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SubjectRe: [PATCH v1.3 3/4] keys: add new trusted key-type
Date
Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:

> +enum {
> + Opt_err = -1,
> + Opt_new = 1, Opt_load, Opt_update,
> + Opt_keyhandle, Opt_keyauth, Opt_blobauth,
> + Opt_pcrinfo, Opt_pcrlock, Opt_migratable
> +};

The compiler can generate slightly more efficient code if you don't skip 0 in
your enum.

> +static match_table_t key_tokens = {

const.

> +static int getoptions(char *c, struct trusted_key_payload *pay,
> + struct trusted_key_options *opt)
> +{
> + substring_t args[MAX_OPT_ARGS];
> + char *p = c;
> + int token;
> + int res;
> + unsigned long handle;
> + unsigned long lock;
> +
> + while ((p = strsep(&c, " \t"))) {
> + if ((*p == '\0') || (*p == ' ') || (*p == '\t'))

Superfluous brackets round the individual comparisons.

> + continue;
> + token = match_token(p, key_tokens, args);
> +
> + switch (token) {
> + case Opt_pcrinfo:
> + opt->pcrinfo_len = strlen(args[0].from) / 2;
> + if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
> + return -EINVAL;
> + hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
> + break;
> + case Opt_keyhandle:
> + res = strict_strtoul(args[0].from, 16, &handle);
> + if (res < 0)
> + return -EINVAL;
> + opt->keytype = SEALKEYTYPE;
> + opt->keyhandle = (uint32_t) handle;

Unnecessary cast.

> + break;
> + case Opt_keyauth:
> + if (strlen(args[0].from) != 2 * TPM_HASH_SIZE)
> + return -EINVAL;
> + hex2bin(opt->keyauth, args[0].from, TPM_HASH_SIZE);
> + break;
> + case Opt_blobauth:
> + if (strlen(args[0].from) != 2 * TPM_HASH_SIZE)
> + return -EINVAL;
> + hex2bin(opt->blobauth, args[0].from, TPM_HASH_SIZE);
> + break;
> + case Opt_migratable:
> + if (*args[0].from == '0')
> + pay->migratable = 0;
> + else
> + return -EINVAL;
> + break;
> + case Opt_pcrlock:
> + res = strict_strtoul(args[0].from, 10, &lock);
> + if (res < 0)
> + return -EINVAL;
> + opt->pcrlock = (int)lock;

Unnecessary cast.

> + break;
> + default:
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> +/*
> + * datablob_parse - parse the keyctl data and fill in the
> + * payload and options structures
> + *
> + * On success returns 0, otherwise -EINVAL.
> + */
> +static int datablob_parse(char *datablob, struct trusted_key_payload *p,
> + struct trusted_key_options *o)
> +{
> ...
> + ret = strict_strtol(c, 10, (long *)&p->key_len);

NAK! You cannot do this. It won't work on 64-bit machines, especially
big-endian ones. Casting the pointer does not change the size of the
destination variable. You must use a temporary var.

> + if ((ret < 0) || (p->key_len < MIN_KEY_SIZE) ||
> + (p->key_len > MAX_KEY_SIZE))

Superfluous parenthesization.

> +static int trusted_instantiate(struct key *key, const void *data,
> + size_t datalen)
> +{
> ...
> + switch (key_cmd) {
> + case Opt_load:
> + ret = key_unseal(payload, options);
> + if (ret < 0)
> + 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) {
> + pr_info("trusted_key: key_create failed (%d)\n", ret);
> + goto out;
> + }
> + ret = key_seal(payload, options);
> + if (ret < 0)
> + pr_info("trusted_key: key_seal failed (%d)\n", ret);
> + break;

Aha! I see how this works now. Using add/update key seems the right way to
do things.

> + default:
> + ret = -EINVAL;
> + }
> + if (options->pcrlock)
> + ret = pcrlock(options->pcrlock);

Do you really want to go through pcrlock() if you're going to return -EINVAL?

> +out:
> + kfree(datablob);
> + if (options)
> + kfree(options);

kfree() can handle NULL pointers.

> + if (!ret)
> + rcu_assign_pointer(key->payload.data, payload);
> + else if (payload)
> + kfree(payload);

Again, kfree() can handle a NULL pointer.

