On Tue, Jan 25, 2022 at 12:40:14AM +0800, Zhou Qingyang wrote:
> In acpi_db_convert_to_package(), the variable elements is assigned by
> ACPI_ALLOCATE_ZEROED() and passes its address to
> acpi_db_convert_to_object(). In that function we may have a dereference
> of elements without checks. ACPI_ALLOCATE_ZEROED() would return NULL on
> failure, which may lead to NULL pointer dereference.
>
> Fix this bug by adding a NULL check of elements.
>
> This bug was found by a static analyzer.
>
> Builds with 'make allyesconfig' show no new warnings,
> and our static analyzer no longer warns about this code.
>
> Fixes: 995751025572 ("ACPICA: Linuxize: Export debugger files to Linux")
> Signed-off-by: Zhou Qingyang <zhou1615@xxxxxxx>
> ---
> The analysis employs differential checking to identify inconsistent
> security operations (e.g., checks or kfrees) between two code paths
> and confirms that the inconsistent operations are not recovered in the
> current function or the callers, so they constitute bugs.
>
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger. Multiple researchers have cross-reviewed
> the bug.
>
> drivers/acpi/acpica/dbconvert.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/acpi/acpica/dbconvert.c b/drivers/acpi/acpica/dbconvert.c
> index 2b84ac093698..8dbab6932049 100644
> --- a/drivers/acpi/acpica/dbconvert.c
> +++ b/drivers/acpi/acpica/dbconvert.c
> @@ -174,6 +174,8 @@ acpi_status acpi_db_convert_to_package(char *string, union acpi_object *object)
> elements =
> ACPI_ALLOCATE_ZEROED(DB_DEFAULT_PKG_ELEMENTS *
> sizeof(union acpi_object));
> + if (!elements)
> + return (AE_NO_MEMORY);
>
> this = string;
> for (i = 0; i < (DB_DEFAULT_PKG_ELEMENTS - 1); i++) {
> --
> 2.25.1
>
As stated before, umn.edu is still not allowed to contribute to the
Linux kernel. Please work with your administration to resolve this
issue.
