16 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 16:30 ` Theodore Ts'o 2016-12-22 16:36 ` Jason A. Donenfeld 2016-12-22 12:47 ` Hannes Frederic Sowa 2016-12-22 12:47 ` [kernel-hardening] " Hannes Frederic Sowa 2016-12-22 13:10 ` Jason A. Donenfeld 2016-12-22 15:05 ` Hannes Frederic Sowa 2016-12-22 15:12 ` Jason A. Donenfeld 2016-12-22 15:29 ` Jason A. Donenfeld 2016-12-22 15:33 ` Hannes Frederic Sowa 2016-12-22 15:33 ` [kernel-hardening] " Hannes Frederic Sowa 2016-12-22 15:41 ` Jason A. Donenfeld 2016-12-22 15:51 ` Hannes Frederic Sowa 2016-12-22 15:51 ` [kernel-hardening] " Hannes Frederic Sowa 2016-12-22 15:53 ` Jason A. Donenfeld 2016-12-22 15:54 ` Theodore Ts'o 2016-12-22 15:54 ` [kernel-hardening] " Theodore Ts'o 2016-12-22 18:08 ` Hannes Frederic Sowa 2016-12-22 18:13 ` Jason A. Donenfeld 2016-12-22 18:13 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 19:50 ` Theodore Ts'o 2016-12-22 2:31 ` Jason A. Donenfeld 2016-12-22 2:31 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 2:31 ` Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 4/6] md5: remove from lib and only live in crypto Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 5/6] syncookies: use SipHash in place of SHA1 Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-21 23:02 ` [PATCH v7 6/6] siphash: implement HalfSipHash1-3 for hash tables Jason A. Donenfeld 2016-12-21 23:02 ` [kernel-hardening] " Jason A. Donenfeld 2016-12-22 0:46 ` Andi Kleen 2016-12-22 0:46 ` [kernel-hardening] " Andi Kleen 2016-12-16 20:43 [PATCH v5 1/4] siphash: add cryptographically secure PRF Jason A. Donenfeld 2016-12-16 20:49 Jason A. Donenfeld 2016-12-16 21:25 ` George Spelvin
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