736 lines
18 KiB
C
736 lines
18 KiB
C
/*
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* linux/net/sunrpc/gss_krb5_crypto.c
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*
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* Copyright (c) 2000-2008 The Regents of the University of Michigan.
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* All rights reserved.
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*
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* Andy Adamson <andros@umich.edu>
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* Bruce Fields <bfields@umich.edu>
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*/
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/*
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* Copyright (C) 1998 by the FundsXpress, INC.
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*
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* All rights reserved.
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*
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* Export of this software from the United States of America may require
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* a specific license from the United States Government. It is the
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* responsibility of any person or organization contemplating export to
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* obtain such a license before exporting.
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*
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* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
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* distribute this software and its documentation for any purpose and
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* without fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright notice and
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* this permission notice appear in supporting documentation, and that
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* the name of FundsXpress. not be used in advertising or publicity pertaining
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* to distribution of the software without specific, written prior
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* permission. FundsXpress makes no representations about the suitability of
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* this software for any purpose. It is provided "as is" without express
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* or implied warranty.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include <linux/err.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/scatterlist.h>
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#include <linux/crypto.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/random.h>
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#include <linux/sunrpc/gss_krb5.h>
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#include <linux/sunrpc/xdr.h>
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#ifdef RPC_DEBUG
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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u32
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krb5_encrypt(
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struct crypto_blkcipher *tfm,
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void * iv,
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void * in,
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void * out,
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int length)
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{
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u32 ret = -EINVAL;
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struct scatterlist sg[1];
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u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
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struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
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if (length % crypto_blkcipher_blocksize(tfm) != 0)
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goto out;
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if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
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dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
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crypto_blkcipher_ivsize(tfm));
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goto out;
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}
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if (iv)
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memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
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memcpy(out, in, length);
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sg_init_one(sg, out, length);
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ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
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out:
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dprintk("RPC: krb5_encrypt returns %d\n", ret);
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return ret;
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}
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u32
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krb5_decrypt(
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struct crypto_blkcipher *tfm,
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void * iv,
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void * in,
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void * out,
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int length)
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{
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u32 ret = -EINVAL;
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struct scatterlist sg[1];
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u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
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struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
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if (length % crypto_blkcipher_blocksize(tfm) != 0)
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goto out;
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if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
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dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
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crypto_blkcipher_ivsize(tfm));
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goto out;
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}
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if (iv)
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memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
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memcpy(out, in, length);
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sg_init_one(sg, out, length);
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ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
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out:
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dprintk("RPC: gss_k5decrypt returns %d\n",ret);
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return ret;
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}
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static int
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checksummer(struct scatterlist *sg, void *data)
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{
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struct hash_desc *desc = data;
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return crypto_hash_update(desc, sg, sg->length);
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}
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/*
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* checksum the plaintext data and hdrlen bytes of the token header
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* The checksum is performed over the first 8 bytes of the
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* gss token header and then over the data body
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*/
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u32
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make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
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struct xdr_buf *body, int body_offset, u8 *cksumkey,
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unsigned int usage, struct xdr_netobj *cksumout)
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{
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struct hash_desc desc;
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struct scatterlist sg[1];
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int err;
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u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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unsigned int checksumlen;
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if (cksumout->len < kctx->gk5e->cksumlength) {
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dprintk("%s: checksum buffer length, %u, too small for %s\n",
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__func__, cksumout->len, kctx->gk5e->name);
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return GSS_S_FAILURE;
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}
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desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(desc.tfm))
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return GSS_S_FAILURE;
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desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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checksumlen = crypto_hash_digestsize(desc.tfm);
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if (cksumkey != NULL) {
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err = crypto_hash_setkey(desc.tfm, cksumkey,
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kctx->gk5e->keylength);
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if (err)
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goto out;
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}
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err = crypto_hash_init(&desc);
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if (err)
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goto out;
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sg_init_one(sg, header, hdrlen);
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err = crypto_hash_update(&desc, sg, hdrlen);
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if (err)
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goto out;
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err = xdr_process_buf(body, body_offset, body->len - body_offset,
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checksummer, &desc);
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if (err)
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goto out;
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err = crypto_hash_final(&desc, checksumdata);
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if (err)
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goto out;
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switch (kctx->gk5e->ctype) {
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case CKSUMTYPE_RSA_MD5:
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err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata,
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checksumdata, checksumlen);
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if (err)
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goto out;
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memcpy(cksumout->data,
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checksumdata + checksumlen - kctx->gk5e->cksumlength,
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kctx->gk5e->cksumlength);
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break;
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case CKSUMTYPE_HMAC_SHA1_DES3:
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memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
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break;
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default:
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BUG();
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break;
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}
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cksumout->len = kctx->gk5e->cksumlength;
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out:
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crypto_free_hash(desc.tfm);
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return err ? GSS_S_FAILURE : 0;
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}
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/*
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* checksum the plaintext data and hdrlen bytes of the token header
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* Per rfc4121, sec. 4.2.4, the checksum is performed over the data
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* body then over the first 16 octets of the MIC token
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* Inclusion of the header data in the calculation of the
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* checksum is optional.
