/* * Copyright (c) 2007 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /************* * These functions implement RPCSEC_GSS security for the NFS client and server. * The code is specific to the use of Kerberos v5 and the use of DES MAC MD5 * protection as described in Internet RFC 2203 and 2623. * * In contrast to the original AUTH_SYS authentication, RPCSEC_GSS is stateful. * It requires the client and server negotiate a secure connection as part of a * security context. The context state is maintained in client and server structures. * On the client side, each user of an NFS mount is assigned their own context, * identified by UID, on their first use of the mount, and it persists until the * unmount or until the context is renewed. Each user context has a corresponding * server context which the server maintains until the client destroys it, or * until the context expires. * * The client and server contexts are set up dynamically. When a user attempts * to send an NFS request, if there is no context for the user, then one is * set up via an exchange of NFS null procedure calls as described in RFC 2203. * During this exchange, the client and server pass a security token that is * forwarded via Mach upcall to the gssd, which invokes the GSS-API to authenticate * the user to the server (and vice-versa). The client and server also receive * a unique session key that can be used to digitally sign the credentials and * verifier or optionally to provide data integrity and/or privacy. * * Once the context is complete, the client and server enter a normal data * exchange phase - beginning with the NFS request that prompted the context * creation. During this phase, the client's RPC header contains an RPCSEC_GSS * credential and verifier, and the server returns a verifier as well. * For simple authentication, the verifier contains a signed checksum of the * RPC header, including the credential. The server's verifier has a signed * checksum of the current sequence number. * * Each client call contains a sequence number that nominally increases by one * on each request. The sequence number is intended to prevent replay attacks. * Since the protocol can be used over UDP, there is some allowance for * out-of-sequence requests, so the server checks whether the sequence numbers * are within a sequence "window". If a sequence number is outside the lower * bound of the window, the server silently drops the request. This has some * implications for retransmission. If a request needs to be retransmitted, the * client must bump the sequence number even if the request XID is unchanged. * * When the NFS mount is unmounted, the client sends a "destroy" credential * to delete the server's context for each user of the mount. Since it's * possible for the client to crash or disconnect without sending the destroy * message, the server has a thread that reaps contexts that have been idle * too long. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define NFS_GSS_MACH_MAX_RETRIES 3 #if NFSSERVER u_long nfs_gss_svc_ctx_hash; struct nfs_gss_svc_ctx_hashhead *nfs_gss_svc_ctx_hashtbl; lck_mtx_t *nfs_gss_svc_ctx_mutex; lck_grp_t *nfs_gss_svc_grp; #endif /* NFSSERVER */ #if NFSCLIENT lck_grp_t *nfs_gss_clnt_grp; #endif /* NFSCLIENT */ /* * These octet strings are used to encode/decode ASN.1 tokens * in the RPCSEC_GSS verifiers. */ static u_char krb5_tokhead[] = { 0x60, 0x23 }; static u_char krb5_mech[] = { 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x01, 0x02, 0x02 }; static u_char krb5_mic[] = { 0x01, 0x01, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff }; static u_char krb5_wrap[] = { 0x02, 0x01, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff }; static u_char iv0[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // DES MAC Initialization Vector /* * The size of the Kerberos v5 ASN.1 token * in the verifier. * * Note that the second octet of the krb5_tokhead (0x23) is a * DER-encoded size field that has variable length. If the size * is 128 bytes or greater, then it uses two bytes, three bytes * if 65536 or greater, and so on. Since the MIC tokens are * separate from the data, the size is always the same: 35 bytes (0x23). * However, the wrap token is different. Its size field includes the * size of the token + the encrypted data that follows. So the size * field may be two, three or four bytes. */ #define KRB5_SZ_TOKHEAD sizeof(krb5_tokhead) #define KRB5_SZ_MECH sizeof(krb5_mech) #define KRB5_SZ_ALG sizeof(krb5_mic) // 8 - same as krb5_wrap #define KRB5_SZ_SEQ 8 #define KRB5_SZ_CKSUM 8 #define KRB5_SZ_EXTRA 3 // a wrap token may be longer by up to this many octets #define KRB5_SZ_TOKEN (KRB5_SZ_TOKHEAD + KRB5_SZ_MECH + KRB5_SZ_ALG + KRB5_SZ_SEQ + KRB5_SZ_CKSUM) #define KRB5_SZ_TOKMAX (KRB5_SZ_TOKEN + KRB5_SZ_EXTRA) #if NFSCLIENT static int nfs_gss_clnt_ctx_find(struct nfsreq *); static int nfs_gss_clnt_ctx_failover(struct nfsreq *); static int nfs_gss_clnt_ctx_init(struct nfsreq *, struct nfs_gss_clnt_ctx *); static int nfs_gss_clnt_ctx_callserver(struct nfsreq *, struct nfs_gss_clnt_ctx *); static char *nfs_gss_clnt_svcname(struct nfsmount *); static int nfs_gss_clnt_gssd_upcall(struct nfsreq *, struct nfs_gss_clnt_ctx *); static void nfs_gss_clnt_ctx_remove(struct nfsmount *, struct nfs_gss_clnt_ctx *); static int nfs_gss_clnt_ctx_delay(struct nfsreq *, int *); #endif /* NFSCLIENT */ #if NFSSERVER static struct nfs_gss_svc_ctx *nfs_gss_svc_ctx_find(uint32_t); static void nfs_gss_svc_ctx_insert(struct nfs_gss_svc_ctx *); static void nfs_gss_svc_ctx_timer(void *, void *); static int nfs_gss_svc_gssd_upcall(struct nfs_gss_svc_ctx *); static int nfs_gss_svc_seqnum_valid(struct nfs_gss_svc_ctx *, uint32_t); #endif /* NFSSERVER */ static void task_release_special_port(mach_port_t); static mach_port_t task_copy_special_port(mach_port_t); static void nfs_gss_mach_alloc_buffer(u_char *, uint32_t, vm_map_copy_t *); static int nfs_gss_mach_vmcopyout(vm_map_copy_t, uint32_t, u_char *); static int nfs_gss_token_get(des_key_schedule, u_char *, u_char *, int, uint32_t *, u_char *); static int nfs_gss_token_put(des_key_schedule, u_char *, u_char *, int, int, u_char *); static int nfs_gss_der_length_size(int); static void nfs_gss_der_length_put(u_char **, int); static int nfs_gss_der_length_get(u_char **); static int nfs_gss_mchain_length(mbuf_t); static int nfs_gss_append_chain(struct nfsm_chain *, mbuf_t); static void nfs_gss_nfsm_chain(struct nfsm_chain *, mbuf_t); static void nfs_gss_cksum_mchain(des_key_schedule, mbuf_t, u_char *, int, int, u_char *); static void nfs_gss_cksum_chain(des_key_schedule, struct nfsm_chain *, u_char *, int, int, u_char *); static void nfs_gss_cksum_rep(des_key_schedule, uint32_t, u_char *); static void nfs_gss_encrypt_mchain(u_char *, mbuf_t, int, int, int); static void nfs_gss_encrypt_chain(u_char *, struct nfsm_chain *, int, int, int); static DES_LONG des_cbc_cksum(des_cblock *, des_cblock *, long, des_key_schedule, des_cblock *); static void des_cbc_encrypt(des_cblock *, des_cblock *, long, des_key_schedule, des_cblock *, des_cblock *, int); #if NFSSERVER thread_call_t nfs_gss_svc_ctx_timer_call; int nfs_gss_timer_on = 0; uint32_t nfs_gss_ctx_count = 0; const uint32_t nfs_gss_ctx_max = GSS_SVC_MAXCONTEXTS; #endif /* NFSSERVER */ /* * Initialization when NFS starts */ void nfs_gss_init(void) { #if NFSCLIENT nfs_gss_clnt_grp = lck_grp_alloc_init("rpcsec_gss_clnt", LCK_GRP_ATTR_NULL); #endif /* NFSCLIENT */ #if NFSSERVER nfs_gss_svc_grp = lck_grp_alloc_init("rpcsec_gss_svc", LCK_GRP_ATTR_NULL); nfs_gss_svc_ctx_hashtbl = hashinit(SVC_CTX_HASHSZ, M_TEMP, &nfs_gss_svc_ctx_hash); nfs_gss_svc_ctx_mutex = lck_mtx_alloc_init(nfs_gss_svc_grp, LCK_ATTR_NULL); nfs_gss_svc_ctx_timer_call = thread_call_allocate(nfs_gss_svc_ctx_timer, NULL); #endif /* NFSSERVER */ } #if NFSCLIENT /* * Find the context for a particular user. * * If the context doesn't already exist * then create a new context for this user. * * Note that the code allows superuser (uid == 0) * to adopt the context of another user. */ static int nfs_gss_clnt_ctx_find(struct nfsreq *req) { struct nfsmount *nmp = req->r_nmp; struct nfs_gss_clnt_ctx *cp; uid_t uid = kauth_cred_getuid(req->r_cred); int error = 0; int retrycnt = 0; retry: lck_mtx_lock(&nmp->nm_lock); TAILQ_FOREACH(cp, &nmp->nm_gsscl, gss_clnt_entries) { if (cp->gss_clnt_uid == uid) { if (cp->gss_clnt_flags & GSS_CTX_INVAL) continue; lck_mtx_unlock(&nmp->nm_lock); nfs_gss_clnt_ctx_ref(req, cp); return (0); } } if (uid == 0) { /* * If superuser is trying to get access, then co-opt * the first valid context in the list. * XXX Ultimately, we need to allow superuser to * go ahead and attempt to set up its own context * in case one is set up for it. */ TAILQ_FOREACH(cp, &nmp->nm_gsscl, gss_clnt_entries) { if (!(cp->gss_clnt_flags & GSS_CTX_INVAL)) { lck_mtx_unlock(&nmp->nm_lock); nfs_gss_clnt_ctx_ref(req, cp); return (0); } } } /* * Not found - create a new context */ /* * If the thread is async, then it cannot get * kerberos creds and set up a proper context. * If no sec= mount option is given, attempt * to failover to sec=sys. */ if (req->r_thread == NULL) { if ((nmp->nm_flag & NFSMNT_SECGIVEN) == 0) { error = nfs_gss_clnt_ctx_failover(req); } else { printf("nfs_gss_clnt_ctx_find: no context for async\n"); error = EAUTH; } lck_mtx_unlock(&nmp->nm_lock); return (error); } MALLOC(cp, struct nfs_gss_clnt_ctx *, sizeof(*cp), M_TEMP, M_WAITOK|M_ZERO); if (cp == NULL) { lck_mtx_unlock(&nmp->nm_lock); return (ENOMEM); } cp->gss_clnt_uid = uid; cp->gss_clnt_mtx = lck_mtx_alloc_init(nfs_gss_clnt_grp, LCK_ATTR_NULL); cp->gss_clnt_thread = current_thread(); nfs_gss_clnt_ctx_ref(req, cp); TAILQ_INSERT_TAIL(&nmp->nm_gsscl, cp, gss_clnt_entries); lck_mtx_unlock(&nmp->nm_lock); error = nfs_gss_clnt_ctx_init(req, cp); if (error) nfs_gss_clnt_ctx_unref(req); if (error == ENEEDAUTH) { error = nfs_gss_clnt_ctx_delay(req, &retrycnt); if (!error) goto retry; } /* * If we failed to set up a Kerberos context for this * user and no sec= mount option was given then set * up a dummy context that allows this user to attempt * sec=sys calls. */ if (error && (nmp->nm_flag & NFSMNT_SECGIVEN) == 0) { lck_mtx_lock(&nmp->nm_lock); error = nfs_gss_clnt_ctx_failover(req); lck_mtx_unlock(&nmp->nm_lock); } return (error); } /* * Set up a dummy context to allow the use of sec=sys * for this user, if the server allows sec=sys. * The context is valid for GSS_CLNT_SYS_VALID seconds, * so that the user will periodically attempt to fail back * and get a real credential. * * Assumes context list (nm_lock) is locked */ static int nfs_gss_clnt_ctx_failover(struct nfsreq *req) { struct nfsmount *nmp = req->r_nmp; struct nfs_gss_clnt_ctx *cp; uid_t uid = kauth_cred_getuid(req->r_cred); struct timeval now; MALLOC(cp, struct nfs_gss_clnt_ctx *, sizeof(*cp), M_TEMP, M_WAITOK|M_ZERO); if (cp == NULL) return (ENOMEM); cp->gss_clnt_service = RPCSEC_GSS_SVC_SYS; cp->gss_clnt_uid = uid; cp->gss_clnt_mtx = lck_mtx_alloc_init(nfs_gss_clnt_grp, LCK_ATTR_NULL); microuptime(&now); cp->gss_clnt_ctime = now.tv_sec; // time stamp nfs_gss_clnt_ctx_ref(req, cp); TAILQ_INSERT_TAIL(&nmp->nm_gsscl, cp, gss_clnt_entries); return (0); } /* * Inserts an RPCSEC_GSS credential into an RPC header. * After the credential is inserted, the code continues * to build the verifier which contains a signed checksum * of the RPC header. */ int nfs_gss_clnt_cred_put(struct nfsreq *req, struct nfsm_chain *nmc, mbuf_t args) { struct nfsmount *nmp = req->r_nmp; struct nfs_gss_clnt_ctx *cp; uint32_t seqnum = 0; int error = 0; int slpflag = 0; int start, len, offset = 0; int pad, toklen; struct nfsm_chain nmc_tmp; struct gss_seq *gsp; u_char tokbuf[KRB5_SZ_TOKMAX]; u_char cksum[8]; struct timeval now; retry: if (req->r_gss_ctx == NULL) { /* * Find the context for this user. * If no context is found, one will * be created. */ error = nfs_gss_clnt_ctx_find(req); if (error) return (error); } cp = req->r_gss_ctx; /* * If it's a dummy context for a user that's using * a fallback to sec=sys, then just return an error * so rpchead can encode an RPCAUTH_UNIX cred. */ if (cp->gss_clnt_service == RPCSEC_GSS_SVC_SYS) { /* * The dummy context is valid for just * GSS_CLNT_SYS_VALID seconds. If the context * is older than this, mark it invalid and try * again to get a real one. */ lck_mtx_lock(cp->gss_clnt_mtx); microuptime(&now); if (now.tv_sec > cp->gss_clnt_ctime + GSS_CLNT_SYS_VALID) { cp->gss_clnt_flags |= GSS_CTX_INVAL; lck_mtx_unlock(cp->gss_clnt_mtx); nfs_gss_clnt_ctx_unref(req); goto retry; } lck_mtx_unlock(cp->gss_clnt_mtx); return (ENEEDAUTH); } /* * If the context thread isn't null, then the context isn't * yet complete and is for the exclusive use of the thread * doing the context setup. Wait until the context thread * is null. */ lck_mtx_lock(cp->gss_clnt_mtx); if (cp->gss_clnt_thread && cp->gss_clnt_thread != current_thread()) { cp->gss_clnt_flags |= GSS_NEEDCTX; slpflag = (PZERO-1) | PDROP | (((nmp->nm_flag & NFSMNT_INT) && req->r_thread) ? PCATCH : 0); msleep(cp, cp->gss_clnt_mtx, slpflag, "ctxwait", NULL); if ((error = nfs_sigintr(nmp, req, req->r_thread, 0))) return (error); nfs_gss_clnt_ctx_unref(req); goto retry; } lck_mtx_unlock(cp->gss_clnt_mtx); if (cp->gss_clnt_flags & GSS_CTX_COMPLETE) { /* * Get a sequence number for this request. * Check whether the oldest request in the window is complete. * If it's still pending, then wait until it's done before * we allocate a new sequence number and allow this request * to proceed. */ lck_mtx_lock(cp->gss_clnt_mtx); while (win_getbit(cp->gss_clnt_seqbits, ((cp->gss_clnt_seqnum - cp->gss_clnt_seqwin) + 1) % cp->gss_clnt_seqwin)) { cp->gss_clnt_flags |= GSS_NEEDSEQ; slpflag = (PZERO-1) | (((nmp->nm_flag & NFSMNT_INT) && req->r_thread) ? PCATCH : 0); msleep(cp, cp->gss_clnt_mtx, slpflag, "seqwin", NULL); if ((error = nfs_sigintr(nmp, req, req->r_thread, 0))) { lck_mtx_unlock(cp->gss_clnt_mtx); return (error); } if (cp->gss_clnt_flags & GSS_CTX_INVAL) { /* Renewed while while we were waiting */ lck_mtx_unlock(cp->gss_clnt_mtx); nfs_gss_clnt_ctx_unref(req); goto retry; } } seqnum = ++cp->gss_clnt_seqnum; win_setbit(cp->gss_clnt_seqbits, seqnum % cp->gss_clnt_seqwin); lck_mtx_unlock(cp->gss_clnt_mtx); MALLOC(gsp, struct gss_seq *, sizeof(*gsp), M_TEMP, M_WAITOK|M_ZERO); if (gsp == NULL) return (ENOMEM); gsp->gss_seqnum = seqnum; SLIST_INSERT_HEAD(&req->r_gss_seqlist, gsp, gss_seqnext); } /* Insert the credential */ nfsm_chain_add_32(error, nmc, RPCSEC_GSS); nfsm_chain_add_32(error, nmc, 5 * NFSX_UNSIGNED + cp->gss_clnt_handle_len); nfsm_chain_add_32(error, nmc, RPCSEC_GSS_VERS_1); nfsm_chain_add_32(error, nmc, cp->gss_clnt_proc); nfsm_chain_add_32(error, nmc, seqnum); nfsm_chain_add_32(error, nmc, cp->gss_clnt_service); nfsm_chain_add_32(error, nmc, cp->gss_clnt_handle_len); nfsm_chain_add_opaque(error, nmc, cp->gss_clnt_handle, cp->gss_clnt_handle_len); /* * Now