svn commit: r345842 - head/sys/dev/tpm
Marcin Wojtas
mw at FreeBSD.org
Wed Apr 3 08:22:59 UTC 2019
Author: mw
Date: Wed Apr 3 08:22:58 2019
New Revision: 345842
URL: https://svnweb.freebsd.org/changeset/base/345842
Log:
Add a cv_wait to the TPM2.0 harvesting function
Harvesting has to compete for the TPM chip with userspace.
Before this change the callout could hijack an unread buffer
causing a userspace call to the TPM to fail.
Submitted by: Kornel Duleba <mindal at semihalf.com>
Reviewed by: delphij
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D19712
Modified:
head/sys/dev/tpm/tpm20.c
Modified: head/sys/dev/tpm/tpm20.c
==============================================================================
--- head/sys/dev/tpm/tpm20.c Wed Apr 3 08:18:18 2019 (r345841)
+++ head/sys/dev/tpm/tpm20.c Wed Apr 3 08:22:58 2019 (r345842)
@@ -263,6 +263,8 @@ tpm20_harvest(void *arg)
sc = arg;
sx_xlock(&sc->dev_lock);
+ while (sc->pending_data_length != 0)
+ cv_wait(&sc->buf_cv, &sc->dev_lock);
memcpy(sc->buf, cmd, sizeof(cmd));
result = sc->transmit(sc, sizeof(cmd));
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