1145 lines
31 KiB
C
1145 lines
31 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 <crypto/algapi.h>
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#include <crypto/hash.h>
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#include <crypto/skcipher.h>
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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/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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#include <kunit/visibility.h>
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#include "gss_krb5_internal.h"
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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/**
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* krb5_make_confounder - Generate a confounder string
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* @p: memory location into which to write the string
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* @conflen: string length to write, in octets
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*
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* RFCs 1964 and 3961 mention only "a random confounder" without going
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* into detail about its function or cryptographic requirements. The
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* assumed purpose is to prevent repeated encryption of a plaintext with
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* the same key from generating the same ciphertext. It is also used to
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* pad minimum plaintext length to at least a single cipher block.
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*
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* However, in situations like the GSS Kerberos 5 mechanism, where the
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* encryption IV is always all zeroes, the confounder also effectively
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* functions like an IV. Thus, not only must it be unique from message
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* to message, but it must also be difficult to predict. Otherwise an
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* attacker can correlate the confounder to previous or future values,
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* making the encryption easier to break.
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*
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* Given that the primary consumer of this encryption mechanism is a
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* network storage protocol, a type of traffic that often carries
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* predictable payloads (eg, all zeroes when reading unallocated blocks
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* from a file), our confounder generation has to be cryptographically
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* strong.
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*/
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void krb5_make_confounder(u8 *p, int conflen)
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{
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get_random_bytes(p, conflen);
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}
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/**
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* krb5_encrypt - simple encryption of an RPCSEC GSS payload
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* @tfm: initialized cipher transform
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* @iv: pointer to an IV
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* @in: plaintext to encrypt
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* @out: OUT: ciphertext
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* @length: length of input and output buffers, in bytes
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*
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* @iv may be NULL to force the use of an all-zero IV.
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* The buffer containing the IV must be as large as the
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* cipher's ivsize.
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*
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* Return values:
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* %0: @in successfully encrypted into @out
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* negative errno: @in not encrypted
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*/
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u32
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krb5_encrypt(
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struct crypto_sync_skcipher *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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SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
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if (length % crypto_sync_skcipher_blocksize(tfm) != 0)
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goto out;
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if (crypto_sync_skcipher_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_sync_skcipher_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_sync_skcipher_ivsize(tfm));
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memcpy(out, in, length);
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sg_init_one(sg, out, length);
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skcipher_request_set_sync_tfm(req, tfm);
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skcipher_request_set_callback(req, 0, NULL, NULL);
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skcipher_request_set_crypt(req, sg, sg, length, local_iv);
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ret = crypto_skcipher_encrypt(req);
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skcipher_request_zero(req);
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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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/**
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* krb5_decrypt - simple decryption of an RPCSEC GSS payload
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* @tfm: initialized cipher transform
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* @iv: pointer to an IV
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* @in: ciphertext to decrypt
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* @out: OUT: plaintext
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* @length: length of input and output buffers, in bytes
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*
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* @iv may be NULL to force the use of an all-zero IV.
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* The buffer containing the IV must be as large as the
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* cipher's ivsize.
