1 /* 2 * linux/net/sunrpc/gss_krb5_unseal.c 3 * 4 * Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c 5 * 6 * Copyright (c) 2000-2008 The Regents of the University of Michigan. 7 * All rights reserved. 8 * 9 * Andy Adamson <andros@umich.edu> 10 */ 11 12 /* 13 * Copyright 1993 by OpenVision Technologies, Inc. 14 * 15 * Permission to use, copy, modify, distribute, and sell this software 16 * and its documentation for any purpose is hereby granted without fee, 17 * provided that the above copyright notice appears in all copies and 18 * that both that copyright notice and this permission notice appear in 19 * supporting documentation, and that the name of OpenVision not be used 20 * in advertising or publicity pertaining to distribution of the software 21 * without specific, written prior permission. OpenVision makes no 22 * representations about the suitability of this software for any 23 * purpose. It is provided "as is" without express or implied warranty. 24 * 25 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 26 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO 27 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR 28 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF 29 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR 30 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 31 * PERFORMANCE OF THIS SOFTWARE. 32 */ 33 34 /* 35 * Copyright (C) 1998 by the FundsXpress, INC. 36 * 37 * All rights reserved. 38 * 39 * Export of this software from the United States of America may require 40 * a specific license from the United States Government. It is the 41 * responsibility of any person or organization contemplating export to 42 * obtain such a license before exporting. 43 * 44 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 45 * distribute this software and its documentation for any purpose and 46 * without fee is hereby granted, provided that the above copyright 47 * notice appear in all copies and that both that copyright notice and 48 * this permission notice appear in supporting documentation, and that 49 * the name of FundsXpress. not be used in advertising or publicity pertaining 50 * to distribution of the software without specific, written prior 51 * permission. FundsXpress makes no representations about the suitability of 52 * this software for any purpose. It is provided "as is" without express 53 * or implied warranty. 54 * 55 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 56 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 57 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 58 */ 59 60 #include <crypto/algapi.h> 61 #include <linux/types.h> 62 #include <linux/jiffies.h> 63 #include <linux/sunrpc/gss_krb5.h> 64 #include <linux/crypto.h> 65 66 #include "gss_krb5_internal.h" 67 68 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) 69 # define RPCDBG_FACILITY RPCDBG_AUTH 70 #endif 71 72 u32 73 gss_krb5_verify_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *message_buffer, 74 struct xdr_netobj *read_token) 75 { 76 struct crypto_ahash *tfm = ctx->initiate ? 77 ctx->acceptor_sign : ctx->initiator_sign; 78 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN]; 79 struct xdr_netobj cksumobj = { 80 .len = ctx->gk5e->cksumlength, 81 .data = cksumdata, 82 }; 83 u8 *ptr = read_token->data; 84 __be16 be16_ptr; 85 time64_t now; 86 u8 flags; 87 int i; 88 89 dprintk("RPC: %s\n", __func__); 90 91 memcpy(&be16_ptr, (char *) ptr, 2); 92 if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC) 93 return GSS_S_DEFECTIVE_TOKEN; 94 95 flags = ptr[2]; 96 if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) || 97 (ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR))) 98 return GSS_S_BAD_SIG; 99 100 if (flags & KG2_TOKEN_FLAG_SEALED) { 101 dprintk("%s: token has unexpected sealed flag\n", __func__); 102 return GSS_S_FAILURE; 103 } 104 105 for (i = 3; i < 8; i++) 106 if (ptr[i] != 0xff) 107 return GSS_S_DEFECTIVE_TOKEN; 108 109 if (gss_krb5_checksum(tfm, ptr, GSS_KRB5_TOK_HDR_LEN, 110 message_buffer, 0, &cksumobj)) 111 return GSS_S_FAILURE; 112 113 if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN, 114 ctx->gk5e->cksumlength)) 115 return GSS_S_BAD_SIG; 116 117 /* it got through unscathed. Make sure the context is unexpired */ 118 now = ktime_get_real_seconds(); 119 if (now > ctx->endtime) 120 return GSS_S_CONTEXT_EXPIRED; 121 122 /* 123 * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss 124 * doesn't want it checked; see page 6 of rfc 2203. 125 */ 126 127 return GSS_S_COMPLETE; 128 } 129