From: Eric Biggers <ebiggers3@gmail.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
George Spelvin <linux@horizon.com>,
Scott Bauer <sbauer@eng.utah.edu>,
Andi Kleen <ak@linux.intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Greg KH <gregkh@linuxfoundation.org>,
Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>,
"Daniel J . Bernstein" <djb@cr.yp.to>
Subject: [kernel-hardening] Re: [PATCH v3] siphash: add cryptographically secure hashtable function
Date: Tue, 13 Dec 2016 00:39:48 -0800 [thread overview]
Message-ID: <20161213083948.GA8994@zzz> (raw)
In-Reply-To: <20161212221832.10653-1-Jason@zx2c4.com>
On Mon, Dec 12, 2016 at 11:18:32PM +0100, Jason A. Donenfeld wrote:
> + for (; data != end; data += sizeof(u64)) {
> + m = get_unaligned_le64(data);
> + v3 ^= m;
> + SIPROUND;
> + SIPROUND;
> + v0 ^= m;
> + }
> +#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
> + b |= le64_to_cpu(load_unaligned_zeropad(data) & bytemask_from_count(left));
> +#else
Hmm, I don't think you can really do load_unaligned_zeropad() without first
checking for 'left != 0'. The fixup section for load_unaligned_zeropad()
assumes that rounding the pointer down to a word boundary will produce an
address from which an 'unsigned long' can be loaded. But if 'left = 0' and we
happen to be on a page boundary with the next page unmapped, then this will not
be true and the second load will still fault.
Eric
WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers3@gmail.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
George Spelvin <linux@horizon.com>,
Scott Bauer <sbauer@eng.utah.edu>,
Andi Kleen <ak@linux.intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Greg KH <gregkh@linuxfoundation.org>,
Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>,
"Daniel J . Bernstein" <djb@cr.yp.to>
Subject: Re: [PATCH v3] siphash: add cryptographically secure hashtable function
Date: Tue, 13 Dec 2016 00:39:48 -0800 [thread overview]
Message-ID: <20161213083948.GA8994@zzz> (raw)
In-Reply-To: <20161212221832.10653-1-Jason@zx2c4.com>
On Mon, Dec 12, 2016 at 11:18:32PM +0100, Jason A. Donenfeld wrote:
> + for (; data != end; data += sizeof(u64)) {
> + m = get_unaligned_le64(data);
> + v3 ^= m;
> + SIPROUND;
> + SIPROUND;
> + v0 ^= m;
> + }
> +#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
> + b |= le64_to_cpu(load_unaligned_zeropad(data) & bytemask_from_count(left));
> +#else
Hmm, I don't think you can really do load_unaligned_zeropad() without first
checking for 'left != 0'. The fixup section for load_unaligned_zeropad()
assumes that rounding the pointer down to a word boundary will produce an
address from which an 'unsigned long' can be loaded. But if 'left = 0' and we
happen to be on a page boundary with the next page unmapped, then this will not
be true and the second load will still fault.
Eric
next prev parent reply other threads:[~2016-12-13 8:39 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 18:36 [kernel-hardening] [PATCH] siphash: add cryptographically secure hashtable function Jason A. Donenfeld
2016-12-09 18:36 ` Jason A. Donenfeld
2016-12-10 12:37 ` [kernel-hardening] " Greg KH
2016-12-11 15:30 ` Jason A. Donenfeld
2016-12-11 15:30 ` Jason A. Donenfeld
2016-12-11 20:43 ` [kernel-hardening] " Greg KH
2016-12-12 3:48 ` [kernel-hardening] [PATCH v2] " Jason A. Donenfeld
2016-12-12 3:48 ` Jason A. Donenfeld
2016-12-12 4:01 ` [kernel-hardening] " Linus Torvalds
2016-12-12 4:01 ` Linus Torvalds
2016-12-12 5:48 ` [kernel-hardening] " Jason A. Donenfeld
2016-12-12 5:48 ` Jason A. Donenfeld
2016-12-12 21:37 ` [kernel-hardening] " Linus Torvalds
2016-12-12 21:37 ` Linus Torvalds
2016-12-12 22:18 ` [kernel-hardening] [PATCH v3] " Jason A. Donenfeld
2016-12-12 22:18 ` Jason A. Donenfeld
2016-12-12 23:01 ` [kernel-hardening] " Andi Kleen
2016-12-12 23:01 ` Andi Kleen
2016-12-13 8:39 ` Eric Biggers [this message]
2016-12-13 8:39 ` Eric Biggers
2016-12-13 19:26 ` [kernel-hardening] " Linus Torvalds
2016-12-13 19:26 ` Linus Torvalds
2016-12-13 22:43 ` [kernel-hardening] " Jason A. Donenfeld
2016-12-13 22:43 ` Jason A. Donenfeld
2016-12-13 22:48 ` [kernel-hardening] [PATCH v4] " Jason A. Donenfeld
2016-12-13 22:48 ` Jason A. Donenfeld
2016-12-12 5:42 ` [kernel-hardening] Re: [PATCH v2] " Eric Biggers
2016-12-12 5:42 ` Eric Biggers
2016-12-12 21:17 ` [kernel-hardening] " Jason A. Donenfeld
2016-12-12 21:17 ` Jason A. Donenfeld
2016-12-10 14:17 ` [kernel-hardening] Re: [PATCH] " Vegard Nossum
2016-12-10 14:17 ` Vegard Nossum
2016-12-10 15:35 ` [kernel-hardening] " George Spelvin
2016-12-10 15:35 ` George Spelvin
2016-12-10 18:13 ` [kernel-hardening] " Jean-Philippe Aumasson
2016-12-10 18:13 ` Jean-Philippe Aumasson
-- strict thread matches above, loose matches on Subject: below --
2016-12-12 23:04 [kernel-hardening] Re: [PATCH v3] " Jason A. Donenfeld
2016-12-13 19:25 ` Linus Torvalds
2016-12-13 23:36 ` Jason A. Donenfeld
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