@@ -296,15 +296,16 @@ follows:
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
- .salg_type = "rng", /* this selects the symmetric cipher */
- .salg_name = "drbg_nopr_sha256" /* this is the cipher name */
+ .salg_type = "rng", /* this selects the random number generator */
+ .salg_name = "drbg_nopr_sha256" /* this is the RNG name */
};
Depending on the RNG type, the RNG must be seeded. The seed is provided
using the setsockopt interface to set the key. For example, the
ansi_cprng requires a seed. The DRBGs do not require a seed, but may be
-seeded.
+seeded. The seed is also known as a *Personalization String* in NIST SP 800-90A
+standard.
Using the read()/recvmsg() system calls, random numbers can be obtained.
The kernel generates at most 128 bytes in one call. If user space
@@ -314,6 +315,16 @@ WARNING: The user space caller may invoke the initially mentioned accept
system call multiple times. In this case, the returned file descriptors
have the same state.
+Following CAVP testing interfaces are enabled when kernel is built with
+CRYPTO_USER_API_RNG_CAVP option:
+
+- the concatenation of *Entropy* and *Nonce* can be provided to the RNG via
+ ALG_SET_DRBG_ENTROPY setsockopt interface. Setting the entropy requires
+ CAP_SYS_ADMIN permission.
+
+- *Additional Data* can be provided using the send()/sendmsg() system calls,
+ but only after the entropy has been set.
+
Zero-Copy Interface
-------------------
@@ -377,6 +388,9 @@ mentioned optname:
provided ciphertext is assumed to contain an authentication tag of
the given size (see section about AEAD memory layout below).
+- ALG_SET_DRBG_ENTROPY -- Setting the entropy of the random number generator.
+ This option is applicable to RNG cipher type only.
+
User space API example
----------------------
@@ -1870,6 +1870,15 @@ config CRYPTO_USER_API_RNG
This option enables the user-spaces interface for random
number generator algorithms.
+config CRYPTO_USER_API_RNG_CAVP
+ bool "Enable CAVP testing of DRBG"
+ depends on CRYPTO_USER_API_RNG && CRYPTO_DRBG
+ help
+ This option enables extra API for CAVP testing via the user-space
+ interface: resetting of DRBG entropy, and providing Additional Data.
+ This should only be enabled for CAVP testing. You should say
+ no unless you know what this is.
+
config CRYPTO_USER_API_AEAD
tristate "User-space interface for AEAD cipher algorithms"
depends on NET
@@ -253,6 +253,14 @@ static int alg_setsockopt(struct socket *sock, int level, int optname,
if (!type->setauthsize)
goto unlock;
err = type->setauthsize(ask->private, optlen);
+ break;
+ case ALG_SET_DRBG_ENTROPY:
+ if (sock->state == SS_CONNECTED)
+ goto unlock;
+ if (!type->setentropy)
+ goto unlock;
+
+ err = type->setentropy(ask->private, optval, optlen);
}
unlock:
@@ -285,6 +293,11 @@ int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
security_sock_graft(sk2, newsock);
security_sk_clone(sk, sk2);
+ /*
+ * newsock->ops assigned here to allow type->accept call to override
+ * them when required.
+ */
+ newsock->ops = type->ops;
err = type->accept(ask->private, sk2);
nokey = err == -ENOKEY;
@@ -303,7 +316,6 @@ int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
alg_sk(sk2)->parent = sk;
alg_sk(sk2)->type = type;
- newsock->ops = type->ops;
newsock->state = SS_CONNECTED;
if (nokey)
@@ -38,6 +38,7 @@
* DAMAGE.
