From: Trond Myklebust Subject: [PATCH 21/22] gss_krb5: Add support for rc4-hmac encryption Date: Wed, 14 Apr 2010 13:36:57 -0400 Message-ID: <1271266618-26016-22-git-send-email-Trond.Myklebust@netapp.com> References: <1271266618-26016-1-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-2-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-3-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-4-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-5-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-6-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-7-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-8-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-9-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-10-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-11-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-12-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-13-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-14-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-15-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-16-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-17-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-18-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-19-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-20-git-send-email-Trond.Myklebust@netapp.com> <1271266618-26016-21-git-send-email-Trond.Myklebust@netapp.com> To: linux-nfs@vger.kernel.org Return-path: Received: from mx2.netapp.com ([216.240.18.37]:48907 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756574Ab0DNRhW (ORCPT ); Wed, 14 Apr 2010 13:37:22 -0400 Received: from localhost.localdomain (pd07336a.hq.netapp.com [10.58.61.110] (may be forged)) by smtp1.corp.netapp.com (8.13.1/8.13.1/NTAP-1.6) with ESMTP id o3EHawKH021574 for ; Wed, 14 Apr 2010 10:37:11 -0700 (PDT) In-Reply-To: <1271266618-26016-21-git-send-email-Trond.Myklebust@netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Kevin Coffman Add necessary changes to add kernel support for the rc4-hmac Kerberos encryption type used by Microsoft and described in rfc4757. Signed-off-by: Kevin Coffman Signed-off-by: Steve Dickson Signed-off-by: Trond Myklebust --- include/linux/sunrpc/gss_krb5.h | 9 ++ net/sunrpc/auth_gss/gss_krb5_crypto.c | 255 +++++++++++++++++++++++++++++++++ net/sunrpc/auth_gss/gss_krb5_mech.c | 96 ++++++++++++ net/sunrpc/auth_gss/gss_krb5_seal.c | 1 + net/sunrpc/auth_gss/gss_krb5_seqnum.c | 77 ++++++++++ net/sunrpc/auth_gss/gss_krb5_unseal.c | 1 + net/sunrpc/auth_gss/gss_krb5_wrap.c | 66 +++++++-- 7 files changed, 492 insertions(+), 13 deletions(-) diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h index 79f6ac2..5e774a5 100644 --- a/include/linux/sunrpc/gss_krb5.h +++ b/include/linux/sunrpc/gss_krb5.h @@ -317,5 +317,14 @@ gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, u32 *plainoffset, u32 *plainlen); +int +krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, + struct crypto_blkcipher *cipher, + unsigned char *cksum); + +int +krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, + struct crypto_blkcipher *cipher, + s32 seqnum); void gss_krb5_make_confounder(char *p, u32 conflen); diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c index ed4106a..75ee993 100644 --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c @@ -124,6 +124,114 @@ checksummer(struct scatterlist *sg, void *data) return crypto_hash_update(desc, sg, sg->length); } +static int +arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4]) +{ + unsigned int ms_usage; + + switch (usage) { + case KG_USAGE_SIGN: + ms_usage = 15; + break; + case KG_USAGE_SEAL: + ms_usage = 13; + break; + default: + return EINVAL;; + } + salt[0] = (ms_usage >> 0) & 0xff; + salt[1] = (ms_usage >> 8) & 0xff; + salt[2] = (ms_usage >> 16) & 0xff; + salt[3] = (ms_usage >> 24) & 0xff; + + return 0; +} + +static u32 +make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen, + struct xdr_buf *body, int body_offset, u8 *cksumkey, + unsigned int usage, struct xdr_netobj *cksumout) +{ + struct hash_desc desc; + struct scatterlist sg[1]; + int err; + u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; + u8 rc4salt[4]; + struct crypto_hash *md5; + struct crypto_hash *hmac_md5; + + if (cksumkey == NULL) + return