6.15-stable review patch. If anyone has any objections, please let me know.
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From: Kees Cook kees@kernel.org
[ Upstream commit 3aa1dc3c9060e335e82e9c182bf3d1db29220b1b ]
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: zepta z3ptaa@gmail.com Closes: https://lore.kernel.org/all/CAPBS6KoaWV9=dtjTESZiU6KK__OZX0KpDk-=JEH8jCHFLUY... Fixes: eb9e749c0182 ("Bluetooth: btintel: Allow configuring drive strength of BRI") Signed-off-by: Kees Cook kees@kernel.org Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/btintel.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c index 48e2f400957bc..46d9bbd8e411b 100644 --- a/drivers/bluetooth/btintel.c +++ b/drivers/bluetooth/btintel.c @@ -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;