From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D98292C95 for ; Thu, 3 Oct 2024 00:21:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=104.130.231.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727914904; cv=none; b=ERqLBhoGLTNZKIQexng0XyZTv5ZZbaIE5OViJsNEFxPhSBfud8BhPOkwT824iaL3P3M5WqhxdrJAYfuadMv0pXI3Jou/A8XhTC0UY8Uf27G6WgxvPPINjzeHuMeRFeoZ45EHqjfCK4MONl4FAGkTtWso442zqvxaSUGSFh2D1ws= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727914904; c=relaxed/simple; bh=OYPR8hJUPMQ9rGr/3NODvc3h7dT9GHu5u20NzX7NmuM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PjnPWi3N5p0MMogVA4qhG948HgbxhYCtV7pCvq83DzJfVxr2HR2EW1qA/QyQUA8+BVCiX2PmqbWbGtcFh2SeIMOkt1LECJlFtB2Hw9XnH8QbtstZFu6Y/CeQgdxm6USINhvCpZ1PDLaplbD5fiWvvXyQSM5Prfr8Pbr51IjIE1A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net; spf=pass smtp.mailfrom=peff.net; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b=CFkRL54X; arc=none smtp.client-ip=104.130.231.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=peff.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b="CFkRL54X" Received: (qmail 10894 invoked by uid 109); 3 Oct 2024 00:21:42 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=peff.net; h=date:from:to:cc:subject:message-id:references:mime-version:content-type:in-reply-to; s=20240930; bh=OYPR8hJUPMQ9rGr/3NODvc3h7dT9GHu5u20NzX7NmuM=; b=CFkRL54XRIeOL72zk5lf++7zIZZCnMPtwOi58JXxknzbDR7MJwlhTC/wHCsS2mG40vlpaTE5EldwbpX3tHbsmKMx21xkymdJcUkSziiJXMyBa7xAo2lh0TFONDZGRqreje9hqJh4cQfMJGA9l+d1nI2Im7BCSIGslv/crwAy7D3wftK9djh5kGsTaQOq/xRnMJ1mh1ygiWjnJaMBX+MBVA6z1EbaKF24p24illZNPX7WqMXcIlESRYCbxiIfPcyuBsqBrwHp5CXDDMiNOcdQvU4xRFhQ/2gA7Xpv1z910vws763ejZxFdZxT965NI5vTQDUL+stO8M5RyjwlTc8P4A== Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Thu, 03 Oct 2024 00:21:42 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 11276 invoked by uid 111); 3 Oct 2024 00:21:41 -0000 Received: from coredump.intra.peff.net (HELO coredump.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Wed, 02 Oct 2024 20:21:41 -0400 Authentication-Results: peff.net; auth=none Date: Wed, 2 Oct 2024 20:21:40 -0400 From: Jeff King To: "brian m. carlson" Cc: git@vger.kernel.org, Taylor Blau , Junio C Hamano Subject: Re: [PATCH (v2.47 regression)] hash.h: set NEEDS_CLONE_HELPER_UNSAFE in fallback mode Message-ID: <20241003002140.GB3486271@coredump.intra.peff.net> References: <20241002232618.GA3442753@coredump.intra.peff.net> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, Oct 03, 2024 at 12:13:47AM +0000, brian m. carlson wrote: > On 2024-10-02 at 23:26:18, Jeff King wrote: > > This is a regression in v2.47.0-rc0. As mentioned above, I kind of doubt > > anybody will hit it in practice (I only did because I was trying to do > > some timing tests between the fast and dc variants). And it is almost > > tempting to leave it as a wake-up call for anybody who is still not > > using a collision-detecting sha1. ;) > > I think this is a fine fix for 2.47. I have a branch on my remote > (sha1-dc-only), which I'll send out after it passes CI (probably later > this week), that removes support for the everything but SHA-1-DC (except > for the unsafe code). > > I don't think there's a reasonable configuration where people can use > Git with other SHA-1 code except in extremely limited circumstances we > shouldn't have to maintain code for. The code is open source, so people > who really must have maximum performance with all of the vulnerabilities > can patch it back in themselves. Yeah, I feel the same way. I only happened to try this because it was the easiest way to speed-compare different implementations using "test-tool sha1". ;) Possibly that helper could grow an option to use the unsafe variant, though even that is probably not a high priority. -Peff