GSS_S_FAILURE; + + if (cksumout->len < kctx->gk5e->cksumlength) { + dprintk("%s: checksum buffer length, %u, too small for %s\n", + __func__, cksumout->len, kctx->gk5e->name); + return GSS_S_FAILURE; + } + + if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) { + dprintk("%s: invalid usage value %u\n", __func__, usage); + return GSS_S_FAILURE; + } + + md5 = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(md5)) + return GSS_S_FAILURE; + + hmac_md5 = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac_md5)) { + crypto_free_hash(md5); + return GSS_S_FAILURE; + } + + desc.tfm = md5; + desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + err = crypto_hash_init(&desc); + if (err) + goto out; + sg_init_one(sg, rc4salt, 4); + err = crypto_hash_update(&desc, sg, 4); + if (err) + goto out; + + sg_init_one(sg, header, hdrlen); + err = crypto_hash_update(&desc, sg, hdrlen); + if (err) + goto out; + err = xdr_process_buf(body, body_offset, body->len - body_offset, + checksummer, &desc); + if (err) + goto out; + err = crypto_hash_final(&desc, checksumdata); + if (err) + goto out; + + desc.tfm = hmac_md5; + desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + err = crypto_hash_init(&desc); + if (err) + goto out; + err = crypto_hash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength); + if (err) + goto out; + + sg_init_one(sg, checksumdata, crypto_hash_digestsize(md5)); + err = crypto_hash_digest(&desc, sg, crypto_hash_digestsize(md5), + checksumdata); + if (err) + goto out; + + memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength); + cksumout->len = kctx->gk5e->cksumlength; +out: + crypto_free_hash(md5); + crypto_free_hash(hmac_md5); + return err ? GSS_S_FAILURE : 0; +} + /* * checksum the plaintext data and hdrlen bytes of the token header * The checksum is performed over the first 8 bytes of the @@ -140,6 +248,11 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen, u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; unsigned int checksumlen; + if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR) + return make_checksum_hmac_md5(kctx, header, hdrlen, + body, body_offset, + cksumkey, usage, cksumout); + if (cksumout->len < kctx->gk5e->cksumlength) { dprintk("%s: checksum buffer length, %u, too small for %s\n", __func__, cksumout->len, kctx->gk5e->name); @@ -733,3 +846,145 @@ out_err: ret = GSS_S_FAILURE; return ret; } + +/* + * Compute Kseq given the initial session key and the checksum. + * Set the key of the given cipher. + */ +int +krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher, + unsigned char *cksum) +{ + struct crypto_hash *hmac; + struct hash_desc desc; + struct scatterlist sg[1]; + u8 Kseq[GSS_KRB5_MAX_KEYLEN]; + u32 zeroconstant = 0; + int err; + + dprintk("%s: entered\n", __func__); + + hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac)) { + dprintk("%s: error %ld, allocating hash '%s'\n", + __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name); + return PTR_ERR(hmac); + } + + desc.tfm = hmac; + desc.flags = 0; + + err = crypto_hash_init(&desc); + if (err) + goto out_err; + + /* Compute intermediate Kseq from session key */ + err = crypto_hash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength); + if (err) + goto out_err; + + sg_init_table(sg, 1); + sg_set_buf(sg, &zeroconstant, 4); + + err = crypto_hash_digest(&desc, sg, 4, Kseq); + if (err) + goto out_err; + + /* Compute final Kseq from the checksum and intermediate Kseq */ + err = crypto_hash_setkey(hmac, Kseq, kctx->gk5e->keylength); + if (err) + goto out_err; + + sg_set_buf(sg, cksum, 8); + + err = crypto_hash_digest(&desc, sg, 8, Kseq); + if (err) + goto out_err; + + err = crypto_blkcipher_setkey(cipher, Kseq, kctx->gk5e->keylength); + if (err) + goto out_err; + + err = 0; + +out_err: + crypto_free_hash(hmac); + dprintk("%s: returning %d\n", __func__, err); + return err; +} + +/* + * Compute Kcrypt given the initial session key and the plaintext seqnum. + * Set the key of cipher kctx->enc. + */ +int +krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher, + s32 seqnum) +{ + struct crypto_hash *hmac; + struct hash_desc desc; + struct scatterlist sg[1]; + u8 Kcrypt[GSS_KRB5_MAX_KEYLEN]; + u8 zeroconstant[4] = {0}; + u8 seqnumarray[4]; + int