KEYS: trusted: Don't use 'buf->handles'

[PATCH] KEYS: trusted: Don't use 'buf->handles'

Posted by Jarkko Sakkinen 1 week, 2 days ago

tpm2_unseal_trusted() deduces number of handles in run-time even tho the
expected value is known at compile time. Address the issue.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
 security/keys/trusted-keys/trusted_tpm2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 9074ae1a5896..e78061ee2d99 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -491,7 +491,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		if (tpm2_chip_auth(chip)) {
 			tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT, NULL, 0);
 		} else  {
-			offset = buf->handles * 4 + TPM_HEADER_SIZE;
+			offset = TPM_HEADER_SIZE + 2 * sizeof(u32);
 			head = (struct tpm_header *)buf->data;
 			if (tpm_buf_length(buf) == offset)
 				head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
-- 
2.39.5

Re: [PATCH] KEYS: trusted: Don't use 'buf->handles'

Posted by Jarkko Sakkinen 1 week, 2 days ago

On Tue, Dec 09, 2025 at 09:11:43AM +0200, Jarkko Sakkinen wrote:
> tpm2_unseal_trusted() deduces number of handles in run-time even tho the
> expected value is known at compile time. Address the issue.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
>  security/keys/trusted-keys/trusted_tpm2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
> index 9074ae1a5896..e78061ee2d99 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -491,7 +491,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
>  		if (tpm2_chip_auth(chip)) {
>  			tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT, NULL, 0);
>  		} else  {
> -			offset = buf->handles * 4 + TPM_HEADER_SIZE;
> +			offset = TPM_HEADER_SIZE + 2 * sizeof(u32);

Oops.

Should be 'TPM_HEADER_SIZE + sizeof(u32)'. There's just a single handle.

>  			head = (struct tpm_header *)buf->data;
>  			if (tpm_buf_length(buf) == offset)
>  				head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> -- 
> 2.39.5
> 

BR, Jarkko