Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   Hangyu Hua <hbh25y@gmail.com>
To:     mchehab@kernel.org, senozhatsky@chromium.org, caihuoqing@baidu.com,
        hverkuil-cisco@xs4all.nl
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hangyu Hua <hbh25y@gmail.com>
Subject: [PATCH] media: dvb_vb2: fix possible out of bound access
Date:   Thu, 24 Mar 2022 16:01:19 +0800
Message-Id: <20220324080119.40133-1-hbh25y@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

vb2_core_qbuf and vb2_core_querybuf don't check the range of b->index
controlled by the user.

Fix this by adding range checking code before using them.

Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
 drivers/media/dvb-core/dvb_vb2.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
index a1bd6d9c9223..f410800b92e7 100644
--- a/drivers/media/dvb-core/dvb_vb2.c
+++ b/drivers/media/dvb-core/dvb_vb2.c
@@ -354,6 +354,12 @@ int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req)
 
 int dvb_vb2_querybuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
 {
+	struct vb2_queue *q = &ctx->vb_q;
+
+	if (b->index >= q->num_buffers) {
+		dprintk(q, 1, "buffer index out of range\n");
+		return -EINVAL;
+	}
 	vb2_core_querybuf(&ctx->vb_q, b->index, b);
 	dprintk(3, "[%s] index=%d\n", ctx->name, b->index);
 	return 0;
@@ -378,8 +384,13 @@ int dvb_vb2_expbuf(struct dvb_vb2_ctx *ctx, struct dmx_exportbuffer *exp)
 
 int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
 {
+	struct vb2_queue *q = &ctx->vb_q;
 	int ret;
 
+	if (b->index >= q->num_buffers) {
+		dprintk(q, 1, "buffer index out of range\n");
+		return -EINVAL;
+	}
 	ret = vb2_core_qbuf(&ctx->vb_q, b->index, b, NULL);
 	if (ret) {
 		dprintk(1, "[%s] index=%d errno=%d\n", ctx->name,
-- 
2.25.1