add the verifier */ if (cp->gss_clnt_proc == RPCSEC_GSS_INIT || cp->gss_clnt_proc == RPCSEC_GSS_CONTINUE_INIT) { /* * If the context is still being created * then use a null verifier. */ nfsm_chain_add_32(error, nmc, RPCAUTH_NULL); // flavor nfsm_chain_add_32(error, nmc, 0); // length nfsm_chain_build_done(error, nmc); if (!error) nfs_gss_append_chain(nmc, args); return (error); } offset = nmp->nm_sotype == SOCK_STREAM ? NFSX_UNSIGNED : 0; // record mark nfsm_chain_build_done(error, nmc); nfs_gss_cksum_chain(cp->gss_clnt_sched, nmc, krb5_mic, offset, 0, cksum); toklen = nfs_gss_token_put(cp->gss_clnt_sched, krb5_mic, tokbuf, 1, 0, cksum); nfsm_chain_add_32(error, nmc, RPCSEC_GSS); // flavor nfsm_chain_add_32(error, nmc, toklen); // length nfsm_chain_add_opaque(error, nmc, tokbuf, toklen); nfsm_chain_build_done(error, nmc); if (error) return (error); /* * Now we may have to compute integrity or encrypt the call args * per RFC 2203 Section 5.3.2 */ switch (cp->gss_clnt_service) { case RPCSEC_GSS_SVC_NONE: nfs_gss_append_chain(nmc, args); break; case RPCSEC_GSS_SVC_INTEGRITY: len = nfs_gss_mchain_length(args); // Find args length req->r_gss_arglen = len; // Stash the args len len += NFSX_UNSIGNED; // Add seqnum length nfsm_chain_add_32(error, nmc, len); // and insert it start = nfsm_chain_offset(nmc); nfsm_chain_add_32(error, nmc, seqnum); // Insert seqnum req->r_gss_argoff = nfsm_chain_offset(nmc); // Offset to args nfsm_chain_build_done(error, nmc); if (error) return (error); nfs_gss_append_chain(nmc, args); // Append the args mbufs /* Now compute a checksum over the seqnum + args */ nfs_gss_cksum_chain(cp->gss_clnt_sched, nmc, krb5_mic, start, len, cksum); /* Insert it into a token and append to the request */ toklen = nfs_gss_token_put(cp->gss_clnt_sched, krb5_mic, tokbuf, 1, 0, cksum); nfsm_chain_finish_mbuf(error, nmc); // force checksum into new mbuf nfsm_chain_add_32(error, nmc, toklen); nfsm_chain_add_opaque(error, nmc, tokbuf, toklen); nfsm_chain_build_done(error, nmc); break; case RPCSEC_GSS_SVC_PRIVACY: /* Prepend a new mbuf with the confounder & sequence number */ nfsm_chain_build_alloc_init(error, &nmc_tmp, 3 * NFSX_UNSIGNED); nfsm_chain_add_32(error, &nmc_tmp, random()); // confounder bytes 1-4 nfsm_chain_add_32(error, &nmc_tmp, random()); // confounder bytes 4-8 nfsm_chain_add_32(error, &nmc_tmp, seqnum); nfsm_chain_build_done(error, &nmc_tmp); if (error) return (error); nfs_gss_append_chain(&nmc_tmp, args); // Append the args mbufs len = nfs_gss_mchain_length(args); // Find args length len += 3 * NFSX_UNSIGNED; // add confounder & seqnum req->r_gss_arglen = len; // Stash length /* * Append a pad trailer - per RFC 1964 section 1.2.2.3 * Since XDR data is always 32-bit aligned, it * needs to be padded either by 4 bytes or 8 bytes. */ nfsm_chain_finish_mbuf(error, &nmc_tmp); // force padding into new mbuf if (len % 8 > 0) { nfsm_chain_add_32(error, &nmc_tmp, 0x04040404); len += NFSX_UNSIGNED; } else { nfsm_chain_add_32(error, &nmc_tmp, 0x08080808); nfsm_chain_add_32(error, &nmc_tmp, 0x08080808); len += 2 * NFSX_UNSIGNED; } nfsm_chain_build_done(error, &nmc_tmp); /* Now compute a checksum over the confounder + seqnum + args */ nfs_gss_cksum_chain(cp->gss_clnt_sched, &nmc_tmp, krb5_wrap, 0, len, cksum); /* Insert it into a token */ toklen = nfs_gss_token_put(cp->gss_clnt_sched, krb5_wrap, tokbuf, 1, len, cksum); nfsm_chain_add_32(error, nmc, toklen + len); // token + args length nfsm_chain_add_opaque_nopad(error, nmc, tokbuf, toklen); req->r_gss_argoff = nfsm_chain_offset(nmc); // Stash offset nfsm_chain_build_done(error, nmc); if (error) return (error); nfs_gss_append_chain(nmc, nmc_tmp.nmc_mhead); // Append the args mbufs /* Finally, encrypt the args */ nfs_gss_encrypt_chain(cp->gss_clnt_skey, &nmc_tmp, 0, len, DES_ENCRYPT); /* Add null XDR pad if the ASN.1 token misaligned the data */ pad = nfsm_pad(toklen + len); if (pad > 0) { nfsm_chain_add_opaque_nopad(error, nmc, iv0, pad); nfsm_chain_build_done(error, nmc); } break; } return (error); } /* * When receiving a reply, the client checks the verifier * returned by the server. Check that the verifier is the * correct type, then extract the sequence number checksum * from the token in the credential and compare it with a * computed checksum of the sequence number in the request * that was sent. */ int nfs_gss_clnt_verf_get( struct nfsreq *req, struct nfsm_chain *nmc, uint32_t verftype, uint32_t verflen, uint32_t *accepted_statusp) { u_char tokbuf[KRB5_SZ_TOKMAX]; u_char cksum1[8], cksum2[8]; uint32_t seqnum = 0; struct nfs_gss_clnt_ctx *cp = req->r_gss_ctx; struct nfsm_chain nmc_tmp; struct gss_seq *gsp; uint32_t reslen, start, cksumlen, toklen; int error = 0; reslen = cksumlen = 0; *accepted_statusp = 0; if (cp == NULL) return (EAUTH); /* * If it's not an RPCSEC_GSS verifier, then it has to * be a null verifier that resulted from either * a CONTINUE_NEEDED reply during context setup or * from the reply to an AUTH_UNIX call from a dummy * context that resulted from a fallback to sec=sys. */ if (verftype != RPCSEC_GSS) { if (verftype != RPCAUTH_NULL) return (EAUTH); if (cp->gss_clnt_flags & GSS_CTX_COMPLETE && cp->gss_clnt_service != RPCSEC_GSS_SVC_SYS) return (EAUTH); if (verflen > 0) nfsm_chain_adv(error, nmc, nfsm_rndup(verflen)); nfsm_chain_get_32(error, nmc, *accepted_statusp); return (error); } if (verflen != KRB5_SZ_TOKEN) return (EAUTH); /* * If we received an RPCSEC_GSS verifier but the * context isn't yet complete, then it must be * the context complete message from the server. * The verifier will contain an encrypted checksum * of the window but we don't have the session key * yet so we can't decrypt it. Stash the verifier * and check it later in nfs_gss_clnt_ctx_init() when * the context is complete. */ if (!(cp->gss_clnt_flags & GSS_CTX_COMPLETE)) { MALLOC(cp->gss_clnt_verf, u_char *, verflen, M_TEMP, M_WAITOK|M_ZERO); if (cp->gss_clnt_verf == NULL) return (ENOMEM); nfsm_chain_get_opaque(error, nmc, verflen, cp->gss_clnt_verf); nfsm_chain_get_32(error, nmc, *accepted_statusp); return (error); } /* * Get the 8 octet sequence number * checksum out of the verifier token. */ nfsm_chain_get_opaque(error, nmc, verflen, tokbuf); if (error) goto nfsmout; error = nfs_gss_token_get(cp->gss_clnt_sched, krb5_mic, tokbuf, 0, NULL, cksum1); if (error) goto nfsmout; /* * Search the request sequence numbers for this reply, starting * with the most recent, looking for a checksum that matches * the one in the verifier returned by the server. */ SLIST_FOREACH(gsp, &req->r_gss_seqlist, gss_seqnext) { nfs_gss_cksum_rep(cp->gss_clnt_sched, gsp->gss_seqnum, cksum2); if (bcmp(cksum1, cksum2, 8) == 0) break; } if (gsp == NULL) return (EAUTH); /* * Get the RPC accepted status */ nfsm_chain_get_32(error, nmc, *accepted_statusp); if (*accepted_statusp != RPC_SUCCESS) return (0); /* * Now we may have to check integrity or decrypt the results * per RFC 2203 Section 5.3.2 */ switch (cp->gss_clnt_service) { case RPCSEC_GSS_SVC_NONE: /* nothing to do */ break; case RPCSEC_GSS_SVC_INTEGRITY: /* * Here's what we expect in the integrity results: * * - length of seq num + results (4 bytes) * - sequence number (4 bytes) * - results (variable bytes) * - length of checksum token (37) * - checksum of seqnum + results (37 bytes) */ nfsm_chain_get_32(error, nmc, reslen); // length of results if (reslen > NFS_MAXPACKET) { error = EBADRPC; goto nfsmout; } /* Compute a checksum over the sequence number + results */ start = nfsm_chain_offset(nmc); nfs_gss_cksum_chain(cp->gss_clnt_sched, nmc, krb5_mic, start, reslen, cksum1); /* * Get the sequence number prepended to the results * and compare it against the list in the request. */ nfsm_chain_get_32(error, nmc, seqnum); SLIST_FOREACH(gsp, &req->r_gss_seqlist, gss_seqnext) { if (seqnum == gsp->gss_seqnum) break; } if (gsp == NULL) { error = EBADRPC; goto nfsmout; } /* * Advance to the end of the results and * fetch the checksum computed by the server. */ nmc_tmp = *nmc; reslen -= NFSX_UNSIGNED; // already skipped seqnum nfsm_chain_adv(error, &nmc_tmp, reslen); // skip over the results nfsm_chain_get_32(error, &nmc_tmp, cksumlen); // length of checksum if (cksumlen != KRB5_SZ_TOKEN) { error = EBADRPC; goto nfsmout; } nfsm_chain_get_opaque(error, &nmc_tmp, cksumlen, tokbuf); if (error) goto nfsmout; error = nfs_gss_token_get(cp->gss_clnt_sched, krb5_mic, tokbuf, 0, NULL, cksum2); if (error) goto nfsmout; /* Verify that the checksums are the same */ if (bcmp(cksum1, cksum2, 8) != 0) { error = EBADRPC; goto nfsmout; } break; case RPCSEC_GSS_SVC_PRIVACY: /* * Here's what we expect in the privacy results: * * - length of confounder + seq num + token + results * - wrap token (37-40 bytes) * - confounder (8 bytes) * - sequence number (4 bytes) * - results (encrypted) */ nfsm_chain_get_32(error, nmc, reslen); // length of results if (reslen > NFS_MAXPACKET) { error = EBADRPC; goto nfsmout; } /* Get the token that prepends the encrypted results */ nfsm_chain_get_opaque(error, nmc, KRB5_SZ_TOKMAX, tokbuf); if (error) goto nfsmout; error = nfs_gss_token_get(cp->gss_clnt_sched, krb5_wrap, tokbuf, 0, &toklen, cksum1); if (error) goto nfsmout; nfsm_chain_reverse(nmc, nfsm_pad(toklen)); reslen -= toklen; // size of confounder + seqnum + results /* decrypt the confounder + sequence number + results */ start = nfsm_chain_offset(nmc); nfs_gss_encrypt_chain(cp->gss_clnt_skey, nmc, start, reslen, DES_DECRYPT); /* Compute a checksum over the confounder + sequence number + results */ nfs_gss_cksum_chain(cp->gss_clnt_sched, nmc, krb5_wrap, start, reslen, cksum2); /* Verify that the checksums are the same */ if (bcmp(cksum1, cksum2, 8) != 0) { error = EBADRPC; goto nfsmout; } nfsm_chain_adv(error, nmc, 8); // skip over the confounder /* * Get the sequence number prepended to the results * and compare it against the list in the request. */ nfsm_chain_get_32(error, nmc, seqnum); SLIST_FOREACH(gsp, &req->r_gss_seqlist, gss_seqnext) { if (seqnum == gsp->gss_seqnum) break; } if (gsp == NULL) { error = EBADRPC; goto nfsmout; } break; } nfsmout: return (error); } /* * An RPCSEC_GSS request with no integrity or privacy consists * of just the header mbufs followed by the arg mbufs. * * However, integrity or privacy both trailer mbufs to the args, * which means we have to do some work to restore the arg mbuf * chain to its previous state in case we need to retransmit. * * The location and length of the args is marked by two fields * in the request structure: r_gss_argoff and r_gss_arglen, * which are stashed when the NFS request is built. */ int nfs_gss_clnt_args_restore(struct nfsreq *req) { struct nfs_gss_clnt_ctx *cp = req->r_gss_ctx; struct nfsm_chain mchain, *nmc = &mchain; int len, error = 0; if (cp == NULL) return (EAUTH); if ((cp->gss_clnt_flags & GSS_CTX_COMPLETE) == 0) return (ENEEDAUTH); nfsm_chain_dissect_init(error, nmc, req->r_mhead); // start at RPC header nfsm_chain_adv(error, nmc, req->r_gss_argoff); // advance to args if (error) return (error); switch (cp->gss_clnt_service) { case RPCSEC_GSS_SVC_NONE: /* nothing to do */ break; case RPCSEC_GSS_SVC_INTEGRITY: /* * All we have to do here is remove the appended checksum mbufs. * We know that the checksum starts in a new mbuf beyond the end * of the args. */ nfsm_chain_adv(error, nmc, req->r_gss_arglen); // adv to last args mbuf if (error) return (error); mbuf_freem(mbuf_next(nmc->nmc_mcur)); // free the cksum mbuf error = mbuf_setnext(nmc->nmc_mcur, NULL); break; case RPCSEC_GSS_SVC_PRIVACY: /* * The args are encrypted along with prepended confounders and seqnum. * First we decrypt, the confounder, seqnum and args then skip to the * final mbuf of the args. * The arglen includes 8 bytes of confounder and 4 bytes of seqnum. * Finally, we remove between 4 and 8 bytes of encryption padding * as well as any alignment padding in the trailing mbuf. */ len = req->r_gss_arglen; len += len % 8 > 0 ? 4 : 8; // add DES padding length nfs_gss_encrypt_chain(cp->gss_clnt_skey, nmc, req->r_gss_argoff, len, DES_DECRYPT); nfsm_chain_adv(error, nmc, req->r_gss_arglen); if (error) return (error); mbuf_freem(mbuf_next(nmc->nmc_mcur)); // free the pad mbuf error = mbuf_setnext(nmc->nmc_mcur, NULL); break; } return (error); } /* * This function sets up a new context on the client. * Context setup alternates upcalls to the gssd with NFS nullproc calls * to the server. Each of these calls exchanges an opaque token, obtained * via the gssd's calls into the GSS-API on either the client or the server. * This cycle of calls ends when the client's upcall to the gssd and the * server's response both return GSS_S_COMPLETE. At this point, the client * should have its session key and a handle that it can use to refer to its * new context on the server. */ static int nfs_gss_clnt_ctx_init(struct nfsreq *req, struct nfs_gss_clnt_ctx *cp) { struct nfsmount *nmp = req->r_nmp; int client_complete = 0; int server_complete = 0; u_char cksum1[8], cksum2[8]; int error = 0; struct timeval now; /* Initialize a new client context */ cp->gss_clnt_svcname = nfs_gss_clnt_svcname(nmp); if (cp->gss_clnt_svcname == NULL) { error = EAUTH; goto nfsmout; } cp->gss_clnt_proc = RPCSEC_GSS_INIT; cp->gss_clnt_service = nmp->nm_auth == RPCAUTH_KRB5 ? RPCSEC_GSS_SVC_NONE : nmp->nm_auth == RPCAUTH_KRB5I ? RPCSEC_GSS_SVC_INTEGRITY : nmp->nm_auth == RPCAUTH_KRB5P ? RPCSEC_GSS_SVC_PRIVACY : 0; /* * Now loop around alternating gss_init_sec_context and * gss_accept_sec_context upcalls to the gssd on the client * and server side until the context is complete - or fails. */ for (;;) { /* Upcall to the gss_init_sec_context in the gssd */ error = nfs_gss_clnt_gssd_upcall(req, cp); if (error) goto nfsmout; if (cp->gss_clnt_major == GSS_S_COMPLETE) { client_complete = 1; if (server_complete) break; } else if (cp->gss_clnt_major != GSS_S_CONTINUE_NEEDED) { error = EAUTH; goto nfsmout; } /* * Pass the token to the server. */ error = nfs_gss_clnt_ctx_callserver(req, cp); if (error) goto nfsmout; if (cp->gss_clnt_major == GSS_S_COMPLETE) { server_complete = 1; if (client_complete) break; } else if (cp->gss_clnt_major != GSS_S_CONTINUE_NEEDED) { error = EAUTH; goto nfsmout; } cp->gss_clnt_proc = RPCSEC_GSS_CONTINUE_INIT; } /* * The context is apparently established successfully */ cp->gss_clnt_flags |= GSS_CTX_COMPLETE; cp->gss_clnt_proc = RPCSEC_GSS_DATA; microuptime(&now); cp->gss_clnt_ctime = now.tv_sec; // time stamp /* * Construct a key schedule from our shiny new session key */ error = des_key_sched((des_cblock *) cp->gss_clnt_skey, cp->gss_clnt_sched); if (error) { error = EAUTH; goto nfsmout; } /* * Compute checksum of the server's window */ nfs_gss_cksum_rep(cp->gss_clnt_sched, cp->gss_clnt_seqwin, cksum1); /* * and see if it matches the one in the * verifier the server returned. */ error = nfs_gss_token_get(cp->gss_clnt_sched, krb5_mic, cp->gss_clnt_verf, 0, NULL, cksum2); FREE(cp->gss_clnt_verf, M_TEMP); cp->gss_clnt_verf = NULL; if (error || bcmp(cksum1, cksum2, 8) != 0) { error = EAUTH; goto nfsmout; } /* * Set an initial sequence number somewhat randomized. * Start small so we don't overflow GSS_MAXSEQ too quickly. * Add the size of the sequence window so seqbits arithmetic * doesn't go negative. */ cp->gss_clnt_seqnum = (random() & 0xffff) + cp->gss_clnt_seqwin; /* * Allocate a bitmap to keep track of which requests * are pending within the sequence number window. */ MALLOC(cp->gss_clnt_seqbits, uint32_t *, nfsm_rndup((cp->gss_clnt_seqwin + 7) / 8), M_TEMP, M_WAITOK|M_ZERO); if (cp->gss_clnt_seqbits == NULL) error = EAUTH; nfsmout: /* * If there's an error, just mark it as invalid. * It will be removed when the reference count * drops to zero. */ if (error) cp->gss_clnt_flags |= GSS_CTX_INVAL; /* * Wake any threads waiting to use the context */ lck_mtx_lock(cp->gss_clnt_mtx); cp->gss_clnt_thread = NULL; if (cp->gss_clnt_flags & GSS_NEEDCTX) { cp->gss_clnt_flags &= ~GSS_NEEDCTX; wakeup(cp); } lck_mtx_unlock(cp->gss_clnt_mtx); return (error); } /* * Call the NFS server using a null procedure for context setup. * Even though it's a null procedure and nominally has no arguments * RFC 2203 requires that the GSS-API token be passed as an argument * and received as a reply. */ static int nfs_gss_clnt_ctx_callserver(struct nfsreq *req, struct nfs_gss_clnt_ctx *cp) { struct nfsmount *nmp = req->r_nmp; struct nfsm_chain nmreq, nmrep; int error = 0, status; u_int64_t xid; int sz; nfsm_chain_null(&nmreq); nfsm_chain_null(&nmrep); sz = NFSX_UNSIGNED + nfsm_rndup(cp->gss_clnt_tokenlen); nfsm_chain_build_alloc_init(error, &nmreq, sz); nfsm_chain_add_32(error, &nmreq, cp->gss_clnt_tokenlen); nfsm_chain_add_opaque(error, &nmreq, cp->gss_clnt_token, cp->gss_clnt_tokenlen); nfsm_chain_build_done(error, &nmreq); if (error) goto nfsmout; /* Call the server */ error = nfs_request2(NULL, nmp->nm_mountp, &nmreq, NFSPROC_NULL, req->r_thread, req->r_cred, 0, &nmrep, &xid, &status); if (cp->gss_clnt_token != NULL) { FREE(cp->gss_clnt_token, M_TEMP); cp->gss_clnt_token = NULL; } if (!error) error = status; if (error) goto nfsmout; /* Get the server's reply */ nfsm_chain_get_32(error, &nmrep, cp->gss_clnt_handle_len); if (cp->gss_clnt_handle != NULL) FREE(cp->gss_clnt_handle, M_TEMP); if (cp->gss_clnt_handle_len > 0) { MALLOC(cp->gss_clnt_handle, u_char *, cp->gss_clnt_handle_len, M_TEMP, M_WAITOK); if (cp->gss_clnt_handle == NULL) { error = ENOMEM; goto nfsmout; } nfsm_chain_get_opaque(error, &nmrep, cp->gss_clnt_handle_len, cp->gss_clnt_handle); } nfsm_chain_get_32(error, &nmrep, cp->gss_clnt_major); nfsm_chain_get_32(error, &nmrep, cp->gss_clnt_minor); nfsm_chain_get_32(error, &nmrep, cp->gss_clnt_seqwin); nfsm_chain_get_32(error, &nmrep, cp->gss_clnt_tokenlen); if (error) goto nfsmout; if (cp->gss_clnt_tokenlen > 0) { MALLOC(cp->gss_clnt_token, u_char *, cp->gss_clnt_tokenlen, M_TEMP, M_WAITOK); if (cp->gss_clnt_token == NULL) { error = ENOMEM; goto nfsmout; } nfsm_chain_get_opaque(error, &nmrep, cp->gss_clnt_tokenlen, cp->gss_clnt_token); } /* * Make sure any unusual errors are expanded and logged by gssd */ if (cp->gss_clnt_major != GSS_S_COMPLETE && cp->gss_clnt_major != GSS_S_CONTINUE_NEEDED) { char who[] = "server"; (void) mach_gss_log_error( cp->gss_clnt_mport, vfs_statfs(nmp->nm_mountp)->f_mntfromname, cp->gss_clnt_uid, who, cp->gss_clnt_major, cp->gss_clnt_minor); } nfsmout: nfsm_chain_cleanup(&nmreq); nfsm_chain_cleanup(&nmrep); return (error); } /* * Ugly hack to get the service principal from the f_mntfromname field in * the statfs struct. We assume a format of server:path. We don't currently * support url's or other bizarre formats like path@server. A better solution * here might be to allow passing the service principal down in the mount args. * For kerberos we just use the default realm. */ static char * nfs_gss_clnt_svcname(struct nfsmount *nmp) { char *svcname, *d; char* mntfromhere = &vfs_statfs(nmp->nm_mountp)->f_mntfromname[0]; int len; len = strlen(mntfromhere) + 5; /* "nfs/" plus null */ MALLOC(svcname, char *, len, M_TEMP, M_NOWAIT); if (svcname == NULL) return (NULL); strlcpy(svcname, "nfs/", len); strlcat(svcname, mntfromhere, len); d = strchr(svcname, ':'); if (d) *d = '\0'; return (svcname); } /* * Make an upcall to the gssd using Mach RPC * The upcall is made using a task special port. * This allows launchd to fire up the gssd in the * user's session. This is important, since gssd * must have access to the user's credential cache. */ static int nfs_gss_clnt_gssd_upcall(struct nfsreq *req, struct nfs_gss_clnt_ctx *cp) { kern_return_t kr; byte_buffer okey = NULL; uint32_t skeylen = 0; int retry_cnt = 0; vm_map_copy_t itoken = NULL; byte_buffer otoken = NULL; int error = 0; char uprinc[1]; /* * NFS currently only supports default principals or * principals based on the uid of the caller. * * N.B. Note we define a one character array for the principal * so that we can hold an empty string required by mach, since * the kernel is being compiled with -Wwrite-strings. */ uprinc[0] = '\0'; if (cp->gss_clnt_mport == NULL) { kr = task_get_gssd_port(get_threadtask(req->r_thread), &cp->gss_clnt_mport); if (kr != KERN_SUCCESS) { printf("nfs_gss_clnt_gssd_upcall: can't get gssd port, status %d\n", kr); return (EAUTH); } if (!IPC_PORT_VALID(cp->gss_clnt_mport)) { printf("nfs_gss_clnt_gssd_upcall: gssd port not valid\n"); cp->gss_clnt_mport = NULL; return (EAUTH); } } if (cp->gss_clnt_tokenlen > 0) nfs_gss_mach_alloc_buffer(cp->gss_clnt_token, cp->gss_clnt_tokenlen, &itoken); retry: kr = mach_gss_init_sec_context( cp->gss_clnt_mport, KRB5_MECH, (byte_buffer) itoken, (mach_msg_type_number_t) cp->gss_clnt_tokenlen, cp->gss_clnt_uid, uprinc, cp->gss_clnt_svcname, GSSD_MUTUAL_FLAG | GSSD_NO_UI, &cp->gss_clnt_gssd_verf, &cp->gss_clnt_context, &cp->gss_clnt_cred_handle, &okey, (mach_msg_type_number_t *) &skeylen, &otoken, (mach_msg_type_number_t *) &cp->gss_clnt_tokenlen, &cp->gss_clnt_major, &cp->gss_clnt_minor); if (kr != 0) { printf("nfs_gss_clnt_gssd_upcall: mach_gss_init_sec_context failed: %x\n", kr); if (kr == MIG_SERVER_DIED && cp->gss_clnt_cred_handle == 0 && retry_cnt++ < NFS_GSS_MACH_MAX_RETRIES) goto retry; task_release_special_port(cp->gss_clnt_mport); cp->gss_clnt_mport = NULL; return (EAUTH); } /* * Make sure any unusual errors are expanded and logged by gssd */ if (cp->gss_clnt_major != GSS_S_COMPLETE && cp->gss_clnt_major != GSS_S_CONTINUE_NEEDED) { char who[] = "client"; (void) mach_gss_log_error( cp->gss_clnt_mport, vfs_statfs(req->r_nmp->nm_mountp)->f_mntfromname, cp->gss_clnt_uid, who, cp->gss_clnt_major, cp->gss_clnt_minor); } if (skeylen > 0) { if (skeylen != SKEYLEN) { printf("nfs_gss_clnt_gssd_upcall: bad key length (%d)\n", skeylen); return (EAUTH); } error = nfs_gss_mach_vmcopyout((vm_map_copy_t) okey, skeylen, cp->gss_clnt_skey); if (error) return (EAUTH); } if (cp->gss_clnt_tokenlen > 0) { MALLOC(cp->gss_clnt_token, u_char *, cp->gss_clnt_tokenlen, M_TEMP, M_WAITOK); if (cp->gss_clnt_token == NULL) return (ENOMEM); error = nfs_gss_mach_vmcopyout((vm_map_copy_t) otoken, cp->gss_clnt_tokenlen, cp->gss_clnt_token); if (error) return (EAUTH); } return (0); } /* * Invoked at the completion of an RPC call that uses an RPCSEC_GSS * credential. The sequence number window that the server returns * at context setup indicates the maximum number of client calls that * can be outstanding on a context. The client maintains a bitmap that * represents the server's window. Each pending request has a bit set * in the window bitmap. When a reply comes in or times out, we reset * the bit in the bitmap and if there are any other threads waiting for * a context slot we notify the waiting thread(s). * * Note that if a request is retransmitted, it will have a single XID * but it may be associated with multiple sequence numbers. So we * may have to reset multiple sequence number bits in the window bitmap. */ void nfs_gss_clnt_rpcdone(struct nfsreq *req) { struct nfs_gss_clnt_ctx *cp = req->r_gss_ctx; struct gss_seq *gsp, *ngsp; int i = 0; if (cp == NULL || !