From d3c2df71613a8fa3a2005213a7895ed222b36cf0 Mon Sep 17 00:00:00 2001 From: Mary Guillemard Date: Tue, 3 Sep 2024 16:49:55 +0200 Subject: [PATCH] drm/panthor: Restrict high priorities on group_create We were allowing any users to create a high priority group without any permission checks. As a result, this was allowing possible denial of service. We now only allow the DRM master or users with the CAP_SYS_NICE capability to set higher priorities than PANTHOR_GROUP_PRIORITY_MEDIUM. As the sole user of that uAPI lives in Mesa and hardcode a value of MEDIUM [1], this should be safe to do. Additionally, as those checks are performed at the ioctl level, panthor_group_create now only check for priority level validity. [1]https://gitlab.freedesktop.org/mesa/mesa/-/blob/f390835074bdf162a63deb0311d1a6de527f9f89/src/gallium/drivers/panfrost/pan_csf.c#L1038 Signed-off-by: Mary Guillemard Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block") Cc: stable@vger.kernel.org Reviewed-by: Boris Brezillon Signed-off-by: Boris Brezillon Link: https://patchwork.freedesktop.org/patch/msgid/20240903144955.144278-2-mary.guillemard@collabora.com --- drivers/gpu/drm/panthor/panthor_drv.c | 23 +++++++++++++++++++++++ drivers/gpu/drm/panthor/panthor_sched.c | 2 +- include/uapi/drm/panthor_drm.h | 6 +++++- 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c index e6c50c97b9c7d..61f9d6b2348b9 100644 --- a/drivers/gpu/drm/panthor/panthor_drv.c +++ b/drivers/gpu/drm/panthor/panthor_drv.c @@ -10,6 +10,7 @@ #include #include +#include #include #include #include @@ -995,6 +996,24 @@ static int panthor_ioctl_group_destroy(struct drm_device *ddev, void *data, return panthor_group_destroy(pfile, args->group_handle); } +static int group_priority_permit(struct drm_file *file, + u8 priority) +{ + /* Ensure that priority is valid */ + if (priority > PANTHOR_GROUP_PRIORITY_HIGH) + return -EINVAL; + + /* Medium priority and below are always allowed */ + if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM) + return 0; + + /* Higher priorities require CAP_SYS_NICE or DRM_MASTER */ + if (capable(CAP_SYS_NICE) || drm_is_current_master(file)) + return 0; + + return -EACCES; +} + static int panthor_ioctl_group_create(struct drm_device *ddev, void *data, struct drm_file *file) { @@ -1010,6 +1029,10 @@ static int panthor_ioctl_group_create(struct drm_device *ddev, void *data, if (ret) return ret; + ret = group_priority_permit(file, args->priority); + if (ret) + return ret; + ret = panthor_group_create(pfile, args, queue_args); if (ret >= 0) { args->group_handle = ret; diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 463bcd3cf00f3..12b272a912f86 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -3092,7 +3092,7 @@ int panthor_group_create(struct panthor_file *pfile, if (group_args->pad) return -EINVAL; - if (group_args->priority > PANTHOR_CSG_PRIORITY_HIGH) + if (group_args->priority >= PANTHOR_CSG_PRIORITY_COUNT) return -EINVAL; if ((group_args->compute_core_mask & ~ptdev->gpu_info.shader_present) || diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h index 4e1fd1212454d..aeafb0bde203f 100644 --- a/include/uapi/drm/panthor_drm.h +++ b/include/uapi/drm/panthor_drm.h @@ -692,7 +692,11 @@ enum drm_panthor_group_priority { /** @PANTHOR_GROUP_PRIORITY_MEDIUM: Medium priority group. */ PANTHOR_GROUP_PRIORITY_MEDIUM, - /** @PANTHOR_GROUP_PRIORITY_HIGH: High priority group. */ + /** + * @PANTHOR_GROUP_PRIORITY_HIGH: High priority group. + * + * Requires CAP_SYS_NICE or DRM_MASTER. + */ PANTHOR_GROUP_PRIORITY_HIGH, };