Hi Fengguang,
於 一，2012-09-17 於 08:41 +0800，Fengguang Wu 提到：
> Hi Chun-Yi,
>
> coccinelle warns about:
>
> drivers/platform/x86/acer-wmi.c:1200:17-21: ERROR: obj is NULL but dereferenced.
> drivers/platform/x86/acer-wmi.c:891:17-21: ERROR: obj is NULL but dereferenced.
> drivers/platform/x86/acer-wmi.c:1953:17-21: ERROR: obj is NULL but dereferenced.
>
> Which are first introduced by commit
>
> commit 987dfbaa65b2c3568b85e29d2598da08a011ee09
> Author: Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx>
> AuthorDate: Fri May 27 14:52:14 2011 +0800
> Commit: Matthew Garrett <mjg@xxxxxxxxxx>
> CommitDate: Fri May 27 12:40:10 2011 -0400
>
> acer-wmi: support integer return type from WMI methods
>
> Thanks,
> Fengguang
>
Thanks a lot for you catch this problem!
This patch can fix it.
Thanks a lot!
Joey Lee
>From 89fca446093ee172f029be75341852da8afa3f1c Mon Sep 17 00:00:00 2001
From: Lee, Chun-Yi <jlee@xxxxxxxx>
Date: Mon, 17 Sep 2012 11:13:24 +0800
Subject: [PATCH] acer-wmi: fix obj is NULL but dereferenced
Fengguang Wu run coccinelle and warns about:
drivers/platform/x86/acer-wmi.c:1200:17-21: ERROR: obj is NULL but dereferenced.
drivers/platform/x86/acer-wmi.c:891:17-21: ERROR: obj is NULL but dereferenced.
drivers/platform/x86/acer-wmi.c:1953:17-21: ERROR: obj is NULL but dereferenced.
It causes by the code in patch 987dfbaa65b2c3568b85e29d2598da08a011ee09 doesn't check
obj variable should not be NULL. There have risk for dereference a NULL obj, so add
this patch to fix.
Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
drivers/platform/x86/acer-wmi.c | 46 +++++++++++++++++++++-----------------
1 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 00d8c39..5ff493e 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -884,7 +884,7 @@ WMI_execute_u32(u32 method_id, u32 in, u32 *out)
struct acpi_buffer input = { (acpi_size) sizeof(u32), (void *)(&in) };
struct acpi_buffer result = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
- u32 tmp;
+ u32 tmp = 0;
acpi_status status;
status = wmi_evaluate_method(WMID_GUID1, 1, method_id, &input, &result);
@@ -893,14 +893,14 @@ WMI_execute_u32(u32 method_id, u32 in, u32 *out)
return status;
obj = (union acpi_object *) result.pointer;
- if (obj && obj->type == ACPI_TYPE_BUFFER &&
- (obj->buffer.length == sizeof(u32) ||
- obj->buffer.length == sizeof(u64))) {
- tmp = *((u32 *) obj->buffer.pointer);
- } else if (obj->type == ACPI_TYPE_INTEGER) {
- tmp = (u32) obj->integer.value;
- } else {
- tmp = 0;
+ if (obj) {
+ if (obj->type == ACPI_TYPE_BUFFER &&
+ (obj->buffer.length == sizeof(u32) ||
+ obj->buffer.length == sizeof(u64))) {
+ tmp = *((u32 *) obj->buffer.pointer);
+ } else if (obj->type == ACPI_TYPE_INTEGER) {
+ tmp = (u32) obj->integer.value;
+ }
}
if (out)
@@ -1202,12 +1202,14 @@ static acpi_status WMID_set_capabilities(void)
return status;
obj = (union acpi_object *) out.pointer;
- if (obj && obj->type == ACPI_TYPE_BUFFER &&
- (obj->buffer.length == sizeof(u32) ||
- obj->buffer.length == sizeof(u64))) {
- devices = *((u32 *) obj->buffer.pointer);
- } else if (obj->type == ACPI_TYPE_INTEGER) {
- devices = (u32) obj->integer.value;
+ if (obj) {
+ if (obj->type == ACPI_TYPE_BUFFER &&
+ (obj->buffer.length == sizeof(u32) ||
+ obj->buffer.length == sizeof(u64))) {
+ devices = *((u32 *) obj->buffer.pointer);
+ } else if (obj->type == ACPI_TYPE_INTEGER) {
+ devices = (u32) obj->integer.value;
+ }
} else {
kfree(out.pointer);
return AE_ERROR;
@@ -1955,12 +1957,14 @@ static u32 get_wmid_devices(void)
return 0;
obj = (union acpi_object *) out.pointer;
- if (obj && obj->type == ACPI_TYPE_BUFFER &&
- (obj->buffer.length == sizeof(u32) ||
- obj->buffer.length == sizeof(u64))) {
- devices = *((u32 *) obj->buffer.pointer);
- } else if (obj->type == ACPI_TYPE_INTEGER) {
- devices = (u32) obj->integer.value;
+ if (obj) {
+ if (obj->type == ACPI_TYPE_BUFFER &&
+ (obj->buffer.length == sizeof(u32) ||
+ obj->buffer.length == sizeof(u64))) {
+ devices = *((u32 *) obj->buffer.pointer);
+ } else if (obj->type == ACPI_TYPE_INTEGER) {
+ devices = (u32) obj->integer.value;
+ }
}
kfree(out.pointer);
--
1.6.0.2
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