(cp->gss_clnt_flags & GSS_CTX_COMPLETE)) return; // no context - don't bother /* * Reset the bit for this request in the * sequence number window to indicate it's done. * We do this even if the request timed out. */ lck_mtx_lock(cp->gss_clnt_mtx); gsp = SLIST_FIRST(&req->r_gss_seqlist); if (gsp && gsp->gss_seqnum > (cp->gss_clnt_seqnum - cp->gss_clnt_seqwin)) win_resetbit(cp->gss_clnt_seqbits, gsp->gss_seqnum % cp->gss_clnt_seqwin); /* * Limit the seqnum list to GSS_CLNT_SEQLISTMAX entries */ SLIST_FOREACH_SAFE(gsp, &req->r_gss_seqlist, gss_seqnext, ngsp) { if (++i > GSS_CLNT_SEQLISTMAX) { SLIST_REMOVE(&req->r_gss_seqlist, gsp, gss_seq, gss_seqnext); FREE(gsp, M_TEMP); } } /* * If there's a thread waiting for * the window to advance, wake it up. */ if (cp->gss_clnt_flags & GSS_NEEDSEQ) { cp->gss_clnt_flags &= ~GSS_NEEDSEQ; wakeup(cp); } lck_mtx_unlock(cp->gss_clnt_mtx); } /* * Create a reference to a context from a request * and bump the reference count */ void nfs_gss_clnt_ctx_ref(struct nfsreq *req, struct nfs_gss_clnt_ctx *cp) { req->r_gss_ctx = cp; lck_mtx_lock(cp->gss_clnt_mtx); cp->gss_clnt_refcnt++; lck_mtx_unlock(cp->gss_clnt_mtx); } /* * Remove a context reference from a request * If the reference count drops to zero, and the * context is invalid, destroy the context */ void nfs_gss_clnt_ctx_unref(struct nfsreq *req) { struct nfsmount *nmp = req->r_nmp; struct nfs_gss_clnt_ctx *cp = req->r_gss_ctx; if (cp == NULL) return; req->r_gss_ctx = NULL; lck_mtx_lock(cp->gss_clnt_mtx); if (--cp->gss_clnt_refcnt == 0 && cp->gss_clnt_flags & GSS_CTX_INVAL) { lck_mtx_unlock(cp->gss_clnt_mtx); if (nmp) lck_mtx_lock(&nmp->nm_lock); nfs_gss_clnt_ctx_remove(nmp, cp); if (nmp) lck_mtx_unlock(&nmp->nm_lock); return; } lck_mtx_unlock(cp->gss_clnt_mtx); } /* * Remove a context */ static void nfs_gss_clnt_ctx_remove(struct nfsmount *nmp, struct nfs_gss_clnt_ctx *cp) { /* * If dequeueing, assume nmp->nm_lock is held */ if (nmp != NULL) TAILQ_REMOVE(&nmp->nm_gsscl, cp, gss_clnt_entries); if (cp->gss_clnt_mport) task_release_special_port(cp->gss_clnt_mport); if (cp->gss_clnt_mtx) lck_mtx_destroy(cp->gss_clnt_mtx, nfs_gss_clnt_grp); if (cp->gss_clnt_handle) FREE(cp->gss_clnt_handle, M_TEMP); if (cp->gss_clnt_seqbits) FREE(cp->gss_clnt_seqbits, M_TEMP); if (cp->gss_clnt_token) FREE(cp->gss_clnt_token, M_TEMP); if (cp->gss_clnt_svcname) FREE(cp->gss_clnt_svcname, M_TEMP); FREE(cp, M_TEMP); } /* * The context for a user is invalid. * Mark the context as invalid, then * create a new context. */ int nfs_gss_clnt_ctx_renew(struct nfsreq *req) { struct nfs_gss_clnt_ctx *cp = req->r_gss_ctx; struct nfsmount *nmp = req->r_nmp; struct nfs_gss_clnt_ctx *ncp; int error = 0; uid_t saved_uid; mach_port_t saved_mport; int retrycnt = 0; if (cp == NULL || !(cp->gss_clnt_flags & GSS_CTX_COMPLETE)) return (0); lck_mtx_lock(cp->gss_clnt_mtx); if (cp->gss_clnt_flags & GSS_CTX_INVAL) { lck_mtx_unlock(cp->gss_clnt_mtx); nfs_gss_clnt_ctx_unref(req); return (0); // already being renewed } saved_uid = cp->gss_clnt_uid; saved_mport = task_copy_special_port(cp->gss_clnt_mport); /* Remove the old context */ lck_mtx_lock(&nmp->nm_lock); cp->gss_clnt_flags |= GSS_CTX_INVAL; lck_mtx_unlock(&nmp->nm_lock); /* * If there's a thread waiting * in the old context, wake it up. */ if (cp->gss_clnt_flags & (GSS_NEEDCTX | GSS_NEEDSEQ)) { cp->gss_clnt_flags &= ~GSS_NEEDSEQ; wakeup(cp); } lck_mtx_unlock(cp->gss_clnt_mtx); retry: /* * Create a new context */ MALLOC(ncp, struct nfs_gss_clnt_ctx *, sizeof(*ncp), M_TEMP, M_WAITOK|M_ZERO); if (ncp == NULL) { return (ENOMEM); } ncp->gss_clnt_uid = saved_uid; ncp->gss_clnt_mport = task_copy_special_port(saved_mport); // re-use the gssd port ncp->gss_clnt_mtx = lck_mtx_alloc_init(nfs_gss_clnt_grp, LCK_ATTR_NULL); ncp->gss_clnt_thread = current_thread(); lck_mtx_lock(&nmp->nm_lock); TAILQ_INSERT_TAIL(&nmp->nm_gsscl, ncp, gss_clnt_entries); lck_mtx_unlock(&nmp->nm_lock); /* Adjust reference counts to new and old context */ nfs_gss_clnt_ctx_unref(req); nfs_gss_clnt_ctx_ref(req, ncp); error = nfs_gss_clnt_ctx_init(req, ncp); // Initialize new context if (error == ENEEDAUTH) { error = nfs_gss_clnt_ctx_delay(req, &retrycnt); if (!error) goto retry; } task_release_special_port(saved_mport); if (error) nfs_gss_clnt_ctx_unref(req); return (error); } /* * Destroy all the contexts associated with a mount. * The contexts are also destroyed by the server. */ void nfs_gss_clnt_ctx_unmount(struct nfsmount *nmp, int mntflags) { struct nfs_gss_clnt_ctx *cp; struct ucred temp_cred; kauth_cred_t cred; struct nfsm_chain nmreq, nmrep; u_int64_t xid; int error, status; struct nfsreq req; bzero((caddr_t) &temp_cred, sizeof(temp_cred)); temp_cred.cr_ngroups = 1; req.r_nmp = nmp; for (;;) { lck_mtx_lock(&nmp->nm_lock); cp = TAILQ_FIRST(&nmp->nm_gsscl); lck_mtx_unlock(&nmp->nm_lock); if (cp == NULL) break; nfs_gss_clnt_ctx_ref(&req, cp); /* * Tell the server to destroy its context. * But don't bother if it's a forced unmount * or if it's a dummy sec=sys context. */ if (!(mntflags & MNT_FORCE) && cp->gss_clnt_service != RPCSEC_GSS_SVC_SYS) { temp_cred.cr_uid = cp->gss_clnt_uid; cred = kauth_cred_create(&temp_cred); cp->gss_clnt_proc = RPCSEC_GSS_DESTROY; error = 0; nfsm_chain_null(&nmreq); nfsm_chain_null(&nmrep); nfsm_chain_build_alloc_init(error, &nmreq, 0); nfsm_chain_build_done(error, &nmreq); if (!error) nfs_request2(NULL, nmp->nm_mountp, &nmreq, NFSPROC_NULL, current_thread(), cred, 0, &nmrep, &xid, &status); nfsm_chain_cleanup(&nmreq); nfsm_chain_cleanup(&nmrep); kauth_cred_unref(&cred); } /* * Mark the context invalid then drop * the reference to remove it if its * refcount is zero. */ cp->gss_clnt_flags |= GSS_CTX_INVAL; nfs_gss_clnt_ctx_unref(&req); } } /* * If we get a failure in trying to establish a context we need to wait a * little while to see if the server is feeling better. In our case this is * probably a failure in directory services not coming up in a timely fashion. * This routine sort of mimics receiving a jukebox error. */ static int nfs_gss_clnt_ctx_delay(struct nfsreq *req, int *retry) { int timeo = (1 << *retry) * NFS_TRYLATERDEL; int error = 0; struct nfsmount *nmp = req->r_nmp; struct timeval now; time_t waituntil; if ((nmp->nm_flag & NFSMNT_SOFT) && *retry > nmp->nm_retry) return (ETIMEDOUT); if (timeo > 60) timeo = 60; microuptime(&now); waituntil = now.tv_sec + timeo; while (now.tv_sec < waituntil) { tsleep(&lbolt, PSOCK, "nfs_gss_clnt_ctx_delay", 0); error = nfs_sigintr(nmp, req, current_thread(), 0); if (error) break; microuptime(&now); } *retry += 1; return (error); } #endif /* NFSCLIENT */ /************* * * Server functions */ #if NFSSERVER /* * Find a server context based