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*
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* Return values:
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* %0: @in successfully decrypted into @out
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* negative errno: @in not decrypted
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*/
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u32
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krb5_decrypt(
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struct crypto_sync_skcipher *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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SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
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if (length % crypto_sync_skcipher_blocksize(tfm) != 0)
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goto out;
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if (crypto_sync_skcipher_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_sync_skcipher_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_sync_skcipher_ivsize(tfm));
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memcpy(out, in, length);
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sg_init_one(sg, out, length);
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skcipher_request_set_sync_tfm(req, tfm);
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skcipher_request_set_callback(req, 0, NULL, NULL);
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skcipher_request_set_crypt(req, sg, sg, length, local_iv);
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ret = crypto_skcipher_decrypt(req);
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skcipher_request_zero(req);
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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 ahash_request *req = data;
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ahash_request_set_crypt(req, sg, NULL, sg->length);
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return crypto_ahash_update(req);
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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 crypto_ahash *tfm;
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struct ahash_request *req;
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struct scatterlist sg[1];
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int err = -1;
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u8 *checksumdata;
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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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checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_KERNEL);
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if (checksumdata == NULL)
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return GSS_S_FAILURE;
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tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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goto out_free_cksum;
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req = ahash_request_alloc(tfm, GFP_KERNEL);
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if (!req)
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goto out_free_ahash;
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ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
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checksumlen = crypto_ahash_digestsize(tfm);
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if (cksumkey != NULL) {
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err = crypto_ahash_setkey(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_ahash_init(req);
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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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ahash_request_set_crypt(req, sg, NULL, hdrlen);
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err = crypto_ahash_update(req);
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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, req);
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if (err)
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goto out;
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ahash_request_set_crypt(req, NULL, checksumdata, 0);
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err = crypto_ahash_final(req);
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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 = krb5_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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ahash_request_free(req);
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out_free_ahash:
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crypto_free_ahash(tfm);
