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-rw-r--r--crypto/dh.c66
-rw-r--r--crypto/dh_helper.c15
2 files changed, 75 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, &params->key_size, sizeof(params->key_size));
ptr = dh_pack_data(ptr, &params->p_size, sizeof(params->p_size));
+ ptr = dh_pack_data(ptr, &params->q_size, sizeof(params->q_size));
ptr = dh_pack_data(ptr, &params->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(&params->key_size, ptr, sizeof(params->key_size));
ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
+ ptr = dh_unpack_data(&params->q_size, ptr, sizeof(params->q_size));
ptr = dh_unpack_data(&params->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);