Reads on tpm/tpm0/ppi/*operations can become very long on
misconfigured systems. Reading the TPM is a blocking operation,
thus a user could effectively trigger a DOS.
Resolve this by caching the results and avoiding the blocking
operations after the first read.
[ jarkko: fixed atomic sleep:
sed -i 's/spin_/mutex_/g' drivers/char/tpm/tpm_ppi.c
sed -i 's/DEFINE_SPINLOCK/DEFINE_MUTEX/g' drivers/char/tpm/tpm_ppi.c ]
Signed-off-by: Denis Aleksandrov <daleksan@redhat.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Closes: https://lore.kernel.org/linux-integrity/20250915210829.6661-1-daleksan@redhat.com/T/#u
Suggested-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
a29ad21b98