diff options
| -rw-r--r-- | drivers/char/tpm/tpm.c | 59 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm.h | 23 | ||||
| -rw-r--r-- | include/linux/tpm.h | 4 | ||||
| -rw-r--r-- | security/keys/trusted.c | 54 |
4 files changed, 92 insertions, 48 deletions
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c index 677c6e2..36e43e5 100644 --- a/drivers/char/tpm/tpm.c +++ b/drivers/char/tpm/tpm.c @@ -32,12 +32,6 @@ #include "tpm.h" #include "tpm_eventlog.h" -enum tpm_const { - TPM_MINOR = 224, /* officially assigned */ - TPM_BUFSIZE = 4096, - TPM_NUM_DEVICES = 256, -}; - enum tpm_duration { TPM_SHORT = 0, TPM_MEDIUM = 1, @@ -483,6 +477,7 @@ static ssize_t transmit_cmd(struct tpm_chip *chip, struct tpm_cmd_t *cmd, #define TPM_INTERNAL_RESULT_SIZE 200 #define TPM_TAG_RQU_COMMAND cpu_to_be16(193) #define TPM_ORD_GET_CAP cpu_to_be32(101) +#define TPM_ORD_GET_RANDOM cpu_to_be32(70) static const struct tpm_input_header tpm_getcap_header = { .tag = TPM_TAG_RQU_COMMAND, @@ -1327,6 +1322,58 @@ int tpm_pm_resume(struct device *dev) } EXPORT_SYMBOL_GPL(tpm_pm_resume); +#define TPM_GETRANDOM_RESULT_SIZE 18 +static struct tpm_input_header tpm_getrandom_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(14), + .ordinal = TPM_ORD_GET_RANDOM +}; + +/** + * tpm_get_random() - Get random bytes from the tpm's RNG + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @out: destination buffer for the random bytes + * @max: the max number of bytes to write to @out + * + * Returns < 0 on error and the number of bytes read on success + */ +int tpm_get_random(u32 chip_num, u8 *out, size_t max) +{ + struct tpm_chip *chip; + struct tpm_cmd_t tpm_cmd; + u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA); + int err, total = 0, retries = 5; + u8 *dest = out; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + + if (!out || !num_bytes || max > TPM_MAX_RNG_DATA) + return -EINVAL; + + do { + tpm_cmd.header.in = tpm_getrandom_header; + tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes); + + err = transmit_cmd(chip, &tpm_cmd, + TPM_GETRANDOM_RESULT_SIZE + num_bytes, + "attempting get random"); + if (err) + break; + + recd = be32_to_cpu(tpm_cmd.params.getrandom_out.rng_data_len); + memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd); + + dest += recd; + total += recd; + num_bytes -= recd; + } while (retries-- && total < max); + + return total ? total : -EIO; +} +EXPORT_SYMBOL_GPL(tpm_get_random); + /* In case vendor provided release function, call it too.*/ void tpm_dev_vendor_release(struct tpm_chip *chip) diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 917f727..645136e 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -28,6 +28,12 @@ #include <linux/io.h> #include <linux/tpm.h> +enum tpm_const { + TPM_MINOR = 224, /* officially assigned */ + TPM_BUFSIZE = 4096, + TPM_NUM_DEVICES = 256, +}; + enum tpm_timeout { TPM_TIMEOUT = 5, /* msecs */ }; @@ -269,6 +275,21 @@ struct tpm_pcrextend_in { u8 hash[TPM_DIGEST_SIZE]; }__attribute__((packed)); +/* 128 bytes is an arbitrary cap. This could be as large as TPM_BUFSIZE - 18 + * bytes, but 128 is still a relatively large number of random bytes and + * anything much bigger causes users of struct tpm_cmd_t to start getting + * compiler warnings about stack frame size. */ +#define TPM_MAX_RNG_DATA 128 + +struct tpm_getrandom_out { + __be32 rng_data_len; + u8 rng_data[TPM_MAX_RNG_DATA]; +}__attribute__((packed)); + +struct tpm_getrandom_in { + __be32 num_bytes; +}__attribute__((packed)); + typedef union { struct tpm_getcap_params_out getcap_out; struct tpm_readpubek_params_out readpubek_out; @@ -277,6 +298,8 @@ typedef union { struct tpm_pcrread_in pcrread_in; struct tpm_pcrread_out pcrread_out; struct tpm_pcrextend_in pcrextend_in; + struct tpm_getrandom_in getrandom_in; + struct tpm_getrandom_out