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*/
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u32
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make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
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struct xdr_buf *body, int body_offset, u8 *cksumkey,
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unsigned int usage, struct xdr_netobj *cksumout)
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{
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struct hash_desc desc;
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struct scatterlist sg[1];
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int err;
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u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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unsigned int checksumlen;
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if (kctx->gk5e->keyed_cksum == 0) {
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dprintk("%s: expected keyed hash for %s\n",
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__func__, kctx->gk5e->name);
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return GSS_S_FAILURE;
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}
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if (cksumkey == NULL) {
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dprintk("%s: no key supplied for %s\n",
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__func__, kctx->gk5e->name);
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return GSS_S_FAILURE;
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}
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desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0,
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CRYPTO_ALG_ASYNC);
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if (IS_ERR(desc.tfm))
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return GSS_S_FAILURE;
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checksumlen = crypto_hash_digestsize(desc.tfm);
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desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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err = crypto_hash_setkey(desc.tfm, cksumkey, kctx->gk5e->keylength);
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if (err)
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goto out;
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err = crypto_hash_init(&desc);
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if (err)
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goto out;
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err = xdr_process_buf(body, body_offset, body->len - body_offset,
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checksummer, &desc);
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if (err)
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goto out;
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if (header != NULL) {
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sg_init_one(sg, header, hdrlen);
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err = crypto_hash_update(&desc, sg, hdrlen);
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if (err)
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goto out;
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}
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err = crypto_hash_final(&desc, checksumdata);
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if (err)
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goto out;
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cksumout->len = kctx->gk5e->cksumlength;
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switch (kctx->gk5e->ctype) {
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case CKSUMTYPE_HMAC_SHA1_96_AES128:
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case CKSUMTYPE_HMAC_SHA1_96_AES256:
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/* note that this truncates the hash */
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memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
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break;
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default:
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BUG();
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break;
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}
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out:
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crypto_free_hash(desc.tfm);
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return err ? GSS_S_FAILURE : 0;
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}
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struct encryptor_desc {
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u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
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struct blkcipher_desc desc;
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int pos;
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struct xdr_buf *outbuf;
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struct page **pages;
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struct scatterlist infrags[4];
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struct scatterlist outfrags[4];
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int fragno;
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int fraglen;
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};
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static int
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encryptor(struct scatterlist *sg, void *data)
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{
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struct encryptor_desc *desc = data;
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struct xdr_buf *outbuf = desc->outbuf;
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struct page *in_page;
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int thislen = desc->fraglen + sg->length;
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int fraglen, ret;
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int page_pos;
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/* Worst case is 4 fragments: head, end of page 1, start
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* of page 2, tail. Anything more is a bug. */
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BUG_ON(desc->fragno > 3);
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page_pos = desc->pos - outbuf->head[0].iov_len;
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if (page_pos >= 0 && page_pos < outbuf->page_len) {
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/* pages are not in place: */
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int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
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in_page = desc->pages[i];
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} else {
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in_page = sg_page(sg);
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}
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sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
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sg->offset);
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sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
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sg->offset);
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desc->fragno++;
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desc->fraglen += sg->length;
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desc->pos += sg->length;
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fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