err, i; + + dprintk("%s: entered, seqnum %u\n", __func__, seqnum); + + hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac)) { + dprintk("%s: error %ld, allocating hash '%s'\n", + __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name); + return PTR_ERR(hmac); + } + + desc.tfm = hmac; + desc.flags = 0; + + err = crypto_hash_init(&desc); + if (err) + goto out_err; + + /* Compute intermediate Kcrypt from session key */ + for (i = 0; i < kctx->gk5e->keylength; i++) + Kcrypt[i] = kctx->Ksess[i] ^ 0xf0; + + err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength); + if (err) + goto out_err; + + sg_init_table(sg, 1); + sg_set_buf(sg, zeroconstant, 4); + + err = crypto_hash_digest(&desc, sg, 4, Kcrypt); + if (err) + goto out_err; + + /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */ + err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength); + if (err) + goto out_err; + + seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff); + seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff); + seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff); + seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff); + + sg_set_buf(sg, seqnumarray, 4); + + err = crypto_hash_digest(&desc, sg, 4, Kcrypt); + if (err) + goto out_err; + + err = crypto_blkcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength); + if (err) + goto out_err; + + err = 0; + +out_err: + crypto_free_hash(hmac); + dprintk("%s: returning %d\n", __func__, err); + return err; +} + diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c index 1135056..4187c6e 100644 --- a/net/sunrpc/auth_gss/gss_krb5_mech.c +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c @@ -73,6 +73,27 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = { .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); diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c index 36fe487..d7941ea 100644 --- a/net/sunrpc/auth_gss/gss_krb5_seal.c +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c @@ -213,6 +213,7 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text, BUG(); case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: + case ENCTYPE_ARCFOUR_HMAC: return gss_get_mic_v1(ctx, text, token); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: diff --git a/net/sunrpc/auth_gss/gss_krb5_seqnum.c b/net/sunrpc/auth_gss/gss_krb5_seqnum.c index 83b5930..415c013 100644 --- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c +++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c @@ -39,6 +39,38 @@ # define RPCDBG_FACILITY RPCDBG_AUTH #endif +static s32 +krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum, + unsigned char *cksum, unsigned char *buf) +{ + struct crypto_blkcipher *cipher; + unsigned char plain[8]; + s32 code; + + dprintk("RPC: %s:\n", __func__); + cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + plain[0] = (unsigned char) ((seqnum >> 24) & 0xff); + plain[1] = (unsigned char) ((seqnum >> 16) & 0xff); + plain[2] = (unsigned char) ((seqnum >> 8) & 0xff); + plain[3] = (unsigned char) ((seqnum >> 0) & 0xff); + plain[4] = direction; + plain[5] = direction; + plain[6] = direction; + plain[7] = direction; + + code = krb5_rc4_setup_seq_key(kctx, cipher, cksum); + if (code) + goto out; + + code = krb5_encrypt(cipher, cksum, plain, buf, 8); +out: + crypto_free_blkcipher(cipher); + return code; +} s32 krb5_make_seq_num(struct krb5_ctx *kctx, struct crypto_blkcipher *key, @@ -48,6 +80,10 @@ krb5_make_seq_num(struct krb5_ctx *kctx, { unsigned char plain[8]; + if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) + return krb5_make_rc4_seq_num(kctx, direction, seqnum, + cksum, buf); + plain[0] = (unsigned char) (seqnum & 0xff); plain[1] = (unsigned char) ((seqnum >> 8) & 0xff); plain[2] = (unsigned char) ((seqnum >> 16) & 0xff); @@ -61,6 +97,43 @@ krb5_make_seq_num(struct krb5_ctx *kctx, return krb5_encrypt(key, cksum, plain, buf, 8); } +static s32 +krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum, + unsigned char *buf, int *direction, s32 *seqnum) +{ + struct crypto_blkcipher *cipher; + unsigned char plain[8]; + s32 code; + + dprintk("RPC: %s:\n", __func__); + cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + code = krb5_rc4_setup_seq_key(kctx, cipher, cksum); + if (code) + goto out; + + code = krb5_decrypt(cipher, cksum, buf, plain, 8); + if (code) + goto out; + + if ((plain[4] != plain[5]) || (plain[4] != plain[6]) + || (plain[4] != plain[7])) { + code = (s32)KG_BAD_SEQ; + goto out; + } + + *direction = plain[4]; + + *seqnum = ((plain[0] << 24) | (plain[1] << 16) | + (plain[2] << 8) | (plain[3])); +out: + crypto_free_blkcipher(cipher); + return code; +} + s32 krb5_get_seq_num(struct krb5_ctx *kctx, unsigned char *cksum, @@ -73,6 +146,10 @@ krb5_get_seq_num(struct krb5_ctx *kctx, dprintk("RPC: krb5_get_seq_num:\n"); + if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) + return krb5_get_rc4_seq_num(kctx, cksum, buf, + direction, seqnum); + if ((code = krb5_decrypt(key, cksum, buf, plain, 8))) return code; diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c index 97eb91b..6cd930f 100644 --- a/net/sunrpc/auth_gss/gss_krb5_unseal.c +++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c @@ -216,6 +216,7 @@ gss_verify_mic_kerberos(struct gss_ctx *gss_ctx, BUG(); case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: + case ENCTYPE_ARCFOUR_HMAC: return gss_verify_mic_v1(ctx, message_buffer, read_token); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c index 383db89..2763e3e 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -232,9 +232,26 @@ gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset, seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))) return GSS_S_FAILURE; - if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - conflen, - pages)) - return GSS_S_FAILURE; + if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) { + struct crypto_blkcipher *cipher; + int err; + cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(cipher)) + return GSS_S_FAILURE; + + krb5_rc4_setup_enc_key(kctx, cipher, seq_send); + + err = gss_encrypt_xdr_buf(cipher, buf, + offset + headlen - conflen, pages); + crypto_free_blkcipher(cipher); + if (err) + return GSS_S_FAILURE; + } else { + if (gss_encrypt_xdr_buf(kctx->enc, buf, + offset + headlen - conflen, pages)) + return GSS_S_FAILURE; + } return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE; } @@ -291,8 +308,37 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf) */ crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) - (unsigned char *)buf->head[0].iov_base; - if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset)) - return GSS_S_DEFECTIVE_TOKEN; + + /* + * Need plaintext seqnum to derive encryption key for arcfour-hmac + */ + if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN, + ptr + 8, &direction, &seqnum)) + return GSS_S_BAD_SIG; + + if ((kctx->initiate && direction != 0xff) || + (!kctx->initiate && direction != 0)) + return GSS_S_BAD_SIG; + + if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) { + struct crypto_blkcipher *cipher; + int err; + + cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(cipher)) + return GSS_S_FAILURE; + + krb5_rc4_setup_enc_key(kctx, cipher, seqnum); + + err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset); + crypto_free_blkcipher(cipher); + if (err) + return GSS_S_DEFECTIVE_TOKEN; + } else { + if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset)) + return GSS_S_DEFECTIVE_TOKEN; + } if (kctx->gk5e->keyed_cksum) cksumkey = kctx->cksum; @@ -316,14 +362,6 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf) /* do sequencing checks */ - if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN, - ptr + 8, &direction, &seqnum)) - return GSS_S_BAD_SIG; - - if ((kctx->initiate && direction != 0xff) || - (!kctx->initiate && direction != 0)) - return GSS_S_BAD_SIG; - /* Copy the data back to the right position. XXX: Would probably be * better to copy and encrypt at the same time. */ @@ -521,6 +559,7 @@ gss_wrap_kerberos(struct gss_ctx *gctx, int offset, BUG(); case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: + case ENCTYPE_ARCFOUR_HMAC: return gss_wrap_kerberos_v1(kctx, offset, buf, pages); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: @@ -538,6 +577,7 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf) BUG(); case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: + case ENCTYPE_ARCFOUR_HMAC: return gss_unwrap_kerberos_v1(kctx, offset, buf); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: -- 1.6.6.1