*/
+#include <linux/capability.h>
#include <linux/module.h>
#include <crypto/rng.h>
#include <linux/random.h>
@@ -53,15 +54,26 @@ struct rng_ctx {
#define MAXSIZE 128
unsigned int len;
struct crypto_rng *drng;
+ u8 *addtl;
+ size_t addtl_len;
};
-static int rng_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
- int flags)
+struct rng_parent_ctx {
+ struct crypto_rng *drng;
+ u8 *entropy;
+};
+
+static void rng_reset_addtl(struct rng_ctx *ctx)
{
- struct sock *sk = sock->sk;
- struct alg_sock *ask = alg_sk(sk);
- struct rng_ctx *ctx = ask->private;
- int err;
+ kfree_sensitive(ctx->addtl);
+ ctx->addtl = NULL;
+ ctx->addtl_len = 0;
+}
+
+static int _rng_recvmsg(struct crypto_rng *drng, struct msghdr *msg, size_t len,
+ u8 *addtl, size_t addtl_len)
+{
+ int err = 0;
int genlen = 0;
u8 result[MAXSIZE];
@@ -82,7 +94,7 @@ static int rng_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
* seeding as they automatically seed. The X9.31 DRNG will return
* an error if it was not seeded properly.
*/
- genlen = crypto_rng_get_bytes(ctx->drng, result, len);
+ genlen = crypto_rng_generate(drng, addtl, addtl_len, result, len);
if (genlen < 0)
return genlen;
@@ -92,6 +104,63 @@ static int rng_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
return err ? err : len;
}
+static int rng_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+ int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct rng_ctx *ctx = ask->private;
+
+ return _rng_recvmsg(ctx->drng, msg, len, NULL, 0);
+}
+
+static int rng_test_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+ int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct rng_ctx *ctx = ask->private;
+ int ret;
+
+ lock_sock(sock->sk);
+ ret = _rng_recvmsg(ctx->drng, msg, len, ctx->addtl, ctx->addtl_len);
+ rng_reset_addtl(ctx);
+ release_sock(sock->sk);
+
+ return ret;
+}
+
+static int rng_test_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+ int err;
+ struct alg_sock *ask = alg_sk(sock->sk);
+ struct rng_ctx *ctx = ask->private;
+
+ lock_sock(sock->sk);
+ if (len > MAXSIZE) {
+ err = -EMSGSIZE;
+ goto unlock;
+ }
+
+ rng_reset_addtl(ctx);
+ ctx->addtl = kmalloc(len, GFP_KERNEL);
+ if (!ctx->addtl) {
+ err = -ENOMEM;
+ goto unlock;
+ }
+
+ err = memcpy_from_msg(ctx->addtl, msg, len);
+ if (err) {
+ rng_reset_addtl(ctx);
+ goto unlock;
+ }
+ ctx->addtl_len = len;
+
+unlock:
+ release_sock(sock->sk);
+ return err ? err : len;
+}
+
static struct proto_ops algif_rng_ops = {
.family = PF_ALG,
@@ -111,14 +180,53 @@ static struct proto_ops algif_rng_ops = {
.recvmsg = rng_recvmsg,
};
+static struct proto_ops __maybe_unused algif_rng_test_ops = {
+ .family = PF_ALG,
+
+ .connect = sock_no_connect,
+ .socketpair = sock_no_socketpair,
+ .getname = sock_no_getname,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .mmap = sock_no_mmap,
+ .bind = sock_no_bind,
+ .accept = sock_no_accept,
+ .sendpage = sock_no_sendpage,
+
+ .release = af_alg_release,
+ .recvmsg = rng_test_recvmsg,
+ .sendmsg = rng_test_sendmsg,
+};
+
static void *rng_bind(const char *name, u32 type, u32 mask)
{
- return crypto_alloc_rng(name, type, mask);
+ struct rng_parent_ctx *pctx;
+ struct crypto_rng *rng;
+
+ pctx = kzalloc(sizeof(*pctx), GFP_KERNEL);
+ if (!pctx)
+ return ERR_PTR(-ENOMEM);
+
+ rng = crypto_alloc_rng(name, type, mask);
+ if (IS_ERR(rng)) {
+ kfree(pctx);
+ return ERR_CAST(rng);
+ }
+
+ pctx->drng = rng;
+ return pctx;
}
static void rng_release(void *private)
{
- crypto_free_rng(private);
+ struct rng_parent_ctx *pctx = private;
+
+ if (unlikely(!pctx))
+ return;
+ crypto_free_rng(pctx->drng);
+ kfree_sensitive(pctx->entropy);
+ kfree_sensitive(pctx);
}
static void rng_sock_destruct(struct sock *sk)
@@ -126,6 +234,7 @@ static void rng_sock_destruct(struct sock *sk)
struct alg_sock *ask = alg_sk(sk);
struct rng_ctx *ctx = ask->private;
+ rng_reset_addtl(ctx);
sock_kfree_s(sk, ctx, ctx->len);
af_alg_release_parent(sk);
}
@@ -133,6 +242,7 @@ static void rng_sock_destruct(struct sock *sk)
static int rng_accept_parent(void *private, struct sock *sk)
{
struct rng_ctx *ctx;
+ struct rng_parent_ctx *pctx = private;
struct alg_sock *ask = alg_sk(sk);
unsigned int len = sizeof(*ctx);
@@ -141,6 +251,8 @@ static int rng_accept_parent(void *private, struct sock *sk)
return -ENOMEM;
ctx->len = len;
+ ctx->addtl = NULL;
+ ctx->addtl_len = 0;
/*
* No seeding done at that point -- if multiple accepts are
@@ -148,20 +260,58 @@ static int rng_accept_parent(void *private, struct sock *sk)
* state of the RNG.
