From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4FAA2171A1 for ; Mon, 22 May 2023 19:24:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3B36C4339B; Mon, 22 May 2023 19:24:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684783465; bh=sOFCupPmco37yPY4TQcRSbwtpvyDHpYMv3Rmg9UkMo0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T1gjst4cJFFYmPgn/dW8JvgckCz+ZefChb9AEDcRQStohIhEenxUtaQfRbJEOq9Q8 mrVZnNMa4am/VBah4ImF53yTk/WOf8gLF4DNmpwsH/aA16Af0JBIEY0HcPkmwpKcts byxT8m/cXQsXIod+uu64KGV0kc/sewD9GgwUQhFo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, harperchen , Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 6.1 051/292] media: pci: tw68: Fix null-ptr-deref bug in buf prepare and finish Date: Mon, 22 May 2023 20:06:48 +0100 Message-Id: <20230522190407.210880601@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190405.880733338@linuxfoundation.org> References: <20230522190405.880733338@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: harperchen [ Upstream commit 1634b7adcc5bef645b3666fdd564e5952a9e24e0 ] When the driver calls tw68_risc_buffer() to prepare the buffer, the function call dma_alloc_coherent may fail, resulting in a empty buffer buf->cpu. Later when we free the buffer or access the buffer, null ptr deref is triggered. This bug is similar to the following one: https://git.linuxtv.org/media_stage.git/commit/?id=2b064d91440b33fba5b452f2d1b31f13ae911d71. We believe the bug can be also dynamically triggered from user side. Similarly, we fix this by checking the return value of tw68_risc_buffer() and the value of buf->cpu before buffer free. Signed-off-by: harperchen Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/pci/tw68/tw68-video.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/media/pci/tw68/tw68-video.c b/drivers/media/pci/tw68/tw68-video.c index 0cbc5b038073b..773a18702d369 100644 --- a/drivers/media/pci/tw68/tw68-video.c +++ b/drivers/media/pci/tw68/tw68-video.c @@ -437,6 +437,7 @@ static void tw68_buf_queue(struct vb2_buffer *vb) */ static int tw68_buf_prepare(struct vb2_buffer *vb) { + int ret; struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct vb2_queue *vq = vb->vb2_queue; struct tw68_dev *dev = vb2_get_drv_priv(vq); @@ -452,30 +453,30 @@ static int tw68_buf_prepare(struct vb2_buffer *vb) bpl = (dev->width * dev->fmt->depth) >> 3; switch (dev->field) { case V4L2_FIELD_TOP: - tw68_risc_buffer(dev->pci, buf, dma->sgl, + ret = tw68_risc_buffer(dev->pci, buf, dma->sgl, 0, UNSET, bpl, 0, dev->height); break; case V4L2_FIELD_BOTTOM: - tw68_risc_buffer(dev->pci, buf, dma->sgl, + ret = tw68_risc_buffer(dev->pci, buf, dma->sgl, UNSET, 0, bpl, 0, dev->height); break; case V4L2_FIELD_SEQ_TB: - tw68_risc_buffer(dev->pci, buf, dma->sgl, + ret = tw68_risc_buffer(dev->pci, buf, dma->sgl, 0, bpl * (dev->height >> 1), bpl, 0, dev->height >> 1); break; case V4L2_FIELD_SEQ_BT: - tw68_risc_buffer(dev->pci, buf, dma->sgl, + ret = tw68_risc_buffer(dev->pci, buf, dma->sgl, bpl * (dev->height >> 1), 0, bpl, 0, dev->height >> 1); break; case V4L2_FIELD_INTERLACED: default: - tw68_risc_buffer(dev->pci, buf, dma->sgl, + ret = tw68_risc_buffer(dev->pci, buf, dma->sgl, 0, bpl, bpl, bpl, dev->height >> 1); break; } - return 0; + return ret; } static void tw68_buf_finish(struct vb2_buffer *vb) @@ -485,7 +486,8 @@ static void tw68_buf_finish(struct vb2_buffer *vb) struct tw68_dev *dev = vb2_get_drv_priv(vq); struct tw68_buf *buf = container_of(vbuf, struct tw68_buf, vb); - dma_free_coherent(&dev->pci->dev, buf->size, buf->cpu, buf->dma); + if (buf->cpu) + dma_free_coherent(&dev->pci->dev, buf->size, buf->cpu, buf->dma); } static int tw68_start_streaming(struct vb2_queue *q, unsigned int count) -- 2.39.2