[v3,1/8] tpm: Initialize crypto_id of allocated_banks to HASH_ALGO__LAST
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Message ID 20200210100048.21448-2-roberto.sassu@huawei.com
State New
Headers show
Series
  • ima: support stronger algorithms for attestation
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Commit Message

Roberto Sassu Feb. 10, 2020, 10 a.m. UTC
chip->allocated_banks, an array of tpm_bank_info structures, contains the
list of TPM algorithm IDs of allocated PCR banks. It also contains the
corresponding ID of the crypto subsystem, so that users of the TPM driver
can calculate a digest for a PCR extend operation.

However, if there is no mapping between TPM algorithm ID and crypto ID, the
crypto_id field of tpm_bank_info remains set to zero (the array is
allocated and initialized with kcalloc() in tpm2_get_pcr_allocation()).
Zero should not be used as value for unknown mappings, as it is a valid
crypto ID (HASH_ALGO_MD4).

Thus, initialize crypto_id to HASH_ALGO__LAST.

Cc: stable@vger.kernel.org # 5.1.x
Fixes: 879b589210a9 ("tpm: retrieve digest size of unknown algorithms with PCR read")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
---
 drivers/char/tpm/tpm2-cmd.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Jarkko Sakkinen Feb. 10, 2020, 4 p.m. UTC | #1
On Mon, Feb 10, 2020 at 11:00:41AM +0100, Roberto Sassu wrote:
> chip->allocated_banks, an array of tpm_bank_info structures, contains the
> list of TPM algorithm IDs of allocated PCR banks. It also contains the
> corresponding ID of the crypto subsystem, so that users of the TPM driver
> can calculate a digest for a PCR extend operation.
> 
> However, if there is no mapping between TPM algorithm ID and crypto ID, the
> crypto_id field of tpm_bank_info remains set to zero (the array is
> allocated and initialized with kcalloc() in tpm2_get_pcr_allocation()).
> Zero should not be used as value for unknown mappings, as it is a valid
> crypto ID (HASH_ALGO_MD4).
> 
> Thus, initialize crypto_id to HASH_ALGO__LAST.
> 
> Cc: stable@vger.kernel.org # 5.1.x
> Fixes: 879b589210a9 ("tpm: retrieve digest size of unknown algorithms with PCR read")
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Reviewed-by: Petr Vorel <pvorel@suse.cz>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

Patch
diff mbox series

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 13696deceae8..760329598b99 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -525,6 +525,8 @@  static int tpm2_init_bank_info(struct tpm_chip *chip, u32 bank_index)
 		return 0;
 	}
 
+	bank->crypto_id = HASH_ALGO__LAST;
+
 	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
 }