The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Thanks, Sasha
------------------ original commit in Linus's tree ------------------
From 517621b7060096e48e42f545fa6646fc00252eac Mon Sep 17 00:00:00 2001 From: Zack Rusin zack.rusin@broadcom.com Date: Wed, 10 Jan 2024 15:03:05 -0500 Subject: [PATCH] drm/vmwgfx: Fix possible null pointer derefence with invalid contexts
vmw_context_cotable can return either an error or a null pointer and its usage sometimes went unchecked. Subsequent code would then try to access either a null pointer or an error value.
The invalid dereferences were only possible with malformed userspace apps which never properly initialized the rendering contexts.
Check the results of vmw_context_cotable to fix the invalid derefs.
Thanks: ziming zhang(@ezrak1e) from Ant Group Light-Year Security Lab who was the first person to discover it. Niels De Graef who reported it and helped to track down the poc.
Fixes: 9c079b8ce8bf ("drm/vmwgfx: Adapt execbuf to the new validation api") Cc: stable@vger.kernel.org # v4.20+ Reported-by: Niels De Graef ndegraef@redhat.com Signed-off-by: Zack Rusin zack.rusin@broadcom.com Cc: Martin Krastev martin.krastev@broadcom.com Cc: Maaz Mombasawala maaz.mombasawala@broadcom.com Cc: Ian Forbes ian.forbes@broadcom.com Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: dri-devel@lists.freedesktop.org Reviewed-by: Maaz Mombasawala maaz.mombasawala@broadcom.com Reviewed-by: Martin Krastev martin.krastev@broadcom.com Link: https://patchwork.freedesktop.org/patch/msgid/20240110200305.94086-1-zack.ru... --- drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index 4c22fe7ec79b7..cc3086e649eb5 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -447,7 +447,7 @@ static int vmw_resource_context_res_add(struct vmw_private *dev_priv, vmw_res_type(ctx) == vmw_res_dx_context) { for (i = 0; i < cotable_max; ++i) { res = vmw_context_cotable(ctx, i); - if (IS_ERR(res)) + if (IS_ERR_OR_NULL(res)) continue;
ret = vmw_execbuf_res_val_add(sw_context, res, @@ -1266,6 +1266,8 @@ static int vmw_cmd_dx_define_query(struct vmw_private *dev_priv, return -EINVAL;
cotable_res = vmw_context_cotable(ctx_node->ctx, SVGA_COTABLE_DXQUERY); + if (IS_ERR_OR_NULL(cotable_res)) + return cotable_res ? PTR_ERR(cotable_res) : -EINVAL; ret = vmw_cotable_notify(cotable_res, cmd->body.queryId);
return ret; @@ -2484,6 +2486,8 @@ static int vmw_cmd_dx_view_define(struct vmw_private *dev_priv, return ret;
res = vmw_context_cotable(ctx_node->ctx, vmw_view_cotables[view_type]); + if (IS_ERR_OR_NULL(res)) + return res ? PTR_ERR(res) : -EINVAL; ret = vmw_cotable_notify(res, cmd->defined_id); if (unlikely(ret != 0)) return ret; @@ -2569,8 +2573,8 @@ static int vmw_cmd_dx_so_define(struct vmw_private *dev_priv,
so_type = vmw_so_cmd_to_type(header->id); res = vmw_context_cotable(ctx_node->ctx, vmw_so_cotables[so_type]); - if (IS_ERR(res)) - return PTR_ERR(res); + if (IS_ERR_OR_NULL(res)) + return res ? PTR_ERR(res) : -EINVAL; cmd = container_of(header, typeof(*cmd), header); ret = vmw_cotable_notify(res, cmd->defined_id);
@@ -2689,6 +2693,8 @@ static int vmw_cmd_dx_define_shader(struct vmw_private *dev_priv, return -EINVAL;
res = vmw_context_cotable(ctx_node->ctx, SVGA_COTABLE_DXSHADER); + if (IS_ERR_OR_NULL(res)) + return res ? PTR_ERR(res) : -EINVAL; ret = vmw_cotable_notify(res, cmd->body.shaderId); if (ret) return ret; @@ -3010,6 +3016,8 @@ static int vmw_cmd_dx_define_streamoutput(struct vmw_private *dev_priv, }
res = vmw_context_cotable(ctx_node->ctx, SVGA_COTABLE_STREAMOUTPUT); + if (IS_ERR_OR_NULL(res)) + return res ? PTR_ERR(res) : -EINVAL; ret = vmw_cotable_notify(res, cmd->body.soid); if (ret) return ret;