From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C93F14175D for ; Tue, 14 Nov 2023 15:33:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NL4YL7Ac" Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61954125 for ; Tue, 14 Nov 2023 07:33:41 -0800 (PST) Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-40a46ea95f0so36555235e9.2 for ; Tue, 14 Nov 2023 07:33:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1699976020; x=1700580820; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=iTeM1dBsqSMrj7dJ0Y7ppqb+rwjsKONfTRk0U9DB+v8=; b=NL4YL7AcU+VBBJu9bMXIW8WSq1wqh3XX+uqaD5ppTr8d28EIQBXdVqlshkRYP2XHUu f5F6lXzmep58z6yl51jw8BWb04B1RcDlGLTQdR3smX/t4USMlEMEQRKUClb6LAhvRmKu ipMK3aCrMvXZBd33BauhBSjAvfvlYYWSSwhfCcgWOobvI1z6Uww0b7ZaQbn0lNYN+aOu ujgC/DHAzjw66O7WaLHFv5TqX0gXmoZRk96XO9Mb+xLDV+gepd2wL/ARzUIb6+ixyg+s XMnXtYpgWmJTzGT2NtBl64B+QJJmhvVTlDcrV4PTVYuRt/Pxg9ORtBOqdTKz3DK6Zyp9 2rFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699976020; x=1700580820; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=iTeM1dBsqSMrj7dJ0Y7ppqb+rwjsKONfTRk0U9DB+v8=; b=SVGikC/1nmLbPJcOOKi8Dv1LXB/UJ71iXWl1HiND83yyhqHY1tKPVigxsHKm/J51aw OgZ9UXilTUqKlusfNUPMxcSGQxYH+vJaWyjhWjLtcSSKd9kIhnWEMkNAeMPByPpZUJR9 +PM+Wfdc3j7MiPI3JUtVszpp0zbgxxxdCdzPxYdWV28/nO0h54GDrPiHjIN3lJCQNmdF /FgdpuzG+Tpcc7hV93viHGxlEm10jmQjkFTX62YdhWnr4ILBF/8fFo5BWFOZsgpgx/tA qc2TmqdQj02E+fD9zo0eEx73JZvE953CPsX3+FWay2gcpzvydCcJG4P8LXbGyiWiLQgp 5TuA== X-Gm-Message-State: AOJu0YwC/oW0qmu0H/rz5xyrh18/OmXpeBq+nu1ivoihu5zJezrTdQ0T CYxUtuQgMy1igqD14WlK7+M= X-Google-Smtp-Source: AGHT+IEB4v8Sk3yNzGeSiHRAaNSSw6T9iJ+ae45cLxOsudwuVpg1D+qf6QOLdsv7sZNoGcfx2BbJLA== X-Received: by 2002:a5d:584d:0:b0:32d:ba1e:5cee with SMTP id i13-20020a5d584d000000b0032dba1e5ceemr9362104wrf.45.1699976019803; Tue, 14 Nov 2023 07:33:39 -0800 (PST) Received: from amir-ThinkPad-T480.lan ([5.29.249.86]) by smtp.gmail.com with ESMTPSA id o9-20020a5d58c9000000b0032d9caeab0fsm8146527wrf.77.2023.11.14.07.33.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Nov 2023 07:33:39 -0800 (PST) From: Amir Goldstein To: Christian Brauner Cc: Al Viro , Jan Kara , Jens Axboe , Miklos Szeredi , David Howells , linux-fsdevel@vger.kernel.org Subject: [PATCH 10/15] fs: move permission hook out of do_iter_write() Date: Tue, 14 Nov 2023 17:33:16 +0200 Message-Id: <20231114153321.1716028-11-amir73il@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231114153321.1716028-1-amir73il@gmail.com> References: <20231114153321.1716028-1-amir73il@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In many of the vfs helpers, the rw_verity_area() checks are called before taking sb_start_write(), making them "start-write-safe". do_iter_write() is an exception to this rule. do_iter_write() has two callers - vfs_iter_write() and vfs_writev(). Move rw_verify_area() and other checks from do_iter_write() out to its callers to make them "start-write-safe". Move also the fsnotify_modify() hook to align with similar pattern used in vfs_write() and other vfs helpers. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara Signed-off-by: Amir Goldstein --- fs/read_write.c | 76 ++++++++++++++++++++++++++++++------------------- 1 file changed, 46 insertions(+), 30 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 8cdc6e6a9639..d4891346d42e 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -848,28 +848,10 @@ EXPORT_SYMBOL(vfs_iter_read); static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, loff_t *pos, rwf_t flags) { - size_t tot_len; - ssize_t ret = 0; - - if (!(file->f_mode & FMODE_WRITE)) - return -EBADF; - if (!(file->f_mode & FMODE_CAN_WRITE)) - return -EINVAL; - - tot_len = iov_iter_count(iter); - if (!tot_len) - return 0; - ret = rw_verify_area(WRITE, file, pos, tot_len); - if (ret < 0) - return ret; - if (file->f_op->write_iter) - ret = do_iter_readv_writev(file, iter, pos, WRITE, flags); + return do_iter_readv_writev(file, iter, pos, WRITE, flags); else - ret = do_loop_readv_writev(file, iter, pos, WRITE, flags); - if (ret > 0) - fsnotify_modify(file); - return ret; + return do_loop_readv_writev(file, iter, pos, WRITE, flags); } ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, @@ -903,13 +885,28 @@ EXPORT_SYMBOL(vfs_iocb_iter_write); ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, rwf_t flags) { - int ret; + size_t tot_len; + ssize_t ret; + if (!(file->f_mode & FMODE_WRITE)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_WRITE)) + return -EINVAL; if (!file->f_op->write_iter) return -EINVAL; + tot_len = iov_iter_count(iter); + if (!tot_len) + return 0; + + ret = rw_verify_area(WRITE, file, ppos, tot_len); + if (ret < 0) + return ret; + file_start_write(file); ret = do_iter_write(file, iter, ppos, flags); + if (ret > 0) + fsnotify_modify(file); file_end_write(file); return ret; @@ -934,20 +931,39 @@ static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, } static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, - unsigned long vlen, loff_t *pos, rwf_t flags) + unsigned long vlen, loff_t *pos, rwf_t flags) { struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; - ssize_t ret; + size_t tot_len; + ssize_t ret = 0; - ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); - if (ret >= 0) { - file_start_write(file); - ret = do_iter_write(file, &iter, pos, flags); - file_end_write(file); - kfree(iov); - } + if (!(file->f_mode & FMODE_WRITE)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_WRITE)) + return -EINVAL; + + ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, + &iter); + if (ret < 0) + return ret; + + tot_len = iov_iter_count(&iter); + if (!tot_len) + goto out; + + ret = rw_verify_area(WRITE, file, pos, tot_len); + if (ret < 0) + goto out; + + file_start_write(file); + ret = do_iter_write(file, &iter, pos, flags); + if (ret > 0) + fsnotify_modify(file); + file_end_write(file); +out: + kfree(iov); return ret; } -- 2.34.1