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authorDave Airlie <airlied@redhat.com>2020-03-12 12:42:41 +1000
committerDave Airlie <airlied@redhat.com>2020-03-12 12:42:56 +1000
commit9e12da086e5e38f7b4f8d6e02a82447f4165fbee (patch)
tree96e6029378ccb9ae3f9530d019c8216a3ca4a556 /drivers/dma-buf
parentd3bd37f587b4438d47751d0f1d5aaae3d39bd416 (diff)
parentbc1a4130fc0309cc2f43b9cc616ebbc295e886ff (diff)
downloadlinux-9e12da086e5e38f7b4f8d6e02a82447f4165fbee.tar.bz2
Merge tag 'drm-misc-next-2020-03-09' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for 5.7: UAPI Changes: Cross-subsystem Changes: Core Changes: Driver Changes: - fb-helper: Remove drm_fb_helper_{add,add_all,remove}_one_connector - fbdev: some cleanups and dead-code removal - Conversions to simple-encoder - zero-length array removal - Panel: panel-dpi support in panel-simple, Novatek NT35510, Elida KD35T133, Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maxime Ripard <maxime@cerno.tech> Link: https://patchwork.freedesktop.org/patch/msgid/20200309135439.dicfnbo4ikj4tkz7@gilmour
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/Kconfig10
-rw-r--r--drivers/dma-buf/dma-buf.c110
2 files changed, 111 insertions, 9 deletions
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index e7d820ce0724..ef73b678419c 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -39,6 +39,16 @@ config UDMABUF
A driver to let userspace turn memfd regions into dma-bufs.
Qemu can use this to create host dmabufs for guest framebuffers.
+config DMABUF_MOVE_NOTIFY
+ bool "Move notify between drivers (EXPERIMENTAL)"
+ default n
+ help
+ Don''t pin buffers if the dynamic DMA-buf interface is available on both the
+ exporter as well as the importer. This fixes a security problem where
+ userspace is able to pin unrestricted amounts of memory through DMA-buf.
+ But marked experimental because we don''t jet have a consistent execution
+ context and memory management between drivers.
+
config DMABUF_SELFTESTS
tristate "Selftests for the dma-buf interfaces"
default n
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index c343c7c10b4c..ccc9eda1bc28 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -525,7 +525,10 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
}
if (WARN_ON(exp_info->ops->cache_sgt_mapping &&
- exp_info->ops->dynamic_mapping))
+ (exp_info->ops->pin || exp_info->ops->unpin)))
+ return ERR_PTR(-EINVAL);
+
+ if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin))
return ERR_PTR(-EINVAL);
if (!try_module_get(exp_info->owner))
@@ -652,7 +655,8 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
* calls attach() of dma_buf_ops to allow device-specific attach functionality
* @dmabuf: [in] buffer to attach device to.
* @dev: [in] device to be attached.
- * @dynamic_mapping: [in] calling convention for map/unmap
+ * @importer_ops [in] importer operations for the attachment
+ * @importer_priv [in] importer private pointer for the attachment
*
* Returns struct dma_buf_attachment pointer for this attachment. Attachments
* must be cleaned up by calling dma_buf_detach().
@@ -668,7 +672,8 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
*/
struct dma_buf_attachment *
dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
- bool dynamic_mapping)
+ const struct dma_buf_attach_ops *importer_ops,
+ void *importer_priv)
{
struct dma_buf_attachment *attach;
int ret;
@@ -676,13 +681,17 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
if (WARN_ON(!dmabuf || !dev))
return ERR_PTR(-EINVAL);
+ if (WARN_ON(importer_ops && !importer_ops->move_notify))
+ return ERR_PTR(-EINVAL);
+
attach = kzalloc(sizeof(*attach), GFP_KERNEL);
if (!attach)
return ERR_PTR(-ENOMEM);
attach->dev = dev;
attach->dmabuf = dmabuf;
- attach->dynamic_mapping = dynamic_mapping;
+ attach->importer_ops = importer_ops;
+ attach->importer_priv = importer_priv;
if (dmabuf->ops->attach) {
ret = dmabuf->ops->attach(dmabuf, attach);
@@ -701,15 +710,19 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
dma_buf_is_dynamic(dmabuf)) {
struct sg_table *sgt;
- if (dma_buf_is_dynamic(attach->dmabuf))
