efi/efi_test: Prevent an Oops in efi_runtime_query_capsulecaps()

If "qcaps.capsule_count" is ULONG_MAX then "qcaps.capsule_count + 1"
will overflow to zero and kcalloc() will return the ZERO_SIZE_PTR.  We
try to dereference it inside the loop and crash.

Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Acked-by: Ivan Hu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: ff6301dabc ("efi: Add efi_test driver for exporting UEFI runtime service interfaces")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Dan Carpenter 2017-10-25 11:04:47 +01:00 • committed by Ingo Molnar
commit 092e72c9ed

View file

@ -593,6 +593,9 @@ static long efi_runtime_query_capsulecaps(unsigned long arg)
if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps)))
return -EFAULT;
if (qcaps.capsule_count == ULONG_MAX)
return -EINVAL;
capsules = kcalloc(qcaps.capsule_count + 1,
sizeof(efi_capsule_header_t), GFP_KERNEL);
if (!capsules)