6.6-stable review patch. If anyone has any objections, please let me know.
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From: Nicholas Kazlauskas nicholas.kazlauskas@amd.com
commit 1ffa8602e39b89469dc703ebab7a7e44c33da0f7 upstream.
[WHY] HW can return invalid values on register read, guard against these being set and causing us to access memory out of range and page fault.
[HOW] Guard at sync_inbox1 and guard at pushing commands.
Cc: Mario Limonciello mario.limonciello@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Reviewed-by: Hansen Dsouza hansen.dsouza@amd.com Acked-by: Alex Hung alex.hung@amd.com Signed-off-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c +++ b/drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c @@ -658,9 +658,16 @@ enum dmub_status dmub_srv_sync_inbox1(st return DMUB_STATUS_INVALID;
if (dmub->hw_funcs.get_inbox1_rptr && dmub->hw_funcs.get_inbox1_wptr) { - dmub->inbox1_rb.rptr = dmub->hw_funcs.get_inbox1_rptr(dmub); - dmub->inbox1_rb.wrpt = dmub->hw_funcs.get_inbox1_wptr(dmub); - dmub->inbox1_last_wptr = dmub->inbox1_rb.wrpt; + uint32_t rptr = dmub->hw_funcs.get_inbox1_rptr(dmub); + uint32_t wptr = dmub->hw_funcs.get_inbox1_wptr(dmub); + + if (rptr > dmub->inbox1_rb.capacity || wptr > dmub->inbox1_rb.capacity) { + return DMUB_STATUS_HW_FAILURE; + } else { + dmub->inbox1_rb.rptr = rptr; + dmub->inbox1_rb.wrpt = wptr; + dmub->inbox1_last_wptr = dmub->inbox1_rb.wrpt; + } }
return DMUB_STATUS_OK; @@ -694,6 +701,11 @@ enum dmub_status dmub_srv_cmd_queue(stru if (!dmub->hw_init) return DMUB_STATUS_INVALID;
+ if (dmub->inbox1_rb.rptr > dmub->inbox1_rb.capacity || + dmub->inbox1_rb.wrpt > dmub->inbox1_rb.capacity) { + return DMUB_STATUS_HW_FAILURE; + } + if (dmub_rb_push_front(&dmub->inbox1_rb, cmd)) return DMUB_STATUS_OK;