*/
- ctx->drng = private;
+ ctx->drng = pctx->drng;
ask->private = ctx;
sk->sk_destruct = rng_sock_destruct;
+ /*
+ * Non NULL pctx->entropy means that CAVP test has been initiated on
+ * this socket, replace proto_ops algif_rng_ops with algif_rng_test_ops.
+ */
+ if (IS_ENABLED(CONFIG_CRYPTO_USER_API_RNG_CAVP) && pctx->entropy)
+ sk->sk_socket->ops = &algif_rng_test_ops;
+
return 0;
}
static int rng_setkey(void *private, const u8 *seed, unsigned int seedlen)
{
+ struct rng_parent_ctx *pctx = private;
/*
* Check whether seedlen is of sufficient size is done in RNG
* implementations.
*/
- return crypto_rng_reset(private, seed, seedlen);
+ return crypto_rng_reset(pctx->drng, seed, seedlen);
+}
+
+static int __maybe_unused rng_setentropy(void *private, sockptr_t entropy,
+ unsigned int len)
+{
+ struct rng_parent_ctx *pctx = private;
+ u8 *kentropy = NULL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (pctx->entropy)
+ return -EINVAL;
+
+ if (len > MAXSIZE)
+ return -EMSGSIZE;
+
+ if (len) {
+ kentropy = memdup_sockptr(entropy, len);
+ if (IS_ERR(kentropy))
+ return PTR_ERR(kentropy);
+ }
+
+ crypto_rng_alg(pctx->drng)->set_ent(pctx->drng, kentropy, len);
+ /*
+ * Since rng doesn't perform any memory management for the entropy
+ * buffer, save kentropy pointer to pctx now to free it after use.
+ */
+ pctx->entropy = kentropy;
+ return 0;
}
static const struct af_alg_type algif_type_rng = {
@@ -169,6 +319,9 @@ static const struct af_alg_type algif_type_rng = {
.release = rng_release,
.accept = rng_accept_parent,
.setkey = rng_setkey,
+#ifdef CONFIG_CRYPTO_USER_API_RNG_CAVP
+ .setentropy = rng_setentropy,
+#endif
.ops = &algif_rng_ops,
.name = "rng",
.owner = THIS_MODULE
@@ -46,6 +46,7 @@ struct af_alg_type {
void *(*bind)(const char *name, u32 type, u32 mask);
void (*release)(void *private);
int (*setkey)(void *private, const u8 *key, unsigned int keylen);
+ int (*setentropy)(void *private, sockptr_t entropy, unsigned int len);
int (*accept)(void *private, struct sock *sk);
int (*accept_nokey)(void *private, struct sock *sk);
int (*setauthsize)(void *private, unsigned int authsize);
@@ -35,6 +35,7 @@ struct af_alg_iv {
#define ALG_SET_OP 3
#define ALG_SET_AEAD_ASSOCLEN 4
#define ALG_SET_AEAD_AUTHSIZE 5
+#define ALG_SET_DRBG_ENTROPY 6
/* Operations */
#define ALG_OP_DECRYPT 0