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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C8AF5C43218 for ; Sat, 27 Apr 2019 01:42:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 979BF20675 for ; Sat, 27 Apr 2019 01:42:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556329347; bh=q7jProe1msS4gIrO0qulYcDE1JbeXNYZTX9jn0Zvrz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eLW7MNjGNZdEmv0Ty/ThKYXFgtg8LxWi0791+wxLbw74vnKpPIJaPbVxMp6QQ7/2S aixep0jHFCNNBooS1dtzwajf6qRaVeYYwiQkyi9GdKhzEjvWS8ubinan3/0d2g13NM L2sgm4tGDSzY7OoSI2vrSSQEgP7pkpUwuPsIeT8E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728565AbfD0BmZ (ORCPT ); Fri, 26 Apr 2019 21:42:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:46514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728553AbfD0BmY (ORCPT ); Fri, 26 Apr 2019 21:42:24 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D7BB20679; Sat, 27 Apr 2019 01:42:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556329342; bh=q7jProe1msS4gIrO0qulYcDE1JbeXNYZTX9jn0Zvrz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p8me0tvYCaWUl52pyvZn0C/+5YMl4ipc4R8pEZY0LXYbt5r7F4NTweM2GwJkoQYot RAjEHXGEsJCR1LhFkgoeWic+34R9dexC1XYxOcCfr0+91hoV9TLr4SzsB5BVO/FvOz sPfGHIJ6T15BMT2T1iM0VXfNnN2wLdsBworomF9Q= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Matthew Wilcox , stable@kernel.org, Linus Torvalds , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 53/53] fs: prevent page refcount overflow in pipe_buf_get Date: Fri, 26 Apr 2019 21:40:50 -0400 Message-Id: <20190427014051.7522-53-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190427014051.7522-1-sashal@kernel.org> References: <20190427014051.7522-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Matthew Wilcox [ Upstream commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb ] Change pipe_buf_get() to return a bool indicating whether it succeeded in raising the refcount of the page (if the thing in the pipe is a page). This removes another mechanism for overflowing the page refcount. All callers converted to handle a failure. Reported-by: Jann Horn Signed-off-by: Matthew Wilcox Cc: stable@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/fuse/dev.c | 12 ++++++------ fs/pipe.c | 4 ++-- fs/splice.c | 12 ++++++++++-- include/linux/pipe_fs_i.h | 10 ++++++---- kernel/trace/trace.c | 6 +++++- 5 files changed, 29 insertions(+), 15 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index baaed4d05b22..249de20f752a 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1989,10 +1989,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; ret = -EINVAL; - if (rem < len) { - pipe_unlock(pipe); - goto out; - } + if (rem < len) + goto out_free; rem = len; while (rem) { @@ -2010,7 +2008,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); pipe->nrbufs--; } else { - pipe_buf_get(pipe, ibuf); + if (!pipe_buf_get(pipe, ibuf)) + goto out_free; + *obuf = *ibuf; obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->len = rem; @@ -2033,11 +2033,11 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, ret = fuse_dev_do_write(fud, &cs, len); pipe_lock(pipe); +out_free: for (idx = 0; idx < nbuf; idx++) pipe_buf_release(pipe, &bufs[idx]); pipe_unlock(pipe); -out: kvfree(bufs); return ret; } diff --git a/fs/pipe.c b/fs/pipe.c index c51750ed4011..2a297bce381f 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -189,9 +189,9 @@ EXPORT_SYMBOL(generic_pipe_buf_steal); * in the tee() system call, when we duplicate the buffers in one * pipe into another. */ -void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) +bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - get_page(buf->page); + return try_get_page(buf->page); } EXPORT_SYMBOL(generic_pipe_buf_get); diff --git a/fs/splice.c b/fs/splice.c index 29e92b506394..3ca117e79ee4 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1584,7 +1584,11 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } *obuf = *ibuf; /* @@ -1658,7 +1662,11 @@ static int link_pipe(struct pipe_inode_info *ipipe, * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } obuf = opipe->bufs + nbuf; *obuf = *ibuf; diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 3ecd7ea212ae..bbee2caf5837 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -108,18 +108,20 @@ struct pipe_buf_operations { /* * Get a reference to the pipe buffer. */ - void (*get)(struct pipe_inode_info *, struct pipe_buffer *); + bool (*get)(struct pipe_inode_info *, struct pipe_buffer *); }; /** * pipe_buf_get - get a reference to a pipe_buffer * @pipe: the pipe that the buffer belongs to * @buf: the buffer to get a reference to + * + * Return: %true if the reference was successfully obtained. */ -static inline void pipe_buf_get(struct pipe_inode_info *pipe, +static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - buf->ops->get(pipe, buf); + return buf->ops->get(pipe, buf); } /** @@ -178,7 +180,7 @@ struct pipe_inode_info *alloc_pipe_info(void); void free_pipe_info(struct pipe_inode_info *); /* Generic pipe buffer ops functions */ -void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); +bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *); int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *); void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c65cea71d1ee..b01260f7b445 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6816,12 +6816,16 @@ static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, buf->private = 0; } -static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, +static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; + if (ref->ref > INT_MAX/2) + return false; + ref->ref++; + return true; } /* Pipe buffer operations for a buffer. */ -- 2.19.1