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thislen -= fraglen;
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if (thislen == 0)
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return 0;
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sg_mark_end(&desc->infrags[desc->fragno - 1]);
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sg_mark_end(&desc->outfrags[desc->fragno - 1]);
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ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
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desc->infrags, thislen);
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if (ret)
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return ret;
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sg_init_table(desc->infrags, 4);
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sg_init_table(desc->outfrags, 4);
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if (fraglen) {
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sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
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sg->offset + sg->length - fraglen);
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desc->infrags[0] = desc->outfrags[0];
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sg_assign_page(&desc->infrags[0], in_page);
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desc->fragno = 1;
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desc->fraglen = fraglen;
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} else {
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desc->fragno = 0;
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desc->fraglen = 0;
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}
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return 0;
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}
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|
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int
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gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
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int offset, struct page **pages)
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{
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int ret;
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struct encryptor_desc desc;
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BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
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memset(desc.iv, 0, sizeof(desc.iv));
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desc.desc.tfm = tfm;
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desc.desc.info = desc.iv;
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desc.desc.flags = 0;
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desc.pos = offset;
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desc.outbuf = buf;
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desc.pages = pages;
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desc.fragno = 0;
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desc.fraglen = 0;
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sg_init_table(desc.infrags, 4);
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sg_init_table(desc.outfrags, 4);
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ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
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return ret;
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}
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struct decryptor_desc {
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u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
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struct blkcipher_desc desc;
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struct scatterlist frags[4];
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int fragno;
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int fraglen;
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};
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static int
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decryptor(struct scatterlist *sg, void *data)
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{
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struct decryptor_desc *desc = data;
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int thislen = desc->fraglen + sg->length;
|
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int fraglen, ret;
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|
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/* Worst case is 4 fragments: head, end of page 1, start
|
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* of page 2, tail. Anything more is a bug. */
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BUG_ON(desc->fragno > 3);
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sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
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sg->offset);
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desc->fragno++;
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desc->fraglen += sg->length;
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|
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fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
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thislen -= fraglen;
|
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|
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if (thislen == 0)
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return 0;
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|
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sg_mark_end(&desc->frags[desc->fragno - 1]);
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|
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ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
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desc->frags, thislen);
|
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if (ret)
|
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return ret;
|
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|
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sg_init_table(desc->frags, 4);
|
|
|
|
if (fraglen) {
|
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sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
|
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sg->offset + sg->length - fraglen);
|
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desc->fragno = 1;
|
|
desc->fraglen = fraglen;
|
|
} else {
|
|
desc->fragno = 0;
|
|
desc->fraglen = 0;
|
|
}
|
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return 0;
|
|
}
|
|
|
|
int
|
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gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
|
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int offset)
|
|
{
|
|
struct decryptor_desc desc;
|
|
|
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/* XXXJBF: */
|
|
BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
desc.desc.tfm = tfm;
|
|
desc.desc.info = desc.iv;
|
|
desc.desc.flags = 0;
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
|
|
sg_init_table(desc.frags, 4);
|
|
|
|
return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
|
|
}
|
|
|
|
/*
|
|
* This function makes the assumption that it was ultimately called
|
|
* from gss_wrap().
|
|
*
|
|
* The client auth_gss code moves any existing tail data into a
|
|
* separate page before calling gss_wrap.
|
|
* The server svcauth_gss code ensures that both the head and the
|
|
* tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
|
|
*
|
|
* Even with that guarantee, this function may be called more than
|
|
* once in the processing of gss_wrap(). The best we can do is
|
|
* verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
|
|
* largest expected shift will fit within RPC_MAX_AUTH_SIZE.
