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 14838C433EF for ; Mon, 6 Jun 2022 02:45:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349730AbiFFCpb (ORCPT ); Sun, 5 Jun 2022 22:45:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238762AbiFFCpZ (ORCPT ); Sun, 5 Jun 2022 22:45:25 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1E49C4C425 for ; Sun, 5 Jun 2022 19:45:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654483524; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aNDoMccQ7mEW7iwCLiSB8XQaZrFaD9G9J8zeTIHHoD4=; b=WsJznzY9StKhP6vq62G6EZRpA7jIBkGqYRyywvbq2eq1PmSJKzRPlr1dvNtM4vZw1bYTmX chPxHGAlhbzeI7dLhV5R0vB3EII4JIWFMErY9QJK2GH2hzWAZwklZAzX+NAdXIUTnz+nBr xJ79I2f4VigSx+XlIf2qF5D/SCBnF8Q= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-88-AOWKI5UJNA2j7AViM93Ciw-1; Sun, 05 Jun 2022 22:45:21 -0400 X-MC-Unique: AOWKI5UJNA2j7AViM93Ciw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8325E801228; Mon, 6 Jun 2022 02:45:20 +0000 (UTC) Received: from localhost (ovpn-12-209.pek2.redhat.com [10.72.12.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4A8BE2166B26; Mon, 6 Jun 2022 02:45:18 +0000 (UTC) Date: Mon, 6 Jun 2022 10:45:15 +0800 From: Baoquan He To: Pasha Tatashin Cc: sashal@kernel.org, ebiederm@xmission.com, rburanyi@google.com, gthelen@google.com, viro@zeniv.linux.org.uk, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] fs/kernel_read_file: Allow to read files up-to ssize_t Message-ID: References: <20220527025535.3953665-1-pasha.tatashin@soleen.com> <20220527025535.3953665-2-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220527025535.3953665-2-pasha.tatashin@soleen.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/27/22 at 02:55am, Pasha Tatashin wrote: > Currently, the maximum file size that is supported is 2G. This may be > too small in some cases. For example, kexec_file_load() system call > loads initramfs. In some netboot cases initramfs can be rather large. > > Allow to use up-to ssize_t bytes. The callers still can limit the > maximum file size via buf_size. If we really met initramfs bigger than 2G, it's reasonable to increase the limit. While wondering why we should take sszie_t, but not size_t. > > Signed-off-by: Pasha Tatashin > --- > fs/kernel_read_file.c | 38 ++++++++++++++++---------------- > include/linux/kernel_read_file.h | 32 +++++++++++++-------------- > include/linux/limits.h | 1 + > 3 files changed, 36 insertions(+), 35 deletions(-) > > diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c > index 1b07550485b9..5d826274570c 100644 > --- a/fs/kernel_read_file.c > +++ b/fs/kernel_read_file.c > @@ -29,15 +29,15 @@ > * change between calls to kernel_read_file(). > * > * Returns number of bytes read (no single read will be bigger > - * than INT_MAX), or negative on error. > + * than SSIZE_MAX), or negative on error. > * > */ > -int kernel_read_file(struct file *file, loff_t offset, void **buf, > - size_t buf_size, size_t *file_size, > - enum kernel_read_file_id id) > +ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf, > + size_t buf_size, size_t *file_size, > + enum kernel_read_file_id id) > { > loff_t i_size, pos; > - size_t copied; > + ssize_t copied; > void *allocated = NULL; > bool whole_file; > int ret; > @@ -58,7 +58,7 @@ int kernel_read_file(struct file *file, loff_t offset, void **buf, > goto out; > } > /* The file is too big for sane activities. */ > - if (i_size > INT_MAX) { > + if (i_size > SSIZE_MAX) { > ret = -EFBIG; > goto out; > } > @@ -124,12 +124,12 @@ int kernel_read_file(struct file *file, loff_t offset, void **buf, > } > EXPORT_SYMBOL_GPL(kernel_read_file); > > -int kernel_read_file_from_path(const char *path, loff_t offset, void **buf, > - size_t buf_size, size_t *file_size, > - enum kernel_read_file_id id) > +ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf, > + size_t buf_size, size_t *file_size, > + enum kernel_read_file_id id) > { > struct file *file; > - int ret; > + ssize_t ret; > > if (!path || !