getrandom_out; } tpm_cmd_params; struct tpm_cmd_t { diff --git a/include/linux/tpm.h b/include/linux/tpm.h index fdc718a..fcb627f 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -32,6 +32,7 @@ extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf); extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash); extern int tpm_send(u32 chip_num, void *cmd, size_t buflen); +extern int tpm_get_random(u32 chip_num, u8 *data, size_t max); #else static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) { return -ENODEV; @@ -42,5 +43,8 @@ static inline int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) { static inline int tpm_send(u32 chip_num, void *cmd, size_t buflen) { return -ENODEV; } +static inline int tpm_get_random(u32 chip_num, u8 *data, size_t max) { + return -ENODEV; +} #endif #endif diff --git a/security/keys/trusted.c b/security/keys/trusted.c index 2d5d041..3f163d0 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -369,38 +369,6 @@ static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd, } /* - * get a random value from TPM - */ -static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len) -{ - int ret; - - INIT_BUF(tb); - store16(tb, TPM_TAG_RQU_COMMAND); - store32(tb, TPM_GETRANDOM_SIZE); - store32(tb, TPM_ORD_GETRANDOM); - store32(tb, len); - ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data); - if (!ret) - memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len); - return ret; -} - -static int my_get_random(unsigned char *buf, int len) -{ - struct tpm_buf *tb; - int ret; - - tb = kmalloc(sizeof *tb, GFP_KERNEL); - if (!tb) - return -ENOMEM; - ret = tpm_get_random(tb, buf, len); - - kfree(tb); - return ret; -} - -/* * Lock a trusted key, by extending a selected PCR. * * Prevents a trusted key that is sealed to PCRs from being accessed. @@ -413,8 +381,8 @@ static int pcrlock(const int pcrnum) if (!capable(CAP_SYS_ADMIN)) return -EPERM; - ret = my_get_random(hash, SHA1_DIGEST_SIZE); - if (ret < 0) + ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE); + if (ret != SHA1_DIGEST_SIZE) return ret; return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0; } @@ -429,8 +397,8 @@ static int osap(struct tpm_buf *tb, struct osapsess *s, unsigned char ononce[TPM_NONCE_SIZE]; int ret; - ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE); - if (ret < 0) + ret = tpm_get_random(TPM_ANY_NUM, ononce, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) return ret; INIT_BUF(tb); @@ -524,8 +492,8 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, if (ret < 0) goto out; - ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE); - if (ret < 0) + ret = tpm_get_random(TPM_ANY_NUM, td->nonceodd, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) goto out; ordinal = htonl(TPM_ORD_SEAL); datsize = htonl(datalen); @@ -634,8 +602,8 @@ static int tpm_unseal(struct tpm_buf *tb, ordinal = htonl(TPM_ORD_UNSEAL); keyhndl = htonl(SRKHANDLE); - ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE); - if (ret < 0) { + ret = tpm_get_random(TPM_ANY_NUM, nonceodd, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) { pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); return ret; } @@ -935,6 +903,7 @@ static int trusted_instantiate(struct key *key, const void *data, char *datablob; int ret = 0; int key_cmd; + size_t key_len; if (datalen <= 0 || datalen > 32767 || !data) return -EINVAL; @@ -974,8 +943,9 @@ static int trusted_instantiate(struct key *key, const void *data, pr_info("trusted_key: key_unseal failed (%d)\n", ret); break; case Opt_new: - ret = my_get_random(payload->key, payload->key_len); - if (ret < 0) { + key_len = payload->key_len; + ret = tpm_get_random(TPM_ANY_NUM, payload->key, key_len); + if (ret != key_len) { pr_info("trusted_key: key_create failed (%d)\n", ret); goto out; } |
