diff options
| -rw-r--r-- | crypto/dh.c | 66 | ||||
| -rw-r--r-- | crypto/dh_helper.c | 15 | ||||
| -rw-r--r-- | include/crypto/dh.h | 4 |
3 files changed, 79 insertions, 6 deletions
diff --git a/crypto/dh.c b/crypto/dh.c index 5659fe7f446d..8f79269db2b7 100644 --- a/crypto/dh.c +++ b/crypto/dh.c @@ -16,14 +16,16 @@ #include <linux/mpi.h> struct dh_ctx { - MPI p; - MPI g; - MPI xa; + MPI p; /* Value is guaranteed to be set. */ + MPI q; /* Value is optional. */ + MPI g; /* Value is guaranteed to be set. */ + MPI xa; /* Value is guaranteed to be set. */ }; static void dh_clear_ctx(struct dh_ctx *ctx) { mpi_free(ctx->p); + mpi_free(ctx->q); mpi_free(ctx->g); mpi_free(ctx->xa); memset(ctx, 0, sizeof(*ctx)); @@ -60,6 +62,12 @@ static int dh_set_params(struct dh_ctx *ctx, struct dh *params) if (!ctx->p) return -EINVAL; + if (params->q && params->q_size) { + ctx->q = mpi_read_raw_data(params->q, params->q_size); + if (!ctx->q) + return -EINVAL; + } + ctx->g = mpi_read_raw_data(params->g, params->g_size); if (!ctx->g) return -EINVAL; @@ -93,6 +101,55 @@ err_clear_ctx: return -EINVAL; } +/* + * SP800-56A public key verification: + * + * * If Q is provided as part of the domain paramenters, a full validation + * according to SP800-56A section 5.6.2.3.1 is performed. + * + * * If Q is not provided, a partial validation according to SP800-56A section + * 5.6.2.3.2 is performed. + */ +static int dh_is_pubkey_valid(struct dh_ctx *ctx, MPI y) +{ + if (unlikely(!ctx->p)) + return -EINVAL; + + /* + * Step 1: Verify that 2 <= y <= p - 2. + * + * The upper limit check is actually y < p instead of y < p - 1 + * as the mpi_sub_ui function is yet missing. + */ + if (mpi_cmp_ui(y, 1) < 1 || mpi_cmp(y, ctx->p) >= 0) + return -EINVAL; + + /* Step 2: Verify that 1 = y^q mod p */ + if (ctx->q) { + MPI val = mpi_alloc(0); + int ret; + + if (!val) + return -ENOMEM; + + ret = mpi_powm(val, y, ctx->q, ctx->p); + + if (ret) { + mpi_free(val); + return ret; + } + + ret = mpi_cmp_ui(val, 1); + + mpi_free(val); + + if (ret != 0) + return -EINVAL; + } + + return 0; +} + static int dh_compute_value(struct kpp_request *req) { struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); @@ -115,6 +172,9 @@ static int dh_compute_value(struct kpp_request *req) ret = -EINVAL; goto err_free_val; } + ret = dh_is_pubkey_valid(ctx, base); + if (ret) + goto err_free_val; } else { base = ctx->g; } diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c index 24fdb2ecaa85..a7de3d9ce5ac 100644 --- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -30,7 +30,7 @@ static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size) static inline unsigned int dh_data_size(const struct dh *p) { - return p->key_size + p->p_size + p->g_size; + return p->key_size + p->p_size + p->q_size + p->g_size; } unsigned int crypto_dh_key_len(const struct dh *p) @@ -56,9 +56,11 @@ int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params) ptr = dh_pack_data(ptr, &secret, sizeof(secret)); ptr = dh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size)); ptr = dh_pack_data(ptr, ¶ms->p_size, sizeof(params->p_size)); + ptr = dh_pack_data(ptr, ¶ms->q_size, sizeof(params->q_size)); ptr = dh_pack_data(ptr, ¶ms->g_size, sizeof(params->g_size)); ptr = dh_pack_data(ptr, params->key, params->key_size); ptr = dh_pack_data(ptr, params->p, params->p_size); + ptr = dh_pack_data(ptr, params->q, params->q_size); dh_pack_data(ptr, params->g, params->g_size); return 0; @@ -79,6 +81,7 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) ptr = dh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size)); ptr = dh_unpack_data(¶ms->p_size, ptr, sizeof(params->p_size)); + ptr = dh_unpack_data(¶ms->q_size, ptr, sizeof(params->q_size)); ptr = dh_unpack_data(¶ms->g_size, ptr, sizeof(params->g_size)); if (secret.len != crypto_dh_key_len(params)) return -EINVAL; @@ -88,7 +91,7 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) * some drivers assume otherwise. */ if (params->key_size > params->p_size || - params->g_size > params->p_size) + params->g_size > params->p_size || params->q_size > params->p_size) return -EINVAL; /* Don't allocate memory. Set pointers to data within @@ -96,7 +99,9 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) */ params->key = (void *)ptr; params->p = (void *)(ptr + params->key_size); - params->g = (void *)(ptr + params->key_size + params->p_size); + params->q = (void *)(ptr + params->key_size + params->p_size); + params->g = (void *)(ptr + params->key_size + params->p_size + + params->q_size); /* * Don't permit 'p' to be 0. It's not a prime number, and it's subject @@ -106,6 +111,10 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) if (memchr_inv(params->p, 0, params->p_size) == NULL) return -EINVAL; + /* It is permissible to not provide Q. */ + if (params->q_size == 0) + params->q = NULL; + return 0; } EXPORT_SYMBOL_GPL(crypto_dh_decode_key); diff --git a/include/crypto/dh.h b/include/crypto/dh.h index 71e1bb24d79f..7e0dad94cb2b 100644 --- a/include/crypto/dh.h +++ b/include/crypto/dh.h @@ -29,17 +29,21 @@ * * @key: Private DH key * @p: Diffie-Hellman parameter P + * @q: Diffie-Hellman parameter Q * @g: Diffie-Hellman generator G * @key_size: Size of the private DH key * @p_size: Size of DH parameter P + * @q_size: Size of DH parameter Q * @g_size: Size of DH generator G */ struct dh { void *key; void *p; + void *q; void *g; unsigned int key_size; unsigned int p_size; + unsigned int q_size; unsigned int g_size; }; |