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-rw-r--r--drivers/char/tpm/tpm-interface.c16
-rw-r--r--drivers/char/tpm/tpm.h5
-rw-r--r--drivers/char/tpm/tpm1-cmd.c4
-rw-r--r--drivers/char/tpm/tpm2-cmd.c85
-rw-r--r--include/linux/tpm.h12
-rw-r--r--security/integrity/ima/ima_crypto.c10
6 files changed, 96 insertions, 36 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 9c6aa77b5dee..1c92dbeef736 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -281,11 +281,12 @@ EXPORT_SYMBOL_GPL(tpm_is_tpm2);
* tpm_pcr_read - read a PCR value from SHA1 bank
* @chip: a &struct tpm_chip instance, %NULL for the default chip
* @pcr_idx: the PCR to be retrieved
- * @res_buf: the value of the PCR
+ * @digest: the PCR bank and buffer current PCR value is written to
*
* Return: same as with tpm_transmit_cmd()
*/
-int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+ struct tpm_digest *digest)
{
int rc;
@@ -294,9 +295,9 @@ int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
- rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
+ rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
else
- rc = tpm1_pcr_read(chip, pcr_idx, res_buf);
+ rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
tpm_put_ops(chip);
return rc;
@@ -309,9 +310,8 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
* @pcr_idx: the PCR to be retrieved
* @hash: the hash value used to extend the PCR value
*
- * Note: with TPM 2.0 extends also those banks with a known digest size to the
- * cryto subsystem in order to prevent malicious use of those PCR banks. In the
- * future we should dynamically determine digest sizes.
+ * Note: with TPM 2.0 extends also those banks for which no digest was
+ * specified in order to prevent malicious use of those PCR banks.
*
* Return: same as with tpm_transmit_cmd()
*/
@@ -332,7 +332,7 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
return -ENOMEM;
for (i = 0; i < chip->nr_allocated_banks; i++) {
- digest_list[i].alg_id = chip->allocated_banks[i];
+ digest_list[i].alg_id = chip->allocated_banks[i].alg_id;
memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 0e54061d3fd1..4efa304e9ece 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -247,7 +247,7 @@ struct tpm_chip {
unsigned int groups_cnt;
u32 nr_allocated_banks;
- u16 *allocated_banks;
+ struct tpm_bank_info *allocated_banks;
#ifdef CONFIG_ACPI
acpi_handle acpi_dev_handle;
char ppi_version[TPM_PPI_VERSION_LEN + 1];
@@ -532,7 +532,8 @@ static inline u32 tpm2_rc_value(u32 rc)
}
int tpm2_get_timeouts(struct tpm_chip *chip);
-int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+ struct tpm_digest *digest, u16 *digest_size_ptr);
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
struct tpm_digest *digests);
int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 3eb7e03889a0..85dcf2654d11 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -703,7 +703,9 @@ int tpm1_auto_startup(struct tpm_chip *chip)
goto out;
}
- chip->allocated_banks[0] = TPM_ALG_SHA1;
+ chip->allocated_banks[0].alg_id = TPM_ALG_SHA1;
+ chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1];
+ chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1;
chip->nr_allocated_banks = 1;
return rc;
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 440ae6ee29e4..6967f15a6585 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -171,20 +171,36 @@ struct tpm2_pcr_read_out {
* tpm2_pcr_read() - read a PCR value
* @chip: TPM chip to use.
* @pcr_idx: index of the PCR to read.
- * @res_buf: buffer to store the resulting hash.
+ * @digest: PCR bank and buffer current PCR value is written to.
+ * @digest_size_ptr: pointer to variable that stores the digest size.
*
* Return: Same as with tpm_transmit_cmd.
*/
-int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+ struct tpm_digest *digest, u16 *digest_size_ptr)
{
+ int i;
int rc;
struct tpm_buf buf;
struct tpm2_pcr_read_out *out;
u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
+ u16 digest_size;
+ u16 expected_digest_size = 0;
if (pcr_idx >= TPM2_PLATFORM_PCR)
return -EINVAL;
+ if (!digest_size_ptr) {
+ for (i = 0; i < chip->nr_allocated_banks &&
+ chip->allocated_banks[i].alg_id != digest->alg_id; i++)
+ ;
+
+ if (i == chip->nr_allocated_banks)
+ return -EINVAL;
+
+ expected_digest_size = chip->allocated_banks[i].digest_size;
+ }
+
rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
if (rc)
return rc;
@@ -192,18 +208,28 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
tpm_buf_append_u32(&buf, 1);
- tpm_buf_append_u16(&buf, TPM_ALG_SHA1);
+ tpm_buf_append_u16(&buf, digest->alg_id);
tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
tpm_buf_append(&buf, (const unsigned char *)pcr_select,
sizeof(pcr_select));
- rc = tpm_transmit_cmd(chip, &buf, 0, res_buf ?
