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Commit 124bdcf4 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen
Browse files

tpm: fix byte order related arithmetic inconsistency in tpm_getcap() 



You should not do arithmetic with __be32 or __le32 types because
sometimes it results incorrect results. Calculations must be done only
with integers that are in in the CPU byte order. This commit migrates
tpm_getcap() to struct tpm_buf in order to sort out these issues.

Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgunthorpe@obsidianresearch.com>
parent d8c3eab5

drivers/char/tpm/tpm-interface.c

+16 −14
Original line number Diff line number Diff line
@@ -552,31 +552,33 @@ static const struct tpm_input_header tpm_getcap_header = { 
ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,

		   const char *desc, size_t min_cap_length)

{

	struct tpm_cmd_t tpm_cmd;

	struct tpm_buf buf;

	int rc;



	tpm_cmd.header.in = tpm_getcap_header;

	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_CAP);

	if (rc)

		return rc;



	if (subcap_id == TPM_CAP_VERSION_1_1 ||

	    subcap_id == TPM_CAP_VERSION_1_2) {

		tpm_cmd.params.getcap_in.cap = cpu_to_be32(subcap_id);

		/*subcap field not necessary */

		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(0);

		tpm_cmd.header.in.length -= cpu_to_be32(sizeof(__be32));

		tpm_buf_append_u32(&buf, subcap_id);

		tpm_buf_append_u32(&buf, 0);

	} else {

		if (subcap_id == TPM_CAP_FLAG_PERM ||

		    subcap_id == TPM_CAP_FLAG_VOL)

			tpm_cmd.params.getcap_in.cap =

				cpu_to_be32(TPM_CAP_FLAG);

			tpm_buf_append_u32(&buf, TPM_CAP_FLAG);

		else

			tpm_cmd.params.getcap_in.cap =

				cpu_to_be32(TPM_CAP_PROP);

		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);

		tpm_cmd.params.getcap_in.subcap = cpu_to_be32(subcap_id);

			tpm_buf_append_u32(&buf, TPM_CAP_PROP);



		tpm_buf_append_u32(&buf, 4);

		tpm_buf_append_u32(&buf, subcap_id);

	}

	rc = tpm_transmit_cmd(chip, NULL, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,

	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE,

			      min_cap_length, 0, desc);

	if (!rc)

		*cap = tpm_cmd.params.getcap_out.cap;

		*cap = *(cap_t *)&buf.data[TPM_HEADER_SIZE + 4];



	tpm_buf_destroy(&buf);

	return rc;

}

EXPORT_SYMBOL_GPL(tpm_getcap);

drivers/char/tpm/tpm.h

+0 −13
Original line number Diff line number Diff line
@@ -339,17 +339,6 @@ enum tpm_sub_capabilities { 
	TPM_CAP_PROP_TIS_DURATION = 0x120,

};



struct	tpm_getcap_params_in {

	__be32	cap;

	__be32	subcap_size;

	__be32	subcap;

} __packed;



struct	tpm_getcap_params_out {

	__be32	cap_size;

	cap_t	cap;

} __packed;



struct	tpm_readpubek_params_out {

	u8	algorithm[4];

	u8	encscheme[2];
@@ -399,10 +388,8 @@ struct tpm_startup_in { 
} __packed;



typedef union {

	struct	tpm_getcap_params_out getcap_out;

	struct	tpm_readpubek_params_out readpubek_out;

	u8	readpubek_out_buffer[sizeof(struct tpm_readpubek_params_out)];

	struct	tpm_getcap_params_in getcap_in;

	struct	tpm_pcrread_in	pcrread_in;

	struct	tpm_pcrread_out	pcrread_out;

	struct	tpm_pcrextend_in pcrextend_in;