From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05BC1C2D0C0 for ; Mon, 23 Dec 2019 08:21:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2D3A2166E for ; Mon, 23 Dec 2019 08:21:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577089282; bh=yobLkD/qNXqlZt/C7XbBodidvrvEBfnG1iiwZXLMWu0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H8Q+RuPdo7/qYa/CT0kWYw/OXMug7kKsmsw/YMm/O0W5ls/3CDEe/A6lHMZPdV/JL fRR6JxEtZJ/9LH+F9xQaHOrQF0vAmN4Lot+F3Bt6m4flWkukOU5L5G92eBSNAI/mTv PbFGok1oz1ZnW4D3wWsDSS0zyf+9wZZ1onD2i9vs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726897AbfLWIVV (ORCPT ); Mon, 23 Dec 2019 03:21:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:39048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726764AbfLWIVU (ORCPT ); Mon, 23 Dec 2019 03:21:20 -0500 Received: from localhost (36-236-5-169.dynamic-ip.hinet.net [36.236.5.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B36552146E; Mon, 23 Dec 2019 08:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577089279; bh=yobLkD/qNXqlZt/C7XbBodidvrvEBfnG1iiwZXLMWu0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=muUw6K42felR/oRa2LkYUFrE9aU4UjSkm0OsnQSH1gBbbC26RgO+VrtCckQRdjgHo qCqMeii+IEZnlWyoEpbdzI6YMkkyOxKpt4YuZuUdjwUmwQfSeSdD02JHbdSBnhRg+i ee4wZadLyRSzBkjLyZakypy554I4aTxzqw/Wn/i4= From: Andy Lutomirski To: Ted Ts'o Cc: LKML , Linux API , Kees Cook , "Jason A. Donenfeld" , "Ahmed S. Darwish" , Lennart Poettering , "Eric W. Biederman" , "Alexander E. Patrakov" , Michael Kerrisk , Willy Tarreau , Matthew Garrett , Ext4 Developers List , linux-man , Stephan Mueller , Andy Lutomirski Subject: [PATCH v3 6/8] random: Remove the blocking pool Date: Mon, 23 Dec 2019 00:20:49 -0800 Message-Id: <511225a224bf0a291149d3c0b8b45393cd03ab96.1577088521.git.luto@kernel.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is no longer any interface to read data from the blocking pool, so remove it. This enables quite a bit of code deletion, much of which will be done in subsequent patches. Signed-off-by: Andy Lutomirski --- drivers/char/random.c | 106 ------------------------------------------ 1 file changed, 106 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index cf131f5989a1..b4f834893d9d 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -470,7 +470,6 @@ static const struct poolinfo { /* * Static global variables */ -static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); static struct fasync_struct *fasync; @@ -530,7 +529,6 @@ struct entropy_store { __u32 *pool; const char *name; struct entropy_store *pull; - struct work_struct push_work; /* read-write data: */ unsigned long last_pulled; @@ -549,9 +547,7 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf, size_t nbytes, int fips); static void crng_reseed(struct crng_state *crng, struct entropy_store *r); -static void push_to_pool(struct work_struct *work); static __u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy; -static __u32 blocking_pool_data[OUTPUT_POOL_WORDS] __latent_entropy; static struct entropy_store input_pool = { .poolinfo = &poolinfo_table[0], @@ -560,16 +556,6 @@ static struct entropy_store input_pool = { .pool = input_pool_data }; -static struct entropy_store blocking_pool = { - .poolinfo = &poolinfo_table[1], - .name = "blocking", - .