2010-07-09 03:51:04

by Axel Lin

Subject: [PATCH] acer-wmi: fix memory leaks in wmab_execute error path

When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
the caller must kfree the returned buffer if AE_OK is returned.

Call Trace:
wmab_execute
-> wmi_evaluate_method
-> acpi_evaluate_object

Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
the return buffer must be kfreed if wmab_execute return AE_OK.

Signed-off-by: Axel Lin <[email protected]>
---
drivers/platform/x86/acer-wmi.c | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 1ea6c43..a158d39 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}

@@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}

@@ -607,15 +609,24 @@ static acpi_status AMW0_set_capabilities(void)
args.ebx = 2 << 8;
args.ebx |= ACER_AMW0_BLUETOOTH_MASK;

+ /*
+ * It's ok to use existing buffer for next wmab_execute call.
+ * But we need to kfree(out.pointer) if next wmab_execute call
+ * returns AE_BUFFER_OVERFLOW.
+ */
status = wmab_execute(&args, &out);
- if (ACPI_FAILURE(status))
+ if (ACPI_FAILURE(status)) {
+ if (status == AE_BUFFER_OVERFLOW)
+ kfree(out.pointer);
return status;
+ }

obj = (union acpi_object *) out.pointer;
if (obj && obj->type == ACPI_TYPE_BUFFER
&& obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}

--
1.5.4.3

2010-07-09 20:54:11

by Carlos Corbacho

Subject: Re: [PATCH] acer-wmi: fix memory leaks in wmab_execute error path

On Friday 09 July 2010 04:51:15 Axel Lin wrote:
> When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
> the caller must kfree the returned buffer if AE_OK is returned.
>
> Call Trace:
> wmab_execute
> -> wmi_evaluate_method
> -> acpi_evaluate_object
>
> Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
> the return buffer must be kfreed if wmab_execute return AE_OK.
>
> Signed-off-by: Axel Lin <[email protected]>

Acked-by: Carlos Corbacho <[email protected]>
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