From 05bb0167c80b8f93c6a4e0451b7da9b96db990c2 Mon Sep 17 00:00:00 2001

From: Tamir Duberstein <tamird@google.com>

Date: Wed, 5 Apr 2023 15:42:43 +0200

Subject: [PATCH] ACPICA: Avoid undefined behavior: applying zero offset to null pointer

Git-commit: 05bb0167c80b8f93c6a4e0451b7da9b96db990c2

Patch-mainline: v6.4-rc1

References: git-fixes

ACPICA commit 770653e3ba67c30a629ca7d12e352d83c2541b1e

Before this change we see the following UBSAN stack trace in Fuchsia:

  #0    0x000021e4213b3302 in acpi_ds_init_aml_walk(struct acpi_walk_state*, union acpi_parse_object*, struct acpi_namespace_node*, u8*, u32, struct acpi_evaluate_info*, u8) ../../third_party/acpica/source/components/dispatcher/dswstate.c:682 <platform-bus-x86.so>+0x233302

  #1.2  0x000020d0f660777f in ubsan_get_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:41 <libclang_rt.asan.so>+0x3d77f

  #1.1  0x000020d0f660777f in maybe_print_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:51 <libclang_rt.asan.so>+0x3d77f

  #1    0x000020d0f660777f in ~scoped_report() compiler-rt/lib/ubsan/ubsan_diag.cpp:387 <libclang_rt.asan.so>+0x3d77f

  #2    0x000020d0f660b96d in handlepointer_overflow_impl() compiler-rt/lib/ubsan/ubsan_handlers.cpp:809 <libclang_rt.asan.so>+0x4196d

  #3    0x000020d0f660b50d in compiler-rt/lib/ubsan/ubsan_handlers.cpp:815 <libclang_rt.asan.so>+0x4150d

  #4    0x000021e4213b3302 in acpi_ds_init_aml_walk(struct acpi_walk_state*, union acpi_parse_object*, struct acpi_namespace_node*, u8*, u32, struct acpi_evaluate_info*, u8) ../../third_party/acpica/source/components/dispatcher/dswstate.c:682 <platform-bus-x86.so>+0x233302

  #5    0x000021e4213e2369 in acpi_ds_call_control_method(struct acpi_thread_state*, struct acpi_walk_state*, union acpi_parse_object*) ../../third_party/acpica/source/components/dispatcher/dsmethod.c:605 <platform-bus-x86.so>+0x262369

  #6    0x000021e421437fac in acpi_ps_parse_aml(struct acpi_walk_state*) ../../third_party/acpica/source/components/parser/psparse.c:550 <platform-bus-x86.so>+0x2b7fac

  #7    0x000021e4214464d2 in acpi_ps_execute_method(struct acpi_evaluate_info*) ../../third_party/acpica/source/components/parser/psxface.c:244 <platform-bus-x86.so>+0x2c64d2

  #8    0x000021e4213aa052 in acpi_ns_evaluate(struct acpi_evaluate_info*) ../../third_party/acpica/source/components/namespace/nseval.c:250 <platform-bus-x86.so>+0x22a052

  #9    0x000021e421413dd8 in acpi_ns_init_one_device(acpi_handle, u32, void*, void**) ../../third_party/acpica/source/components/namespace/nsinit.c:735 <platform-bus-x86.so>+0x293dd8

  #10   0x000021e421429e98 in acpi_ns_walk_namespace(acpi_object_type, acpi_handle, u32, u32, acpi_walk_callback, acpi_walk_callback, void*, void**) ../../third_party/acpica/source/components/namespace/nswalk.c:298 <platform-bus-x86.so>+0x2a9e98

  #11   0x000021e4214131ac in acpi_ns_initialize_devices(u32) ../../third_party/acpica/source/components/namespace/nsinit.c:268 <platform-bus-x86.so>+0x2931ac

  #12   0x000021e42147c40d in acpi_initialize_objects(u32) ../../third_party/acpica/source/components/utilities/utxfinit.c:304 <platform-bus-x86.so>+0x2fc40d

  #13   0x000021e42126d603 in acpi::acpi_impl::initialize_acpi(acpi::acpi_impl*) ../../src/devices/board/lib/acpi/acpi-impl.cc:224 <platform-bus-x86.so>+0xed603

Add a simple check that avoids incrementing a pointer by zero, but

otherwise behaves as before. Note that our findings are against ACPICA

20221020, but the same code exists on master.

Link: https://github.com/acpica/acpica/commit/770653e3

Signed-off-by: Bob Moore <robert.moore@intel.com>

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/acpi/acpica/dswstate.c | 11 ++++++++---

 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpica/dswstate.c b/drivers/acpi/acpica/dswstate.c

index 95af370a7dce..d3841ded3a81 100644

--- a/drivers/acpi/acpica/dswstate.c

+++ b/drivers/acpi/acpica/dswstate.c

@@ -576,9 +576,14 @@ acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,

 	ACPI_FUNCTION_TRACE(ds_init_aml_walk);

 	walk_state->parser_state.aml =

-	    walk_state->parser_state.aml_start = aml_start;

-	walk_state->parser_state.aml_end =

-	    walk_state->parser_state.pkg_end = aml_start + aml_length;

+	    walk_state->parser_state.aml_start =

+	    walk_state->parser_state.aml_end =

+	    walk_state->parser_state.pkg_end = aml_start;

+	/* Avoid undefined behavior: applying zero offset to null pointer */

+	if (aml_length != 0) {

+		walk_state->parser_state.aml_end += aml_length;

+		walk_state->parser_state.pkg_end += aml_length;

+	}

 	/* The next_op of the next_walk will be the beginning of the method */

-- 

2.35.3