* [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields
@ 2021-04-27 1:41 Lv Yunlong
2021-04-29 18:00 ` Kaneda, Erik
0 siblings, 1 reply; 3+ messages in thread
From: Lv Yunlong @ 2021-04-27 1:41 UTC (permalink / raw)
To: robert.moore, erik.kaneda, rafael.j.wysocki, lenb
Cc: linux-acpi, devel, linux-kernel, Lv Yunlong
In acpi_db_walk_for_fields, buffer.pointer is freed in the first
time via ACPI_FREE() after acpi_os_printf("%s ", (char *)buffer.pointer).
But later, buffer.pointer is assigned to ret_value, and the freed
pointer is dereferenced by ret_value, which is use after free.
In addition, buffer.pointer is freed by ACPI_FREE() again after
acpi_os_printf("}\n"), which is a double free.
My patch removes the first ACPI_FREE() to avoid the uaf and double
free bugs.
Fixes: 5fd033288a866 ("ACPICA: debugger: add command to dump all fields of particular subtype")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
drivers/acpi/acpica/dbnames.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/acpi/acpica/dbnames.c b/drivers/acpi/acpica/dbnames.c
index 3615e1a6efd8..dabd76df15ec 100644
--- a/drivers/acpi/acpica/dbnames.c
+++ b/drivers/acpi/acpica/dbnames.c
@@ -547,7 +547,6 @@ acpi_db_walk_for_fields(acpi_handle obj_handle,
}
acpi_os_printf("%s ", (char *)buffer.pointer);
- ACPI_FREE(buffer.pointer);
buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
acpi_evaluate_object(obj_handle, NULL, NULL, &buffer);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields
2021-04-27 1:41 [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields Lv Yunlong
@ 2021-04-29 18:00 ` Kaneda, Erik
2021-05-05 23:11 ` Kaneda, Erik
0 siblings, 1 reply; 3+ messages in thread
From: Kaneda, Erik @ 2021-04-29 18:00 UTC (permalink / raw)
To: Lv Yunlong, Moore, Robert, Wysocki, Rafael J, lenb
Cc: linux-acpi, devel, linux-kernel
> -----Original Message-----
> From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> Sent: Monday, April 26, 2021 6:42 PM
> To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
> <erik.kaneda@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
> lenb@kernel.org
> Cc: linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> kernel@vger.kernel.org; Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> Subject: [PATCH] ACPICA:dbnames: Fix a error free in
> acpi_db_walk_for_fields
>
> In acpi_db_walk_for_fields, buffer.pointer is freed in the first
> time via ACPI_FREE() after acpi_os_printf("%s ", (char *)buffer.pointer).
> But later, buffer.pointer is assigned to ret_value, and the freed
> pointer is dereferenced by ret_value, which is use after free.
>
> In addition, buffer.pointer is freed by ACPI_FREE() again after
> acpi_os_printf("}\n"), which is a double free.
>
> My patch removes the first ACPI_FREE() to avoid the uaf and double
> free bugs.
>
I'll take a look
Thanks
> Fixes: 5fd033288a866 ("ACPICA: debugger: add command to dump all fields
> of particular subtype")
> Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> ---
> drivers/acpi/acpica/dbnames.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/acpi/acpica/dbnames.c b/drivers/acpi/acpica/dbnames.c
> index 3615e1a6efd8..dabd76df15ec 100644
> --- a/drivers/acpi/acpica/dbnames.c
> +++ b/drivers/acpi/acpica/dbnames.c
> @@ -547,7 +547,6 @@ acpi_db_walk_for_fields(acpi_handle obj_handle,
> }
>
> acpi_os_printf("%s ", (char *)buffer.pointer);
> - ACPI_FREE(buffer.pointer);
>
> buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
> acpi_evaluate_object(obj_handle, NULL, NULL, &buffer);
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields
2021-04-29 18:00 ` Kaneda, Erik
@ 2021-05-05 23:11 ` Kaneda, Erik
0 siblings, 0 replies; 3+ messages in thread
From: Kaneda, Erik @ 2021-05-05 23:11 UTC (permalink / raw)
To: Kaneda, Erik, Lv Yunlong, Moore, Robert, Wysocki, Rafael J, lenb
Cc: linux-acpi, devel, linux-kernel
> -----Original Message-----
> From: Kaneda, Erik <erik.kaneda@intel.com>
> Sent: Thursday, April 29, 2021 11:01 AM
> To: Lv Yunlong <lyl2019@mail.ustc.edu.cn>; Moore, Robert
> <robert.moore@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
> lenb@kernel.org
> Cc: linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> kernel@vger.kernel.org
> Subject: RE: [PATCH] ACPICA:dbnames: Fix a error free in
> acpi_db_walk_for_fields
>
>
>
> > -----Original Message-----
> > From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> > Sent: Monday, April 26, 2021 6:42 PM
> > To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
> > <erik.kaneda@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
> > lenb@kernel.org
> > Cc: linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> > kernel@vger.kernel.org; Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> > Subject: [PATCH] ACPICA:dbnames: Fix a error free in
> > acpi_db_walk_for_fields
> >
> > In acpi_db_walk_for_fields, buffer.pointer is freed in the first
> > time via ACPI_FREE() after acpi_os_printf("%s ", (char *)buffer.pointer).
> > But later, buffer.pointer is assigned to ret_value, and the freed
> > pointer is dereferenced by ret_value, which is use after free.
> >
> > In addition, buffer.pointer is freed by ACPI_FREE() again after
> > acpi_os_printf("}\n"), which is a double free.
> >
> > My patch removes the first ACPI_FREE() to avoid the uaf and double
> > free bugs.
> >
>
> I'll take a look
>
> Thanks
>
> > Fixes: 5fd033288a866 ("ACPICA: debugger: add command to dump all fields
> > of particular subtype")
> > Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> > ---
> > drivers/acpi/acpica/dbnames.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/acpi/acpica/dbnames.c b/drivers/acpi/acpica/dbnames.c
> > index 3615e1a6efd8..dabd76df15ec 100644
> > --- a/drivers/acpi/acpica/dbnames.c
> > +++ b/drivers/acpi/acpica/dbnames.c
> > @@ -547,7 +547,6 @@ acpi_db_walk_for_fields(acpi_handle obj_handle,
> > }
> >
> > acpi_os_printf("%s ", (char *)buffer.pointer);
> > - ACPI_FREE(buffer.pointer);
This is freeing the pointer allocated by acpi_ns_handle_to_pathname
> >
> > buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
> > acpi_evaluate_object(obj_handle, NULL, NULL, &buffer);
This call to acpi_evaluate_object will allocate an object in Buffer.Pointer object so the dereference of buffer->pointer is not a use after free
> > --
> > 2.25.1
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-05 23:11 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-27 1:41 [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields Lv Yunlong
2021-04-29 18:00 ` Kaneda, Erik
2021-05-05 23:11 ` Kaneda, Erik
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