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// SPDX-License-Identifier: GPL-2.0
/*
* Handling of TPM command and other buffers.
*/
#include <linux/tpm_command.h>
#include <linux/module.h>
#include <linux/tpm.h>
/**
* tpm_buf_init() - Allocate and initialize a TPM command
* @buf: A &tpm_buf
* @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
* @ordinal: A command ordinal
*
* Return: 0 or -ENOMEM
*/
int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
{
buf->data = (u8 *)__get_free_page(GFP_KERNEL);
if (!buf->data)
return -ENOMEM;
tpm_buf_reset(buf, tag, ordinal);
return 0;
}
EXPORT_SYMBOL_GPL(tpm_buf_init);
/**
* tpm_buf_reset() - Initialize a TPM command
* @buf: A &tpm_buf
* @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
* @ordinal: A command ordinal
*/
void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
{
struct tpm_header *head = (struct tpm_header *)buf->data;
WARN_ON(tag != TPM_TAG_RQU_COMMAND && tag != TPM2_ST_NO_SESSIONS &&
tag != TPM2_ST_SESSIONS && tag != 0);
buf->flags = 0;
buf->length = sizeof(*head);
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
buf->handles = 0;
}
EXPORT_SYMBOL_GPL(tpm_buf_reset);
/**
* tpm_buf_init_sized() - Allocate and initialize a sized (TPM2B) buffer
* @buf: A @tpm_buf
*
* Return: 0 or -ENOMEM
*/
int tpm_buf_init_sized(struct tpm_buf *buf)
{
buf->data = (u8 *)__get_free_page(GFP_KERNEL);
if (!buf->data)
return -ENOMEM;
tpm_buf_reset_sized(buf);
return 0;
}
EXPORT_SYMBOL_GPL(tpm_buf_init_sized);
/**
* tpm_buf_reset_sized() - Initialize a sized buffer
* @buf: A &tpm_buf
*/
void tpm_buf_reset_sized(struct tpm_buf *buf)
{
buf->flags = TPM_BUF_TPM2B;
buf->length = 2;
buf->data[0] = 0;
buf->data[1] = 0;
}
EXPORT_SYMBOL_GPL(tpm_buf_reset_sized);
void tpm_buf_destroy(struct tpm_buf *buf)
{
free_page((unsigned long)buf->data);
}
EXPORT_SYMBOL_GPL(tpm_buf_destroy);
/**
* tpm_buf_length() - Return the number of bytes consumed by the data
* @buf: A &tpm_buf
*
* Return: The number of bytes consumed by the buffer
*/
u32 tpm_buf_length(struct tpm_buf *buf)
{
return buf->length;
}
EXPORT_SYMBOL_GPL(tpm_buf_length);
/**
* tpm_buf_append() - Append data to an initialized buffer
* @buf: A &tpm_buf
* @new_data: A data blob
* @new_length: Size of the appended data
*/
void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length)
{
/* Return silently if overflow has already happened. */
if (buf->flags & TPM_BUF_OVERFLOW)
return;
if ((buf->length + new_length) > PAGE_SIZE) {
WARN(1, "tpm_buf: write overflow\n");
buf->flags |= TPM_BUF_OVERFLOW;
return;
}
memcpy(&buf->data[buf->length], new_data, new_length);
buf->length += new_length;
if (buf->flags & TPM_BUF_TPM2B)
((__be16 *)buf->data)[0] = cpu_to_be16(buf->length - 2);
else
((struct tpm_header *)buf->data)->length = cpu_to_be32(buf->length);
}
EXPORT_SYMBOL_GPL(tpm_buf_append);
void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value)
{
tpm_buf_append(buf, &value, 1);
}
EXPORT_SYMBOL_GPL(tpm_buf_append_u8);
void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value)
{
__be16 value2 = cpu_to_be16(value);
tpm_buf_append(buf, (u8 *)&value2, 2);
}
EXPORT_SYMBOL_GPL(tpm_buf_append_u16);
void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value)
{
__be32 value2 = cpu_to_be32(value);
tpm_buf_append(buf, (u8 *)&value2, 4);
}
EXPORT_SYMBOL_GPL(tpm_buf_append_u32);
/**
* tpm_buf_read() - Read from a TPM buffer
* @buf: &tpm_buf instance
* @offset: offset within the buffer
* @count: the number of bytes to read
* @output: the output buffer
*/
static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void *output)
{
off_t next_offset;
/* Return silently if overflow has already happened. */
if (buf->flags & TPM_BUF_BOUNDARY_ERROR)
return;
next_offset = *offset + count;
if (next_offset > buf->length) {
WARN(1, "tpm_buf: read out of boundary\n");
buf->flags |= TPM_BUF_BOUNDARY_ERROR;
return;
}
memcpy(output, &buf->data[*offset], count);
*offset = next_offset;
}
/**
* tpm_buf_read_u8() - Read 8-bit word from a TPM buffer
* @buf: &tpm_buf instance
* @offset: offset within the buffer
*
* Return: next 8-bit word
*/
u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset)
{
u8 value;
tpm_buf_read(buf, offset, sizeof(value), &value);
return value;
}
EXPORT_SYMBOL_GPL(tpm_buf_read_u8);
/**
* tpm_buf_read_u16() - Read 16-bit word from a TPM buffer
* @buf: &tpm_buf instance
* @offset: offset within the buffer
*
* Return: next 16-bit word
*/
u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset)
{
u16 value;
tpm_buf_read(buf, offset, sizeof(value), &value);
return be16_to_cpu(value);
}
EXPORT_SYMBOL_GPL(tpm_buf_read_u16);
/**
* tpm_buf_read_u32() - Read 32-bit word from a TPM buffer
* @buf: &tpm_buf instance
* @offset: offset within the buffer
*
* Return: next 32-bit word
*/
u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset)
{
u32 value;
tpm_buf_read(buf, offset, sizeof(value), &value);
return be32_to_cpu(value);
}
EXPORT_SYMBOL_GPL(tpm_buf_read_u32);
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