From 879b589210a9a0c9f77d301aaf0ddee20f2c5052 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Wed, 6 Feb 2019 17:24:49 +0100 Subject: tpm: retrieve digest size of unknown algorithms with PCR read Currently, the TPM driver retrieves the digest size from a table mapping TPM algorithms identifiers to identifiers defined by the crypto subsystem. If the algorithm is not defined by the latter, the digest size can be retrieved from the output of the PCR read command. The patch modifies the definition of tpm_pcr_read() and tpm2_pcr_read() to pass the desired hash algorithm and obtain the digest size at TPM startup. Algorithms and corresponding digest sizes are stored in the new structure tpm_bank_info, member of tpm_chip, so that the information can be used by other kernel subsystems. tpm_bank_info contains: the TPM algorithm identifier, necessary to generate the event log as defined by Trusted Computing Group (TCG); the digest size, to pad/truncate a digest calculated with a different algorithm; the crypto subsystem identifier, to calculate the digest of event data. This patch also protects against data corruption that could happen in the bus, by checking that the digest size returned by the TPM during a PCR read matches the size of the algorithm passed to tpm2_pcr_read(). For the initial PCR read, when digest sizes are not yet available, this patch ensures that the amount of data copied from the output returned by the TPM does not exceed the size of the array data are copied to. Signed-off-by: Roberto Sassu Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Acked-by: Mimi Zohar Signed-off-by: Jarkko Sakkinen --- security/integrity/ima/ima_crypto.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'security') 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); -- cgit v1.2.3-59-g8ed1b From 240730437deb213a58915830884e1a99045624dc Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Wed, 6 Feb 2019 17:24:51 +0100 Subject: KEYS: trusted: explicitly use tpm_chip structure from tpm_default_chip() When crypto agility support will be added to the TPM driver, users of the driver have to retrieve the allocated banks from chip->allocated_banks and use this information to prepare the array of tpm_digest structures to be passed to tpm_pcr_extend(). This patch retrieves a tpm_chip pointer from tpm_default_chip() so that the pointer can be used to prepare the array of tpm_digest structures. Signed-off-by: Roberto Sassu Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- security/keys/trusted.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-) (limited to 'security') diff --git a/security/keys/trusted.c b/security/keys/trusted.c index 4d98f4f87236..5b852263eae1 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -34,6 +34,7 @@ static const char hmac_alg[] = "hmac(sha1)"; static const char hash_alg[] = "sha1"; +static struct tpm_chip *chip; struct sdesc { struct shash_desc shash; @@ -362,7 +363,7 @@ int trusted_tpm_send(unsigned char *cmd, size_t buflen) int rc; dump_tpm_buf(cmd); - rc = tpm_send(NULL, cmd, buflen); + rc = tpm_send(chip, cmd, buflen); dump_tpm_buf(cmd); if (rc > 0) /* Can't return positive return codes values to keyctl */ @@ -384,10 +385,10 @@ static int pcrlock(const int pcrnum) if (!capable(CAP_SYS_ADMIN)) return -EPERM; - ret = tpm_get_random(NULL, hash, SHA1_DIGEST_SIZE); + ret = tpm_get_random(chip, hash, SHA1_DIGEST_SIZE); if (ret != SHA1_DIGEST_SIZE) return ret; - return tpm_pcr_extend(NULL, pcrnum, hash) ? -EINVAL : 0; + return tpm_pcr_extend(chip, pcrnum, hash) ? -EINVAL : 0; } /* @@ -400,7 +401,7 @@ static int osap(struct tpm_buf *tb, struct osapsess *s, unsigned char ononce[TPM_NONCE_SIZE]; int ret; - ret = tpm_get_random(NULL, ononce, TPM_NONCE_SIZE); + ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE); if (ret != TPM_NONCE_SIZE) return ret; @@ -496,7 +497,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, if (ret < 0) goto out; - ret = tpm_get_random(NULL, td->nonceodd, TPM_NONCE_SIZE); + ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE); if (ret != TPM_NONCE_SIZE) goto out; ordinal = htonl(TPM_ORD_SEAL); @@ -606,7 +607,7 @@ static int