On Thu, 12 Dec 2019 at 13:45, Hans de Goede hdegoede@redhat.com wrote:
Hi,
On 12-12-2019 12:29, Ard Biesheuvel wrote:
On Thu, 12 Dec 2019 at 11:32, Hans de Goede hdegoede@redhat.com wrote:
When running in EFI mixed mode (running a 64 bit kernel on 32 bit EFI firmware), we _must_ initialize any pointers which are returned by reference by an EFI call to NULL before making the EFI call.
In mixed mode pointers are 64 bit, but when running on a 32 bit firmware, EFI calls which return a pointer value by reference only fill the lower 32 bits of the passed pointer, leaving the upper 32 bits uninitialized unless we explicitly set them to 0 before the call.
We have had this bug in the efi-stub-helper.c file reading code for a while now, but this has likely not been noticed sofar because this code only gets triggered when LILO style file=... arguments are present on the kernel cmdline.
Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com
drivers/firmware/efi/libstub/efi-stub-helper.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index e02579907f2e..6ca7d86743af 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -365,7 +365,7 @@ static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh, u64 *file_sz) { efi_file_handle_t *h, *fh = __fh;
What about h? Doesn't it suffer from the same problem?
efi_file_info_t *info;
efi_file_info_t *info = NULL; efi_status_t status; efi_guid_t info_guid = EFI_FILE_INFO_ID; unsigned long info_sz;And info_sz?
And "efi_file_io_interface_t *io" and "efi_file_handle_t *fh" in efi_open_volume().
I think that is all of them.
OK.
I'll fix it up locally.