drm/vmwgfx: Fix shader stage validation

For multiple commands the driver was not correctly validating the shader
stages resulting in possible kernel oopses. The validation code was only.
if ever, checking the upper bound on the shader stages but never a lower
bound (valid shader stages start at 1 not 0).

Fixes kernel oopses ending up in vmw_binding_add, e.g.:
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 2443 Comm: testcase Not tainted 6.3.0-rc4-vmwgfx #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
RIP: 0010:vmw_binding_add+0x4c/0x140 [vmwgfx]
Code: 7e 30 49 83 ff 0e 0f 87 ea 00 00 00 4b 8d 04 7f 89 d2 89 cb 48 c1 e0 03 4c 8b b0 40 3d 93 c0 48 8b 80 48 3d 93 c0 49 0f af de <48> 03 1c d0 4c 01 e3 49 8>
RSP: 0018:ffffb8014416b968 EFLAGS: 00010206
RAX: ffffffffc0933ec0 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000ffffffff RSI: ffffb8014416b9c0 RDI: ffffb8014316f000
RBP: ffffb8014416b998 R08: 0000000000000003 R09: 746f6c735f726564
R10: ffffffffaaf2bda0 R11: 732e676e69646e69 R12: ffffb8014316f000
R13: ffffb8014416b9c0 R14: 0000000000000040 R15: 0000000000000006
FS:  00007fba8c0af740(0000) GS:ffff8a1277c80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000007c0933eb8 CR3: 0000000118244001 CR4: 00000000003706e0
Call Trace:
 <TASK>
 vmw_view_bindings_add+0xf5/0x1b0 [vmwgfx]
 ? ___drm_dbg+0x8a/0xb0 [drm]
 vmw_cmd_dx_set_shader_res+0x8f/0xc0 [vmwgfx]
 vmw_execbuf_process+0x590/0x1360 [vmwgfx]
 vmw_execbuf_ioctl+0x173/0x370 [vmwgfx]
 ? __drm_dev_dbg+0xb4/0xe0 [drm]
 ? __pfx_vmw_execbuf_ioctl+0x10/0x10 [vmwgfx]
 drm_ioctl_kernel+0xbc/0x160 [drm]
 drm_ioctl+0x2d2/0x580 [drm]
 ? __pfx_vmw_execbuf_ioctl+0x10/0x10 [vmwgfx]
 ? do_fault+0x1a6/0x420
 vmw_generic_ioctl+0xbd/0x180 [vmwgfx]
 vmw_unlocked_ioctl+0x19/0x20 [vmwgfx]
 __x64_sys_ioctl+0x96/0xd0
 do_syscall_64+0x5d/0x90
 ? handle_mm_fault+0xe4/0x2f0
 ? debug_smp_processor_id+0x1b/0x30
 ? fpregs_assert_state_consistent+0x2e/0x50
 ? exit_to_user_mode_prepare+0x40/0x180
 ? irqentry_exit_to_user_mode+0xd/0x20
 ? irqentry_exit+0x3f/0x50
 ? exc_page_fault+0x8b/0x180
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
Signed-off-by: Zack Rusin <zackr@vmware.com>
Cc: security@openanolis.org
Reported-by: Ziming Zhang <ezrakiez@gmail.com>
Testcase-found-by: Niels De Graef <ndegraef@redhat.com>
Fixes: d80efd5c ("drm/vmwgfx: Initial DX support")
Cc: <stable@vger.kernel.org> # v4.3+
Reviewed-by: Maaz Mombasawala<mombasawalam@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230616190934.54828-1-zack@kde.org

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

@@ -1513,4 +1513,16 @@ static inline bool vmw_has_fences(struct vmw_private *vmw)
 	return (vmw_fifo_caps(vmw) & SVGA_FIFO_CAP_FENCE) != 0;
 }
 
+static inline bool vmw_shadertype_is_valid(enum vmw_sm_type shader_model,
+					   u32 shader_type)
+{
+	SVGA3dShaderType max_allowed = SVGA3D_SHADERTYPE_PREDX_MAX;
+
+	if (shader_model >= VMW_SM_5)
+		max_allowed = SVGA3D_SHADERTYPE_MAX;
+	else if (shader_model >= VMW_SM_4)
+		max_allowed = SVGA3D_SHADERTYPE_DX10_MAX;
+	return shader_type >= SVGA3D_SHADERTYPE_MIN && shader_type < max_allowed;
+}
+
 #endif

drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c

@@ -1992,7 +1992,7 @@ static int vmw_cmd_set_shader(struct vmw_private *dev_priv,
 
 	cmd = container_of(header, typeof(*cmd), header);
 
