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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5752C433EF for ; Fri, 20 May 2022 09:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347827AbiETJpp (ORCPT ); Fri, 20 May 2022 05:45:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347939AbiETJp1 (ORCPT ); Fri, 20 May 2022 05:45:27 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D68EF14AF63 for ; Fri, 20 May 2022 02:45:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0ADDCB82956 for ; Fri, 20 May 2022 09:45:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CE73C34113; Fri, 20 May 2022 09:45:18 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Vv0CbJwB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1653039917; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AjqxppiLVbK2RRhIoss04u4+2YUT3AE7xNSn/In95Hk=; b=Vv0CbJwBVd8C3Svpv1DhZ+an2yySZJ1EUfFMolbtu4ZGaXEtnTpdnLuAdwvKDGZSKgq01i Tp7ZvLnneVpjDb8HC3JoLB9zQivdiFa4B83FI/ecMfxI9V3lpqRv9HRaAGmi7Eb6lF42hr ssW5afDKU4lo2tSTEeLX64XF/RyAQks= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id f8dcb615 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Fri, 20 May 2022 09:45:17 +0000 (UTC) From: "Jason A. Donenfeld" To: Jens Axboe , Theodore Ts'o , Christoph Hellwig , LKML , Al Viro Cc: "Jason A . Donenfeld" Subject: [PATCH v4 2/3] random: convert to using fops->write_iter() Date: Fri, 20 May 2022 11:44:58 +0200 Message-Id: <20220520094459.116240-3-Jason@zx2c4.com> In-Reply-To: <20220520094459.116240-1-Jason@zx2c4.com> References: <20220520094459.116240-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jens Axboe Now that the read side has been converted to fix a regression with splice, convert the write side as well to have some symmetry in the interface used (and help deprecate ->write()). Signed-off-by: Jens Axboe [Jason: cleaned up random_ioctl a bit, require full writes in RNDADDENTROPY since it's crediting entropy, simplify control flow of write_pool(), and incorporate suggestions from Al.] Cc: Al Viro Signed-off-by: Jason A. Donenfeld --- drivers/char/random.c | 67 ++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index f8cd747acec2..831cafcd1034 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1274,39 +1274,31 @@ static __poll_t random_poll(struct file *file, poll_table *wait) return crng_ready() ? EPOLLIN | EPOLLRDNORM : EPOLLOUT | EPOLLWRNORM; } -static int write_pool(const char __user *ubuf, size_t len) +static ssize_t write_pool(struct iov_iter *from) { - size_t block_len; - int ret = 0; u8 block[BLAKE2S_BLOCK_SIZE]; + ssize_t ret = 0; + size_t copied; - while (len) { - block_len = min(len, sizeof(block)); - if (copy_from_user(block, ubuf, block_len)) { - ret = -EFAULT; - goto out; - } - len -= block_len; - ubuf += block_len; - mix_pool_bytes(block, block_len); + if (!iov_iter_count(from)) + return 0; + + for (;;) { + copied = copy_from_iter(block, sizeof(block), from); + ret += copied; + mix_pool_bytes(block, copied); + if (!iov_iter_count(from) || copied != sizeof(block)) + break; cond_resched(); } -out: memzero_explicit(block, sizeof(block)); - return ret; + return ret ? ret : -EFAULT; } -static ssize_t random_write(struct file *file, const char __user *ubuf, - size_t len, loff_t *ppos) +static ssize_t random_write_iter(struct kiocb *kiocb, struct iov_iter *from) { - int ret; - - ret = write_pool(ubuf, len); - if (ret) - return ret; - - return (ssize_t)len; + return write_pool(from); } static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *to) @@ -1345,9 +1337,8 @@ static ssize_t random_read_iter(struct kiocb *kiocb, struct iov_iter *to) static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) { - int size, ent_count; int __user *p = (int __user *)arg; - int retval; + int ent_count; switch (cmd) { case RNDGETENTCNT: @@ -1364,20 +1355,32 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) return -EINVAL; credit_init_bits(ent_count); return 0; - case RNDADDENTROPY: + case RNDADDENTROPY: { + struct iov_iter from; + struct iovec iov; + ssize_t ret; + int len; + if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ent_count, p++)) return -EFAULT; if (ent_count < 0) return -EINVAL; - if (get_user(size, p++)) + if (get_user(len, p++)) + return -EFAULT; + + ret = import_single_range(WRITE, p, len, &iov, &from); + if (unlikely(ret)) + return ret; + ret = write_pool(&from); + if (unlikely(ret < 0)) + return ret; + if (unlikely(ret != len)) return -EFAULT; - retval = write_pool((const char __user *)p, size); - if (retval < 0) - return retval; credit_init_bits(ent_count); return 0; + } case RNDZAPENTCNT: case RNDCLEARPOOL: /* No longer has any effect. */ @@ -1403,7 +1406,7 @@ static int random_fasync(int fd, struct file *filp, int on) const struct file_operations random_fops = { .read_iter = random_read_iter, - .write = random_write, + .write_iter = random_write_iter, .poll = random_poll, .unlocked_ioctl = random_ioctl, .compat_ioctl = compat_ptr_ioctl, @@ -1413,7 +1416,7 @@ const struct file_operations random_fops = { const struct file_operations urandom_fops = { .read_iter = urandom_read_iter, - .write = random_write, + .write_iter = random_write_iter, .unlocked_ioctl = random_ioctl, .compat_ioctl = compat_ptr_ioctl, .fasync = random_fasync, -- 2.35.1