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out_free_cksum:
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kfree(checksumdata);
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return err ? GSS_S_FAILURE : 0;
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}
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/**
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* gss_krb5_checksum - Compute the MAC for a GSS Wrap or MIC token
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* @tfm: an initialized hash transform
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* @header: pointer to a buffer containing the token header, or NULL
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* @hdrlen: number of octets in @header
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* @body: xdr_buf containing an RPC message (body.len is the message length)
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* @body_offset: byte offset into @body to start checksumming
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* @cksumout: OUT: a buffer to be filled in with the computed HMAC
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*
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* Usually expressed as H = HMAC(K, message)[1..h] .
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*
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* Caller provides the truncation length of the output token (h) in
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* cksumout.len.
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*
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* Return values:
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* %GSS_S_COMPLETE: Digest computed, @cksumout filled in
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* %GSS_S_FAILURE: Call failed
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*/
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u32
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gss_krb5_checksum(struct crypto_ahash *tfm, char *header, int hdrlen,
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const struct xdr_buf *body, int body_offset,
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struct xdr_netobj *cksumout)
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{
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struct ahash_request *req;
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int err = -ENOMEM;
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u8 *checksumdata;
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checksumdata = kmalloc(crypto_ahash_digestsize(tfm), GFP_KERNEL);
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if (!checksumdata)
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return GSS_S_FAILURE;
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req = ahash_request_alloc(tfm, GFP_KERNEL);
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if (!req)
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goto out_free_cksum;
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ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
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err = crypto_ahash_init(req);
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if (err)
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goto out_free_ahash;
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/*
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* Per RFC 4121 Section 4.2.4, the checksum is performed over the
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* data body first, then over the octets in "header".
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*/
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err = xdr_process_buf(body, body_offset, body->len - body_offset,
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checksummer, req);
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if (err)
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goto out_free_ahash;
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if (header) {
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struct scatterlist sg[1];
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|
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sg_init_one(sg, header, hdrlen);
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ahash_request_set_crypt(req, sg, NULL, hdrlen);
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err = crypto_ahash_update(req);
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if (err)
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goto out_free_ahash;
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}
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|
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ahash_request_set_crypt(req, NULL, checksumdata, 0);
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err = crypto_ahash_final(req);
