| Message ID | 20181102190126.5628-1-colin.king@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [staging-next] drivers: staging: cedrus: find ctx before dereferencing it ctx | expand |
On Fri, Nov 02, 2018 at 07:01:26PM +0000, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > Currently if count is an invalid value the v4l2_info message will > dereference a null ctx pointer to get the dev information. Fix > this by finding ctx first and then checking for an invalid count, > this way ctxt will be non-null hence avoiding the null pointer > dereference. > > Detected by CoverityScan, CID#1475337 ("Explicit null dereferenced") > > Fixes: 50e761516f2b ("media: platform: Add Cedrus VPU decoder driver") > Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com> Thanks! Maxime
On 11/02/18 20:01, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > Currently if count is an invalid value the v4l2_info message will > dereference a null ctx pointer to get the dev information. Fix > this by finding ctx first and then checking for an invalid count, > this way ctxt will be non-null hence avoiding the null pointer > dereference. > > Detected by CoverityScan, CID#1475337 ("Explicit null dereferenced") > > Fixes: 50e761516f2b ("media: platform: Add Cedrus VPU decoder driver") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/staging/media/sunxi/cedrus/cedrus.c | 22 ++++++++++----------- > 1 file changed, 11 insertions(+), 11 deletions(-) > > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c > index 82558455384a..699d62dceb6c 100644 > --- a/drivers/staging/media/sunxi/cedrus/cedrus.c > +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c > @@ -108,17 +108,6 @@ static int cedrus_request_validate(struct media_request *req) > unsigned int count; > unsigned int i; > > - count = vb2_request_buffer_cnt(req); > - if (!count) { > - v4l2_info(&ctx->dev->v4l2_dev, > - "No buffer was provided with the request\n"); > - return -ENOENT; > - } else if (count > 1) { > - v4l2_info(&ctx->dev->v4l2_dev, > - "More than one buffer was provided with the request\n"); > - return -EINVAL; > - } > - > list_for_each_entry(obj, &req->objects, list) { > struct vb2_buffer *vb; > > @@ -133,6 +122,17 @@ static int cedrus_request_validate(struct media_request *req) > if (!ctx) > return -ENOENT; > > + count = vb2_request_buffer_cnt(req); > + if (!count) { > + v4l2_info(&ctx->dev->v4l2_dev, > + "No buffer was provided with the request\n"); > + return -ENOENT; > + } else if (count > 1) { > + v4l2_info(&ctx->dev->v4l2_dev, > + "More than one buffer was provided with the request\n"); > + return -EINVAL; > + } > + Is this right? If there are no buffers in the request, then the list_for_each_entry() loop won't find a ctx either. This needs to be done differently: for these initial v4l2_info() statements you can get the cedrus_dev struct from req->mdev since the media_device is embedded in the cedrus_dev struct. In other words, some container_of magic is needed here. Regards, Hans > parent_hdl = &ctx->hdl; > > hdl = v4l2_ctrl_request_hdl_find(req, parent_hdl); >
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c index 82558455384a..699d62dceb6c 100644 --- a/drivers/staging/media/sunxi/cedrus/cedrus.c +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c @@ -108,17 +108,6 @@ static int cedrus_request_validate(struct media_request *req) unsigned int count; unsigned int i; - count = vb2_request_buffer_cnt(req); - if (!count) { - v4l2_info(&ctx->dev->v4l2_dev, - "No buffer was provided with the request\n"); - return -ENOENT; - } else if (count > 1) { - v4l2_info(&ctx->dev->v4l2_dev, - "More than one buffer was provided with the request\n"); - return -EINVAL; - } - list_for_each_entry(obj, &req->objects, list) { struct vb2_buffer *vb; @@ -133,6 +122,17 @@ static int cedrus_request_validate(struct media_request *req) if (!ctx) return -ENOENT; + count = vb2_request_buffer_cnt(req); + if (!count) { + v4l2_info(&ctx->dev->v4l2_dev, + "No buffer was provided with the request\n"); + return -ENOENT; + } else if (count > 1) { + v4l2_info(&ctx->dev->v4l2_dev, + "More than one buffer was provided with the request\n"); + return -EINVAL; + } + parent_hdl = &ctx->hdl; hdl = v4l2_ctrl_request_hdl_find(req, parent_hdl);