tpm: add vendor flag to command code validation

Some TPM 2.0 devices have support for additional commands which are not
part of the TPM 2.0 specifications.
These commands are identified with bit 29 of the 32 bits command codes.
Contrarily to other fields of the TPMA_CC spec structure used to list
available commands, the Vendor flag also has to be present in the
command code itself (TPM_CC) when called.

Add this flag to tpm_find_cc() mask to prevent blocking vendor command
codes that can actually be supported by the underlying TPM device.

Signed-off-by: Julien Gomes <[e-mail]>
Tested-by: Jarkko Sakkinen <[e-mail]>
Reviewed-by: Jarkko Sakkinen <[e-mail]>
Signed-off-by: Jarkko Sakkinen <[e-mail]>

drivers/char/tpm/tpm2-cmd.c

···
 
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc)
 {
+	u32 cc_mask;
 	int i;
 
+	cc_mask = 1 << TPM2_CC_ATTR_VENDOR | GENMASK(15, 0);
 	for (i = 0; i < chip->nr_commands; i++)
-		if (cc == (chip->cc_attrs_tbl[i] & GENMASK(15, 0)))
+		if (cc == (chip->cc_attrs_tbl[i] & cc_mask))
 			return i;
 
 	return -1;

include/linux/tpm.h

···
 enum tpm2_cc_attrs {
 	TPM2_CC_ATTR_CHANDLES	= 25,
 	TPM2_CC_ATTR_RHANDLE	= 28,
+	TPM2_CC_ATTR_VENDOR	= 29,
 };
 
 #define TPM_VID_INTEL    0x8086