Commit bfe981a0 authored by Daniel Thompson's avatar Daniel Thompson Committed by Daniel Vetter
Browse files

drm: prime: Honour O_RDWR during prime-handle-to-fd 



Currently DRM_IOCTL_PRIME_HANDLE_TO_FD rejects all flags except
(DRM|O)_CLOEXEC making it difficult (maybe impossible) for userspace
to mmap() the resulting dma-buf even when this is supported by the
DRM driver.

It is trivial to relax the restriction and permit read/write access.
This is safe because the flags are seldom touched by drm; mostly they
are passed verbatim to dma_buf calls.

v3 (Tiago): removed unused flags variable from drm_prime_handle_to_fd_ioctl.

Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarTiago Vignatti <tiago.vignatti@intel.com>
Reviewed-by: default avatarStéphane Marchesin <marcheu@chromium.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1450820214-12509-2-git-send-email-tiago.vignatti@intel.com
parent 10c1b618

drivers/gpu/drm/drm_prime.c

+3 −7
Original line number Diff line number Diff line
@@ -329,7 +329,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { 
 * drm_gem_prime_export - helper library implementation of the export callback

 * @dev: drm_device to export from

 * @obj: GEM object to export

 * @flags: flags like DRM_CLOEXEC

 * @flags: flags like DRM_CLOEXEC and DRM_RDWR

 *

 * This is the implementation of the gem_prime_export functions for GEM drivers

 * using the PRIME helpers.
@@ -628,7 +628,6 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, 
				 struct drm_file *file_priv)

{

	struct drm_prime_handle *args = data;

	uint32_t flags;



	if (!drm_core_check_feature(dev, DRIVER_PRIME))

		return -EINVAL;
@@ -637,14 +636,11 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, 
		return -ENOSYS;



	/* check flags are valid */

	if (args->flags & ~DRM_CLOEXEC)

	if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))

		return -EINVAL;



	/* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */

	flags = args->flags & DRM_CLOEXEC;



	return dev->driver->prime_handle_to_fd(dev, file_priv,

			args->handle, flags, &args->fd);

			args->handle, args->flags, &args->fd);

}



int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,

include/uapi/drm/drm.h

+1 −0
Original line number Diff line number Diff line
@@ -669,6 +669,7 @@ struct drm_set_client_cap { 
	__u64 value;

};



#define DRM_RDWR O_RDWR

#define DRM_CLOEXEC O_CLOEXEC

struct drm_prime_handle {

	__u32 handle;

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