diff options
| author | James Bottomley <James.Bottomley@HansenPartnership.com> | 2022-03-07 15:58:03 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-28 08:46:48 +0200 |
| commit | 5b1d2561a03e534064b51c50c774657833d3d2cf (patch) | |
| tree | 370f110cd026439df9c7b66d7747845c53792f74 | |
| parent | 3bbd0000d012f92aec423b224784fbf0f7bf40f8 (diff) | |
tpm: use try_get_ops() in tpm-space.c
commit fb5abce6b2bb5cb3d628aaa63fa821da8c4600f9 upstream.
As part of the series conversion to remove nested TPM operations:
https://lore.kernel.org/all/20190205224723.19671-1-jarkko.sakkinen@linux.intel.com/
exposure of the chip->tpm_mutex was removed from much of the upper
level code. In this conversion, tpm2_del_space() was missed. This
didn't matter much because it's usually called closely after a
converted operation, so there's only a very tiny race window where the
chip can be removed before the space flushing is done which causes a
NULL deref on the mutex. However, there are reports of this window
being hit in practice, so fix this by converting tpm2_del_space() to
use tpm_try_get_ops(), which performs all the teardown checks before
acquring the mutex.
Cc: stable@vger.kernel.org # 5.4.x
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/tpm/tpm2-space.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c index 97e916856cf3e..d2225020e4d2c 100644 --- a/drivers/char/tpm/tpm2-space.c +++ b/drivers/char/tpm/tpm2-space.c @@ -58,12 +58,12 @@ int tpm2_init_space(struct tpm_space *space, unsigned int buf_size) void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space) { - mutex_lock(&chip->tpm_mutex); - if (!tpm_chip_start(chip)) { + + if (tpm_try_get_ops(chip) == 0) { tpm2_flush_sessions(chip, space); - tpm_chip_stop(chip); + tpm_put_ops(chip); } - mutex_unlock(&chip->tpm_mutex); + kfree(space->context_buf); kfree(space->session_buf); } |