|
|
* At run-time we can verify that a single invocation of this
|
|
* function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
|
|
*/
|
|
|
|
int
|
|
xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
|
|
{
|
|
u8 *p;
|
|
|
|
if (shiftlen == 0)
|
|
return 0;
|
|
|
|
BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
|
|
BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
|
|
|
|
p = buf->head[0].iov_base + base;
|
|
|
|
memmove(p + shiftlen, p, buf->head[0].iov_len - base);
|
|
|
|
buf->head[0].iov_len += shiftlen;
|
|
buf->len += shiftlen;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static u32
|
|
gss_krb5_cts_crypt(struct crypto_blkcipher *cipher, struct xdr_buf *buf,
|
|
u32 offset, u8 *iv, struct page **pages, int encrypt)
|
|
{
|
|
u32 ret;
|
|
struct scatterlist sg[1];
|
|
struct blkcipher_desc desc = { .tfm = cipher, .info = iv };
|
|
u8 data[crypto_blkcipher_blocksize(cipher) * 2];
|
|
struct page **save_pages;
|
|
u32 len = buf->len - offset;
|
|
|
|
BUG_ON(len > crypto_blkcipher_blocksize(cipher) * 2);
|
|
|
|
/*
|
|
* For encryption, we want to read from the cleartext
|
|
* page cache pages, and write the encrypted data to
|
|
* the supplied xdr_buf pages.
|
|
*/
|
|
save_pages = buf->pages;
|
|
if (encrypt)
|
|
buf->pages = pages;
|
|
|
|
ret = read_bytes_from_xdr_buf(buf, offset, data, len);
|
|
buf->pages = save_pages;
|
|
if (ret)
|
|
goto out;
|
|
|
|
sg_init_one(sg, data, len);
|
|
|
|
if (encrypt)
|
|
ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
|
|
else
|
|
ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, len);
|
|
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = write_bytes_to_xdr_buf(buf, offset, data, len);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
u32
|
|
gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
|
|
struct xdr_buf *buf, int ec, struct page **pages)
|
|
{
|
|
u32 err;
|
|
struct xdr_netobj hmac;
|
|
u8 *cksumkey;
|
|
u8 *ecptr;
|
|
struct crypto_blkcipher *cipher, *aux_cipher;
|
|
int blocksize;
|
|
struct page **save_pages;
|
|
int nblocks, nbytes;
|
|
struct encryptor_desc desc;
|
|
u32 cbcbytes;
|
|
unsigned int usage;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
cksumkey = kctx->initiator_integ;
|
|
usage = KG_USAGE_INITIATOR_SEAL;
|
|
} else {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
cksumkey = kctx->acceptor_integ;
|
|
usage = KG_USAGE_ACCEPTOR_SEAL;
|
|
}
|
|
blocksize = crypto_blkcipher_blocksize(cipher);
|
|
|
|
/* hide the gss token header and insert the confounder */
|
|
offset += GSS_KRB5_TOK_HDR_LEN;
|
|
if (xdr_extend_head(buf, offset, blocksize))
|
|
return GSS_S_FAILURE;
|
|
gss_krb5_make_confounder(buf->head[0].iov_base + offset, blocksize);
|
|
offset -= GSS_KRB5_TOK_HDR_LEN;
|
|
|
|
if (buf->tail[0].iov_base != NULL) {
|
|
ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
|
|
} else {
|
|
buf->tail[0].iov_base = buf->head[0].iov_base
|
|
+ buf->head[0].iov_len;
|
|
buf->tail[0].iov_len = 0;
|
|
ecptr = buf->tail[0].iov_base;
|
|
}
|
|
|
|
memset(ecptr, 'X', ec);
|
|
buf->tail[0].iov_len += ec;
|
|
buf->len += ec;
|
|
|
|
/* copy plaintext gss token header after filler (if any) */
|
|
memcpy(ecptr + ec, buf->head[0].iov_base + offset,
|
|
GSS_KRB5_TOK_HDR_LEN);
|
|
buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
|
|
buf->len += GSS_KRB5_TOK_HDR_LEN;
|
|
|
|
/* Do the HMAC */
|
|
hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
|
|
hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
|
|
|
|
/*
|
|
* When we are called, pages points to the real page cache
|
|
* data -- which we can't go and encrypt! buf->pages points
|
|
* to scratch pages which we are going to send off to the
|
|
* client/server. Swap in the plaintext pages to calculate
|
|
* the hmac.
