From: Stefan Mahnke-Hartmann stefan.mahnke-hartmann@infineon.com
commit e57b2523bd37e6434f4e64c7a685e3715ad21e9a upstream.
Under certain conditions uninitialized memory will be accessed. As described by TCG Trusted Platform Module Library Specification, rev. 1.59 (Part 3: Commands), if a TPM2_GetCapability is received, requesting a capability, the TPM in field upgrade mode may return a zero length list. Check the property count in tpm2_get_tpm_pt().
Fixes: 2ab3241161b3 ("tpm: migrate tpm2_get_tpm_pt() to use struct tpm_buf") Cc: stable@vger.kernel.org Signed-off-by: Stefan Mahnke-Hartmann stefan.mahnke-hartmann@infineon.com Reviewed-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/tpm/tpm2-cmd.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
--- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -400,7 +400,16 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip if (!rc) { out = (struct tpm2_get_cap_out *) &buf.data[TPM_HEADER_SIZE]; - *value = be32_to_cpu(out->value); + /* + * To prevent failing boot up of some systems, Infineon TPM2.0 + * returns SUCCESS on TPM2_Startup in field upgrade mode. Also + * the TPM2_Getcapability command returns a zero length list + * in field upgrade mode. + */ + if (be32_to_cpu(out->property_cnt) > 0) + *value = be32_to_cpu(out->value); + else + rc = -ENODATA; } tpm_buf_destroy(&buf); return rc;