Commit 3aa1dc3c authored by Kees Cook's avatar Kees Cook Committed by Luiz Augusto von Dentz
Browse files

Bluetooth: btintel: Check dsbr size from EFI variable 



Since the size of struct btintel_dsbr is already known, we can just
start there instead of querying the EFI variable size. If the final
result doesn't match what we expect also fail. This fixes a stack buffer
overflow when the EFI variable is larger than struct btintel_dsbr.

Reported-by: default avatarzepta <z3ptaa@gmail.com>
Closes: https://lore.kernel.org/all/CAPBS6KoaWV9=dtjTESZiU6KK__OZX0KpDk-=JEH8jCHFLUYv3Q@mail.gmail.com


Fixes: eb9e749c ("Bluetooth: btintel: Allow configuring drive strength of BRI")
Signed-off-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 3bb88524

drivers/bluetooth/btintel.c

+2 −8
Original line number Diff line number Diff line
@@ -2719,7 +2719,7 @@ static int btintel_uefi_get_dsbr(u32 *dsbr_var) 
	} __packed data;



	efi_status_t status;

	unsigned long data_size = 0;

	unsigned long data_size = sizeof(data);

	efi_guid_t guid = EFI_GUID(0xe65d8884, 0xd4af, 0x4b20, 0x8d, 0x03,

				   0x77, 0x2e, 0xcc, 0x3d, 0xa5, 0x31);
@@ -2729,16 +2729,10 @@ static int btintel_uefi_get_dsbr(u32 *dsbr_var) 
	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))

		return -EOPNOTSUPP;



	status = efi.get_variable(BTINTEL_EFI_DSBR, &guid, NULL, &data_size,

				  NULL);



	if (status != EFI_BUFFER_TOO_SMALL || !data_size)

		return -EIO;



	status = efi.get_variable(BTINTEL_EFI_DSBR, &guid, NULL, &data_size,

				  &data);



	if (status != EFI_SUCCESS)

	if (status != EFI_SUCCESS || data_size != sizeof(data))

		return -ENXIO;



	*dsbr_var = data.dsbr;