on a handle value received * in an RPCSEC_GSS credential. */ static struct nfs_gss_svc_ctx * nfs_gss_svc_ctx_find(uint32_t handle) { struct nfs_gss_svc_ctx_hashhead *head; struct nfs_gss_svc_ctx *cp; head = &nfs_gss_svc_ctx_hashtbl[SVC_CTX_HASH(handle)]; lck_mtx_lock(nfs_gss_svc_ctx_mutex); LIST_FOREACH(cp, head, gss_svc_entries) if (cp->gss_svc_handle == handle) break; lck_mtx_unlock(nfs_gss_svc_ctx_mutex); return (cp); } /* * Insert a new server context into the hash table * and start the context reap thread if necessary. */ static void nfs_gss_svc_ctx_insert(struct nfs_gss_svc_ctx *cp) { struct nfs_gss_svc_ctx_hashhead *head; head = &nfs_gss_svc_ctx_hashtbl[SVC_CTX_HASH(cp->gss_svc_handle)]; lck_mtx_lock(nfs_gss_svc_ctx_mutex); LIST_INSERT_HEAD(head, cp, gss_svc_entries); nfs_gss_ctx_count++; if (!nfs_gss_timer_on) { nfs_gss_timer_on = 1; nfs_interval_timer_start(nfs_gss_svc_ctx_timer_call, GSS_TIMER_PERIOD * MSECS_PER_SEC); } lck_mtx_unlock(nfs_gss_svc_ctx_mutex); } /* * This function is called via the kernel's callout * mechanism. It runs only when there are * cached RPCSEC_GSS contexts. */ void nfs_gss_svc_ctx_timer(__unused void *param1, __unused void *param2) { struct nfs_gss_svc_ctx_hashhead *head; struct nfs_gss_svc_ctx *cp, *next; uint64_t timenow; int contexts = 0; int i; lck_mtx_lock(nfs_gss_svc_ctx_mutex); clock_get_uptime(&timenow); /* * Scan all the hash chains * Assume nfs_gss_svc_ctx_mutex is held */ for (i = 0; i < SVC_CTX_HASHSZ; i++) { /* * For each hash chain, look for entries * that haven't been used in a while. */ head = &nfs_gss_svc_ctx_hashtbl[i]; for (cp = LIST_FIRST(head); cp; cp = next) { contexts++; next = LIST_NEXT(cp, gss_svc_entries); if (timenow > cp->gss_svc_expiretime) { /* * A stale context - remove it */ LIST_REMOVE(cp, gss_svc_entries); if (cp->gss_svc_seqbits) FREE(cp->gss_svc_seqbits, M_TEMP); lck_mtx_destroy(cp->gss_svc_mtx, nfs_gss_svc_grp); FREE(cp, M_TEMP); contexts--; } } } nfs_gss_ctx_count = contexts; /* * If there are still some cached contexts left, * set up another callout to check on them later. */ nfs_gss_timer_on = nfs_gss_ctx_count > 0; if (nfs_gss_timer_on) nfs_interval_timer_start(nfs_gss_svc_ctx_timer_call, GSS_TIMER_PERIOD * MSECS_PER_SEC); lck_mtx_unlock(nfs_gss_svc_ctx_mutex); } /* * Here the server receives an RPCSEC_GSS credential in an * RPC call header. First there's some checking to make sure * the credential is appropriate - whether the context is still * being set up, or is complete. Then we use the handle to find * the server's context and validate the verifier, which contains * a signed checksum of the RPC header. If the verifier checks * out, we extract the user's UID and groups from the context * and use it to set up a UNIX credential for the user's request. */ int nfs_gss_svc_cred_get(struct nfsrv_descript *nd, struct nfsm_chain *nmc) { uint32_t vers, proc, seqnum, service; uint32_t handle, handle_len; struct nfs_gss_svc_ctx *cp = NULL; uint32_t flavor = 0, verflen = 0; int error = 0; uint32_t arglen, start, toklen, cksumlen; u_char tokbuf[KRB5_SZ_TOKMAX]; u_char cksum1[8], cksum2[8]; struct nfsm_chain nmc_tmp; vers = proc = seqnum = service = handle_len = 0; arglen = cksumlen = 0; nfsm_chain_get_32(error, nmc, vers); if (vers != RPCSEC_GSS_VERS_1) { error = NFSERR_AUTHERR | AUTH_REJECTCRED; goto nfsmout; } nfsm_chain_get_32(error, nmc, proc); nfsm_chain_get_32(error, nmc, seqnum); nfsm_chain_get_32(error, nmc, service); nfsm_chain_get_32(error, nmc, handle_len); if (error) goto nfsmout; /* * Make sure context setup/destroy is being done with a nullproc */ if (proc != RPCSEC_GSS_DATA && nd->nd_procnum != NFSPROC_NULL) { error = NFSERR_AUTHERR | RPCSEC_GSS_CREDPROBLEM; goto nfsmout; } /* * If the sequence number is greater than the max * allowable, reject and have the client init a * new context. */ if (seqnum > GSS_MAXSEQ) { error = NFSERR_AUTHERR | RPCSEC_GSS_CTXPROBLEM; goto nfsmout; } nd->nd_sec = service == RPCSEC_GSS_SVC_NONE ? RPCAUTH_KRB5 : service == RPCSEC_GSS_SVC_INTEGRITY ? RPCAUTH_KRB5I : service == RPCSEC_GSS_SVC_PRIVACY ? RPCAUTH_KRB5P : 0; if (proc == RPCSEC_GSS_INIT) { /* * Limit the total number of contexts */ if (nfs_gss_ctx_count > nfs_gss_ctx_max) { error = NFSERR_AUTHERR | RPCSEC_GSS_CTXPROBLEM; goto nfsmout; } /* * Set up a new context */ MALLOC(cp, struct nfs_gss_svc_ctx *, sizeof(*cp), M_TEMP, M_WAITOK|M_ZERO); if (cp == NULL) { error = ENOMEM; goto nfsmout; } } else { /* * Use the handle to find the context */ if (handle_len != sizeof(handle)) { error = NFSERR_AUTHERR | RPCSEC_GSS_CREDPROBLEM; goto nfsmout; } nfsm_chain_get_32(error, nmc, handle); if (error) goto nfsmout; cp = nfs_gss_svc_ctx_find(handle); if (cp == NULL) { error = NFSERR_AUTHERR | RPCSEC_GSS_CTXPROBLEM; goto nfsmout; } } cp->gss_svc_proc = proc; if (proc == RPCSEC_GSS_DATA || proc == RPCSEC_GSS_DESTROY) { struct ucred temp_cred; if (cp->gss_svc_seqwin == 0) { /* * Context isn't complete */ error = NFSERR_AUTHERR | RPCSEC_GSS_CTXPROBLEM; goto nfsmout; } if (!nfs_gss_svc_seqnum_valid(cp, seqnum)) { /* * Sequence number is bad */ error = EINVAL; // drop the request goto nfsmout; } /* Now compute the client's call header checksum */ nfs_gss_cksum_chain(cp->gss_svc_sched, nmc, krb5_mic, 0, 0, cksum1); /* * Validate the verifier. * The verifier contains an encrypted checksum * of the call header from the XID up to and * including the credential. We compute the * checksum and compare it with what came in * the verifier. */ nfsm_chain_get_32(error, nmc, flavor); nfsm_chain_get_32(error, nmc, verflen); if (flavor != RPCSEC_GSS || verflen != KRB5_SZ_TOKEN) error = NFSERR_AUTHERR | AUTH_BADVERF; nfsm_chain_get_opaque(error, nmc, verflen, tokbuf); if (error) goto nfsmout; /* Get the checksum from the token inside the verifier */ error = nfs_gss_token_get(cp->gss_svc_sched, krb5_mic, tokbuf, 1, NULL, cksum2); if (error) goto nfsmout; if (bcmp(cksum1, cksum2, 8) != 0) { error = NFSERR_AUTHERR | RPCSEC_GSS_CTXPROBLEM; goto nfsmout; } nd->nd_gss_seqnum = seqnum; /* * Set up the user's cred */ bzero(&temp_cred, sizeof(temp_cred)); temp_cred.cr_uid = cp->gss_svc_uid; bcopy(cp->gss_svc_gids, temp_cred.cr_groups, sizeof(gid_t) * cp->gss_svc_ngroups); temp_cred.cr_ngroups = cp->gss_svc_ngroups; nd->nd_cr = kauth_cred_create(&temp_cred); if (nd->nd_cr == NULL) { error = ENOMEM; goto nfsmout; } clock_interval_to_deadline(GSS_CTX_EXPIRE, NSEC_PER_SEC, &cp->gss_svc_expiretime); /* * If the call arguments are integrity or privacy protected * then we need to check them here. */ switch (service) { case RPCSEC_GSS_SVC_NONE: /* nothing to do */ break; case RPCSEC_GSS_SVC_INTEGRITY: /* * Here's what we expect in the integrity call args: * * - length of seq num + call args (4 bytes) * - sequence number (4 bytes) * - call args (variable bytes) * - length of checksum token (37) * - checksum of seqnum + call args (37 bytes) */ nfsm_chain_get_32(error, nmc, arglen); // length of args if (arglen > NFS_MAXPACKET) { error = EBADRPC; goto nfsmout; } /* Compute the checksum over the call args */ start = nfsm_chain_offset(nmc); nfs_gss_cksum_chain(cp->gss_svc_sched, nmc, krb5_mic, start, arglen, cksum1); /* * Get the sequence number prepended to the args * and compare it against the one sent in the * call credential. */ nfsm_chain_get_32(error, nmc, seqnum); if (seqnum != nd->nd_gss_seqnum) { error = EBADRPC; // returns as GARBAGEARGS goto nfsmout; } /* * Advance to the end of