[PATCH v5 04/17] tpm: call tpm2_flush_space() on error in tpm_try_transmit()
From: Jarkko Sakkinen <hidden>
Date: 2018-11-08 14:16:25
Also in:
linux-integrity, lkml, stable
Subsystem:
the rest, tpm device driver · Maintainers:
Linus Torvalds, Peter Huewe, Jarkko Sakkinen
Always call tpm2_flush_space() on failure in tpm_try_transmit() so that
the volatile memory of the TPM gets cleared. If /dev/tpm0 does not have
sufficient permissions (usually it has), this could lead to the leakage
of TPM objects. Through /dev/tpmrm0 this issue does not raise any new
security concerns.
Cc: stable@vger.kernel.org
Fixes: 745b361e989a ("tpm:tpm: infrastructure for TPM spaces")
Signed-off-by: Jarkko Sakkinen <redacted>
---
drivers/char/tpm/tpm-interface.c | 33 +++++++++++++++-----------------
drivers/char/tpm/tpm.h | 1 +
drivers/char/tpm/tpm2-space.c | 2 +-
3 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 64510ed81b46..c9efd1b9fd2c 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c@@ -224,14 +224,14 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, rc = tpm2_prepare_space(chip, space, ordinal, buf); if (rc) - goto out; + goto out_idle; rc = chip->ops->send(chip, buf, count); if (rc < 0) { if (rc != -EPIPE) dev_err(&chip->dev, "%s: tpm_send: error %d\n", __func__, rc); - goto out; + goto out_space; } if (chip->flags & TPM_CHIP_FLAG_IRQ)
@@ -247,7 +247,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, if (chip->ops->req_canceled(chip, status)) { dev_err(&chip->dev, "Operation Canceled\n"); rc = -ECANCELED; - goto out; + goto out_space; } tpm_msleep(TPM_TIMEOUT_POLL);
@@ -257,30 +257,27 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, chip->ops->cancel(chip); dev_err(&chip->dev, "Operation Timed out\n"); rc = -ETIME; - goto out; + goto out_space; out_recv: len = chip->ops->recv(chip, buf, bufsiz); if (len < 0) { rc = len; - dev_err(&chip->dev, - "tpm_transmit: tpm_recv: error %d\n", rc); - goto out; - } else if (len < TPM_HEADER_SIZE) { + dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc); + } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) rc = -EFAULT; - goto out; - } - if (len != be32_to_cpu(header->length)) { - rc = -EFAULT; - goto out; +out_space: + if (rc) { + tpm2_flush_space(chip); + } else { + rc = tpm2_commit_space(chip, space, ordinal, buf, &len); + if (rc) + dev_err(&chip->dev, "tpm2_commit_space: error %d\n", + rc); } - rc = tpm2_commit_space(chip, space, ordinal, buf, &len); - if (rc) - dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc); - -out: +out_idle: /* may fail but do not override previous error value in rc */ tpm_go_idle(chip, flags);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 49bca4d1e786..229ac42b644e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h@@ -579,6 +579,7 @@ int tpm2_probe(struct tpm_chip *chip); int tpm2_find_cc(struct tpm_chip *chip, u32 cc); int tpm2_init_space(struct tpm_space *space); void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space); +void tpm2_flush_space(struct tpm_chip *chip); int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc, u8 *cmd); int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 1131a8e7b79b..d53c882268ff 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c@@ -162,7 +162,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf, return 0; } -static void tpm2_flush_space(struct tpm_chip *chip) +void tpm2_flush_space(struct tpm_chip *chip) { struct tpm_space *space = &chip->work_space; int i;
--
2.19.1