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock), - .pool = blocking_pool_data, - .push_work = __WORK_INITIALIZER(blocking_pool.push_work, - push_to_pool), -}; - static __u32 const twist_table[8] = { 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; @@ -765,15 +751,11 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) entropy_count = 0; } else if (entropy_count > pool_size) entropy_count = pool_size; - if ((r == &blocking_pool) && !r->initialized && - (entropy_count >> ENTROPY_SHIFT) > 128) - has_initialized = 1; if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) goto retry; if (has_initialized) { r->initialized = 1; - wake_up_interruptible(&random_read_wait); kill_fasync(&fasync, SIGIO, POLL_IN); } @@ -782,7 +764,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) if (r == &input_pool) { int entropy_bits = entropy_count >> ENTROPY_SHIFT; - struct entropy_store *other = &blocking_pool; if (crng_init < 2) { if (entropy_bits < 128) @@ -790,27 +771,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) crng_reseed(&primary_crng, r); entropy_bits = r->entropy_count >> ENTROPY_SHIFT; } - - /* initialize the blocking pool if necessary */ - if (entropy_bits >= random_read_wakeup_bits && - !other->initialized) { - schedule_work(&other->push_work); - return; - } - - /* should we wake readers? */ - if (entropy_bits >= random_read_wakeup_bits && - wq_has_sleeper(&random_read_wait)) { - wake_up_interruptible(&random_read_wait); - } - /* If the input pool is getting full, and the blocking - * pool has room, send some entropy to the blocking - * pool. - */ - if (!work_pending(&other->push_work) && - (ENTROPY_BITS(r) > 6 * r->poolinfo->poolbytes) && - (ENTROPY_BITS(other) <= 6 * other->poolinfo->poolbytes)) - schedule_work(&other->push_work); } } @@ -1422,22 +1382,6 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes) credit_entropy_bits(r, bytes*8); } -/* - * Used as a workqueue function so that when the input pool is getting - * full, we can "spill over" some entropy to the output pools. That - * way the output pools can store some of the excess entropy instead - * of letting it go to waste. - */ -static void push_to_pool(struct work_struct *work) -{ - struct entropy_store *r = container_of(work, struct entropy_store, - push_work); - BUG_ON(!r); - _xfer_secondary_pool(r, random_read_wakeup_bits/8); - trace_push_to_pool(r->name, r->entropy_count >> ENTROPY_SHIFT, - r->pull->entropy_count >> ENTROPY_SHIFT); -} - /* * This function decides how many bytes to actually take from the * given pool, and also debits the entropy count accordingly. @@ -1616,54 +1560,6 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf, return _extract_entropy(r, buf, nbytes, fips_enabled); } -/* - * This function extracts randomness from the "entropy pool", and - * returns it in a userspace buffer. - */ -static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, - size_t nbytes) -{ - ssize_t ret = 0, i; - __u8 tmp[EXTRACT_SIZE]; - int large_request = (nbytes > 256); - - trace_extract_entropy_user(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_); - if (!r->initialized && r->pull) { - xfer_secondary_pool(r, ENTROPY_BITS(r->pull)/8); - if (!r->initialized) - return 0; - } - xfer_secondary_pool(r, nbytes); - nbytes = account(r, nbytes, 0, 0); - - while (nbytes) { - if (large_request && need_resched()) { - if (signal_pending(current)) { - if (ret == 0) - ret = -ERESTARTSYS; - break; - } - schedule(); - } - - extract_buf(r, tmp); - i = min_t(int, nbytes, EXTRACT_SIZE); - if (copy_to_user(buf, tmp, i)) { - ret = -EFAULT; - break; - } - - nbytes -= i; - buf += i; - ret += i; - } - - /* Wipe data just returned from memory */ - memzero_explicit(tmp, sizeof(tmp)); - - return ret; -} - #define warn_unseeded_randomness(previous) \ _warn_unseeded_randomness(__func__, (void *) _RET_IP_, (previous)) @@ -1953,7 +1849,6 @@ static void __init init_std_data(struct entropy_store *r) int __init rand_initialize(void) { init_std_data(&input_pool); - init_std_data(&blocking_pool); crng_initialize(&primary_crng); crng_global_init_time = jiffies; if (ratelimit_disable) { @@ -2122,7 +2017,6 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) if (!capable(CAP_SYS_ADMIN)) return -EPERM; input_pool.entropy_count = 0; - blocking_pool.entropy_count = 0; return 0; case RNDRESEEDCRNG: if (!capable(CAP_SYS_ADMIN)) -- 2.23.0