tpm: Return the actual size when receiving an unsupported command
authorRicardo Schwarzmeier <Ricardo.Schwarzmeier@infineon.com>
Tue, 26 Jun 2018 15:31:45 +0000 (17:31 +0200)
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Sat, 28 Jul 2018 14:03:11 +0000 (17:03 +0300)
The userpace expects to read the number of bytes stated in the header.
Returning the size of the buffer instead would be unexpected.

Cc: stable@vger.kernel.org
Fixes: 095531f891e6 ("tpm: return a TPM_RC_COMMAND_CODE response if command is not implemented")
Signed-off-by: Ricardo Schwarzmeier <Ricardo.Schwarzmeier@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
drivers/char/tpm/tpm-interface.c

index 31b86e027f9df9fc4a963ab3fa1384dd460272d2..3a3a7a548a85a9b850f47ad2560009d172f92236 100644 (file)
@@ -450,7 +450,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
                header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
                header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
                                                  TSS2_RESMGR_TPM_RC_LAYER);
-               return bufsiz;
+               return sizeof(*header);
        }
 
        if (bufsiz > TPM_BUFSIZE)