*path) > return -EINVAL; > @@ -144,14 +144,14 @@ int kernel_read_file_from_path(const char *path, loff_t offset, void **buf, > } > EXPORT_SYMBOL_GPL(kernel_read_file_from_path); > > -int kernel_read_file_from_path_initns(const char *path, loff_t offset, > - void **buf, size_t buf_size, > - size_t *file_size, > - enum kernel_read_file_id id) > +ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset, > + void **buf, size_t buf_size, > + size_t *file_size, > + enum kernel_read_file_id id) > { > struct file *file; > struct path root; > - int ret; > + ssize_t ret; > > if (!path || !*path) > return -EINVAL; > @@ -171,12 +171,12 @@ int kernel_read_file_from_path_initns(const char *path, loff_t offset, > } > EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); > > -int kernel_read_file_from_fd(int fd, loff_t offset, void **buf, > - size_t buf_size, size_t *file_size, > - enum kernel_read_file_id id) > +ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf, > + size_t buf_size, size_t *file_size, > + enum kernel_read_file_id id) > { > struct fd f = fdget(fd); > - int ret = -EBADF; > + ssize_t ret = -EBADF; > > if (!f.file || !(f.file->f_mode & FMODE_READ)) > goto out; > diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h > index 575ffa1031d3..90451e2e12bd 100644 > --- a/include/linux/kernel_read_file.h > +++ b/include/linux/kernel_read_file.h > @@ -35,21 +35,21 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) > return kernel_read_file_str[id]; > } > > -int kernel_read_file(struct file *file, loff_t offset, > - void **buf, size_t buf_size, > - size_t *file_size, > - enum kernel_read_file_id id); > -int kernel_read_file_from_path(const char *path, loff_t offset, > - void **buf, size_t buf_size, > - size_t *file_size, > - enum kernel_read_file_id id); > -int kernel_read_file_from_path_initns(const char *path, loff_t offset, > - void **buf, size_t buf_size, > - size_t *file_size, > - enum kernel_read_file_id id); > -int kernel_read_file_from_fd(int fd, loff_t offset, > - void **buf, size_t buf_size, > - size_t *file_size, > - enum kernel_read_file_id id); > +ssize_t kernel_read_file(struct file *file, loff_t offset, > + void **buf, size_t buf_size, > + size_t *file_size, > + enum kernel_read_file_id id); > +ssize_t kernel_read_file_from_path(const char *path, loff_t offset, > + void **buf, size_t buf_size, > + size_t *file_size, > + enum kernel_read_file_id id); > +ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset, > + void **buf, size_t buf_size, > + size_t *file_size, > + enum kernel_read_file_id id); > +ssize_t kernel_read_file_from_fd(int fd, loff_t offset, > + void **buf, size_t buf_size, > + size_t *file_size, > + enum kernel_read_file_id id); > > #endif /* _LINUX_KERNEL_READ_FILE_H */ > diff --git a/include/linux/limits.h b/include/linux/limits.h > index b568b9c30bbf..f6bcc9369010 100644 > --- a/include/linux/limits.h > +++ b/include/linux/limits.h > @@ -7,6 +7,7 @@ > #include > > #define SIZE_MAX (~(size_t)0) > +#define SSIZE_MAX ((ssize_t)(SIZE_MAX >> 1)) > #define PHYS_ADDR_MAX (~(phys_addr_t)0) > > #define U8_MAX ((u8)~0U) > -- > 2.36.1.124.g0e6072fb45-goog >