|
|
*/
|
|
save_pages = buf->pages;
|
|
buf->pages = pages;
|
|
|
|
err = make_checksum_v2(kctx, NULL, 0, buf,
|
|
offset + GSS_KRB5_TOK_HDR_LEN,
|
|
cksumkey, usage, &hmac);
|
|
buf->pages = save_pages;
|
|
if (err)
|
|
return GSS_S_FAILURE;
|
|
|
|
nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
|
|
nblocks = (nbytes + blocksize - 1) / blocksize;
|
|
cbcbytes = 0;
|
|
if (nblocks > 2)
|
|
cbcbytes = (nblocks - 2) * blocksize;
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
|
|
if (cbcbytes) {
|
|
desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
desc.pages = pages;
|
|
desc.outbuf = buf;
|
|
desc.desc.info = desc.iv;
|
|
desc.desc.flags = 0;
|
|
desc.desc.tfm = aux_cipher;
|
|
|
|
sg_init_table(desc.infrags, 4);
|
|
sg_init_table(desc.outfrags, 4);
|
|
|
|
err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
|
|
cbcbytes, encryptor, &desc);
|
|
if (err)
|
|
goto out_err;
|
|
}
|
|
|
|
/* Make sure IV carries forward from any CBC results. */
|
|
err = gss_krb5_cts_crypt(cipher, buf,
|
|
offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
|
|
desc.iv, pages, 1);
|
|
if (err) {
|
|
err = GSS_S_FAILURE;
|
|
goto out_err;
|
|
}
|
|
|
|
/* Now update buf to account for HMAC */
|
|
buf->tail[0].iov_len += kctx->gk5e->cksumlength;
|
|
buf->len += kctx->gk5e->cksumlength;
|
|
|
|
out_err:
|
|
if (err)
|
|
err = GSS_S_FAILURE;
|
|
return err;
|
|
}
|
|
|
|
u32
|
|
gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
|
|
u32 *headskip, u32 *tailskip)
|
|
{
|
|
struct xdr_buf subbuf;
|
|
u32 ret = 0;
|
|
u8 *cksum_key;
|
|
struct crypto_blkcipher *cipher, *aux_cipher;
|
|
struct xdr_netobj our_hmac_obj;
|
|
u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
int nblocks, blocksize, cbcbytes;
|
|
struct decryptor_desc desc;
|
|
unsigned int usage;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
cksum_key = kctx->acceptor_integ;
|
|
usage = KG_USAGE_ACCEPTOR_SEAL;
|
|
} else {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
cksum_key = kctx->initiator_integ;
|
|
usage = KG_USAGE_INITIATOR_SEAL;
|
|
}
|
|
blocksize = crypto_blkcipher_blocksize(cipher);
|
|
|
|
|
|
/* create a segment skipping the header and leaving out the checksum */
|
|
xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
|
|
(buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
|
|
kctx->gk5e->cksumlength));
|
|
|
|
nblocks = (subbuf.len + blocksize - 1) / blocksize;
|
|
|
|
cbcbytes = 0;
|
|
if (nblocks > 2)
|
|
cbcbytes = (nblocks - 2) * blocksize;
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
|
|
if (cbcbytes) {
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
desc.desc.info = desc.iv;
|
|
desc.desc.flags = 0;
|
|
desc.desc.tfm = aux_cipher;
|
|
|
|
sg_init_table(desc.frags, 4);
|
|
|
|
ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
|
|
if (ret)
|
|
goto out_err;
|
|
}
|
|
|
|
/* Make sure IV carries forward from any CBC results. */
|
|
ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
|
|
/* Calculate our hmac over the plaintext data */
|
|
our_hmac_obj.len = sizeof(our_hmac);
|
|
our_hmac_obj.data = our_hmac;
|
|
|
|
ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
|
|
cksum_key, usage, &our_hmac_obj);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
/* Get the packet's hmac value */
|
|
ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
|
|
pkt_hmac, kctx->gk5e->cksumlength);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
|
|
ret = GSS_S_BAD_SIG;
|
|
goto out_err;
|
|
}
|
|
*headskip = crypto_blkcipher_blocksize(cipher);
|
|
*tailskip = kctx->gk5e->cksumlength;
|
|
out_err:
|
|
if (ret && ret != GSS_S_BAD_SIG)
|
|
ret = GSS_S_FAILURE;
|
|
return ret;
|
|
}
|