From: Joachim Eastwood Subject: Re: [PATCH] lib/sha1: use the git implementation of SHA-1 Date: Sun, 7 Aug 2011 20:57:36 +0200 Message-ID: References: <1312595187-3265-1-git-send-email-msb@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Mandeep Singh Baines , linux-kernel@vger.kernel.org, Ramsay Jones , Nicolas Pitre , Herbert Xu , "David S. Miller" , linux-crypto@vger.kernel.org, linux@arm.linux.org.uk To: Linus Torvalds Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On Sun, Aug 7, 2011 at 8:38 PM, Linus Torvalds wrote: > There aren't many users of that define, could you just turn it back t= o the proper 16, and then try changing it to 80 in each place that uses= it? > > That way we'd see exactly *which* use is the buggy one.. Its drivers/char/random.c. Boots fine when forcing workspace array in extract_buf to 80. diff --git a/drivers/char/random.c b/drivers/char/random.c index c35a785..0584bb0 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -816,7 +816,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, static void extract_buf(struct entropy_store *r, __u8 *out) { int i; - __u32 hash[5], workspace[SHA_WORKSPACE_WORDS]; + __u32 hash[5], workspace[80 /*SHA_WORKSPACE_WORDS*/]; __u8 extract[64]; /* Generate a hash across the pool, 16 words (512 bits) at a ti= me */ regards Joachim Eastwood > =A0 =A0 =A0 =A0Linus > > Joachim =A0Eastwood wrote: > >>On Sun, Aug 7, 2011 at 7:44 PM, Linus Torvalds >> wrote: >>> On Sun, Aug 7, 2011 at 10:36 AM, Joachim =A0Eastwood >> wrote: >>>> >>>> These printk's come from drivers/char/random.c >>>> So it doesn't seem like it hangs in any of the sha_* funtions. >>> >>> The only other change is to SHA_WORKSPACE_WORDS - I wonder if some >>> code depends on the old (much bigger) workspace for some reason? >>> >>> The git SHA1 routines are way smarter than the old SHA1, and will >>> re-use the workspace area, so they need only a fraction of the old >>> area. >>> >>> Try changing SHA_WORKSPACE_WORDS back to 80 (in >>> include/linux/cryptohash.h). The git sha1 only needs 16 words, but = =2E. >> >>yup, setting it to 80 makes my kernel boot again :-) >> >>> If that fixes it for you, then it's almost certainly some buggy use= r >>> that uses the SHA1 workspace array for its own odd case, and >>> incorrectly "knows" that it's that old wasteful 320 bytes. There's = a >>> few places in networking that uses SHA_WORKSPACE_WORDS. >> >>Guess more architectures than ARM are affected by this then. >> >>regards >>Joachim Eastwood >> >>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 Linus >>> > >