- "attempting to read a pcr value" : NULL);
- if (rc == 0 && res_buf) {
- out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
- memcpy(res_buf, out->digest, SHA1_DIGEST_SIZE);
+ rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to read a pcr value");
+ if (rc)
+ goto out;
+
+ out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
+ digest_size = be16_to_cpu(out->digest_size);
+ if (digest_size > sizeof(digest->digest) ||
+ (!digest_size_ptr && digest_size != expected_digest_size)) {
+ rc = -EINVAL;
+ goto out;
}
+ if (digest_size_ptr)
+ *digest_size_ptr = digest_size;
+
+ memcpy(digest->digest, out->digest, digest_size);
+out:
tpm_buf_destroy(&buf);
return rc;
}
@@ -232,7 +258,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
struct tpm2_null_auth_area auth_area;
int rc;
int i;
- int j;
if (count > chip->nr_allocated_banks)
return -EINVAL;
@@ -254,14 +279,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
tpm_buf_append_u32(&buf, count);
for (i = 0; i < count; i++) {
- for (j = 0; j < ARRAY_SIZE(tpm2_hash_map); j++) {
- if (digests[i].alg_id != tpm2_hash_map[j].tpm_id)
- continue;
- tpm_buf_append_u16(&buf, digests[i].alg_id);
- tpm_buf_append(&buf, (const unsigned char
- *)&digests[i].digest,
- hash_digest_size[tpm2_hash_map[j].crypto_id]);
- }
+ tpm_buf_append_u16(&buf, digests[i].alg_id);
+ tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
+ chip->allocated_banks[i].digest_size);
}
rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");
@@ -795,6 +815,30 @@ int tpm2_probe(struct tpm_chip *chip)
}
EXPORT_SYMBOL_GPL(tpm2_probe);
+static int tpm2_init_bank_info(struct tpm_chip *chip, u32 bank_index)
+{
+ struct tpm_bank_info *bank = chip->allocated_banks + bank_index;
+ struct tpm_digest digest = { .alg_id = bank->alg_id };
+ int i;
+
+ /*
+ * Avoid unnecessary PCR read operations to reduce overhead
+ * and obtain identifiers of the crypto subsystem.
+ */
+ for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
+ enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
+
+ if (bank->alg_id != tpm2_hash_map[i].tpm_id)
+ continue;
+
+ bank->digest_size = hash_digest_size[crypto_algo];
+ bank->crypto_id = crypto_algo;
+ return 0;
+ }
+
+ return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
+}
+
struct tpm2_pcr_selection {
__be16 hash_alg;
u8 size_of_select;
@@ -858,7 +902,12 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
pcr_selection.size_of_select);
if (pcr_select_offset) {
- chip->allocated_banks[nr_alloc_banks] = hash_alg;
+ chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg;
+
+ rc = tpm2_init_bank_info(chip, nr_alloc_banks);
+ if (rc < 0)
+ break;
+
nr_alloc_banks++;
}
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 9fe8c9816cf0..afd022fc9d3d 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -47,6 +47,12 @@ struct tpm_digest {
u8 digest[TPM_MAX_DIGEST_SIZE];
} __packed;
+struct tpm_bank_info {
+ u16 alg_id;
+ u16 digest_size;
+ u16 crypto_id;
+};
+
enum TPM_OPS_FLAGS {
TPM_OPS_AUTO_STARTUP = BIT(0),
};
@@ -72,7 +78,8 @@ struct tpm_class_ops {
#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
extern int tpm_is_tpm2(struct tpm_chip *chip);
-extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+ struct tpm_digest *digest);
extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash);
extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
@@ -89,7 +96,8 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip)
return -ENODEV;
}
-static inline int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx,
+ struct tpm_digest *digest)
{
return -ENODEV;
}
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index acf2c7df7145..16a4f45863b1 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -643,12 +643,12 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
return calc_buffer_shash(buf, len, hash);
}
-static void __init ima_pcrread(u32 idx, u8 *pcr)
+static void __init ima_pcrread(u32 idx, struct tpm_digest *d)
{
if (!ima_tpm_chip)
return;
- if (tpm_pcr_read(ima_tpm_chip, idx, pcr) != 0)
+ if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
pr_err("Error Communicating to TPM chip\n");
}
@@ -658,7 +658,7 @@ static void __init ima_pcrread(u32 idx, u8 *pcr)
static int __init ima_calc_boot_aggregate_tfm(char *digest,
struct crypto_shash *tfm)
{
- u8 pcr_i[TPM_DIGEST_SIZE];
+ struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} };
int rc;
u32 i;
SHASH_DESC_ON_STACK(shash, tfm);
@@ -672,9 +672,9 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
/* cumulative sha1 over tpm registers 0-7 */
for (i = TPM_PCR0; i < TPM_PCR8; i++) {
- ima_pcrread(i, pcr_i);
+ ima_pcrread(i, &d);
/* now accumulate with current aggregate */
- rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
+ rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE);
}
if (!rc)
crypto_shash_final(shash, digest);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.