On Sun, Oct 25, 2026 at 02:11:19PM -0700, Eric Biggers wrote:
> crypto_kpp_set_secret() can fail, for example if the kernel is booted
> with fips=1 and the broken-by-design FIPS RNG used for ECC private key
> generation doesn't feel like generating random bytes at the moment.
> Check for error, cancelling the TPM session creation rather than
> proceeding with a zero or uninitialized private key.
>
> Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions")
> Cc: [email protected]
> Signed-off-by: Eric Biggers <[email protected]>
> ---
> drivers/char/tpm/tpm2-sessions.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm2-sessions.c
> b/drivers/char/tpm/tpm2-sessions.c
> index ca1e2bf424e14..2aaaad69760dc 100644
> --- a/drivers/char/tpm/tpm2-sessions.c
> +++ b/drivers/char/tpm/tpm2-sessions.c
> @@ -527,7 +527,9 @@ static int tpm_buf_append_salt(struct tpm_buf *buf,
> struct tpm_chip *chip,
> }
> crypto_ecdh_encode_key(encoded_key, buf_len, &p);
> /* this generates a random private key */
Could you delete this comment while at it? It's not helping with
anything.
> - crypto_kpp_set_secret(kpp, encoded_key, buf_len);
> + rc = crypto_kpp_set_secret(kpp, encoded_key, buf_len);
> + if (rc)
> + goto err_free_kpp;
>
> /* salt is now the public point of this private key */
> req = kpp_request_alloc(kpp, GFP_KERNEL);
>
> base-commit: 21a7f44fd0765fcc5194130b28767786eba1d1e7
> --
> 2.56.0
>
[1] https://lore.kernel.org/linux-integrity/[email protected]/
Br, Jarkko
