From: Jarkko Sakkinen <[email protected]> tpm2_get_pcr_allocation() does not cap any upper limit for the number of banks. Cap the limit to eight banks so that out of bounds values coming from external I/O cause on only limited harm.
Cc: Roberto Sassu <[email protected]> Fixes: bcfff8384f6c ("tpm: dynamically allocate the allocated_banks array") Reviewed-By: Jonathan McDowell <[email protected]> Signed-off-by: Jarkko Sakkinen <[email protected]> --- v7: - In Ryzen desktop there is total three banks so yep, eight is probably much safer bet than four banks. Fixed the commit message as per remark from Jonathan: https://lore.kernel.org/linux-integrity/[email protected]/#t And with that added also reviewed-by. v6 - No changes. v5: - No changes. v4: - Revert spurious changes from include/linux/tpm.h. - Increase TPM2_MAX_BANKS to 8. - Rename TPM2_MAX_BANKS as TPM2_MAX_PCR_BANKS for the sake of clarity. v3: - Wrote a more clear commit message. - Fixed pr_err() message. 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 | 8 +++++--- 5 files changed, 17 insertions(+), 38 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index e25daf2396d3..6cb25862688f 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 2726bd38e5ac..a37712c02e44 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 11088bda4e68..708bc553437b 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..97501c567c34 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_PCR_BANKS) { + pr_err("tpm: unexpected number of banks: %u > %u", + nr_possible_banks, TPM2_MAX_PCR_BANKS); rc = -ENOMEM; goto out; } diff --git a/include/linux/tpm.h b/include/linux/tpm.h index dc0338a783f3..eb0ff071bcae 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -26,7 +26,9 @@ #include <crypto/aes.h> #define TPM_DIGEST_SIZE 20 /* Max TPM v1.2 PCR size */ -#define TPM_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE + +#define TPM2_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE +#define TPM2_MAX_PCR_BANKS 8 struct tpm_chip; struct trusted_key_payload; @@ -68,7 +70,7 @@ 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 { @@ -189,7 +191,7 @@ 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_PCR_BANKS]; #ifdef CONFIG_ACPI acpi_handle acpi_dev_handle; char ppi_version[TPM_PPI_VERSION_LEN + 1]; -- 2.52.0
