From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1524846885; cv=none; d=google.com; s=arc-20160816; b=Lz2+yUl/9uLn9nmmumDuCNyL4a1fbp3TAsq4Vlo8GBnMIEg3QEOPt/P582jSKjafgr F5vjLxdpR2kpyMCcbcKYQgxSi4oAof3o+ReetnhwykjuDPY1gJ0cl66BNQCVx1p1ysdV iGZxkzGJY8HTP8D+bFNUmxT5BIq7yDZrY9e3PwmRywfppD/Q+/WzKCgYejFkn7wBLoM9 0Ivc9IaDZGU1iCCfMNXDQSgV79E1yGgjaWwpunzBZ9xekXQNPgC7QH/G+21Tf3ijczGZ uXBQx6PyyOXmBUEaOCK7ood5vb1FGfQKmkdXs9t+ds+tRQSXOacENd4MBmLrc1UsFwYY qcyA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=oFywfgTXT+dWZgWENVhDCqJuJymwTpwuyetSq0LB3VM=; b=V8iIX8Jc5MIrWN/scVKa/kzt4E7ycEaMcDiy+UNQzvL9qHiEg4IwB9JCq7Q/QRziAf X2ZB0LXWrXSha5Mn31tieGEP1yA5Kyg4wSWKKX7GrbHiEi32A1IfANoHe1dXHKhfODjS 7jgycmb1Ey66SkMNe9YCJAYBdsmjyMKOVwxuXseMTrg8T+76rZXcDgfgj4AEicQJs2Ql NUrY6NaQKIl2dPXRec8mhg8+Hie8jmtSrBCrD1Xlwq5jRigvn23Qjgm7tRpy8L50ZSee U10KqsX55wHCr+t2yBWhEmAnjN7t78LYh8ubVlNyYxvntc73muZCuyWvedLDVYWJAEnG Lo3w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=dq9IqEbV; spf=pass (google.com: domain of dan.rue@linaro.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.rue@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=dq9IqEbV; spf=pass (google.com: domain of dan.rue@linaro.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.rue@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org X-Google-Smtp-Source: AB8JxZqL2dMEPXdzyBvtLgOvvsPDEVtjiM5FVLh8GdX4uzgooYTAC2U/eQgfyKXeEWajZh/M2vR/rw== Date: Fri, 27 Apr 2018 11:34:43 -0500 From: Dan Rue To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jann Horn , Theodore Tso , stable@kernel.org, Thierry Escande , Nicolas Dechesne Subject: Re: [PATCH 4.16 163/196] random: fix crng_ready() test Message-ID: <20180427163443.fdsixdsrwwkycuhh@xps> Mail-Followup-To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jann Horn , Theodore Tso , stable@kernel.org, Thierry Escande , Nicolas Dechesne References: <20180422135104.278511750@linuxfoundation.org> <20180422135112.655853962@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180422135112.655853962@linuxfoundation.org> User-Agent: NeoMutt/20180323 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598455333623900338?= X-GMAIL-MSGID: =?utf-8?q?1598917847643237511?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Sun, Apr 22, 2018 at 03:53:03PM +0200, Greg Kroah-Hartman wrote: > 4.16-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Theodore Ts'o > > commit 43838a23a05fbd13e47d750d3dfd77001536dd33 upstream. > > The crng_init variable has three states: > > 0: The CRNG is not initialized at all > 1: The CRNG has a small amount of entropy, hopefully good enough for > early-boot, non-cryptographical use cases > 2: The CRNG is fully initialized and we are sure it is safe for > cryptographic use cases. > > The crng_ready() function should only return true once we are in the > last state. This addresses CVE-2018-1108. > > Reported-by: Jann Horn > Fixes: e192be9d9a30 ("random: replace non-blocking pool...") > Cc: stable@kernel.org # 4.8+ > Signed-off-by: Theodore Ts'o > Reviewed-by: Jann Horn > Signed-off-by: Greg Kroah-Hartman This patch has caused a regression on 4.16 using kselftest lib/printf.sh - specifically, when it runs "/sbin/modprobe test_printf". This regression has been detected on arm64 dragonboard 410c (not seen on other arm64 or x86_64 devices). /sbin/modprobe test_printf [ 22.725551] test_printf: hashing plain 'p' has unexpected format [ 22.726031] test_printf: failed 1 out of 236 tests modprobe: ERROR: could not insert 'test_printf': Invalid argument This problem has not been seen on 4.9 or 4.14 under the same conditions. Dan > > --- > drivers/char/random.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -427,7 +427,7 @@ struct crng_state primary_crng = { > * its value (from 0->1->2). > */ > static int crng_init = 0; > -#define crng_ready() (likely(crng_init > 0)) > +#define crng_ready() (likely(crng_init > 1)) > static int crng_init_cnt = 0; > #define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE) > static void _extract_crng(struct crng_state *crng, > @@ -793,7 +793,7 @@ static int crng_fast_load(const char *cp > > if (!spin_trylock_irqsave(&primary_crng.lock, flags)) > return 0; > - if (crng_ready()) { > + if (crng_init != 0) { > spin_unlock_irqrestore(&primary_crng.lock, flags); > return 0; > } > @@ -855,7 +855,7 @@ static void _extract_crng(struct crng_st > { > unsigned long v, flags; > > - if (crng_init > 1 && > + if (crng_ready() && > time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL)) > crng_reseed(crng, crng == &primary_crng ? &input_pool : NULL); > spin_lock_irqsave(&crng->lock, flags); > @@ -1141,7 +1141,7 @@ void add_interrupt_randomness(int irq, i > fast_mix(fast_pool); > add_interrupt_bench(cycles); > > - if (!crng_ready()) { > + if (unlikely(crng_init == 0)) { > if ((fast_pool->count >= 64) && > crng_fast_load((char *) fast_pool->pool, > sizeof(fast_pool->pool))) { > @@ -2214,7 +2214,7 @@ void add_hwgenerator_randomness(const ch > { > struct entropy_store *poolp = &input_pool; > > - if (!crng_ready()) { > + if (unlikely(crng_init == 0)) { > crng_fast_load(buffer, count); > return; > } > >