-	if (cmd->body.type >= SVGA3D_SHADERTYPE_PREDX_MAX) {
+	if (!vmw_shadertype_is_valid(VMW_SM_LEGACY, cmd->body.type)) {
 		VMW_DEBUG_USER("Illegal shader type %u.\n",
 			       (unsigned int) cmd->body.type);
 		return -EINVAL;
@@ -2115,8 +2115,6 @@ vmw_cmd_dx_set_single_constant_buffer(struct vmw_private *dev_priv,
 				      SVGA3dCmdHeader *header)
 {
 	VMW_DECLARE_CMD_VAR(*cmd, SVGA3dCmdDXSetSingleConstantBuffer);
-	SVGA3dShaderType max_shader_num = has_sm5_context(dev_priv) ?
-		SVGA3D_NUM_SHADERTYPE : SVGA3D_NUM_SHADERTYPE_DX10;
 
 	struct vmw_resource *res = NULL;
 	struct vmw_ctx_validation_info *ctx_node = VMW_GET_CTX_NODE(sw_context);
@@ -2133,6 +2131,14 @@ vmw_cmd_dx_set_single_constant_buffer(struct vmw_private *dev_priv,
 	if (unlikely(ret != 0))
 		return ret;
 
+	if (!vmw_shadertype_is_valid(dev_priv->sm_type, cmd->body.type) ||
+	    cmd->body.slot >= SVGA3D_DX_MAX_CONSTBUFFERS) {
+		VMW_DEBUG_USER("Illegal const buffer shader %u slot %u.\n",
+			       (unsigned int) cmd->body.type,
+			       (unsigned int) cmd->body.slot);
+		return -EINVAL;
+	}
+
 	binding.bi.ctx = ctx_node->ctx;
 	binding.bi.res = res;
 	binding.bi.bt = vmw_ctx_binding_cb;
@@ -2141,14 +2147,6 @@ vmw_cmd_dx_set_single_constant_buffer(struct vmw_private *dev_priv,
 	binding.size = cmd->body.sizeInBytes;
 	binding.slot = cmd->body.slot;
 
-	if (binding.shader_slot >= max_shader_num ||
-	    binding.slot >= SVGA3D_DX_MAX_CONSTBUFFERS) {
-		VMW_DEBUG_USER("Illegal const buffer shader %u slot %u.\n",
-			       (unsigned int) cmd->body.type,
-			       (unsigned int) binding.slot);
-		return -EINVAL;
-	}
-
 	vmw_binding_add(ctx_node->staged, &binding.bi, binding.shader_slot,
 			binding.slot);
 
@@ -2207,15 +2205,13 @@ static int vmw_cmd_dx_set_shader_res(struct vmw_private *dev_priv,
 {
 	VMW_DECLARE_CMD_VAR(*cmd, SVGA3dCmdDXSetShaderResources) =
 		container_of(header, typeof(*cmd), header);
-	SVGA3dShaderType max_allowed = has_sm5_context(dev_priv) ?
-		SVGA3D_SHADERTYPE_MAX : SVGA3D_SHADERTYPE_DX10_MAX;
 
 	u32 num_sr_view = (cmd->header.size - sizeof(cmd->body)) /
 		sizeof(SVGA3dShaderResourceViewId);
 
 	if ((u64) cmd->body.startView + (u64) num_sr_view >
 	    (u64) SVGA3D_DX_MAX_SRVIEWS ||
-	    cmd->body.type >= max_allowed) {
+	    !vmw_shadertype_is_valid(dev_priv->sm_type, cmd->body.type)) {
 		VMW_DEBUG_USER("Invalid shader binding.\n");
 		return -EINVAL;
 	}
@@ -2239,8 +2235,6 @@ static int vmw_cmd_dx_set_shader(struct vmw_private *dev_priv,
 				 SVGA3dCmdHeader *header)
 {
 	VMW_DECLARE_CMD_VAR(*cmd, SVGA3dCmdDXSetShader);
-	SVGA3dShaderType max_allowed = has_sm5_context(dev_priv) ?
-		SVGA3D_SHADERTYPE_MAX : SVGA3D_SHADERTYPE_DX10_MAX;
 	struct vmw_resource *res = NULL;
 	struct vmw_ctx_validation_info *ctx_node = VMW_GET_CTX_NODE(sw_context);
 	struct vmw_ctx_bindinfo_shader binding;
@@ -2251,8 +2245,7 @@ static int vmw_cmd_dx_set_shader(struct vmw_private *dev_priv,
 
 	cmd = container_of(header, typeof(*cmd), header);
 
-	if (cmd->body.type >= max_allowed ||
-	    cmd->body.type < SVGA3D_SHADERTYPE_MIN) {
+	if (!vmw_shadertype_is_valid(dev_priv->sm_type, cmd->body.type)) {
 		VMW_DEBUG_USER("Illegal shader type %u.\n",
 			       (unsigned int) cmd->body.type);
 		return -EINVAL;