Message ID | 1609760177-6083-1-git-send-email-charante@codeaurora.org (mailing list archive) |
---|---|
State | Not Applicable, archived |
Headers |
Received: from vger.kernel.org ([23.128.96.18]) by www.linuxtv.org with esmtp (Exim 4.92) (envelope-from <linux-media-owner@vger.kernel.org>) id 1kwOAq-000E9h-2I; Mon, 04 Jan 2021 11:37:20 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726176AbhADLhS (ORCPT <rfc822;mkrufky@linuxtv.org> + 1 other); Mon, 4 Jan 2021 06:37:18 -0500 Received: from so254-31.mailgun.net ([198.61.254.31]:11372 "EHLO so254-31.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725921AbhADLhS (ORCPT <rfc822;linux-media@vger.kernel.org>); Mon, 4 Jan 2021 06:37:18 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1609760219; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=wpoAlb46a86Zd9QSK2x6ubyhpdnYpT2LwCBikX01FRg=; b=PDmnKk/oFOPazz7LHABv3BpF1jUGSEXtb9gBAnWUxuyxtyi7kXNwjdI/Y0J0slDvBTqEGHuq XnbuaQ+RpgQrVdqsxS/btPwZiIku4zEFrz3le+DCFtQHmZgRQV1WNhuEGQD7p2XB4J/SOkyA gUUebdp8WRzzYJlNr+Ei8Xs2Fqk= X-Mailgun-Sending-Ip: 198.61.254.31 X-Mailgun-Sid: WyI3ZjU0NiIsICJsaW51eC1tZWRpYUB2Z2VyLmtlcm5lbC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n03.prod.us-west-2.postgun.com with SMTP id 5ff2fdbd3d84969114f1f8f9 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 04 Jan 2021 11:36:29 GMT Sender: charante=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 0E3CEC433ED; Mon, 4 Jan 2021 11:36:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=ALL_TRUSTED,BAYES_00,SPF_FAIL, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from charante-linux.qualcomm.com (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: charante) by smtp.codeaurora.org (Postfix) with ESMTPSA id 958A6C433C6; Mon, 4 Jan 2021 11:36:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 958A6C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=charante@codeaurora.org From: Charan Teja Reddy <charante@codeaurora.org> To: sumit.semwal@linaro.org, christian.koenig@amd.com, arnd@arndb.de, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Charan Teja Reddy <charante@codeaurora.org> Subject: [PATCH] dmabuf: fix use-after-free of dmabuf's file->f_inode Date: Mon, 4 Jan 2021 17:06:17 +0530 Message-Id: <1609760177-6083-1-git-send-email-charante@codeaurora.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: <linux-media.vger.kernel.org> X-Mailing-List: linux-media@vger.kernel.org X-LSpam-Score: -2.4 (--) X-LSpam-Report: No, score=-2.4 required=5.0 tests=BAYES_00=-1.9,DKIM_SIGNED=0.1,DKIM_VALID=-0.1,HEADER_FROM_DIFFERENT_DOMAINS=0.5,MAILING_LIST_MULTI=-1 autolearn=ham autolearn_force=no |
Series |
dmabuf: fix use-after-free of dmabuf's file->f_inode
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Commit Message
Charan Teja Reddy
Jan. 4, 2021, 11:36 a.m. UTC
It is observed 'use-after-free' on the dmabuf's file->f_inode with the
race between closing the dmabuf file and reading the dmabuf's debug
info.
Consider the below scenario where P1 is closing the dma_buf file
and P2 is reading the dma_buf's debug info in the system:
P1 P2
dma_buf_debug_show()
dma_buf_put()
__fput()
file->f_op->release()
dput()
....
dentry_unlink_inode()
iput(dentry->d_inode)
(where the inode is freed)
mutex_lock(&db_list.lock)
read 'dma_buf->file->f_inode'
(the same inode is freed by P1)
mutex_unlock(&db_list.lock)
dentry->d_op->d_release()-->
dma_buf_release()
.....
mutex_lock(&db_list.lock)
removes the dmabuf from the list
mutex_unlock(&db_list.lock)
In the above scenario, when dma_buf_put() is called on a dma_buf, it
first frees the dma_buf's file->f_inode(=dentry->d_inode) and then
removes this dma_buf from the system db_list. In between P2 traversing
the db_list tries to access this dma_buf's file->f_inode that was freed
by P1 which is a use-after-free case.