|
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if (err)
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goto out_free_ahash;
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memcpy(cksumout->data, checksumdata,
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min_t(int, cksumout->len, crypto_ahash_digestsize(tfm)));
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|
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out_free_ahash:
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ahash_request_free(req);
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out_free_cksum:
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kfree_sensitive(checksumdata);
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return err ? GSS_S_FAILURE : GSS_S_COMPLETE;
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}
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EXPORT_SYMBOL_IF_KUNIT(gss_krb5_checksum);
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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 skcipher_request *req;
|
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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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|
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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 crypto_sync_skcipher *tfm =
|
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crypto_sync_skcipher_reqtfm(desc->req);
|
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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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|
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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) {
|
|
/* pages are not in place: */
|
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int i = (page_pos + outbuf->page_base) >> PAGE_SHIFT;
|
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in_page = desc->pages[i];
|
|
} else {
|
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in_page = sg_page(sg);
|
|
}
|
|
sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
|
|
sg->offset);
|
|
sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
|
|
sg->offset);
|
|
desc->fragno++;
|
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desc->fraglen += sg->length;
|
|
desc->pos += sg->length;
|
|
|
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fraglen = thislen & (crypto_sync_skcipher_blocksize(tfm) - 1);
|
|
thislen -= fraglen;
|
|
|
|
if (thislen == 0)
|
|
return 0;
|
|
|
|
sg_mark_end(&desc->infrags[desc->fragno - 1]);
|
|
sg_mark_end(&desc->outfrags[desc->fragno - 1]);
|
|
|
|
skcipher_request_set_crypt(desc->req, desc->infrags, desc->outfrags,
|
|
thislen, desc->iv);
|
|
|
|
ret = crypto_skcipher_encrypt(desc->req);
|
|
if (ret)
|
|
return ret;
|
|
|
|
sg_init_table(desc->infrags, 4);
|
|
sg_init_table(desc->outfrags, 4);
|
|
|
|
if (fraglen) {
|
|
sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
|
|
sg->offset + sg->length - fraglen);
|
|
desc->infrags[0] = desc->outfrags[0];
|
|
sg_assign_page(&desc->infrags[0], in_page);
|
|
desc->fragno = 1;
|
|
desc->fraglen = fraglen;
|
|
} else {
|
|
desc->fragno = 0;
|
|
desc->fraglen = 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
gss_encrypt_xdr_buf(struct crypto_sync_skcipher *tfm, struct xdr_buf *buf,
|
|
int offset, struct page **pages)
|
|
{
|
|
int ret;
|
|
struct encryptor_desc desc;
|
|
SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
|
|
|
|
BUG_ON((buf->len - offset) % crypto_sync_skcipher_blocksize(tfm) != 0);
|
|
|
|
skcipher_request_set_sync_tfm(req, tfm);
|
|
skcipher_request_set_callback(req, 0, NULL, NULL);
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
desc.req = req;
|
|
desc.pos = offset;
|
|
desc.outbuf = buf;
|
|
desc.pages = pages;
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
|
|
sg_init_table(desc.infrags, 4);
|
|
sg_init_table(desc.outfrags, 4);
|
|
|
|
ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
|
|
skcipher_request_zero(req);
|
|
return ret;
|
|
}
|
|
|
|
struct decryptor_desc {
|
|
u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
|
|
struct skcipher_request *req;
|
|
struct scatterlist frags[4];
|
|
int fragno;
|
|
int fraglen;
|
|
};
|
|
|
|
static int
|
|
decryptor(struct scatterlist *sg, void *data)
|
|
{
|
|
struct decryptor_desc *desc = data;
|
|
int thislen = desc->fraglen + sg->length;
|
|
struct crypto_sync_skcipher *tfm =
|
|
crypto_sync_skcipher_reqtfm(desc->req);
|
|
int fraglen, ret;
|
|
|
|
/* Worst case is 4 fragments: head, end of page 1, start
|
|
* of page 2, tail. Anything more is a bug. */
|
|
BUG_ON(desc->fragno > 3);
|
|
sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
|
|
sg->offset);
|
|
desc->fragno++;
|
|
desc->fraglen += sg->length;
|
|
|
|
fraglen = thislen & (crypto_sync_skcipher_blocksize(tfm) - 1);
|
|
