Re: [RFC PATCH 3/7] SUNRPC: remove RC4-HMAC-MD5 support from KerberosV
From: J. Bruce Fields
Date: Thu Jul 02 2020 - 11:50:00 EST
Acked-by: J. Bruce Fields <bfields@xxxxxxxxxx>
On Thu, Jul 02, 2020 at 12:19:43PM +0200, Ard Biesheuvel wrote:
> The RC4-HMAC-MD5 KerberosV algorithm is based on RFC 4757 [0], which
> was specifically issued for interoperability with Windows 2000, but was
> never intended to receive the same level of support. The RFC says
>
> The IETF Kerberos community supports publishing this specification as
> an informational document in order to describe this widely
> implemented technology. However, while these encryption types
> provide the operations necessary to implement the base Kerberos
> specification [RFC4120], they do not provide all the required
> operations in the Kerberos cryptography framework [RFC3961]. As a
> result, it is not generally possible to implement potential
> extensions to Kerberos using these encryption types. The Kerberos
> encryption type negotiation mechanism [RFC4537] provides one approach
> for using such extensions even when a Kerberos infrastructure uses
> long-term RC4 keys. Because this specification does not implement
> operations required by RFC 3961 and because of security concerns with
> the use of RC4 and MD4 discussed in Section 8, this specification is
> not appropriate for publication on the standards track.
>
> The RC4-HMAC encryption types are used to ease upgrade of existing
> Windows NT environments, provide strong cryptography (128-bit key
> lengths), and provide exportable (meet United States government
> export restriction requirements) encryption. This document describes
> the implementation of those encryption types.
>
> Furthermore, this RFC was re-classified as 'historic' by RFC 8429 [1] in
> 2018, stating that 'none of the encryption types it specifies should be
> used'
>
> Note that other outdated algorithms are left in place (some of which are
> guarded by CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES), so this should only
> adversely affect interoperability with Windows NT/2000 systems that have
> not received any updates since 2008 (but are connected to a network
> nonetheless)
>
> [0] https://tools.ietf.org/html/rfc4757
> [1] https://tools.ietf.org/html/rfc8429
>
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
> include/linux/sunrpc/gss_krb5.h | 11 -
> include/linux/sunrpc/gss_krb5_enctypes.h | 9 +-
> net/sunrpc/Kconfig | 1 -
> net/sunrpc/auth_gss/gss_krb5_crypto.c | 276 --------------------
> net/sunrpc/auth_gss/gss_krb5_mech.c | 95 -------
> net/sunrpc/auth_gss/gss_krb5_seal.c | 1 -
> net/sunrpc/auth_gss/gss_krb5_seqnum.c | 87 ------
> net/sunrpc/auth_gss/gss_krb5_unseal.c | 1 -
> net/sunrpc/auth_gss/gss_krb5_wrap.c | 65 +----
> 9 files changed, 16 insertions(+), 530 deletions(-)
>
> diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
> index e8f8ffe7448b..91f43d86879d 100644
> --- a/include/linux/sunrpc/gss_krb5.h
> +++ b/include/linux/sunrpc/gss_krb5.h
> @@ -141,14 +141,12 @@ enum sgn_alg {
> SGN_ALG_MD2_5 = 0x0001,
> SGN_ALG_DES_MAC = 0x0002,
> SGN_ALG_3 = 0x0003, /* not published */
> - SGN_ALG_HMAC_MD5 = 0x0011, /* microsoft w2k; no support */
> SGN_ALG_HMAC_SHA1_DES3_KD = 0x0004
> };
> enum seal_alg {
> SEAL_ALG_NONE = 0xffff,
> SEAL_ALG_DES = 0x0000,
> SEAL_ALG_1 = 0x0001, /* not published */
> - SEAL_ALG_MICROSOFT_RC4 = 0x0010,/* microsoft w2k; no support */
> SEAL_ALG_DES3KD = 0x0002
> };
>
> @@ -316,14 +314,5 @@ gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
> struct xdr_buf *buf, u32 *plainoffset,
> u32 *plainlen);
>
> -int
> -krb5_rc4_setup_seq_key(struct krb5_ctx *kctx,
> - struct crypto_sync_skcipher *cipher,
> - unsigned char *cksum);
> -
> -int
> -krb5_rc4_setup_enc_key(struct krb5_ctx *kctx,
> - struct crypto_sync_skcipher *cipher,
> - s32 seqnum);
> void
> gss_krb5_make_confounder(char *p, u32 conflen);
> diff --git a/include/linux/sunrpc/gss_krb5_enctypes.h b/include/linux/sunrpc/gss_krb5_enctypes.h
> index 981c89cef19d..87eea679d750 100644
> --- a/include/linux/sunrpc/gss_krb5_enctypes.h
> +++ b/include/linux/sunrpc/gss_krb5_enctypes.h
> @@ -13,15 +13,13 @@
> #ifdef CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES
>
> /*
> - * NB: This list includes encryption types that were deprecated
> - * by RFC 8429 (DES3_CBC_SHA1 and ARCFOUR_HMAC).
