efi/libstub/tpm: Initialize pointer variables to zero for mixed mode
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Tue, 13 Mar 2018 14:09:21 +0000 (14:09 +0000)
committerIngo Molnar <mingo@kernel.org>
Tue, 13 Mar 2018 14:28:29 +0000 (15:28 +0100)
commit79832f0b5f718e0023d9dd73e6845310609a564d
tree676d06e2e0b97673702dcc7ac8e5a0bfd41028c5
parentfc6eabbbf8ef99efed778dd5afabc83c21dba585
efi/libstub/tpm: Initialize pointer variables to zero for mixed mode

As reported by Jeremy Cline, running the new TPM libstub code in mixed
mode (i.e., 64-bit kernel on 32-bit UEFI) results in hangs when invoking
the TCG2 protocol, or when accessing the log_tbl pool allocation.

The reason turns out to be that in both cases, the 64-bit pointer
variables are not fully initialized by the 32-bit EFI code, and so
we should take care to zero initialize these variables beforehand,
or we'll end up dereferencing bogus pointers.

Reported-by: Jeremy Cline <jeremy@jcline.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hdegoede@redhat.com
Cc: jarkko.sakkinen@linux.intel.com
Cc: javierm@redhat.com
Cc: linux-efi@vger.kernel.org
Cc: tweek@google.com
Link: http://lkml.kernel.org/r/20180313140922.17266-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
drivers/firmware/efi/libstub/tpm.c