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[209.132.180.67]) by mx.google.com with ESMTP id p5si4736592otg.230.2019.12.23.00.21.38; Mon, 23 Dec 2019 00:21:47 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=zdckuGv7; spf=pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726882AbfLWIVV (ORCPT + 99 others); Mon, 23 Dec 2019 03:21:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:38968 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726834AbfLWIVQ (ORCPT ); Mon, 23 Dec 2019 03:21:16 -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 32854208C3; Mon, 23 Dec 2019 08:21:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577089275; bh=aoG1JVryYGj4w5Ih8OAJxPIDnp4zRNz+IsXatHimLSk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zdckuGv7H3Eoh8YMnS2QKzpVgN5A9WGvFRpRCBpFMIaxPf1XSB08ufvVsGML3ifH4 eZadnjBreFpYbyl/Ljg/vkmcyGlqofRBQvIbu8J/sWX53krQXPwUvrVOIvoVTnu/Ci SS99cdMm3vV5yp4DKK/Xi2c7gybgtWcuQaDSsAmM= 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 5/8] random: Make /dev/random be almost like /dev/urandom Date: Mon, 23 Dec 2019 00:20:48 -0800 Message-Id: <5e6ac8831c6cf2e56a7a4b39616d1732b2bdd06c.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-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org This patch changes the read semantics of /dev/random to be the same as /dev/urandom except that reads will block until the CRNG is ready. None of the cleanups that this enables have been done yet. As a result, this gives a warning about an unused function. Signed-off-by: Andy Lutomirski --- drivers/char/random.c | 55 +++++++++++-------------------------------- 1 file changed, 14 insertions(+), 41 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index c0a3032b30ca..cf131f5989a1 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -354,7 +354,6 @@ #define INPUT_POOL_WORDS (1 << (INPUT_POOL_SHIFT-5)) #define OUTPUT_POOL_SHIFT 10 #define OUTPUT_POOL_WORDS (1 << (OUTPUT_POOL_SHIFT-5)) -#define SEC_XFER_SIZE 512 #define EXTRACT_SIZE 10 @@ -803,7 +802,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits) if (entropy_bits >= random_read_wakeup_bits && wq_has_sleeper(&random_read_wait)) { wake_up_interruptible(&random_read_wait); - kill_fasync(&fasync, SIGIO, POLL_IN); } /* If the input pool is getting full, and the blocking * pool has room, send some entropy to the blocking @@ -1031,6 +1029,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r) crng_init = 2; process_random_ready_list(); wake_up_interruptible(&crng_init_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); pr_notice("random: crng init done\n"); if (unseeded_warning.missed) { pr_notice("random: %d get_random_xx warning(s) missed " @@ -1981,43 +1980,6 @@ void rand_initialize_disk(struct gendisk *disk) } #endif -static ssize_t -_random_read(int nonblock, char __user *buf, size_t nbytes) -{ - ssize_t n; - - if (nbytes == 0) - return 0; - - nbytes = min_t(size_t, nbytes, SEC_XFER_SIZE); - while (1) { - n = extract_entropy_user(&blocking_pool, buf, nbytes); - if (n < 0) - return n; - trace_random_read(n*8, (nbytes-n)*8, - ENTROPY_BITS(&blocking_pool), - ENTROPY_BITS(&input_pool)); - if (n > 0) - return n; - - /* Pool is (near) empty. Maybe wait and retry. */ - if (nonblock) - return -EAGAIN; - - wait_event_interruptible(random_read_wait, - blocking_pool.initialized && - (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits)); - if (signal_pending(current)) - return -ERESTARTSYS; - } -} - -static ssize_t -random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) -{ - return _random_read(file->f_flags & O_NONBLOCK, buf, nbytes); -} - static ssize_t urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) @@ -2050,15 +2012,26 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) return urandom_read_nowarn(file, buf, nbytes, ppos); } +static ssize_t +random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +{ + int ret; + + ret = wait_for_random_bytes(); + if (ret != 0) + return ret; + return urandom_read_nowarn(file, buf, nbytes, ppos); +} + static __poll_t random_poll(struct file *file, poll_table * wait) { __poll_t mask; - poll_wait(file, &random_read_wait, wait); + poll_wait(file, &crng_init_wait, wait); poll_wait(file, &random_write_wait, wait); mask = 0; - if (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits) + if (crng_ready()) mask |= EPOLLIN | EPOLLRDNORM; if (ENTROPY_BITS(&input_pool) < random_write_wakeup_bits) mask |= EPOLLOUT | EPOLLWRNORM; -- 2.23.0