> + * NB: This list includes DES3_CBC_SHA1, which was deprecated by RFC 8429.
> *
> * ENCTYPE_AES256_CTS_HMAC_SHA1_96
> * ENCTYPE_AES128_CTS_HMAC_SHA1_96
> * ENCTYPE_DES3_CBC_SHA1
> - * ENCTYPE_ARCFOUR_HMAC
> */
> -#define KRB5_SUPPORTED_ENCTYPES "18,17,16,23"
> +#define KRB5_SUPPORTED_ENCTYPES "18,17,16"
>
> #else /* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
>
> @@ -32,12 +30,11 @@
> * ENCTYPE_AES256_CTS_HMAC_SHA1_96
> * ENCTYPE_AES128_CTS_HMAC_SHA1_96
> * ENCTYPE_DES3_CBC_SHA1
> - * ENCTYPE_ARCFOUR_HMAC
> * ENCTYPE_DES_CBC_MD5
> * ENCTYPE_DES_CBC_CRC
> * ENCTYPE_DES_CBC_MD4
> */
> -#define KRB5_SUPPORTED_ENCTYPES "18,17,16,23,3,1,2"
> +#define KRB5_SUPPORTED_ENCTYPES "18,17,16,3,1,2"
>
> #endif /* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
>
> diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
> index 3bcf985507be..bbbb5af0af13 100644
> --- a/net/sunrpc/Kconfig
> +++ b/net/sunrpc/Kconfig
> @@ -21,7 +21,6 @@ config RPCSEC_GSS_KRB5
> depends on SUNRPC && CRYPTO
> depends on CRYPTO_MD5 && CRYPTO_DES && CRYPTO_CBC && CRYPTO_CTS
> depends on CRYPTO_ECB && CRYPTO_HMAC && CRYPTO_SHA1 && CRYPTO_AES
> - depends on CRYPTO_ARC4
> default y
> select SUNRPC_GSS
> help
> diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
> index e7180da1fc6a..634b6c6e0dcb 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
> @@ -138,135 +138,6 @@ checksummer(struct scatterlist *sg, void *data)
> return crypto_ahash_update(req);
> }
>
> -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 scatterlist sg[1];
> - int err = -1;
> - u8 *checksumdata;
> - u8 *rc4salt;
> - struct crypto_ahash *md5;
> - struct crypto_ahash *hmac_md5;
> - struct ahash_request *req;
> -
> - 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;
> - }
> -
> - rc4salt = kmalloc_array(4, sizeof(*rc4salt), GFP_NOFS);
> - if (!rc4salt)
> - return GSS_S_FAILURE;
> -
> - if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
> - dprintk("%s: invalid usage value %u\n", __func__, usage);
> - goto out_free_rc4salt;
> - }
> -
> - checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
> - if (!checksumdata)
> - goto out_free_rc4salt;
> -
> - md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
> - if (IS_ERR(md5))
> - goto out_free_cksum;
> -
> - hmac_md5 = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0,
> - CRYPTO_ALG_ASYNC);
> - if (IS_ERR(hmac_md5))
> - goto out_free_md5;
> -
> - req = ahash_request_alloc(md5, GFP_NOFS);
> - if (!req)
> - goto out_free_hmac_md5;
> -
> - ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
> -
> - err = crypto_ahash_init(req);
> - if (err)
> - goto out;
> - sg_init_one(sg, rc4salt, 4);
> - ahash_request_set_crypt(req, sg, NULL, 4);
> - err = crypto_ahash_update(req);
> - if (err)
> - goto out;
> -
> - sg_init_one(sg, header, hdrlen);
> - ahash_request_set_crypt(req, sg, NULL, hdrlen);
> - err = crypto_ahash_update(req);
> - if (err)
> - goto out;
> - err = xdr_process_buf(body, body_offset, body->len - body_offset,
> - checksummer, req);
> - if (err)
> - goto out;
> - ahash_request_set_crypt(req, NULL, checksumdata, 0);
> - err = crypto_ahash_final(req);
> - if (err)
> - goto out;
> -
> - ahash_request_free(req);
> - req = ahash_request_alloc(hmac_md5, GFP_NOFS);
> - if (!req)
> - goto out_free_hmac_md5;
> -
> - ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
> -
> - err = crypto_ahash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
> - if (err)
> - goto out;
> -
> - sg_init_one(sg, checksumdata, crypto_ahash_digestsize(md5));
