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authorDaniel Thompson <daniel.thompson@linaro.org>2015-12-22 19:36:44 -0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-02-09 09:25:12 +0100
commitbfe981a0952880df43d08a050bf3ae44aaebd795 (patch)
tree8c6e79fdb82c2ff71b4edb630ea93a24d850cd14 /drivers/gpu/drm/drm_prime.c
parent10c1b6183a163aca59ba92b88f2b4c4cecd20d4c (diff)
downloadlinux-bfe981a0952880df43d08a050bf3ae44aaebd795.tar.gz
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: 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>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1450820214-12509-2-git-send-email-tiago.vignatti@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_prime.c')
-rw-r--r--drivers/gpu/drm/drm_prime.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 27aa7183b20b..df6cdc76a16e 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,