From: Daniel Thompson daniel.thompson@linaro.org
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: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Daniel Thompson daniel.thompson@linaro.org Signed-off-by: Tiago Vignatti tiago.vignatti@intel.com --- drivers/gpu/drm/drm_prime.c | 10 +++------- include/uapi/drm/drm.h | 1 + 2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 27aa718..df6cdc7 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -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, diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index b4e92eb..a0ebfe7 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -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;