From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49YZrFrVdgc6Qjjdk4TQ4NRwyA6zks5WkWtvUCf1XDjNzZdr4ufdg75KH3D9fbpR/sSO8zW ARC-Seal: i=1; a=rsa-sha256; t=1524406446; cv=none; d=google.com; s=arc-20160816; b=y6DQSPoNwrb7shr6yWj+Ie3OlvlaxtZhGGGGzp+wmGi4GQXlo4NdLxm+P39i7F9xI5 Pg3WEiyiJ0bxVh8paovgnrQBxgyeu0C0TuPJiY8DSfzwJ0TkJNKVfIvEPq5sTULy3H/E jHhaQyveegIYSs6vWshuXRVH3awRX3JRFIjMwkZqHy9EnVCgRRvBWD3HvDVAiqrDuOsb zauLKgLvav2r/nerj8xCa2Jc9g/Gpcy2fIdGynaammNy2amzxMWHw9Iz/D7VBANAuNVo 0hXYOTMGMgvW3m+flMsN4h51qkU/hOhuKWskrpxGJ/MsuQjEnYZxaJa2SnnftYwrwcYR 543g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=7kHqg/JNfvryGWxKKrd8XCM3JqM/pVyx951S/3IkKDc=; b=TQlLP+NerPjD1+ptFn7bJ7MuNn+ewBYFceuFpDpY61GSpzd/D4HIFECftlTj2Sy00V hK5/oy5EA/k3q6v0d32E5Uu2YvubaZGnTn2L+TllQDmkCerPqTzxUiLeMK1Cux+Cf4WE YRZ40zTn4eS+EE+Emui+Ij/reGp/+kPcuETsJY8pJXUBiwxEyZDIPR04HeN4YzuB5uaH PprbKK6zJqfy92oBH906hcyb03lNXz+TT3R/nmrGwZHKRV+vZJ4laqvsKSDZms3byrrX uPfCVcivAJUpgzJdc7aZhdDxGkKz46MWWuHFTZwR8B3Gb6tFDncR63A38EafIYS6isjP JpjQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jann Horn , Theodore Tso , stable@kernel.org Subject: [PATCH 4.9 75/95] random: set up the NUMA crng instances after the CRNG is fully initialized Date: Sun, 22 Apr 2018 15:53:44 +0200 Message-Id: <20180422135213.491879480@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135210.432103639@linuxfoundation.org> References: <20180422135210.432103639@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598455339806276515?= X-GMAIL-MSGID: =?utf-8?q?1598456013924350530?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 8ef35c866f8862df074a49a93b0309725812dea8 upstream. Until the primary_crng is fully initialized, don't initialize the NUMA crng nodes. Otherwise users of /dev/urandom on NUMA systems before the CRNG is fully initialized can get very bad quality randomness. Of course everyone should move to getrandom(2) where this won't be an issue, but there's a lot of legacy code out there. This related to CVE-2018-1108. Reported-by: Jann Horn Fixes: 1e7f583af67b ("random: make /dev/urandom scalable for silly...") Cc: stable@kernel.org # 4.8+ Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -818,6 +818,32 @@ static int crng_fast_load(const char *cp return 1; } +#ifdef CONFIG_NUMA +static void numa_crng_init(void) +{ + int i; + struct crng_state *crng; + struct crng_state **pool; + + pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL); + for_each_online_node(i) { + crng = kmalloc_node(sizeof(struct crng_state), + GFP_KERNEL | __GFP_NOFAIL, i); + spin_lock_init(&crng->lock); + crng_initialize(crng); + pool[i] = crng; + } + mb(); + if (cmpxchg(&crng_node_pool, NULL, pool)) { + for_each_node(i) + kfree(pool[i]); + kfree(pool); + } +} +#else +static void numa_crng_init(void) {} +#endif + static void crng_reseed(struct crng_state *crng, struct entropy_store *r) { unsigned long flags; @@ -847,6 +873,7 @@ static void crng_reseed(struct crng_stat memzero_explicit(&buf, sizeof(buf)); crng->init_time = jiffies; if (crng == &primary_crng && crng_init < 2) { + numa_crng_init(); crng_init = 2; process_random_ready_list(); wake_up_interruptible(&crng_init_wait); @@ -1659,28 +1686,9 @@ static void init_std_data(struct entropy */ static int rand_initialize(void) { -#ifdef CONFIG_NUMA - int i; - struct crng_state *crng; - struct crng_state **pool; -#endif - init_std_data(&input_pool); init_std_data(&blocking_pool); crng_initialize(&primary_crng); - -#ifdef CONFIG_NUMA - pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL); - for_each_online_node(i) { - crng = kmalloc_node(sizeof(struct crng_state), - GFP_KERNEL | __GFP_NOFAIL, i); - spin_lock_init(&crng->lock); - crng_initialize(crng); - pool[i] = crng; - } - mb(); - crng_node_pool = pool; -#endif return 0; } early_initcall(rand_initialize);