gss_krb5: Add support for rc4-hmac encryption

[pandora-kernel.git] / net / sunrpc / auth_gss / gss_krb5_mech.c

diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index ef6b313..54eda5f 100644 (file)
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -72,6 +72,27 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
          .cksumlength = 8,
          .keyed_cksum = 0,
        },
+       /*
+        * RC4-HMAC
+        */
+       {
+         .etype = ENCTYPE_ARCFOUR_HMAC,
+         .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
+         .name = "rc4-hmac",
+         .encrypt_name = "ecb(arc4)",
+         .cksum_name = "hmac(md5)",
+         .encrypt = krb5_encrypt,
+         .decrypt = krb5_decrypt,
+         .mk_key = NULL,
+         .signalg = SGN_ALG_HMAC_MD5,
+         .sealalg = SEAL_ALG_MICROSOFT_RC4,
+         .keybytes = 16,
+         .keylength = 16,
+         .blocksize = 1,
+         .conflen = 8,
+         .cksumlength = 8,
+         .keyed_cksum = 1,
+       },
        /*
         * 3DES
         */
@@ -392,6 +413,79 @@ out_err:
        return -EINVAL;
 }
 
+/*
+ * Note that RC4 depends on deriving keys using the sequence
+ * number or the checksum of a token.  Therefore, the final keys
+ * cannot be calculated until the token is being constructed!
+ */
+static int
+context_derive_keys_rc4(struct krb5_ctx *ctx)
+{
+       struct crypto_hash *hmac;
+       char sigkeyconstant[] = "signaturekey";
+       int slen = strlen(sigkeyconstant) + 1;  /* include null terminator */
+       struct hash_desc desc;
+       struct scatterlist sg[1];
+       int err;
+
+       dprintk("RPC:       %s: entered\n", __func__);
+       /*
+        * derive cksum (aka Ksign) key
+        */
+       hmac = crypto_alloc_hash(ctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
+       if (IS_ERR(hmac)) {
+               dprintk("%s: error %ld allocating hash '%s'\n",
+                       __func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
+               err = PTR_ERR(hmac);
+               goto out_err;
+       }
+
+       err = crypto_hash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
+       if (err)
+               goto out_err_free_hmac;
+
+       sg_init_table(sg, 1);
+       sg_set_buf(sg, sigkeyconstant, slen);
+
+       desc.tfm = hmac;
+       desc.flags = 0;
+
+       err = crypto_hash_init(&desc);
+       if (err)
+               goto out_err_free_hmac;
+
+       err = crypto_hash_digest(&desc, sg, slen, ctx->cksum);
+       if (err)
+               goto out_err_free_hmac;
+       /*
+        * allocate hash, and blkciphers for data and seqnum encryption
+        */
+       ctx->enc = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
+                                         CRYPTO_ALG_ASYNC);
+       if (IS_ERR(ctx->enc)) {
+               err = PTR_ERR(ctx->enc);
+               goto out_err_free_hmac;
+       }
+
+       ctx->seq = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
+                                         CRYPTO_ALG_ASYNC);
+       if (IS_ERR(ctx->seq)) {
+               crypto_free_blkcipher(ctx->enc);
+               err = PTR_ERR(ctx->seq);
+               goto out_err_free_hmac;
+       }
+
+       dprintk("RPC:       %s: returning success\n", __func__);
+
+       err = 0;
+
+out_err_free_hmac:
+       crypto_free_hash(hmac);
+out_err:
+       dprintk("RPC:       %s: returning %d\n", __func__, err);
+       return err;
+}
+
 static int
 context_derive_keys_new(struct krb5_ctx *ctx)
 {
@@ -561,6 +655,8 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx)
        switch (ctx->enctype) {
        case ENCTYPE_DES3_CBC_RAW:
                return context_derive_keys_des3(ctx);
+       case ENCTYPE_ARCFOUR_HMAC:
+               return context_derive_keys_rc4(ctx);
        case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
        case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
                return context_derive_keys_new(ctx);