/* * linux/net/sunrpc/gss_krb5_unseal.c * * Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c * * Copyright (c) 2000-2008 The Regents of the University of Michigan. * All rights reserved. * * Andy Adamson */ /* * Copyright 1993 by OpenVision Technologies, Inc. * * Permission to use, copy, modify, distribute, and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appears in all copies and * that both that copyright notice and this permission notice appear in * supporting documentation, and that the name of OpenVision not be used * in advertising or publicity pertaining to distribution of the software * without specific, written prior permission. OpenVision makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR * PERFORMANCE OF THIS SOFTWARE. */ /* * Copyright (C) 1998 by the FundsXpress, INC. * * All rights reserved. * * Export of this software from the United States of America may require * a specific license from the United States Government. It is the * responsibility of any person or organization contemplating export to * obtain such a license before exporting. * * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and * distribute this software and its documentation for any purpose and * without fee is hereby granted, provided that the above copyright * notice appear in all copies and that both that copyright notice and * this permission notice appear in supporting documentation, and that * the name of FundsXpress. not be used in advertising or publicity pertaining * to distribution of the software without specific, written prior * permission. FundsXpress makes no representations about the suitability of * this software for any purpose. It is provided "as is" without express * or implied warranty. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include #include #include #include #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) # define RPCDBG_FACILITY RPCDBG_AUTH #endif /* read_token is a mic token, and message_buffer is the data that the mic was * supposedly taken over. */ static u32 gss_verify_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *message_buffer, struct xdr_netobj *read_token) { int signalg; int sealalg; char cksumdata[GSS_KRB5_MAX_CKSUM_LEN]; struct xdr_netobj md5cksum = {.len = sizeof(cksumdata), .data = cksumdata}; s32 now; int direction; u32 seqnum; unsigned char *ptr = (unsigned char *)read_token->data; int bodysize; u8 *cksumkey; dprintk("RPC: krb5_read_token\n"); if (g_verify_token_header(&ctx->mech_used, &bodysize, &ptr, read_token->len)) return GSS_S_DEFECTIVE_TOKEN; if ((ptr[0] != ((KG_TOK_MIC_MSG >> 8) & 0xff)) || (ptr[1] != (KG_TOK_MIC_MSG & 0xff))) return GSS_S_DEFECTIVE_TOKEN; /* XXX sanity-check bodysize?? */ signalg = ptr[2] + (ptr[3] << 8); if (signalg != ctx->gk5e->signalg) return GSS_S_DEFECTIVE_TOKEN; sealalg = ptr[4] + (ptr[5] << 8); if (sealalg != SEAL_ALG_NONE) return GSS_S_DEFECTIVE_TOKEN; if ((ptr[6] != 0xff) || (ptr[7] != 0xff)) return GSS_S_DEFECTIVE_TOKEN; if (ctx->gk5e->keyed_cksum) cksumkey = ctx->cksum; else cksumkey = NULL; if (make_checksum(ctx, ptr, 8, message_buffer, 0, cksumkey, KG_USAGE_SIGN, &md5cksum)) return GSS_S_FAILURE; if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN, ctx->gk5e->cksumlength)) return GSS_S_BAD_SIG; /* it got through unscathed. Make sure the context is unexpired */ now = get_seconds(); if (now > ctx->endtime) return GSS_S_CONTEXT_EXPIRED; /* do sequencing checks */ if (krb5_get_seq_num(ctx, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8, &direction, &seqnum)) return GSS_S_FAILURE; if ((ctx->initiate && direction != 0xff) || (!ctx->initiate && direction != 0)) return GSS_S_BAD_SIG; return GSS_S_COMPLETE; } static u32 gss_verify_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *message_buffer, struct xdr_netobj *read_token) { char cksumdata[GSS_KRB5_MAX_CKSUM_LEN]; struct xdr_netobj cksumobj = {.len = sizeof(cksumdata), .data = cksumdata}; s32 now; u8 *ptr = read_token->data; u8 *cksumkey; u8 flags; int i; unsigned int cksum_usage; dprintk("RPC: %s\n", __func__); if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_MIC) return GSS_S_DEFECTIVE_TOKEN; flags = ptr[2]; if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) || (ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR))) return GSS_S_BAD_SIG; if (flags & KG2_TOKEN_FLAG_SEALED) { dprintk("%s: token has unexpected sealed flag\n", __func__); return GSS_S_FAILURE; } for (i = 3; i < 8; i++) if (ptr[i] != 0xff) return GSS_S_DEFECTIVE_TOKEN; if (ctx->initiate) { cksumkey = ctx->acceptor_sign; cksum_usage = KG_USAGE_ACCEPTOR_SIGN; } else { cksumkey = ctx->initiator_sign; cksum_usage = KG_USAGE_INITIATOR_SIGN; } if (make_checksum_v2(ctx, ptr, GSS_KRB5_TOK_HDR_LEN, message_buffer, 0, cksumkey, cksum_usage, &cksumobj)) return GSS_S_FAILURE; if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN, ctx->gk5e->cksumlength)) return GSS_S_BAD_SIG; /* it got through unscathed. Make sure the context is unexpired */ now = get_seconds(); if (now > ctx->endtime) return GSS_S_CONTEXT_EXPIRED; /* * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss * doesn't want it checked; see page 6 of rfc 2203. */ return GSS_S_COMPLETE; } u32 gss_verify_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *message_buffer, struct xdr_netobj *read_token) { struct krb5_ctx *ctx = gss_ctx->internal_ctx_id; switch (ctx->enctype) { default: BUG(); case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: case ENCTYPE_ARCFOUR_HMAC: return gss_verify_mic_v1(ctx, message_buffer, read_token); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: return gss_verify_mic_v2(ctx, message_buffer, read_token); } }