From: Tadeusz Struk Subject: [PATCH v5 6/6] crypto: AF_ALG - add support for key_id Date: Fri, 15 Apr 2016 13:23:17 -0700 Message-ID: <20160415202317.29343.93424.stgit@tstruk-mobl1> References: <20160415202245.29343.59603.stgit@tstruk-mobl1> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: herbert@gondor.apana.org.au, tadeusz.struk@intel.com, smueller@chronox.de, linux-api@vger.kernel.org, marcel@holtmann.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, dwmw2@infradead.org, davem@davemloft.net To: dhowells@redhat.com Return-path: Received: from mga01.intel.com ([192.55.52.88]:45741 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626AbcDOU2c (ORCPT ); Fri, 15 Apr 2016 16:28:32 -0400 In-Reply-To: <20160415202245.29343.59603.stgit@tstruk-mobl1> Sender: linux-crypto-owner@vger.kernel.org List-ID: This patch adds support for asymmetric key type to AF_ALG. It will work as follows: A new PF_ALG socket options are added on top of existing ALG_SET_KEY and ALG_SET_PUBKEY, namely ALG_SET_KEY_ID and ALG_SET_PUBKEY_ID for setting public and private keys respectively. When these new options will be used the user, instead of providing the key material, will provide a key id and the key itself will be obtained from kernel keyring subsystem. The user will use the standard tools (keyctl tool or the keyctl syscall) for key instantiation and to obtain the key id. The key id can also be obtained by reading the /proc/keys file. When a key corresponding to the given keyid is found, it is stored in the socket context and subsequent crypto operation invoked by the user will use the new asymmetric accessor functions instead of akcipher api. The asymmetric subtype can internally use akcipher api or invoke operations defined by a given subtype, depending on the key type. Signed-off-by: Tadeusz Struk --- crypto/af_alg.c | 10 ++ crypto/algif_akcipher.c | 207 ++++++++++++++++++++++++++++++++++++++++++- include/crypto/if_alg.h | 1 include/uapi/linux/if_alg.h | 2 4 files changed, 215 insertions(+), 5 deletions(-) diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 24dc082..59c8244 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -260,6 +260,16 @@ static int alg_setsockopt(struct socket *sock, int level, int optname, err = alg_setkey(sk, optval, optlen, type->setpubkey); break; + + case ALG_SET_KEY_ID: + case ALG_SET_PUBKEY_ID: + /* ALG_SET_KEY_ID is only for akcipher */ + if (!strcmp(type->name, "akcipher") || + sock->state == SS_CONNECTED) + goto unlock; + + err = alg_setkey(sk, optval, optlen, type->setkeyid); + break; case ALG_SET_AEAD_AUTHSIZE: if (sock->state == SS_CONNECTED) goto unlock; diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c index e00793d..863866d 100644 --- a/crypto/algif_akcipher.c +++ b/crypto/algif_akcipher.c @@ -14,6 +14,8 @@ #include #include #include +#include +#include #include #include #include @@ -29,6 +31,7 @@ struct akcipher_sg_list { struct akcipher_tfm { struct crypto_akcipher *akcipher; + char keyid[12]; bool has_key; }; @@ -37,6 +40,7 @@ struct akcipher_ctx { struct af_alg_sgl rsgl[ALG_MAX_PAGES]; struct af_alg_completion completion; + struct key *key; unsigned long used; @@ -322,6 +326,153 @@ unlock: return err ? err : size; } +static int asym_key_encrypt(const struct key *key, struct akcipher_request *req) +{ + struct kernel_pkey_params params = {0}; + char *src = NULL, *dst = NULL, *in, *out; + int ret; + + if (!sg_is_last(req->src)) { + src = kmalloc(req->src_len, GFP_KERNEL); + if (!src) + return -ENOMEM; + scatterwalk_map_and_copy(src, req->src, 0, req->src_len, 