Since, __fput() calls f_op->release first and then later calls the
d_op->d_release, move the dma_buf's db_list removal from d_release() to
f_op->release(). This ensures that dma_buf's file->f_inode is not
accessed after it is released.
Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops")
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
---
drivers/dma-buf/dma-buf.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
Comments
Am 04.01.21 um 12:36 schrieb Charan Teja Reddy: > It is observed 'use-after-free' on the dmabuf's file->f_inode with the > race between closing the dmabuf file and reading the dmabuf's debug > info. > > Consider the below scenario where P1 is closing the dma_buf file > and P2 is reading the dma_buf's debug info in the system: > > P1 P2 > dma_buf_debug_show() > dma_buf_put() > __fput() > file->f_op->release() > dput() > .... > dentry_unlink_inode() > iput(dentry->d_inode) > (where the inode is freed) > mutex_lock(&db_list.lock) > read 'dma_buf->file->f_inode' > (the same inode is freed by P1) > mutex_unlock(&db_list.lock) > dentry->d_op->d_release()--> > dma_buf_release() > ..... > mutex_lock(&db_list.lock) > removes the dmabuf from the list > mutex_unlock(&db_list.lock) > > In the above scenario, when dma_buf_put() is called on a dma_buf, it > first frees the dma_buf's file->f_inode(=dentry->d_inode) and then > removes this dma_buf from the system db_list. In between P2 traversing > the db_list tries to access this dma_buf's file->f_inode that was freed > by P1 which is a use-after-free case. > > Since, __fput() calls f_op->release first and then later calls the > d_op->d_release, move the dma_buf's db_list removal from d_release() to > f_op->release(). This ensures that dma_buf's file->f_inode is not > accessed after it is released. > > Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") > Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> Not an expert on the debugfs stuff in DMA-buf, but the explanation sounds perfectly correct to me. Acked-by: Christian König <christian.koenig@amd.com> > --- > drivers/dma-buf/dma-buf.c | 21 +++++++++++++++++---- > 1 file changed, 17 insertions(+), 4 deletions(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 0eb80c1..a14dcbb 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -76,10 +76,6 @@ static void dma_buf_release(struct dentry *dentry) > > dmabuf->ops->release(dmabuf); > > - mutex_lock(&db_list.lock); > - list_del(&dmabuf->list_node); > - mutex_unlock(&db_list.lock); > - > if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) > dma_resv_fini(dmabuf->resv); > > @@ -88,6 +84,22 @@ static void dma_buf_release(struct dentry *dentry) > kfree(dmabuf); > } > > +static int dma_buf_file_release(struct inode *inode, struct file *file) > +{ > + struct dma_buf *dmabuf; > + > + if (!is_dma_buf_file(file)) > + return -EINVAL; > + > + dmabuf = file->private_data; > + > + mutex_lock(&db_list.lock); > + list_del(&dmabuf->list_node); > + mutex_unlock(&db_list.lock); > + > + return 0; > +} > + > static const struct dentry_operations dma_buf_dentry_ops = { > .d_dname = dmabuffs_dname, > .d_release = dma_buf_release, > @@ -413,6 +425,7 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) > } > > static const struct file_operations dma_buf_fops = { > + .release = dma_buf_file_release, > .mmap = dma_buf_mmap_internal, > .llseek = dma_buf_llseek, > .poll = dma_buf_poll,