tpm_unseal(struct tpm_buf *tb, ordinal = htonl(TPM_ORD_UNSEAL); keyhndl = htonl(SRKHANDLE); - ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE); + ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE); if (ret != TPM_NONCE_SIZE) { pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); return ret; @@ -751,7 +752,7 @@ static int getoptions(char *c, struct trusted_key_payload *pay, int i; int tpm2; - tpm2 = tpm_is_tpm2(NULL); + tpm2 = tpm_is_tpm2(chip); if (tpm2 < 0) return tpm2; @@ -920,7 +921,7 @@ static struct trusted_key_options *trusted_options_alloc(void) struct trusted_key_options *options; int tpm2; - tpm2 = tpm_is_tpm2(NULL); + tpm2 = tpm_is_tpm2(chip); if (tpm2 < 0) return NULL; @@ -970,7 +971,7 @@ static int trusted_instantiate(struct key *key, size_t key_len; int tpm2; - tpm2 = tpm_is_tpm2(NULL); + tpm2 = tpm_is_tpm2(chip); if (tpm2 < 0) return tpm2; @@ -1011,7 +1012,7 @@ static int trusted_instantiate(struct key *key, switch (key_cmd) { case Opt_load: if (tpm2) - ret = tpm_unseal_trusted(NULL, payload, options); + ret = tpm_unseal_trusted(chip, payload, options); else ret = key_unseal(payload, options); dump_payload(payload); @@ -1021,13 +1022,13 @@ static int trusted_instantiate(struct key *key, break; case Opt_new: key_len = payload->key_len; - ret = tpm_get_random(NULL, payload->key, key_len); + ret = tpm_get_random(chip, payload->key, key_len); if (ret != key_len) { pr_info("trusted_key: key_create failed (%d)\n", ret); goto out; } if (tpm2) - ret = tpm_seal_trusted(NULL, payload, options); + ret = tpm_seal_trusted(chip, payload, options); else ret = key_seal(payload, options); if (ret < 0) @@ -1225,17 +1226,26 @@ static int __init init_trusted(void) { int ret; + chip = tpm_default_chip(); + if (!chip) + return -ENOENT; ret = trusted_shash_alloc(); if (ret < 0) - return ret; + goto err_put; ret = register_key_type(&key_type_trusted); if (ret < 0) - trusted_shash_release(); + goto err_release; + return 0; +err_release: + trusted_shash_release(); +err_put: + put_device(&chip->dev); return ret; } static void __exit cleanup_trusted(void) { + put_device(&chip->dev); trusted_shash_release(); unregister_key_type(&key_type_trusted); } -- cgit v1.2.3-59-g8ed1b From 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Wed, 6 Feb 2019 17:24:52 +0100 Subject: tpm: pass an array of tpm_extend_digest structures to tpm_pcr_extend() Currently, tpm_pcr_extend() accepts as an input only a SHA1 digest. This patch replaces the hash parameter of tpm_pcr_extend() with an array of tpm_digest structures, so that the caller can provide a digest for each PCR bank currently allocated in the TPM. tpm_pcr_extend() will not extend banks for which no digest was provided, as it happened before this patch, but instead it requires that callers provide the full set of digests. Since the number of digests will always be chip->nr_allocated_banks, the count parameter has been removed. Due to the API change, ima_pcr_extend() and pcrlock() have been modified. Since the number of allocated banks is not known in advance, the memory for the digests must be dynamically allocated. To avoid performance degradation and to avoid that a PCR extend is not done due to lack of memory, the array of tpm_digest structures is allocated by the users of the TPM driver at initialization time. Signed-off-by: Roberto Sassu Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Tested-by: Mimi Zohar (on x86 for TPM 1.2 & PTT TPM 2.0) Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-interface.c | 30 ++++++++++------------------ drivers/char/tpm/tpm.h | 2 +- drivers/char/tpm/tpm2-cmd.c | 10 +++------- include/linux/tpm.h | 5 +++-- security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_init.c | 4 ++++ security/integrity/ima/ima_queue.c | 27 ++++++++++++++++++++++++- security/keys/trusted.c | 41 ++++++++++++++++++++++++++++++-------- 8 files changed, 82 insertions(+), 38 deletions(-) (limited to 'security') diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 1c92dbeef736..83ece5639f86 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -308,42 +308,34 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read); * tpm_pcr_extend - extend a PCR value in SHA1 bank. * @chip: a &struct tpm_chip instance, %NULL for the default chip * @pcr_idx: the PCR to be retrieved - * @hash: the hash value used to extend the PCR value + * @digests: array of tpm_digest structures used to extend PCRs * - * 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. + * Note: callers must pass a digest for every allocated PCR bank, in the same + * order of the banks in chip->allocated_banks. * * Return: same as with tpm_transmit_cmd() */ -int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash) +int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, + struct tpm_digest *digests) { int rc; - struct tpm_digest *digest_list; int i; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; - if (chip->flags & TPM_CHIP_FLAG_TPM2) { - digest_list = kcalloc(chip->nr_allocated_banks, - sizeof(*digest_list), GFP_KERNEL); - if (!digest_list) - return -ENOMEM; - - for (i = 0; i < chip->nr_allocated_banks; i++) { - digest_list[i].alg_id = chip->allocated_banks[i].alg_id; - memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE); - } + for (i = 0; i < chip->nr_allocated_banks; i++) + if (digests[i].alg_id != chip->allocated_banks[i].alg_id) + return -EINVAL; - rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_allocated_banks, - digest_list); - kfree(digest_list); + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + rc = tpm2_pcr_extend(chip, pcr_idx, digests); tpm_put_ops(chip); return rc; } - rc = tpm1_pcr_extend(chip, pcr_idx, hash, + rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest, "attempting extend a PCR value"); tpm_put_ops(chip); return rc; diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 4f85ce909122..2cce072f25b5 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -441,7 +441,7 @@ 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, struct tpm_digest *digest, u16 *digest_size_ptr); -int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count, +int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digests); int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max); void tpm2_flush_context(struct tpm_chip *chip, u32 handle); diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 6967f15a6585..e74c5b7b64bf 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -246,12 +246,11 @@ struct tpm2_null_auth_area { * * @chip: TPM chip to use. * @pcr_idx: index of the PCR. - * @count: number of digests passed. * @digests: list of pcr banks and corresponding digest values to extend. * * Return: Same as with tpm_transmit_cmd. */ -int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count, +int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digests) { struct tpm_buf buf; @@ -259,9 +258,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count, int rc; int i; - if (count > chip->nr_allocated_banks) - return -EINVAL; - rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND); if (rc) return rc; @@ -276,9 +272,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count, tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area)); tpm_buf_append(&buf, (const unsigned char *)&auth_area, sizeof(auth_area)); - tpm_buf_append_u32(&buf, count); + tpm_buf_append_u32(&buf, chip->nr_allocated_banks); - for (i = 0; i < count; i++) { + for (i = 0; i < chip->nr_allocated_banks; i++) { 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); diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 816e686a73ac..1b5436b213a2 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -171,7 +171,8 @@ struct tpm_chip { extern int tpm_is_tpm2(struct tpm_chip *chip); 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_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, + struct tpm_digest *digests); 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); extern int tpm_seal_trusted(struct tpm_chip *chip, @@ -194,7 +195,7 @@ static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, } static inline int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, - const u8 *hash) + struct tpm_digest *digests) { return -ENODEV; } diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index cc12f3449a72..89d65cf8053d 