0); + in = src; + } else { + in = sg_virt(req->src); + } + if (!sg_is_last(req->dst)) { + dst = kmalloc(req->dst_len, GFP_KERNEL); + if (!dst) { + kfree(src); + return -ENOMEM; + } + out = dst; + } else { + out = sg_virt(req->dst); + } + params.key = (struct key *)key; + params.data_len = req->src_len; + params.enc_len = req->dst_len; + ret = encrypt_blob(¶ms, in, out); + if (ret) + goto free; + + if (dst) + scatterwalk_map_and_copy(dst, req->dst, 0, req->dst_len, 1); +free: + kfree(src); + kfree(dst); + return ret; +} + +static int asym_key_decrypt(const struct key *key, struct akcipher_request *req) +{ + struct kernel_pkey_params params = {0}; + char *src = NULL, *dst = NULL, *in, *out; + int ret; + + if (!sg_is_last(req->src)) { + src = kmalloc(req->src_len, GFP_KERNEL); + if (!src) + return -ENOMEM; + scatterwalk_map_and_copy(src, req->src, 0, req->src_len, 0); + in = src; + } else { + in = sg_virt(req->src); + } + if (!sg_is_last(req->dst)) { + dst = kmalloc(req->dst_len, GFP_KERNEL); + if (!dst) { + kfree(src); + return -ENOMEM; + } + out = dst; + } else { + out = sg_virt(req->dst); + } + params.key = (struct key *)key; + params.data_len = req->src_len; + params.enc_len = req->dst_len; + ret = decrypt_blob(¶ms, in, out); + if (ret) + goto free; + + if (dst) + scatterwalk_map_and_copy(dst, req->dst, 0, req->dst_len, 1); +free: + kfree(src); + kfree(dst); + return ret; +} + +static int asym_key_sign(const struct key *key, struct akcipher_request *req) +{ + struct kernel_pkey_params params = {0}; + char *src = NULL, *dst = NULL, *in, *out; + int ret; + + if (!sg_is_last(req->src)) { + src = kmalloc(req->src_len, GFP_KERNEL); + if (!src) + return -ENOMEM; + scatterwalk_map_and_copy(src, req->src, 0, req->src_len, 0); + in = src; + } else { + in = sg_virt(req->src); + } + if (!sg_is_last(req->dst)) { + dst = kmalloc(req->dst_len, GFP_KERNEL); + if (!dst) { + kfree(src); + return -ENOMEM; + } + out = dst; + } else { + out = sg_virt(req->dst); + } + params.key = (struct key *)key; + params.data_len = req->src_len; + params.enc_len = req->dst_len; + ret = create_signature(¶ms, in, out); + if (ret) + goto free; + + if (dst) + scatterwalk_map_and_copy(dst, req->dst, 0, req->dst_len, 1); +free: + kfree(src); + kfree(dst); + return ret; +} + +static int asym_key_verify(const struct key *key, struct akcipher_request *req) +{ + struct public_key_signature sig; + char *src = NULL, *in; + int ret; + + if (!sg_is_last(req->src)) { + src = kmalloc(req->src_len, GFP_KERNEL); + if (!src) + return -ENOMEM; + scatterwalk_map_and_copy(src, req->src, 0, req->src_len, 0); + in = src; + } else { + in = sg_virt(req->src); + } + sig.pkey_algo = "rsa"; + sig.encoding = "pkcs1"; + /* Need to find a way to pass the hash param */ + sig.hash_algo = "sha1"; + sig.digest_size = 20; + sig.s_size = req->src_len; + sig.s = src; + ret = verify_signature(key, &sig); + kfree(src); + return ret; +} + static int akcipher_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored, int flags) { @@ -377,16 +528,28 @@ static int akcipher_recvmsg(struct socket *sock, struct msghdr *msg, usedpages); switch (ctx->op) { case ALG_OP_VERIFY: - err = crypto_akcipher_verify(&ctx->req); + if (ctx->key) + err = asym_key_verify(ctx->key, &ctx->req); + else + err = crypto_akcipher_verify(&ctx->req); break; case ALG_OP_SIGN: - err = crypto_akcipher_sign(&ctx->req); + if (ctx->key) + err = asym_key_sign(ctx->key, &ctx->req); + else + err = crypto_akcipher_sign(&ctx->req); break; case ALG_OP_ENCRYPT: - err = crypto_akcipher_encrypt(&ctx->req); + if (ctx->key) + err = asym_key_encrypt(ctx->key, &ctx->req); + else + err = crypto_akcipher_encrypt(&ctx->req); break; case ALG_OP_DECRYPT: - err = crypto_akcipher_decrypt(&ctx->req); + if (ctx->key) + err = asym_key_decrypt(ctx->key, &ctx->req); + else + err = crypto_akcipher_decrypt(&ctx->req); break; default: err = -EFAULT; @@ -579,6 +742,27 @@ static void akcipher_release(void *private) kfree(tfm); } +static int akcipher_setkeyid(void *private, const u8 *key, unsigned int keylen) +{ + struct akcipher_tfm *tfm = private; + struct key *akey; + u32 keyid = *((u32 *)key); + int err = -ENOKEY; + + /* Store the key id and verify that a key with the given id is present. + * The actual key will be acquired in the accept_parent function + */ + sprintf(tfm->keyid, "id:%08x", keyid); + akey = request_key(&key_type_asymmetric, tfm->keyid, NULL); + if (IS_ERR(key)) + goto out; + + tfm->has_key = true; + key_put(akey); +out: + return err; +} + static int akcipher_setprivkey(void *private, const u8 *key, unsigned int keylen) { @@ -610,6 +794,8 @@ static void akcipher_sock_destruct(struct sock *sk) akcipher_put_sgl(sk); sock_kfree_s(sk, ctx, ctx->len); af_alg_release_parent(sk); + if (ctx->key) + key_put(ctx->key); } static int akcipher_accept_parent_nokey(void *private, struct sock *sk) @@ -618,6 +804,7 @@ static int akcipher_accept_parent_nokey(void *private, struct sock *sk) struct alg_sock *ask = alg_sk(sk); struct akcipher_tfm *tfm = private; struct crypto_akcipher *akcipher = tfm->akcipher; + struct key *key; unsigned int len = sizeof(*ctx) + crypto_akcipher_reqsize(akcipher); ctx = sock_kmalloc(sk, len, GFP_KERNEL); @@ -634,11 +821,20 @@ static int akcipher_accept_parent_nokey(void *private, struct sock *sk) af_alg_init_completion(&ctx->completion); sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES); - ask->private = ctx; + if (strlen(tfm->keyid)) { + key = request_key(&key_type_asymmetric, tfm->keyid, NULL); + if (IS_ERR(key)) { + sock_kfree_s(sk, ctx, len); + return -ENOKEY; + } + ctx->key = key; + memset(tfm->keyid, '\0', sizeof(tfm->keyid)); + } akcipher_request_set_tfm(&ctx->req, akcipher); akcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, af_alg_complete, &ctx->completion); + ask->private = ctx; sk->sk_destruct = akcipher_sock_destruct; @@ -660,6 +856,7 @@ static const struct af_alg_type algif_type_akcipher = { .release = akcipher_release, .setkey = akcipher_setprivkey, .setpubkey = akcipher_setpubkey, + .setkeyid = akcipher_setkeyid, .accept = akcipher_accept_parent, .accept_nokey = akcipher_accept_parent_nokey, .ops = &algif_akcipher_ops, diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index 6c3e6e7..09c99ab 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -53,6 +53,7 @@ struct af_alg_type { void (*release)(void *private); int (*setkey)(void *private, const u8 *key, unsigned int keylen); int (*setpubkey)(void *private, const u8 *key, unsigned int keylen); + int (*setkeyid)(void *private, const u8 *key, unsigned int keylen); int (*accept)(void *private, struct sock *sk); int (*accept_nokey)(void *private, struct sock *sk); int (*setauthsize)(void *private, unsigned int authsize); diff --git a/include/uapi/linux/if_alg.h b/include/uapi/linux/if_alg.h index 02e6162..0379766 100644 --- a/include/uapi/linux/if_alg.h +++ b/include/uapi/linux/if_alg.h @@ -35,6 +35,8 @@ struct af_alg_iv { #define ALG_SET_AEAD_ASSOCLEN 4 #define ALG_SET_AEAD_AUTHSIZE 5 #define ALG_SET_PUBKEY 6 +#define ALG_SET_PUBKEY_ID 7 +#define ALG_SET_KEY_ID 8 /* Operations */ #define ALG_OP_DECRYPT 0