> +#define TPM_MAX_BUF_SIZE 512
> +#define TPM_TAG_RQU_COMMAND 193
> +#define TPM_TAG_RQU_AUTH1_COMMAND 194
> +#define TPM_TAG_RQU_AUTH2_COMMAND 195
> +#define TPM_TAG_RSP_COMMAND 196
> +#define TPM_TAG_RSP_AUTH1_COMMAND 197
> +#define TPM_TAG_RSP_AUTH2_COMMAND 198
> +#define TPM_NONCE_SIZE 20
> +#define TPM_HASH_SIZE 20
> +#define TPM_SIZE_OFFSET 2
> +#define TPM_RETURN_OFFSET 6
> +#define TPM_DATA_OFFSET 10
> +#define TPM_U32_SIZE 4
> +#define TPM_GETRANDOM_SIZE 14
> +#define TPM_GETRANDOM_RETURN 14
> +#define TPM_ORD_GETRANDOM 70
> +#define TPM_RESET_SIZE 10
> +#define TPM_ORD_RESET 90
> +#define TPM_OSAP_SIZE 36
> +#define TPM_ORD_OSAP 11
> +#define TPM_OIAP_SIZE 10
> +#define TPM_ORD_OIAP 10
> +#define TPM_SEAL_SIZE 87
> +#define TPM_ORD_SEAL 23
> +#define TPM_ORD_UNSEAL 24
> +#define TPM_UNSEAL_SIZE 104
> +#define SEALKEYTYPE 1
> +#define SRKKEYTYPE 4
> +#define SRKHANDLE 0x40000000
> +#define TPM_ANY_NUM 0xFFFF
> +#define MAX_PCRINFO_SIZE 64

I suspect some of these should be in somewhere like linux/tpm.h rather than
here. They're specific to TPM access not TPM key management.

> +#define LOAD32(buffer, offset) (ntohl(*(uint32_t *)&buffer[offset]))
> +#define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset])
> +#define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset]))
> +
> +struct tpm_buf {
> + int len;
> + unsigned char data[TPM_MAX_BUF_SIZE];
> +};
> +
> +#define INIT_BUF(tb) (tb->len = 0)
> +
> +struct osapsess {
> + uint32_t handle;
> + unsigned char secret[TPM_HASH_SIZE];
> + unsigned char enonce[TPM_NONCE_SIZE];
> +};
> +
> +struct trusted_key_options {
> + uint16_t keytype;

key type enum?

> + uint32_t keyhandle;
> + unsigned char keyauth[TPM_HASH_SIZE];
> + unsigned char blobauth[TPM_HASH_SIZE];
> + uint32_t pcrinfo_len;
> + unsigned char pcrinfo[MAX_PCRINFO_SIZE];
> + int pcrlock;
> +};
> +
> +#define TPM_DEBUG 0

The TPM_DEBUG stuff should probably be in the directory with the sources, not
in a directory for others to include.

> +#if TPM_DEBUG
> +static inline void dump_options(struct trusted_key_options *o)
> +{
> + pr_info("trusted_key: sealing key type %d\n", o->keytype);
> + pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle);
> + pr_info("trusted_key: pcrlock %d\n", o->pcrlock);
> + pr_info("trusted_key: pcrinfo %d\n", o->pcrinfo_len);
> + print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE,
> + 16, 1, o->pcrinfo, o->pcrinfo_len, 0);
> +}
> +
> +static inline void dump_payload(struct trusted_key_payload *p)
> +{
> + pr_info("trusted_key: key_len %d\n", p->key_len);
> + print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE,
> + 16, 1, p->key, p->key_len, 0);
> + pr_info("trusted_key: bloblen %d\n", p->blob_len);
> + print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE,
> + 16, 1, p->blob, p->blob_len, 0);
> + pr_info("trusted_key: migratable %d\n", p->migratable);
> +}
> +
> +static inline void dump_sess(struct osapsess *s)
> +{
> + print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE,
> + 16, 1, &s->handle, 4, 0);
> + pr_info("trusted-key: secret:\n");
> + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE,
> + 16, 1, &s->secret, TPM_HASH_SIZE, 0);
> + pr_info("trusted-key: enonce:\n");
> + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE,
> + 16, 1, &s->enonce, TPM_HASH_SIZE, 0);
> +}
> +
> +static inline void dump_tpm_buf(unsigned char *buf)
> +{
> + int len;
> +
> + pr_info("\ntrusted-key: tpm buffer\n");
> + len = LOAD32(buf, TPM_SIZE_OFFSET);
> + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0);
> +}
> +#else
> +static inline void dump_options(struct trusted_key_options *o)
> +{
> +}
> +
> +static inline void dump_payload(struct trusted_key_payload *p)
> +{
> +}
> +
> +static inline void dump_sess(struct osapsess *s)
> +{
> +}
> +
> +static inline void dump_tpm_buf(unsigned char *buf)
> +{
> +}
> +#endif
> +
> +static inline void store8(struct tpm_buf *buf, unsigned char value)
> +{
> + buf->data[buf->len++] = value;
> +}
> +
> +static inline void store16(struct tpm_buf *buf, uint16_t value)
> +{
> + *(uint16_t *) & buf->data[buf->len] = htons(value);
> + buf->len += sizeof(value);
> +}
> +
> +static inline void store32(struct tpm_buf *buf, uint32_t value)
> +{
> + *(uint32_t *) & buf->data[buf->len] = htonl(value);
> + buf->len += sizeof(value);
> +}
> +
> +static inline void storebytes(struct tpm_buf *buf, unsigned char *in, int len)
> +{
> + memcpy(buf->data + buf->len, in, len);
> + buf->len += len;
> +}

Also these look like internal functions which shouldn't be in the global
headers.

David


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