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* [PATCH] Revert "ACPICA: Interpreter: fix memory leak by using existing buffer"
@ 2021-02-06  8:49 Ard Biesheuvel
  2021-02-06 10:48 ` Shawn Guo
  0 siblings, 1 reply; 7+ messages in thread
From: Ard Biesheuvel @ 2021-02-06  8:49 UTC (permalink / raw)
  To: linux-arm-kernel
  Cc: Rafael J. Wysocki, Shawn Guo, Erik Kaneda, Robert Moore,
	linux-kernel, linux-acpi, Len Brown, Ard Biesheuvel, devel

This reverts commit 32cf1a12cad43358e47dac8014379c2f33dfbed4.

The 'exisitng buffer' in this case is the firmware provided table, and
we should not modify that in place. This fixes a crash on arm64 with
initrd table overrides, in which case the DSDT is not mapped with
read/write permissions.

Cc: Robert Moore <robert.moore@intel.com>
Cc: Erik Kaneda <erik.kaneda@intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Len Brown <lenb@kernel.org>
Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/acpi/acpica/nsrepair2.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpica/nsrepair2.c b/drivers/acpi/acpica/nsrepair2.c
index d2c8d8279e7a..24c197d91f29 100644
--- a/drivers/acpi/acpica/nsrepair2.c
+++ b/drivers/acpi/acpica/nsrepair2.c
@@ -495,8 +495,9 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 		   union acpi_operand_object **return_object_ptr)
 {
 	union acpi_operand_object *return_object = *return_object_ptr;
-	char *dest;
+	union acpi_operand_object *new_string;
 	char *source;
+	char *dest;
 
 	ACPI_FUNCTION_NAME(ns_repair_HID);
 
@@ -517,6 +518,13 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 		return_ACPI_STATUS(AE_OK);
 	}
 
+	/* It is simplest to always create a new string object */
+
+	new_string = acpi_ut_create_string_object(return_object->string.length);
+	if (!new_string) {
+		return_ACPI_STATUS(AE_NO_MEMORY);
+	}
+
 	/*
 	 * Remove a leading asterisk if present. For some unknown reason, there
 	 * are many machines in the field that contains IDs like this.
@@ -526,7 +534,7 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 	source = return_object->string.pointer;
 	if (*source == '*') {
 		source++;
-		return_object->string.length--;
+		new_string->string.length--;
 
 		ACPI_DEBUG_PRINT((ACPI_DB_REPAIR,
 				  "%s: Removed invalid leading asterisk\n",
@@ -541,11 +549,12 @@ acpi_ns_repair_HID(struct acpi_evaluate_info *info,
 	 * "NNNN####" where N is an uppercase letter or decimal digit, and
 	 * # is a hex digit.
 	 */
-	for (dest = return_object->string.pointer; *source; dest++, source++) {
+	for (dest = new_string->string.pointer; *source; dest++, source++) {
 		*dest = (char)toupper((int)*source);
 	}
-	return_object->string.pointer[return_object->string.length] = 0;
 
+	acpi_ut_remove_reference(return_object);
+	*return_object_ptr = new_string;
 	return_ACPI_STATUS(AE_OK);
 }
 
-- 
2.30.0


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^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-02-08 19:48 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-06  8:49 [PATCH] Revert "ACPICA: Interpreter: fix memory leak by using existing buffer" Ard Biesheuvel
2021-02-06 10:48 ` Shawn Guo
2021-02-08 13:00   ` Rafael J. Wysocki
2021-02-08 19:06     ` Kaneda, Erik
2021-02-08 19:13       ` Ard Biesheuvel
2021-02-08 19:30         ` Kaneda, Erik
2021-02-08 19:46           ` Ard Biesheuvel

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