thislen -= fraglen;
|
|
|
|
if (thislen == 0)
|
|
return 0;
|
|
|
|
sg_mark_end(&desc->frags[desc->fragno - 1]);
|
|
|
|
skcipher_request_set_crypt(desc->req, desc->frags, desc->frags,
|
|
thislen, desc->iv);
|
|
|
|
ret = crypto_skcipher_decrypt(desc->req);
|
|
if (ret)
|
|
return ret;
|
|
|
|
sg_init_table(desc->frags, 4);
|
|
|
|
if (fraglen) {
|
|
sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
|
|
sg->offset + sg->length - fraglen);
|
|
desc->fragno = 1;
|
|
desc->fraglen = fraglen;
|
|
} else {
|
|
desc->fragno = 0;
|
|
desc->fraglen = 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
gss_decrypt_xdr_buf(struct crypto_sync_skcipher *tfm, struct xdr_buf *buf,
|
|
int offset)
|
|
{
|
|
int ret;
|
|
struct decryptor_desc desc;
|
|
SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
|
|
|
|
/* XXXJBF: */
|
|
BUG_ON((buf->len - offset) % crypto_sync_skcipher_blocksize(tfm) != 0);
|
|
|
|
skcipher_request_set_sync_tfm(req, tfm);
|
|
skcipher_request_set_callback(req, 0, NULL, NULL);
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
desc.req = req;
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
|
|
sg_init_table(desc.frags, 4);
|
|
|
|
ret = xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
|
|
skcipher_request_zero(req);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
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_sync_skcipher *cipher, struct xdr_buf *buf,
|
|
u32 offset, u8 *iv, struct page **pages, int encrypt)
|
|
{
|
|
u32 ret;
|
|
struct scatterlist sg[1];
|
|
SYNC_SKCIPHER_REQUEST_ON_STACK(req, cipher);
|
|
u8 *data;
|
|
struct page **save_pages;
|
|
u32 len = buf->len - offset;
|
|
|
|
if (len > GSS_KRB5_MAX_BLOCKSIZE * 2) {
|
|
WARN_ON(0);
|
|
return -ENOMEM;
|
|
}
|
|
data = kmalloc(GSS_KRB5_MAX_BLOCKSIZE * 2, GFP_KERNEL);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* 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);
|
|
|
|
skcipher_request_set_sync_tfm(req, cipher);
|
|
skcipher_request_set_callback(req, 0, NULL, NULL);
|
|
skcipher_request_set_crypt(req, sg, sg, len, iv);
|
|
|
|
if (encrypt)
|
|
ret = crypto_skcipher_encrypt(req);
|
|
else
|
|
ret = crypto_skcipher_decrypt(req);
|
|
|
|
skcipher_request_zero(req);
|
|
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = write_bytes_to_xdr_buf(buf, offset, data, len);
|
|
|
|
out:
|
|
kfree(data);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* krb5_cbc_cts_encrypt - encrypt in CBC mode with CTS
|
|
* @cts_tfm: CBC cipher with CTS
|
|
* @cbc_tfm: base CBC cipher
|
|
* @offset: starting byte offset for plaintext
|
|
* @buf: OUT: output buffer
|
|
* @pages: plaintext
|
|
* @iv: output CBC initialization vector, or NULL
|
|
* @ivsize: size of @iv, in octets
|
|
*
|
|
* To provide confidentiality, encrypt using cipher block chaining
|
|
* with ciphertext stealing. Message integrity is handled separately.
|
|
*
|
|
* Return values:
|
|
* %0: encryption successful
|
|
* negative errno: encryption could not be completed
|
|
*/
|
|
VISIBLE_IF_KUNIT
|
|
int krb5_cbc_cts_encrypt(struct crypto_sync_skcipher *cts_tfm,
|
|
struct crypto_sync_skcipher *cbc_tfm,
|
|
u32 offset, struct xdr_buf *buf, struct page **pages,
|
|
u8 *iv, unsigned int ivsize)
|
|
{
|
|
u32 blocksize, nbytes, nblocks, cbcbytes;
|
|
struct encryptor_desc desc;
|
|
int err;
|
|
|
|
blocksize = crypto_sync_skcipher_blocksize(cts_tfm);
|
|
nbytes = buf->len - offset;
|
|
nblocks = (nbytes + blocksize - 1) / blocksize;
|
|
cbcbytes = 0;
|
|
if (nblocks > 2)
|
|
cbcbytes = (nblocks - 2) * blocksize;
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
|
|
/* Handle block-sized chunks of plaintext with CBC. */
|
|
if (cbcbytes) {
|
|
SYNC_SKCIPHER_REQUEST_ON_STACK(req, cbc_tfm);
|
|
|
|
desc.pos = offset;
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
desc.pages = pages;
|
|
desc.outbuf = buf;
|
|
desc.req = req;
|
|
|
|
skcipher_request_set_sync_tfm(req, cbc_tfm);
|
|
skcipher_request_set_callback(req, 0, NULL, NULL);
|
|
|
|
sg_init_table(desc.infrags, 4);
|
|
sg_init_table(desc.outfrags, 4);
|
|
|
|
err = xdr_process_buf(buf, offset, cbcbytes, encryptor, &desc);
|
|
skcipher_request_zero(req);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/* Remaining plaintext is handled with CBC-CTS. */
|
|
err = gss_krb5_cts_crypt(cts_tfm, buf, offset + cbcbytes,
|
|
desc.iv, pages, 1);
|
|
if (err)
|
|
return err;
|
|
|
|
if (unlikely(iv))
|
|
memcpy(iv, desc.iv, ivsize);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_IF_KUNIT(krb5_cbc_cts_encrypt);
|
|
|
|
/**
|
|
* krb5_cbc_cts_decrypt - decrypt in CBC mode with CTS
|
|
* @cts_tfm: CBC cipher with CTS
|
|
* @cbc_tfm: base CBC cipher
|
|
* @offset: starting byte offset for plaintext
|
|
* @buf: OUT: output buffer
|
|
*
|
|
* Return values:
|
|
* %0: decryption successful
|
|
* negative errno: decryption could not be completed
|
|
*/
|
|
VISIBLE_IF_KUNIT
|
|
