[PATCH 21/23] gss_krb5: Add support for rc4-hmac encryption

steved
2010-03-17T17:26:01Z

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 <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
---
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 582ad76..1889459 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
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 7d6c7ee..08cc69e 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -125,6 +125,114 @@ 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
@@ -141,6 +249,11 @@ 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);
@@ -734,3 +847,145 @@ 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 60bd6e4..8e7ca7b 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 b6bc20f..2b8db81 100644
--- a/net/sunrpc/auth_gss/gss_krb5_seal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_seal.c
@@ -214,6 +214,7 @@ 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 46d900e..5482803 100644
--- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c
+++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
@@ -40,6 +40,38 @@
# 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,
@@ -49,6 +81,10 @@ 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);
@@ -62,6 +98,43 @@ 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,
@@ -74,6 +147,10 @@ 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 b4416e6..e6aec12 100644
--- a/net/sunrpc/auth_gss/gss_krb5_unseal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c
@@ -217,6 +217,7 @@ 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 61cd3be..b313339 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -233,9 +233,26 @@ 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;
}
@@ -292,8 +309,37 @@ 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;
@@ -317,14 +363,6 @@ 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. */

@@ -593,6 +631,7 @@ 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:
@@ -610,6 +649,7 @@ 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