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -153,6 +153,7 @@ int ima_measurements_show(struct seq_file *m, void *v); unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); void ima_init_template_list(void); +int __init ima_init_digests(void); /* * used to protect h_table and sha_table diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 6bb42a9c5e47..6c9295449751 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -123,8 +123,12 @@ int __init ima_init(void) if (rc != 0) return rc; + /* It can be called before ima_init_digests(), it does not use TPM. */ ima_load_kexec_buffer(); + rc = ima_init_digests(); + if (rc != 0) + return rc; rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */ if (rc != 0) return rc; diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 0e41dc1df1d4..6b6d044e0440 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -27,6 +27,9 @@ #define AUDIT_CAUSE_LEN_MAX 32 +/* pre-allocated array of tpm_digest structures to extend a PCR */ +static struct tpm_digest *digests; + LIST_HEAD(ima_measurements); /* list of all measurements */ #ifdef CONFIG_IMA_KEXEC static unsigned long binary_runtime_size; @@ -140,11 +143,15 @@ unsigned long ima_get_binary_runtime_size(void) static int ima_pcr_extend(const u8 *hash, int pcr) { int result = 0; + int i; if (!ima_tpm_chip) return result; - result = tpm_pcr_extend(ima_tpm_chip, pcr, hash); + for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) + memcpy(digests[i].digest, hash, TPM_DIGEST_SIZE); + + result = tpm_pcr_extend(ima_tpm_chip, pcr, digests); if (result != 0) pr_err("Error Communicating to TPM chip, result: %d\n", result); return result; @@ -211,3 +218,21 @@ int ima_restore_measurement_entry(struct ima_template_entry *entry) mutex_unlock(&ima_extend_list_mutex); return result; } + +int __init ima_init_digests(void) +{ + int i; + + if (!ima_tpm_chip) + return 0; + + digests = kcalloc(ima_tpm_chip->nr_allocated_banks, sizeof(*digests), + GFP_NOFS); + if (!digests) + return -ENOMEM; + + for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) + digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id; + + return 0; +} diff --git a/security/keys/trusted.c b/security/keys/trusted.c index 5b852263eae1..bcc9c6ead7fd 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -35,6 +35,7 @@ static const char hmac_alg[] = "hmac(sha1)"; static const char hash_alg[] = "sha1"; static struct tpm_chip *chip; +static struct tpm_digest *digests; struct sdesc { struct shash_desc shash; @@ -380,15 +381,10 @@ EXPORT_SYMBOL_GPL(trusted_tpm_send); */ static int pcrlock(const int pcrnum) { - unsigned char hash[SHA1_DIGEST_SIZE]; - int ret; - if (!capable(CAP_SYS_ADMIN)) return -EPERM; - ret = tpm_get_random(chip, hash, SHA1_DIGEST_SIZE); - if (ret != SHA1_DIGEST_SIZE) - return ret; - return tpm_pcr_extend(chip, pcrnum, hash) ? -EINVAL : 0; + + return tpm_pcr_extend(chip, pcrnum, digests) ? -EINVAL : 0; } /* @@ -1222,6 +1218,29 @@ hashalg_fail: return ret; } +static int __init init_digests(void) +{ + u8 digest[TPM_MAX_DIGEST_SIZE]; + int ret; + int i; + + ret = tpm_get_random(chip, digest, TPM_MAX_DIGEST_SIZE); + if (ret < 0) + return ret; + if (ret < TPM_MAX_DIGEST_SIZE) + return -EFAULT; + + digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests), + GFP_KERNEL); + if (!digests) + return -ENOMEM; + + for (i = 0; i < chip->nr_allocated_banks; i++) + memcpy(digests[i].digest, digest, TPM_MAX_DIGEST_SIZE); + + return 0; +} + static int __init init_trusted(void) { int ret; @@ -1229,15 +1248,20 @@ static int __init init_trusted(void) chip = tpm_default_chip(); if (!chip) return -ENOENT; - ret = trusted_shash_alloc(); + ret = init_digests(); if (ret < 0) goto err_put; + ret = trusted_shash_alloc(); + if (ret < 0) + goto err_free; ret = register_key_type(&key_type_trusted); if (ret < 0) goto err_release; return 0; err_release: trusted_shash_release(); +err_free: + kfree(digests); err_put: put_device(&chip->dev); return ret; @@ -1246,6 +1270,7 @@ err_put: static void __exit cleanup_trusted(void) { put_device(&chip->dev); + kfree(digests); trusted_shash_release(); unregister_key_type(&key_type_trusted); } -- cgit v1.2.3-59-g8ed1b