From: Jarkko Sakkinen <[email protected]> tpm2_get_pcr_allocation() does not cap any upper limit for the number of banks received from external hardware device. This could lead into resource over-consumption with a fauly TPM device.
Cc: Roberto Sassu <[email protected]> Fixes: bcfff8384f6c ("tpm: dynamically allocate the allocated_banks array") Signed-off-by: Jarkko Sakkinen <[email protected]> --- v2: - A new patch. --- drivers/char/tpm/tpm-chip.c | 13 +++++++++---- drivers/char/tpm/tpm.h | 1 - drivers/char/tpm/tpm1-cmd.c | 25 ------------------------- drivers/char/tpm/tpm2-cmd.c | 8 +++----- include/linux/tpm.h | 18 ++++++++---------- 5 files changed, 20 insertions(+), 45 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 687f6d8cd601..9a6538f76f50 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -559,14 +559,19 @@ static int tpm_add_hwrng(struct tpm_chip *chip) static int tpm_get_pcr_allocation(struct tpm_chip *chip) { - int rc; + int rc = 0; if (tpm_is_firmware_upgrade(chip)) return 0; - rc = (chip->flags & TPM_CHIP_FLAG_TPM2) ? - tpm2_get_pcr_allocation(chip) : - tpm1_get_pcr_allocation(chip); + if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { + chip->allocated_banks[0].alg_id = TPM_ALG_SHA1; + chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1]; + chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1; + chip->nr_allocated_banks = 1; + } else { + rc = tpm2_get_pcr_allocation(chip); + } if (rc > 0) return -ENODEV; diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 57ef8589f5f5..769fa6b00c54 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -252,7 +252,6 @@ 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, const char *desc, size_t min_cap_length); int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max); -int tpm1_get_pcr_allocation(struct tpm_chip *chip); unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal); int tpm_pm_suspend(struct device *dev); int tpm_pm_resume(struct device *dev); diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index cf64c7385105..5c49bdff33de 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -786,28 +786,3 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr) return rc; } - -/** - * tpm1_get_pcr_allocation() - initialize the allocated bank - * @chip: TPM chip to use. - * - * The function initializes the SHA1 allocated bank to extend PCR - * - * Return: - * * 0 on success, - * * < 0 on error. - */ -int tpm1_get_pcr_allocation(struct tpm_chip *chip) -{ - chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks), - GFP_KERNEL); - if (!chip->allocated_banks) - return -ENOMEM; - - chip->allocated_banks[0].alg_id = TPM_ALG_SHA1; - chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1]; - chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1; - chip->nr_allocated_banks = 1; - - return 0; -} diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 7d77f6fbc152..e416cc8705e3 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -538,11 +538,9 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) nr_possible_banks = be32_to_cpup( (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]); - - chip->allocated_banks = kcalloc(nr_possible_banks, - sizeof(*chip->allocated_banks), - GFP_KERNEL); - if (!chip->allocated_banks) { + if (nr_possible_banks > TPM2_MAX_BANKS) { + pr_err("tpm:: unexpected large number of banks: %u > %u", + nr_possible_banks, TPM2_MAX_BANKS); rc = -ENOMEM; goto out; } diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 900c81a2bc41..fc7df87dfb9a 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -27,7 +27,12 @@ #include <crypto/aes.h> #define TPM_DIGEST_SIZE 20 /* Max TPM v1.2 PCR size */ -#define TPM_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE +#define TPM_HEADER_SIZE 10 + +#define TPM2_PLATFORM_PCR 24 +#define TPM2_PCR_SELECT_MIN 3 +#define TPM2_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE +#define TPM2_MAX_BANKS 4 struct tpm_chip; struct trusted_key_payload; @@ -69,7 +74,7 @@ enum tpm2_curves { struct tpm_digest { u16 alg_id; - u8 digest[TPM_MAX_DIGEST_SIZE]; + u8 digest[TPM2_MAX_DIGEST_SIZE]; } __packed; struct tpm_bank_info { @@ -190,7 +195,7 @@ struct tpm_chip { unsigned int groups_cnt; u32 nr_allocated_banks; - struct tpm_bank_info *allocated_banks; + struct tpm_bank_info allocated_banks[TPM2_MAX_BANKS]; #ifdef CONFIG_ACPI acpi_handle acpi_dev_handle; char ppi_version[TPM_PPI_VERSION_LEN + 1]; @@ -217,13 +222,6 @@ struct tpm_chip { #endif }; -#define TPM_HEADER_SIZE 10 - -enum tpm2_const { - TPM2_PLATFORM_PCR = 24, - TPM2_PCR_SELECT_MIN = ((TPM2_PLATFORM_PCR + 7) / 8), -}; - enum tpm2_timeouts { TPM2_TIMEOUT_A = 750, TPM2_TIMEOUT_B = 4000, -- 2.39.5
