One of the things we always have to think about and look at is that often, things like
this are *guaranteed" to be valid simply by virtue of the fact that the code has
gotten as far as it has.
So, rather than litter the code with NULL checks for every single access, we know up front
that the object is valid.
This isn't always true and there are some valid situations, but we would appreciate it
if you help track this down.
From: Sudip Mukherjee [mailto:[email protected]
Sent: Thursday, September 10, 2015 3:19 AM
To: Moore, Robert; Zheng, Lv; Wysocki, Rafael J; Len Brown
Cc: linux-kernel(a)vger.kernel.org; linux-acpi(a)vger.kernel.org;
devel(a)acpica.org; Sudip Mukherjee
Subject: [PATCH] ACPICA: fix possible NULL dereference
acpi_ns_get_secondary_object() can return NULL, and if it returns NULL
then we were dereferencing it while calling acpi_ds_execute_arguments().
Lets have a NULL check and return AE_NOT_EXIST.
Signed-off-by: Sudip Mukherjee <sudip(a)vectorindia.org>
drivers/acpi/acpica/dsargs.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/acpi/acpica/dsargs.c b/drivers/acpi/acpica/dsargs.c
index e2ab59e..4bb8952 100644
@@ -192,6 +192,9 @@ acpi_ds_get_buffer_field_arguments(union
/* Get the AML pointer (method object) and buffer_field node */
extra_desc = acpi_ns_get_secondary_object(obj_desc);
+ if (!extra_desc)
node = obj_desc->buffer_field.node;