> - ahash_request_set_crypt(req, sg, checksumdata,
> - crypto_ahash_digestsize(md5));
> - err = crypto_ahash_digest(req);
> - if (err)
> - goto out;
> -
> - memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
> - cksumout->len = kctx->gk5e->cksumlength;
> -out:
> - ahash_request_free(req);
> -out_free_hmac_md5:
> - crypto_free_ahash(hmac_md5);
> -out_free_md5:
> - crypto_free_ahash(md5);
> -out_free_cksum:
> - kfree(checksumdata);
> -out_free_rc4salt:
> - kfree(rc4salt);
> - 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
> @@ -284,11 +155,6 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
> u8 *checksumdata;
> 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);
> @@ -942,145 +808,3 @@ gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
> 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_sync_skcipher *cipher,
> - unsigned char *cksum)
> -{
> - struct crypto_shash *hmac;
> - struct shash_desc *desc;
> - u8 Kseq[GSS_KRB5_MAX_KEYLEN];
> - u32 zeroconstant = 0;
> - int err;
> -
> - dprintk("%s: entered\n", __func__);
> -
> - hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
> - 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 = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
> - GFP_NOFS);
> - if (!desc) {
> - dprintk("%s: failed to allocate shash descriptor for '%s'\n",
> - __func__, kctx->gk5e->cksum_name);
> - crypto_free_shash(hmac);
> - return -ENOMEM;
> - }
> -
> - desc->tfm = hmac;
> -
> - /* Compute intermediate Kseq from session key */
> - err = crypto_shash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
> - if (err)
> - goto out_err;
> -
> - err = crypto_shash_digest(desc, (u8 *)&zeroconstant, 4, Kseq);
> - if (err)
> - goto out_err;
> -
> - /* Compute final Kseq from the checksum and intermediate Kseq */
> - err = crypto_shash_setkey(hmac, Kseq, kctx->gk5e->keylength);
> - if (err)
> - goto out_err;
> -
> - err = crypto_shash_digest(desc, cksum, 8, Kseq);
> - if (err)
> - goto out_err;
> -
> - err = crypto_sync_skcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
> - if (err)
> - goto out_err;
> -
> - err = 0;
> -
> -out_err:
> - kzfree(desc);
> - crypto_free_shash(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_sync_skcipher *cipher,
> - s32 seqnum)
> -{
> - struct crypto_shash *hmac;
> - struct shash_desc *desc;
> - 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_shash(kctx->gk5e->cksum_name, 0, 0);
> - 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 = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
> - GFP_NOFS);
> - if (!desc) {
> - dprintk("%s: failed to allocate shash descriptor for '%s'\n",
> - __func__, kctx->gk5e->cksum_name);
> - crypto_free_shash(hmac);
> - return -ENOMEM;
> - }
> -
> - desc->tfm = hmac;
> -
> - /* Compute intermediate Kcrypt from session key */
> - for (i = 0; i < kctx->gk5e->keylength; i++)
> - Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
> -
> - err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
> - if (err)
> - goto out_err;
> -
> - err = crypto_shash_digest(desc, zeroconstant, 4, Kcrypt);
> - if (err)
> - goto out_err;
> -
> - /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
> - err = crypto_shash_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);
> -
> - err = crypto_shash_digest(desc, seqnumarray, 4, Kcrypt);
> - if (err)
> - goto out_err;
> -
> - err = crypto_sync_skcipher_setkey(cipher, Kcrypt,
> - kctx->gk5e->keylength);
> - if (err)
> - goto out_err;
> -
> - err = 0;
> -
> -out_err:
> - kzfree(desc);
