On Thu, Dec 13, 2018 at 11:29:45AM +0100, Roberto Sassu wrote:
Currently, tpm_pcr_extend() accepts as an input only a SHA1 digest.
This patch modifies the definition of tpm_pcr_extend() to allow other
kernel subsystems to pass a digest for each algorithm supported by the TPM.
All digests are processed by the TPM in one operation.
If a tpm_pcr_extend() caller provides a subset of the supported algorithms,
the TPM driver extends the remaining PCR banks with the first digest
passed as an argument to the function.
The new tpm_extend digest structure has been preferred to the tpm_digest
structure, to let the caller specify the size of the digest (which may be
unknown to the TPM driver).
Due to the API change, ima_pcr_extend() and pcrlock() have been modified.
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
drivers/char/tpm/tpm-interface.c | 24 +++++---------------
drivers/char/tpm/tpm.h | 5 +++--
drivers/char/tpm/tpm1-cmd.c | 13 ++++++++---
drivers/char/tpm/tpm2-cmd.c | 35 +++++++++++++++++++++---------
include/linux/tpm.h | 13 ++++++++---
security/integrity/ima/ima_queue.c | 5 ++++-
security/keys/trusted.c | 5 ++++-
7 files changed, 62 insertions(+), 38 deletions(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index eb7c79ca8a94..911fea19e408 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -478,42 +478,30 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
* tpm_pcr_extend - extend a PCR value in SHA1 bank.
* @chip: a &struct tpm_chip instance, %NULL for the default chip
* @pcr_idx: the PCR to be retrieved
- * @hash: the hash value used to extend the PCR value
+ * @count: number of tpm_extend_digest structures
+ * @digests: array of tpm_extend_digest structures used to extend PCRs
*
* Note: with TPM 2.0 extends also those banks for which no digest was
* specified in order to prevent malicious use of those PCR banks.
*
* Return: same as with tpm_transmit_cmd()
*/
-int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
+int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+ const struct tpm_extend_digest *digests)
Remove const. Document how @digests is used like the special meaning
of the first index. I faintly remember asking this last time.
{
int rc;
- struct tpm_digest *digest_list;
- int i;
chip = tpm_find_get_ops(chip);
if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- digest_list = kcalloc(chip->nr_allocated_banks,
- sizeof(*digest_list), GFP_KERNEL);
- if (!digest_list)
- return -ENOMEM;
-
- for (i = 0; i < chip->nr_allocated_banks; i++) {
- digest_list[i].alg_id = chip->allocated_banks[i].alg_id;
- memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
- }
-
- rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_allocated_banks,
- digest_list);
- kfree(digest_list);
+ rc = tpm2_pcr_extend(chip, pcr_idx, count, digests);
tpm_put_ops(chip);
return rc;
}
- rc = tpm1_pcr_extend(chip, pcr_idx, hash,
+ rc = tpm1_pcr_extend(chip, pcr_idx, count, digests,
"attempting extend a PCR value");
The validation is missing that the provided array has only one element
and the algorithm is SHA1. Could be done also inside tpm1_pcr_extend()
but what you are doing to that function does not make any sense so
better to do it here.
tpm_put_ops(chip);
return rc;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 64d93d26087f..6b446504d2fe 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -504,7 +504,8 @@ int tpm1_auto_startup(struct tpm_chip *chip);
int tpm1_do_selftest(struct tpm_chip *chip);
int tpm1_get_timeouts(struct tpm_chip *chip);
unsigned long tpm1_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
-int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+ const struct tpm_extend_digest *digests,
const char *log_msg);
int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
@@ -551,7 +552,7 @@ int tpm2_get_timeouts(struct tpm_chip *chip);
int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest, u16 *digest_size_ptr);
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
- struct tpm_digest *digests);
+ const struct tpm_extend_digest *digests);
int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
unsigned int flags);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 8b70a7f884a7..04ee10284b8c 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -449,12 +449,20 @@ int tpm1_get_timeouts(struct tpm_chip *chip)
}
#define TPM_ORD_PCR_EXTEND 20
-int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+ const struct tpm_extend_digest *digests,
const char *log_msg)
{
struct tpm_buf buf;
+ u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
+ const u8 *hash;
int rc;
+ hash = dummy_hash;
+ if (count)
+ memcpy(dummy_hash, digests[0].data,
+ min(digests[0].size, (u16)sizeof(dummy_hash)));
+
You copy memory from one place to another without any good reason to do
so. My suggestion is just not to change tpm1_pcr_extend() at all.
rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
if (rc)
return rc;
@@ -743,7 +751,6 @@ int tpm1_auto_startup(struct tpm_chip *chip)
*/
int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
{
- u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
struct tpm_buf buf;
unsigned int try;
int rc;
@@ -751,7 +758,7 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
/* for buggy tpm, flush pcrs with extend to selected dummy */
if (tpm_suspend_pcr)
- rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
+ rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, 0, NULL,
"extending dummy pcr before suspend");
rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 6ce5173cf0e5..77b5808270c6 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -247,21 +247,22 @@ struct tpm2_null_auth_area {
*
* @chip: TPM chip to use.
* @pcr_idx: index of the PCR.
- * @count: number of digests passed.
- * @digests: list of pcr banks and corresponding digest values to extend.
+ * @count: number of tpm_extend_digest passed.
+ * @digests: array of tpm_extend_digest with digest values to extend.
*
* Return: Same as with tpm_transmit_cmd.
*/
The documentation about @digests.
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
- struct tpm_digest *digests)
+ const struct tpm_extend_digest *digests)
{
struct tpm_buf buf;
struct tpm2_null_auth_area auth_area;
+ const struct tpm_extend_digest *digest;
+ u8 dummy_hash[SHA512_DIGEST_SIZE] = { 0 };
+ const u8 *hash;
int rc;
int i;
-
- if (count > chip->nr_allocated_banks)
- return -EINVAL;
+ int j;
rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
if (rc)
@@ -277,11 +278,25 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area));
tpm_buf_append(&buf, (const unsigned char *)&auth_area,
sizeof(auth_area));
- tpm_buf_append_u32(&buf, count);
+ tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
+
+ if (count)
+ memcpy(dummy_hash, digests[0].data, digests[0].size);
+
+ for (i = 0; i < chip->nr_allocated_banks; i++) {
+ tpm_buf_append_u16(&buf, chip->allocated_banks[i].alg_id);
+
+ hash = dummy_hash;
+ for (j = 0; j < count; j++) {
+ digest = digests + j;
+
+ if (digest->alg_id == chip->allocated_banks[i].alg_id) {
+ hash = digest->data;
+ break;
I think the whole design is just wrong. I did re-read your response to
v6 again and I'm very sorry, but I just don't get this. Caller has all
the information (from struct tpm_chip) to give the correct data. This
function should validate that data (check algorithm ID and that's it).