int krb5_cbc_cts_decrypt(struct crypto_sync_skcipher *cts_tfm,
|
|
struct crypto_sync_skcipher *cbc_tfm,
|
|
u32 offset, struct xdr_buf *buf)
|
|
{
|
|
u32 blocksize, nblocks, cbcbytes;
|
|
struct decryptor_desc desc;
|
|
int err;
|
|
|
|
blocksize = crypto_sync_skcipher_blocksize(cts_tfm);
|
|
nblocks = (buf->len + blocksize - 1) / blocksize;
|
|
cbcbytes = 0;
|
|
if (nblocks > 2)
|
|
cbcbytes = (nblocks - 2) * blocksize;
|
|
|
|
memset(desc.iv, 0, sizeof(desc.iv));
|
|
|
|
/* Handle block-sized chunks of plaintext with CBC. */
|
|
if (cbcbytes) {
|
|
SYNC_SKCIPHER_REQUEST_ON_STACK(req, cbc_tfm);
|
|
|
|
desc.fragno = 0;
|
|
desc.fraglen = 0;
|
|
desc.req = req;
|
|
|
|
skcipher_request_set_sync_tfm(req, cbc_tfm);
|
|
skcipher_request_set_callback(req, 0, NULL, NULL);
|
|
|
|
sg_init_table(desc.frags, 4);
|
|
|
|
err = xdr_process_buf(buf, 0, cbcbytes, decryptor, &desc);
|
|
skcipher_request_zero(req);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/* Remaining plaintext is handled with CBC-CTS. */
|
|
return gss_krb5_cts_crypt(cts_tfm, buf, cbcbytes, desc.iv, NULL, 0);
|
|
}
|
|
EXPORT_SYMBOL_IF_KUNIT(krb5_cbc_cts_decrypt);
|
|
|
|
u32
|
|
gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
|
|
struct xdr_buf *buf, struct page **pages)
|
|
{
|
|
u32 err;
|
|
struct xdr_netobj hmac;
|
|
u8 *ecptr;
|
|
struct crypto_sync_skcipher *cipher, *aux_cipher;
|
|
struct crypto_ahash *ahash;
|
|
struct page **save_pages;
|
|
unsigned int conflen;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
ahash = kctx->initiator_integ;
|
|
} else {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
ahash = kctx->acceptor_integ;
|
|
}
|
|
conflen = crypto_sync_skcipher_blocksize(cipher);
|
|
|
|
/* hide the gss token header and insert the confounder */
|
|
offset += GSS_KRB5_TOK_HDR_LEN;
|
|
if (xdr_extend_head(buf, offset, conflen))
|
|
return GSS_S_FAILURE;
|
|
krb5_make_confounder(buf->head[0].iov_base + offset, conflen);
|
|
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;
|
|
}
|
|
|
|
/* copy plaintext gss token header after filler (if any) */
|
|
memcpy(ecptr, 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;
|
|
|
|
hmac.len = kctx->gk5e->cksumlength;
|
|
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 = gss_krb5_checksum(ahash, NULL, 0, buf,
|
|
offset + GSS_KRB5_TOK_HDR_LEN, &hmac);
|
|
buf->pages = save_pages;
|
|
if (err)
|
|
return GSS_S_FAILURE;
|
|
|
|
err = krb5_cbc_cts_encrypt(cipher, aux_cipher,
|
|
offset + GSS_KRB5_TOK_HDR_LEN,
|
|
buf, pages, NULL, 0);
|
|
if (err)
|
|
return GSS_S_FAILURE;
|
|
|
|
/* Now update buf to account for HMAC */
|
|
buf->tail[0].iov_len += kctx->gk5e->cksumlength;
|
|
buf->len += kctx->gk5e->cksumlength;
|
|
|
|
return GSS_S_COMPLETE;
|
|
}
|
|
|
|
u32
|
|
gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
|
|
struct xdr_buf *buf, u32 *headskip, u32 *tailskip)
|
|
{
|
|
struct crypto_sync_skcipher *cipher, *aux_cipher;
|
|
struct crypto_ahash *ahash;
|
|
struct xdr_netobj our_hmac_obj;
|
|
u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
struct xdr_buf subbuf;
|
|
u32 ret = 0;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
ahash = kctx->acceptor_integ;
|
|
} else {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
ahash = kctx->initiator_integ;
|
|
}
|
|
|
|
/* create a segment skipping the header and leaving out the checksum */
|
|
xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
|
|
(len - offset - GSS_KRB5_TOK_HDR_LEN -
|
|
kctx->gk5e->cksumlength));
|
|
|
|
ret = krb5_cbc_cts_decrypt(cipher, aux_cipher, 0, &subbuf);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
our_hmac_obj.len = kctx->gk5e->cksumlength;
|
|
our_hmac_obj.data = our_hmac;
|
|
ret = gss_krb5_checksum(ahash, NULL, 0, &subbuf, 0, &our_hmac_obj);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
/* Get the packet's hmac value */
|
|
ret = read_bytes_from_xdr_buf(buf, len - kctx->gk5e->cksumlength,
|
|
pkt_hmac, kctx->gk5e->cksumlength);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
if (crypto_memneq(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
|
|
ret = GSS_S_BAD_SIG;
|
|
goto out_err;
|
|
}
|
|
*headskip = crypto_sync_skcipher_blocksize(cipher);
|
|
*tailskip = kctx->gk5e->cksumlength;
|
|
out_err:
|
|
if (ret && ret != GSS_S_BAD_SIG)
|
|
ret = GSS_S_FAILURE;
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* krb5_etm_checksum - Compute a MAC for a GSS Wrap token
|
|
* @cipher: an initialized cipher transform
|
|
* @tfm: an initialized hash transform
|
|
* @body: xdr_buf containing an RPC message (body.len is the message length)
|
|
* @body_offset: byte offset into @body to start checksumming
|
|
* @cksumout: OUT: a buffer to be filled in with the computed HMAC
|
|
*
|
|
* Usually expressed as H = HMAC(K, IV | ciphertext)[1..h] .
|
|
*
|
|
* Caller provides the truncation length of the output token (h) in
|
|
* cksumout.len.