> - crypto_free_shash(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 75b3c2e9e8f8..ae9acf3a7389 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_mech.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
> @@ -51,27 +51,6 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
> .keyed_cksum = 0,
> },
> #endif /* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
> - /*
> - * 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
> */
> @@ -401,78 +380,6 @@ context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
> 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_shash *hmac;
> - char sigkeyconstant[] = "signaturekey";
> - int slen = strlen(sigkeyconstant) + 1; /* include null terminator */
> - struct shash_desc *desc;
> - int err;
> -
> - dprintk("RPC: %s: entered\n", __func__);
> - /*
> - * derive cksum (aka Ksign) key
> - */
> - hmac = crypto_alloc_shash(ctx->gk5e->cksum_name, 0, 0);
> - 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_shash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
> - if (err)
> - goto out_err_free_hmac;
> -
> -
> - desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac), GFP_NOFS);
> - if (!desc) {
> - dprintk("%s: failed to allocate hash descriptor for '%s'\n",
> - __func__, ctx->gk5e->cksum_name);
> - err = -ENOMEM;
> - goto out_err_free_hmac;
> - }
> -
> - desc->tfm = hmac;
> -
> - err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
> - kzfree(desc);
> - if (err)
> - goto out_err_free_hmac;
> - /*
> - * allocate hash, and skciphers for data and seqnum encryption
> - */
> - ctx->enc = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
> - if (IS_ERR(ctx->enc)) {
> - err = PTR_ERR(ctx->enc);
> - goto out_err_free_hmac;
> - }
> -
> - ctx->seq = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
> - if (IS_ERR(ctx->seq)) {
> - crypto_free_sync_skcipher(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_shash(hmac);
> -out_err:
> - dprintk("RPC: %s: returning %d\n", __func__, err);
> - return err;
> -}
> -
> static int
> context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
> {
> @@ -649,8 +556,6 @@ 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, gfp_mask);
> - 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, gfp_mask);
> diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c
> index f1d280accf43..33061417ec97 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_seal.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c
> @@ -214,7 +214,6 @@ 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 507105127095..fb117817ff5d 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
> @@ -39,42 +39,6 @@
> # 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_sync_skcipher *cipher;
> - unsigned char *plain;
> - s32 code;
> -
> - dprintk("RPC: %s:\n", __func__);
> - cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name, 0, 0);
> - if (IS_ERR(cipher))
> - return PTR_ERR(cipher);
> -
> - plain = kmalloc(8, GFP_NOFS);
> - if (!plain)
> - return -ENOMEM;
> -
> - 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:
> - kfree(plain);
> - crypto_free_sync_skcipher(cipher);
> - return code;
> -}
> s32
> krb5_make_seq_num(struct krb5_ctx *kctx,
> struct crypto_sync_skcipher *key,
> @@ -85,10 +49,6 @@ krb5_make_seq_num(struct krb5_ctx *kctx,
> unsigned char *plain;
> s32 code;
>
> - if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
> - return krb5_make_rc4_seq_num(kctx, direction, seqnum,
> - cksum, buf);
> -
> plain = kmalloc(8, GFP_NOFS);
> if (!plain)
> return -ENOMEM;
