From dc10e4181c05a2315ddc375e963b7c763b5ee0df Mon Sep 17 00:00:00 2001
From: Roberto Sassu <roberto.sassu@huawei.com>
Date: Mon, 10 Feb 2020 11:00:41 +0100
Subject: [PATCH] tpm: Initialize crypto_id of allocated_banks to HASH_ALGO__LAST
Git-commit: dc10e4181c05a2315ddc375e963b7c763b5ee0df
Patch-mainline: v5.6-rc3
References: git-fixes

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>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/char/tpm/tpm2-cmd.c | 2 ++
 1 file changed, 2 insertions(+)

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);
 }
 
-- 
2.16.4