Parameter check for EINJ error injection - V3

index 8d457b5..9a47d85 100644
@@ -32,6 +32,7 @@
 #include <linux/seq_file.h>
 #include <linux/nmi.h>
 #include <linux/delay.h>
+#include <linux/mm.h>
 #include <acpi/acpi.h>
 
 #include "apei-internal.h"

@@ -41,6 +42,10 @@
 #define SPIN_UNIT		100			/* 100ns */
 /* Firmware should respond within 1 milliseconds */
 #define FIRMWARE_TIMEOUT	(1 * NSEC_PER_MSEC)
+#define ACPI5_VENDOR_BIT	BIT(31)
+#define MEM_ERROR_MASK		(ACPI_EINJ_MEMORY_CORRECTABLE | \
+				ACPI_EINJ_MEMORY_UNCORRECTABLE | \
+				ACPI_EINJ_MEMORY_FATAL)
 
 /*
  * ACPI version 5 provides a SET_ERROR_TYPE_WITH_ADDRESS action.

@@ -367,7 +372,7 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
 	 * This will cause resource conflict with regular memory.  So
 	 * remove it from trigger table resources.
 	 */
-	if ((param_extension || acpi5) && (type & 0x0038) && param2) {
+	if ((param_extension || acpi5) && (type & MEM_ERROR_MASK) && param2) {
 		struct apei_resources addr_resources;
 		apei_resources_init(&addr_resources);
 		trigger_param_region = einj_get_trigger_parameter_region(

@@ -427,7 +432,7 @@ static int __einj_error_inject(u32 type, u64 param1, u64 param2)
 		struct set_error_type_with_address *v5param = einj_param;
 
 		v5param->type = type;
-		if (type & 0x80000000) {
+		if (type & ACPI5_VENDOR_BIT) {
 			switch (vendor_flags) {
 			case SETWA_FLAGS_APICID:
 				v5param->apicid = param1;

@@ -509,10 +514,43 @@ static int __einj_error_inject(u32 type, u64 param1, u64 param2)
 }
 
 /* Inject the specified hardware error */
+
+/*
+ * When injection type is memory related, the param1/param2 should
+ * be check carefully. Especially if param2 is non-page-aligned
+ * like 0xf0f0f0f0f0f0f0f0, that must be strictly forbidden.
+ */
 static int einj_error_inject(u32 type, u64 param1, u64 param2)
 {
 	int rc;
+	unsigned long pfn;
+
+	/*
+	 * We need extra sanity checks for memory errors.
+	 * Other types leap directly to injection.
+	 */
+
+	/* ensure param1/param2 existed */
+	if (!(param_extension || acpi5))
+		goto inject;
+
+	/* ensure injection is memory related */
+	if (type & ACPI5_VENDOR_BIT) {
+		if (vendor_flags != SETWA_FLAGS_MEM)
+			goto inject;
+	} else if (!(type & MEM_ERROR_MASK))
+		goto inject;
+
+	/*
+	 * Disallow crazy address masks that give BIOS leeway to pick
+	 * injection address almost anywhere. Insist on page or
+	 * better granularity.
+	 */
+	pfn = PFN_DOWN(param1 & param2);
+	if (!page_is_ram(pfn) || ((param2 & PAGE_MASK) != PAGE_MASK))
+		return -EINVAL;
 
+inject:
 	mutex_lock(&einj_mutex);
 	rc = __einj_error_inject(type, param1, param2);
 	mutex_unlock(&einj_mutex);

@@ -590,7 +628,7 @@ static int error_type_set(void *data, u64 val)
 	 * Vendor defined types have 0x80000000 bit set, and
 	 * are not enumerated by ACPI_EINJ_GET_ERROR_TYPE
 	 */
-	vendor = val & 0x80000000;
+	vendor = val & ACPI5_VENDOR_BIT;
 	tval = val & 0x7fffffff;
 
 	/* Only one error type can be specified */

index d738698..77bf11a 100644
@@ -409,6 +409,7 @@ int __weak page_is_ram(unsigned long pfn)
 {
 	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 }
+EXPORT_SYMBOL_GPL(page_is_ram);
 
 void __weak arch_remove_reservations(struct resource *avail)
 {