|
|
*
|
|
* Return values:
|
|
* %GSS_S_COMPLETE: Digest computed, @cksumout filled in
|
|
* %GSS_S_FAILURE: Call failed
|
|
*/
|
|
VISIBLE_IF_KUNIT
|
|
u32 krb5_etm_checksum(struct crypto_sync_skcipher *cipher,
|
|
struct crypto_ahash *tfm, const struct xdr_buf *body,
|
|
int body_offset, struct xdr_netobj *cksumout)
|
|
{
|
|
unsigned int ivsize = crypto_sync_skcipher_ivsize(cipher);
|
|
struct ahash_request *req;
|
|
struct scatterlist sg[1];
|
|
u8 *iv, *checksumdata;
|
|
int err = -ENOMEM;
|
|
|
|
checksumdata = kmalloc(crypto_ahash_digestsize(tfm), GFP_KERNEL);
|
|
if (!checksumdata)
|
|
return GSS_S_FAILURE;
|
|
/* For RPCSEC, the "initial cipher state" is always all zeroes. */
|
|
iv = kzalloc(ivsize, GFP_KERNEL);
|
|
if (!iv)
|
|
goto out_free_mem;
|
|
|
|
req = ahash_request_alloc(tfm, GFP_KERNEL);
|
|
if (!req)
|
|
goto out_free_mem;
|
|
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
|
|
err = crypto_ahash_init(req);
|
|
if (err)
|
|
goto out_free_ahash;
|
|
|
|
sg_init_one(sg, iv, ivsize);
|
|
ahash_request_set_crypt(req, sg, NULL, ivsize);
|
|
err = crypto_ahash_update(req);
|
|
if (err)
|
|
goto out_free_ahash;
|
|
err = xdr_process_buf(body, body_offset, body->len - body_offset,
|
|
checksummer, req);
|
|
if (err)
|
|
goto out_free_ahash;
|
|
|
|
ahash_request_set_crypt(req, NULL, checksumdata, 0);
|
|
err = crypto_ahash_final(req);
|
|
if (err)
|
|
goto out_free_ahash;
|
|
memcpy(cksumout->data, checksumdata, cksumout->len);
|
|
|
|
out_free_ahash:
|
|
ahash_request_free(req);
|
|
out_free_mem:
|
|
kfree(iv);
|
|
kfree_sensitive(checksumdata);
|
|
return err ? GSS_S_FAILURE : GSS_S_COMPLETE;
|
|
}
|
|
EXPORT_SYMBOL_IF_KUNIT(krb5_etm_checksum);
|
|
|
|
/**
|
|
* krb5_etm_encrypt - Encrypt using the RFC 8009 rules
|
|
* @kctx: Kerberos context
|
|
* @offset: starting offset of the payload, in bytes
|
|
* @buf: OUT: send buffer to contain the encrypted payload
|
|
* @pages: plaintext payload
|
|
*
|
|
* The main difference with aes_encrypt is that "The HMAC is
|
|
* calculated over the cipher state concatenated with the AES
|
|
* output, instead of being calculated over the confounder and
|
|
* plaintext. This allows the message receiver to verify the
|
|
* integrity of the message before decrypting the message."
|
|
*
|
|
* RFC 8009 Section 5:
|
|
*
|
|
* encryption function: as follows, where E() is AES encryption in
|
|
* CBC-CS3 mode, and h is the size of truncated HMAC (128 bits or
|
|
* 192 bits as described above).
|
|
*
|
|
* N = random value of length 128 bits (the AES block size)
|
|
* IV = cipher state
|
|
* C = E(Ke, N | plaintext, IV)
|
|
* H = HMAC(Ki, IV | C)
|
|
* ciphertext = C | H[1..h]
|
|
*
|
|
* This encryption formula provides AEAD EtM with key separation.
|
|
*
|
|
* Return values:
|
|
* %GSS_S_COMPLETE: Encryption successful
|
|
* %GSS_S_FAILURE: Encryption failed
|
|
*/
|
|
u32
|
|
krb5_etm_encrypt(struct krb5_ctx *kctx, u32 offset,
|
|
struct xdr_buf *buf, struct page **pages)
|
|
{
|
|
struct crypto_sync_skcipher *cipher, *aux_cipher;
|
|
struct crypto_ahash *ahash;
|
|
struct xdr_netobj hmac;
|
|
unsigned int conflen;
|
|
u8 *ecptr;
|
|
u32 err;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
ahash = kctx->initiator_integ;
|
|
} else {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
ahash = kctx->acceptor_integ;
|
|
}
|
|
conflen = crypto_sync_skcipher_blocksize(cipher);
|
|
|
|
offset += GSS_KRB5_TOK_HDR_LEN;
|
|
if (xdr_extend_head(buf, offset, conflen))
|
|
return GSS_S_FAILURE;
|
|
krb5_make_confounder(buf->head[0].iov_base + offset, conflen);
|
|
offset -= GSS_KRB5_TOK_HDR_LEN;
|
|
|
|
if (buf->tail[0].iov_base) {
|
|
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;
|
|
}
|
|
|
|
memcpy(ecptr, 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;
|
|
|
|
err = krb5_cbc_cts_encrypt(cipher, aux_cipher,
|
|
offset + GSS_KRB5_TOK_HDR_LEN,
|
|
buf, pages, NULL, 0);
|
|
if (err)
|
|
return GSS_S_FAILURE;
|
|
|
|
hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
|
|
hmac.len = kctx->gk5e->cksumlength;
|
|
err = krb5_etm_checksum(cipher, ahash,
|
|
buf, offset + GSS_KRB5_TOK_HDR_LEN, &hmac);
|
|
if (err)
|
|
goto out_err;
|
|
buf->tail[0].iov_len += kctx->gk5e->cksumlength;
|
|
buf->len += kctx->gk5e->cksumlength;
|
|
|
|
return GSS_S_COMPLETE;
|
|
|
|
out_err:
|
|
return GSS_S_FAILURE;
|
|
}
|
|
|
|
/**
|
|
* krb5_etm_decrypt - Decrypt using the RFC 8009 rules
|
|
* @kctx: Kerberos context
|
|
* @offset: starting offset of the ciphertext, in bytes
|
|
* @len:
|
|
* @buf:
|
|
* @headskip: OUT: the enctype's confounder length, in octets
|
|
* @tailskip: OUT: the enctype's HMAC length, in octets
|
|
*
|
|
* RFC 8009 Section 5:
|
|
*
|
|
* decryption function: as follows, where D() is AES decryption in
|
|
* CBC-CS3 mode, and h is the size of truncated HMAC.
