1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Handling of TPM command and other buffers. 4 */ 5 6 #include <linux/tpm_command.h> 7 #include <linux/module.h> 8 #include <linux/tpm.h> 9 10 /** 11 * tpm_buf_init() - Allocate and initialize a TPM command 12 * @buf: A &tpm_buf 13 * @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS 14 * @ordinal: A command ordinal 15 * 16 * Return: 0 or -ENOMEM 17 */ 18 int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal) 19 { 20 buf->data = (u8 *)__get_free_page(GFP_KERNEL); 21 if (!buf->data) 22 return -ENOMEM; 23 24 tpm_buf_reset(buf, tag, ordinal); 25 return 0; 26 } 27 EXPORT_SYMBOL_GPL(tpm_buf_init); 28 29 /** 30 * tpm_buf_reset() - Initialize a TPM command 31 * @buf: A &tpm_buf 32 * @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS 33 * @ordinal: A command ordinal 34 */ 35 void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal) 36 { 37 struct tpm_header *head = (struct tpm_header *)buf->data; 38 39 WARN_ON(tag != TPM_TAG_RQU_COMMAND && tag != TPM2_ST_NO_SESSIONS && 40 tag != TPM2_ST_SESSIONS && tag != 0); 41 42 buf->flags = 0; 43 buf->length = sizeof(*head); 44 head->tag = cpu_to_be16(tag); 45 head->length = cpu_to_be32(sizeof(*head)); 46 head->ordinal = cpu_to_be32(ordinal); 47 buf->handles = 0; 48 } 49 EXPORT_SYMBOL_GPL(tpm_buf_reset); 50 51 /** 52 * tpm_buf_init_sized() - Allocate and initialize a sized (TPM2B) buffer 53 * @buf: A @tpm_buf 54 * 55 * Return: 0 or -ENOMEM 56 */ 57 int tpm_buf_init_sized(struct tpm_buf *buf) 58 { 59 buf->data = (u8 *)__get_free_page(GFP_KERNEL); 60 if (!buf->data) 61 return -ENOMEM; 62 63 tpm_buf_reset_sized(buf); 64 return 0; 65 } 66 EXPORT_SYMBOL_GPL(tpm_buf_init_sized); 67 68 /** 69 * tpm_buf_reset_sized() - Initialize a sized buffer 70 * @buf: A &tpm_buf 71 */ 72 void tpm_buf_reset_sized(struct tpm_buf *buf) 73 { 74 buf->flags = TPM_BUF_TPM2B; 75 buf->length = 2; 76 buf->data[0] = 0; 77 buf->data[1] = 0; 78 } 79 EXPORT_SYMBOL_GPL(tpm_buf_reset_sized); 80 81 void tpm_buf_destroy(struct tpm_buf *buf) 82 { 83 free_page((unsigned long)buf->data); 84 } 85 EXPORT_SYMBOL_GPL(tpm_buf_destroy); 86 87 /** 88 * tpm_buf_length() - Return the number of bytes consumed by the data 89 * @buf: A &tpm_buf 90 * 91 * Return: The number of bytes consumed by the buffer 92 */ 93 u32 tpm_buf_length(struct tpm_buf *buf) 94 { 95 return buf->length; 96 } 97 EXPORT_SYMBOL_GPL(tpm_buf_length); 98 99 /** 100 * tpm_buf_append() - Append data to an initialized buffer 101 * @buf: A &tpm_buf 102 * @new_data: A data blob 103 * @new_length: Size of the appended data 104 */ 105 void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length) 106 { 107 /* Return silently if overflow has already happened. */ 108 if (buf->flags & TPM_BUF_OVERFLOW) 109 return; 110 111 if ((buf->length + new_length) > PAGE_SIZE) { 112 WARN(1, "tpm_buf: write overflow\n"); 113 buf->flags |= TPM_BUF_OVERFLOW; 114 return; 115 } 116 117 memcpy(&buf->data[buf->length], new_data, new_length); 118 buf->length += new_length; 119 120 if (buf->flags & TPM_BUF_TPM2B) 121 ((__be16 *)buf->data)[0] = cpu_to_be16(buf->length - 2); 122 else 123 ((struct tpm_header *)buf->data)->length = cpu_to_be32(buf->length); 124 } 125 EXPORT_SYMBOL_GPL(tpm_buf_append); 126 127 void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value) 128 { 129 tpm_buf_append(buf, &value, 1); 130 } 131 EXPORT_SYMBOL_GPL(tpm_buf_append_u8); 132 133 void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value) 134 { 135 __be16 value2 = cpu_to_be16(value); 136 137 tpm_buf_append(buf, (u8 *)&value2, 2); 138 } 139 EXPORT_SYMBOL_GPL(tpm_buf_append_u16); 140 141 void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value) 142 { 143 __be32 value2 = cpu_to_be32(value); 144 145 tpm_buf_append(buf, (u8 *)&value2, 4); 146 } 147 EXPORT_SYMBOL_GPL(tpm_buf_append_u32); 148 149 /** 150 * tpm_buf_read() - Read from a TPM buffer 151 * @buf: &tpm_buf instance 152 * @offset: offset within the buffer 153 * @count: the number of bytes to read 154 * @output: the output buffer 155 */ 156 static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void *output) 157 { 158 off_t next_offset; 159 160 /* Return silently if overflow has already happened. */ 161 if (buf->flags & TPM_BUF_BOUNDARY_ERROR) 162 return; 163 164 next_offset = *offset + count; 165 if (next_offset > buf->length) { 166 WARN(1, "tpm_buf: read out of boundary\n"); 167 buf->flags |= TPM_BUF_BOUNDARY_ERROR; 168 return; 169 } 170 171 memcpy(output, &buf->data[*offset], count); 172 *offset = next_offset; 173 } 174 175 /** 176 * tpm_buf_read_u8() - Read 8-bit word from a TPM buffer 177 * @buf: &tpm_buf instance 178 * @offset: offset within the buffer 179 * 180 * Return: next 8-bit word 181 */ 182 u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset) 183 { 184 u8 value; 185 186 tpm_buf_read(buf, offset, sizeof(value), &value); 187 188 return value; 189 } 190 EXPORT_SYMBOL_GPL(tpm_buf_read_u8); 191 192 /** 193 * tpm_buf_read_u16() - Read 16-bit word from a TPM buffer 194 * @buf: &tpm_buf instance 195 * @offset: offset within the buffer 196 * 197 * Return: next 16-bit word 198 */ 199 u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset) 200 { 201 u16 value; 202 203 tpm_buf_read(buf, offset, sizeof(value), &value); 204 205 return be16_to_cpu(value); 206 } 207 EXPORT_SYMBOL_GPL(tpm_buf_read_u16); 208 209 /** 210 * tpm_buf_read_u32() - Read 32-bit word from a TPM buffer 211 * @buf: &tpm_buf instance 212 * @offset: offset within the buffer 213 * 214 * Return: next 32-bit word 215 */ 216 u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset) 217 { 218 u32 value; 219 220 tpm_buf_read(buf, offset, sizeof(value), &value); 221 222 return be32_to_cpu(value); 223 } 224 EXPORT_SYMBOL_GPL(tpm_buf_read_u32); 225 226 227