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Add a cv_wait to the TPM2.0 harvesting function

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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@semihalf.com>
Reviewed by: delphij
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D19712
This commit is contained in:
mw 2019-04-03 08:22:58 +00:00
parent f7ba4b241e
commit 77b8255fbc
1 changed files with 2 additions and 0 deletions
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2
sys/dev/tpm/tpm20.c
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@ -263,6 +263,8 @@ tpm20_harvest(void *arg)
sc = arg; sc = arg;
sx_xlock(&sc->dev_lock); 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)); memcpy(sc->buf, cmd, sizeof(cmd));
result = sc->transmit(sc, sizeof(cmd)); result = sc->transmit(sc, sizeof(cmd));