Hi Charan, On Mon, 4 Jan 2021 at 17:22, Christian König <ckoenig.leichtzumerken@gmail.com> wrote: > > Am 04.01.21 um 12:36 schrieb Charan Teja Reddy: > > It is observed 'use-after-free' on the dmabuf's file->f_inode with the > > race between closing the dmabuf file and reading the dmabuf's debug > > info. > > > > Consider the below scenario where P1 is closing the dma_buf file > > and P2 is reading the dma_buf's debug info in the system: > > > > P1 P2 > > dma_buf_debug_show() > > dma_buf_put() > > __fput() > > file->f_op->release() > > dput() > > .... > > dentry_unlink_inode() > > iput(dentry->d_inode) > > (where the inode is freed) > > mutex_lock(&db_list.lock) > > read 'dma_buf->file->f_inode' > > (the same inode is freed by P1) > > mutex_unlock(&db_list.lock) > > dentry->d_op->d_release()--> > > dma_buf_release() > > ..... > > mutex_lock(&db_list.lock) > > removes the dmabuf from the list > > mutex_unlock(&db_list.lock) > > > > In the above scenario, when dma_buf_put() is called on a dma_buf, it > > first frees the dma_buf's file->f_inode(=dentry->d_inode) and then > > removes this dma_buf from the system db_list. In between P2 traversing > > the db_list tries to access this dma_buf's file->f_inode that was freed > > by P1 which is a use-after-free case. > > > > Since, __fput() calls f_op->release first and then later calls the > > d_op->d_release, move the dma_buf's db_list removal from d_release() to > > f_op->release(). This ensures that dma_buf's file->f_inode is not > > accessed after it is released. > > > > Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") > > Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> > > Not an expert on the debugfs stuff in DMA-buf, but the explanation > sounds perfectly correct to me. > > Acked-by: Christian König <christian.koenig@amd.com> Thanks for your fix; I will queue it up in the fixes branch. Can you please also send it to be queued to 5.4+ stable branches? > > > --- > > drivers/dma-buf/dma-buf.c | 21 +++++++++++++++++---- > > 1 file changed, 17 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > index 0eb80c1..a14dcbb 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -76,10 +76,6 @@ static void dma_buf_release(struct dentry *dentry) > > > > dmabuf->ops->release(dmabuf); > > > > - mutex_lock(&db_list.lock); > > - list_del(&dmabuf->list_node); > > - mutex_unlock(&db_list.lock); > > - > > if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) > > dma_resv_fini(dmabuf->resv); > > > > @@ -88,6 +84,22 @@ static void dma_buf_release(struct dentry *dentry) > > kfree(dmabuf); > > } > > > > +static int dma_buf_file_release(struct inode *inode, struct file *file) > > +{ > > + struct dma_buf *dmabuf; > > + > > + if (!is_dma_buf_file(file)) > > + return -EINVAL; > > + > > + dmabuf = file->private_data; > > + > > + mutex_lock(&db_list.lock); > > + list_del(&dmabuf->list_node); > > + mutex_unlock(&db_list.lock); > > + > > + return 0; > > +} > > + > > static const struct dentry_operations dma_buf_dentry_ops = { > > .d_dname = dmabuffs_dname, > > .d_release = dma_buf_release, > > @@ -413,6 +425,7 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) > > } > > > > static const struct file_operations dma_buf_fops = { > > + .release = dma_buf_file_release, > > .mmap = dma_buf_mmap_internal, > > .llseek = dma_buf_llseek, > > .poll = dma_buf_poll, > Best, Sumit.
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 0eb80c1..a14dcbb 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -76,10 +76,6 @@ static void dma_buf_release(struct dentry *dentry) dmabuf->ops->release(dmabuf); - mutex_lock(&db_list.lock); - list_del(&dmabuf->list_node); - mutex_unlock(&db_list.lock); - if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) dma_resv_fini(dmabuf->resv); @@ -88,6 +84,22 @@ static void dma_buf_release(struct dentry *dentry) kfree(dmabuf); } +static int dma_buf_file_release(struct inode *inode, struct file *file) +{ + struct dma_buf *dmabuf; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + dmabuf = file->private_data; + + mutex_lock(&db_list.lock); + list_del(&dmabuf->list_node); + mutex_unlock(&db_list.lock); + + return 0; +} + static const struct dentry_operations dma_buf_dentry_ops = { .d_dname = dmabuffs_dname, .d_release = dma_buf_release, @@ -413,6 +425,7 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) } static const struct file_operations dma_buf_fops = { + .release = dma_buf_file_release, .mmap = dma_buf_mmap_internal, .llseek = dma_buf_llseek, .poll = dma_buf_poll,