> @@ -108,50 +68,6 @@ krb5_make_seq_num(struct krb5_ctx *kctx,
> return code;
> }
>
> -static s32
> -krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
> - unsigned char *buf, int *direction, s32 *seqnum)
> -{
> - struct crypto_sync_skcipher *cipher;
> - unsigned char *plain;
> - s32 code;
> -
> - dprintk("RPC: %s:\n", __func__);
> - cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name, 0, 0);
> - if (IS_ERR(cipher))
> - return PTR_ERR(cipher);
> -
> - code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
> - if (code)
> - goto out;
> -
> - plain = kmalloc(8, GFP_NOFS);
> - if (!plain) {
> - code = -ENOMEM;
> - goto out;
> - }
> -
> - code = krb5_decrypt(cipher, cksum, buf, plain, 8);
> - if (code)
> - goto out_plain;
> -
> - if ((plain[4] != plain[5]) || (plain[4] != plain[6])
> - || (plain[4] != plain[7])) {
> - code = (s32)KG_BAD_SEQ;
> - goto out_plain;
> - }
> -
> - *direction = plain[4];
> -
> - *seqnum = ((plain[0] << 24) | (plain[1] << 16) |
> - (plain[2] << 8) | (plain[3]));
> -out_plain:
> - kfree(plain);
> -out:
> - crypto_free_sync_skcipher(cipher);
> - return code;
> -}
> -
> s32
> krb5_get_seq_num(struct krb5_ctx *kctx,
> unsigned char *cksum,
> @@ -164,9 +80,6 @@ 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);
> plain = kmalloc(8, GFP_NOFS);
> if (!plain)
> return -ENOMEM;
> diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c
> index aaab91cf24c8..ba04e3ec970a 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_unseal.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c
> @@ -218,7 +218,6 @@ 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 cf0fd170ac18..a412a734ee17 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
> @@ -236,26 +236,9 @@ 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 (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
> - struct crypto_sync_skcipher *cipher;
> - int err;
> - cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
> - 0, 0);
> - 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_sync_skcipher(cipher);
> - if (err)
> - return GSS_S_FAILURE;
> - } else {
> - if (gss_encrypt_xdr_buf(kctx->enc, buf,
> - offset + headlen - conflen, pages))
> - return GSS_S_FAILURE;
> - }
> + 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;
> }
> @@ -316,37 +299,9 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
> crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
> (unsigned char *)buf->head[0].iov_base;
>
> - /*
> - * 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;
> -
> buf->len = len;
> - if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
> - struct crypto_sync_skcipher *cipher;
> - int err;
> -
> - cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
> - 0, 0);
> - 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_sync_skcipher(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 (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
> + return GSS_S_DEFECTIVE_TOKEN;
>
> if (kctx->gk5e->keyed_cksum)
> cksumkey = kctx->cksum;
> @@ -370,6 +325,14 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
>
> /* 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. */
>
> @@ -605,7 +568,6 @@ 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:
> @@ -624,7 +586,6 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset,
> BUG();
> case ENCTYPE_DES_CBC_RAW:
> case ENCTYPE_DES3_CBC_RAW:
> - case ENCTYPE_ARCFOUR_HMAC:
> return gss_unwrap_kerberos_v1(kctx, offset, len, buf,
> &gctx->slack, &gctx->align);
> case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
> --
> 2.17.1