+ if (dma_buf_is_dynamic(attach->dmabuf)) {
dma_resv_lock(attach->dmabuf->resv, NULL);
+ ret = dma_buf_pin(attach);
+ if (ret)
+ goto err_unlock;
+ }
sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL);
if (!sgt)
sgt = ERR_PTR(-ENOMEM);
if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
- goto err_unlock;
+ goto err_unpin;
}
if (dma_buf_is_dynamic(attach->dmabuf))
dma_resv_unlock(attach->dmabuf->resv);
@@ -723,6 +736,10 @@ err_attach:
kfree(attach);
return ERR_PTR(ret);
+err_unpin:
+ if (dma_buf_is_dynamic(attach->dmabuf))
+ dma_buf_unpin(attach);
+
err_unlock:
if (dma_buf_is_dynamic(attach->dmabuf))
dma_resv_unlock(attach->dmabuf->resv);
@@ -743,7 +760,7 @@ EXPORT_SYMBOL_GPL(dma_buf_dynamic_attach);
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
struct device *dev)
{
- return dma_buf_dynamic_attach(dmabuf, dev, false);
+ return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL);
}
EXPORT_SYMBOL_GPL(dma_buf_attach);
@@ -766,8 +783,10 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir);
- if (dma_buf_is_dynamic(attach->dmabuf))
+ if (dma_buf_is_dynamic(attach->dmabuf)) {
+ dma_buf_unpin(attach);
dma_resv_unlock(attach->dmabuf->resv);
+ }
}
dma_resv_lock(dmabuf->resv, NULL);
@@ -781,6 +800,44 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
EXPORT_SYMBOL_GPL(dma_buf_detach);
/**
+ * dma_buf_pin - Lock down the DMA-buf
+ *
+ * @attach: [in] attachment which should be pinned
+ *
+ * Returns:
+ * 0 on success, negative error code on failure.
+ */
+int dma_buf_pin(struct dma_buf_attachment *attach)
+{
+ struct dma_buf *dmabuf = attach->dmabuf;
+ int ret = 0;
+
+ dma_resv_assert_held(dmabuf->resv);
+
+ if (dmabuf->ops->pin)
+ ret = dmabuf->ops->pin(attach);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dma_buf_pin);
+
+/**
+ * dma_buf_unpin - Remove lock from DMA-buf
+ *
+ * @attach: [in] attachment which should be unpinned
+ */
+void dma_buf_unpin(struct dma_buf_attachment *attach)
+{
+ struct dma_buf *dmabuf = attach->dmabuf;
+
+ dma_resv_assert_held(dmabuf->resv);
+
+ if (dmabuf->ops->unpin)
+ dmabuf->ops->unpin(attach);
+}
+EXPORT_SYMBOL_GPL(dma_buf_unpin);
+
+/**
* dma_buf_map_attachment - Returns the scatterlist table of the attachment;
* mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
* dma_buf_ops.
@@ -799,6 +856,7 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
enum dma_data_direction direction)
{
struct sg_table *sg_table;
+ int r;
might_sleep();
@@ -820,13 +878,23 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
return attach->sgt;
}
- if (dma_buf_is_dynamic(attach->dmabuf))
+ if (dma_buf_is_dynamic(attach->dmabuf)) {
dma_resv_assert_held(attach->dmabuf->resv);
+ if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) {
+ r = dma_buf_pin(attach);
+ if (r)
+ return ERR_PTR(r);
+ }
+ }
sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
if (!sg_table)
sg_table = ERR_PTR(-ENOMEM);
+ if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) &&
+ !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
+ dma_buf_unpin(attach);
+
if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
attach->sgt = sg_table;
attach->dir = direction;
@@ -865,10 +933,34 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
dma_resv_assert_held(attach->dmabuf->resv);
attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
+
+ if (dma_buf_is_dynamic(attach->dmabuf) &&
+ !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
+ dma_buf_unpin(attach);
}
EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
/**
+ * dma_buf_move_notify - notify attachments that DMA-buf is moving
+ *
+ * @dmabuf: [in] buffer which is moving
+ *
+ * Informs all attachmenst that they need to destroy and recreated all their
+ * mappings.
+ */
+void dma_buf_move_notify(struct dma_buf *dmabuf)
+{
+ struct dma_buf_attachment *attach;
+
+ dma_resv_assert_held(dmabuf->resv);
+
+ list_for_each_entry(attach, &dmabuf->attachments, node)
+ if (attach->importer_ops)
+ attach->importer_ops->move_notify(attach);
+}
+EXPORT_SYMBOL_GPL(dma_buf_move_notify);
+
+/**
* DOC: cpu access
*
* There are mutliple reasons for supporting CPU access to a dma buffer object: