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tpm: Fix buffer access in tpm2_get_tpm_pt()

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commit e57b2523bd 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: 2ab3241161 ("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>
This commit is contained in:
Stefan Mahnke-Hartmann 2022-05-13 15:41:51 +02:00 committed by Greg Kroah-Hartman
parent 2139d45a17
commit 2dea756c05
1 changed files with 10 additions and 1 deletions
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11
drivers/char/tpm/tpm2-cmd.c
View file

@ -400,7 +400,16 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value,
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;