|
|
*
|
|
* (C, H) = ciphertext
|
|
* (Note: H is the last h bits of the ciphertext.)
|
|
* IV = cipher state
|
|
* if H != HMAC(Ki, IV | C)[1..h]
|
|
* stop, report error
|
|
* (N, P) = D(Ke, C, IV)
|
|
*
|
|
* Return values:
|
|
* %GSS_S_COMPLETE: Decryption successful
|
|
* %GSS_S_BAD_SIG: computed HMAC != received HMAC
|
|
* %GSS_S_FAILURE: Decryption failed
|
|
*/
|
|
u32
|
|
krb5_etm_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
|
|
struct xdr_buf *buf, u32 *headskip, u32 *tailskip)
|
|
{
|
|
struct crypto_sync_skcipher *cipher, *aux_cipher;
|
|
u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
|
|
struct xdr_netobj our_hmac_obj;
|
|
struct crypto_ahash *ahash;
|
|
struct xdr_buf subbuf;
|
|
u32 ret = 0;
|
|
|
|
if (kctx->initiate) {
|
|
cipher = kctx->acceptor_enc;
|
|
aux_cipher = kctx->acceptor_enc_aux;
|
|
ahash = kctx->acceptor_integ;
|
|
} else {
|
|
cipher = kctx->initiator_enc;
|
|
aux_cipher = kctx->initiator_enc_aux;
|
|
ahash = kctx->initiator_integ;
|
|
}
|
|
|
|
/* Extract the ciphertext into @subbuf. */
|
|
xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
|
|
(len - offset - GSS_KRB5_TOK_HDR_LEN -
|
|
kctx->gk5e->cksumlength));
|
|
|
|
our_hmac_obj.data = our_hmac;
|
|
our_hmac_obj.len = kctx->gk5e->cksumlength;
|
|
ret = krb5_etm_checksum(cipher, ahash, &subbuf, 0, &our_hmac_obj);
|
|
if (ret)
|
|
goto out_err;
|
|
ret = read_bytes_from_xdr_buf(buf, len - kctx->gk5e->cksumlength,
|
|
pkt_hmac, kctx->gk5e->cksumlength);
|
|
if (ret)
|
|
goto out_err;
|
|
if (crypto_memneq(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
|
|
ret = GSS_S_BAD_SIG;
|
|
goto out_err;
|
|
}
|
|
|
|
ret = krb5_cbc_cts_decrypt(cipher, aux_cipher, 0, &subbuf);
|
|
if (ret) {
|
|
ret = GSS_S_FAILURE;
|
|
goto out_err;
|
|
}
|
|
|
|
*headskip = crypto_sync_skcipher_blocksize(cipher);
|
|
*tailskip = kctx->gk5e->cksumlength;
|
|
return GSS_S_COMPLETE;
|
|
|
|
out_err:
|
|
if (ret != GSS_S_BAD_SIG)
|
|
ret = GSS_S_FAILURE;
|
|
return ret;
|
|
}
|