The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x faf07e611dfa464b201223a7253e9dc5ee0f3c9e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025122959-residence-cover-1b11@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From faf07e611dfa464b201223a7253e9dc5ee0f3c9e Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen jarkko@kernel.org Date: Tue, 30 Sep 2025 15:58:02 +0300 Subject: [PATCH] tpm: Cap the number of PCR banks

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: stable@vger.kernel.org # v5.10+ Fixes: bcfff8384f6c ("tpm: dynamically allocate the allocated_banks array") Tested-by: Lai Yi yi1.lai@linux.intel.com Reviewed-by: Jonathan McDowell noodles@meta.com Reviewed-by: Roberto Sassu roberto.sassu@huawei.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@opinsys.com

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 30d00219f9f3..082b910ddf0d 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -246,7 +246,6 @@ static void tpm_dev_release(struct device *dev)

kfree(chip->work_space.context_buf); kfree(chip->work_space.session_buf); - kfree(chip->allocated_banks); #ifdef CONFIG_TCG_TPM2_HMAC kfree(chip->auth); #endif diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index cf64c7385105..b49a790f1bd5 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -799,11 +799,6 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr) */ 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; diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 5532e53a2dd3..dd502322f499 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -550,11 +550,9 @@ 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: out of bank capacity: %u > %u\n", + nr_possible_banks, TPM2_MAX_PCR_BANKS); rc = -ENOMEM; goto out; } diff --git a/include/linux/tpm.h b/include/linux/tpm.h index b15360ff78d7..53de9488c509 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];