the args and * fetch the checksum computed by the client. */ nmc_tmp = *nmc; arglen -= NFSX_UNSIGNED; // skipped seqnum nfsm_chain_adv(error, &nmc_tmp, arglen); // skip args nfsm_chain_get_32(error, &nmc_tmp, cksumlen); // length of checksum if (cksumlen != KRB5_SZ_TOKEN) { error = EBADRPC; goto nfsmout; } nfsm_chain_get_opaque(error, &nmc_tmp, cksumlen, tokbuf); if (error) goto nfsmout; error = nfs_gss_token_get(cp->gss_svc_sched, krb5_mic, tokbuf, 1, NULL, cksum2); /* Verify that the checksums are the same */ if (error || bcmp(cksum1, cksum2, 8) != 0) { error = EBADRPC; goto nfsmout; } break; case RPCSEC_GSS_SVC_PRIVACY: /* * Here's what we expect in the privacy call args: * * - length of confounder + seq num + token + call args * - wrap token (37-40 bytes) * - confounder (8 bytes) * - sequence number (4 bytes) * - call args (encrypted) */ nfsm_chain_get_32(error, nmc, arglen); // length of args if (arglen > NFS_MAXPACKET) { error = EBADRPC; goto nfsmout; } /* Get the token that prepends the encrypted args */ nfsm_chain_get_opaque(error, nmc, KRB5_SZ_TOKMAX, tokbuf); if (error) goto nfsmout; error = nfs_gss_token_get(cp->gss_svc_sched, krb5_wrap, tokbuf, 1, &toklen, cksum1); if (error) goto nfsmout; nfsm_chain_reverse(nmc, nfsm_pad(toklen)); /* decrypt the 8 byte confounder + seqnum + args */ start = nfsm_chain_offset(nmc); arglen -= toklen; nfs_gss_encrypt_chain(cp->gss_svc_skey, nmc, start, arglen, DES_DECRYPT); /* Compute a checksum over the sequence number + results */ nfs_gss_cksum_chain(cp->gss_svc_sched, nmc, krb5_wrap, start, arglen, cksum2); /* Verify that the checksums are the same */ if (bcmp(cksum1, cksum2, 8) != 0) { error = EBADRPC; goto nfsmout; } /* * Get the sequence number prepended to the args * and compare it against the one sent in the * call credential. */ nfsm_chain_adv(error, nmc, 8); // skip over the confounder nfsm_chain_get_32(error, nmc, seqnum); if (seqnum != nd->nd_gss_seqnum) { error = EBADRPC; // returns as GARBAGEARGS goto nfsmout; } break; } } else { /* * If the proc is RPCSEC_GSS_INIT or RPCSEC_GSS_CONTINUE_INIT * then we expect a null verifier. */ nfsm_chain_get_32(error, nmc, flavor); nfsm_chain_get_32(error, nmc, verflen); if (error || flavor != RPCAUTH_NULL || verflen > 0) error = NFSERR_AUTHERR | RPCSEC_GSS_CREDPROBLEM; if (error) goto nfsmout; } nd->nd_gss_context = cp; nfsmout: return (error); } /* * Insert the server's verifier into the RPC reply header. * It contains a signed checksum of the sequence number that * was received in the RPC call. * Then go on to add integrity or privacy if necessary. */ int nfs_gss_svc_verf_put(struct nfsrv_descript *nd, struct nfsm_chain *nmc) { struct nfs_gss_svc_ctx *cp; int error = 0; u_char tokbuf[KRB5_SZ_TOKEN]; int toklen; u_char cksum[8]; cp = nd->nd_gss_context; if (cp->gss_svc_major != GSS_S_COMPLETE) { /* * If the context isn't yet complete * then return a null verifier. */ nfsm_chain_add_32(error, nmc, RPCAUTH_NULL); nfsm_chain_add_32(error, nmc, 0); return (error); } /* * Compute checksum of the request seq number * If it's the final reply of context setup * then return the checksum of the context * window size. */ if (cp->gss_svc_proc == RPCSEC_GSS_INIT || cp->gss_svc_proc == RPCSEC_GSS_CONTINUE_INIT) nfs_gss_cksum_rep(cp->gss_svc_sched, cp->gss_svc_seqwin, cksum); else nfs_gss_cksum_rep(cp->gss_svc_sched, nd->nd_gss_seqnum, cksum); /* * Now wrap it in a token and add * the verifier to the reply. */ toklen = nfs_gss_token_put(cp->gss_svc_sched, krb5_mic, tokbuf, 0, 0, cksum); nfsm_chain_add_32(error, nmc, RPCSEC_GSS); nfsm_chain_add_32(error, nmc, toklen); nfsm_chain_add_opaque(error, nmc, tokbuf, toklen); return (error); } /* * The results aren't available yet, but if they need to be * checksummed for integrity protection or encrypted, then * we can record the start offset here, insert a place-holder * for the results length, as well as the sequence number. * The rest of the work is done later by nfs_gss_svc_protect_reply() * when the results are available. */ int nfs_gss_svc_prepare_reply(struct nfsrv_descript *nd, struct nfsm_chain *nmc) { struct nfs_gss_svc_ctx *cp = nd->nd_gss_context; int error = 0; if (cp->gss_svc_proc == RPCSEC_GSS_INIT || cp->gss_svc_proc == RPCSEC_GSS_CONTINUE_INIT) return (0); switch (nd->nd_sec) { case RPCAUTH_KRB5: /* Nothing to do */ break; case RPCAUTH_KRB5I: nd->nd_gss_mb = nmc->nmc_mcur; // record current mbuf nfsm_chain_finish_mbuf(error, nmc); // split the chain here nfsm_chain_add_32(error, nmc, nd->nd_gss_seqnum); // req sequence number break; case RPCAUTH_KRB5P: nd->nd_gss_mb = nmc->nmc_mcur; // record current mbuf nfsm_chain_finish_mbuf(error, nmc); // split the chain here nfsm_chain_add_32(error, nmc, random()); // confounder bytes 1-4 nfsm_chain_add_32(error, nmc, random()); // confounder bytes 5-8 nfsm_chain_add_32(error, nmc, nd->nd_gss_seqnum); // req sequence number break; } return (error); } /* * The results are checksummed or encrypted for return to the client */ int nfs_gss_svc_protect_reply(struct nfsrv_descript *nd, mbuf_t mrep) { struct nfs_gss_svc_ctx *cp = nd->nd_gss_context; struct nfsm_chain nmrep_res, *nmc_res = &nmrep_res; struct nfsm_chain nmrep_pre, *nmc_pre = &nmrep_pre; mbuf_t mb, results; uint32_t reslen; u_char tokbuf[KRB5_SZ_TOKMAX]; int pad, toklen; u_char cksum[8]; int error = 0; /* * Using a reference to the mbuf where we previously split the reply * mbuf chain, we split the mbuf chain argument into two mbuf chains, * one that allows us to prepend a length field or token, (nmc_pre) * and the second which holds just the results that we're going to * checksum and/or encrypt. When we're done, we join the chains back * together. */ nfs_gss_nfsm_chain(nmc_res, mrep); // set up the results chain mb = nd->nd_gss_mb; // the mbuf where we split results = mbuf_next(mb); // first mbuf in the results reslen = nfs_gss_mchain_length(results); // length of results error = mbuf_setnext(mb, NULL); // disconnect the chains if (error) return (error); nfs_gss_nfsm_chain(nmc_pre, mb); // set up the prepend chain if (nd->nd_sec == RPCAUTH_KRB5I) { nfsm_chain_add_32(error, nmc_pre, reslen); nfsm_chain_build_done(error, nmc_pre); if (error) return (error); nfs_gss_append_chain(nmc_pre, results); // Append the results mbufs /* Now compute the checksum over the results data */ nfs_gss_cksum_mchain(cp->gss_svc_sched, results, krb5_mic, 0, reslen, cksum); /* Put it into a token and append to the request */ toklen = nfs_gss_token_put(cp->gss_svc_sched, krb5_mic, tokbuf, 0, 0, cksum); nfsm_chain_add_32(error, nmc_res, toklen); nfsm_chain_add_opaque(error, nmc_res, tokbuf, toklen); nfsm_chain_build_done(error, nmc_res); } else { /* RPCAUTH_KRB5P */ /* * Append a pad trailer - per RFC 1964 section 1.2.2.3 * Since XDR data is always 32-bit aligned, it * needs to be padded either by 4 bytes or 8 bytes. */ if (reslen % 8 > 0) { nfsm_chain_add_32(error, nmc_res, 0x04040404); reslen += NFSX_UNSIGNED; } else { nfsm_chain_add_32(error, nmc_res, 0x08080808); nfsm_chain_add_32(error, nmc_res, 0x08080808); reslen += 2 * NFSX_UNSIGNED; } nfsm_chain_build_done(error, nmc_res); /* Now compute the checksum over the results data */ nfs_gss_cksum_mchain(cp->gss_svc_sched, results, krb5_wrap, 0, reslen, cksum); /* Put it into a token and insert in the reply */ toklen = nfs_gss_token_put(cp->gss_svc_sched, krb5_wrap, tokbuf, 0, reslen, cksum); nfsm_chain_add_32(error, nmc_pre, toklen + reslen); nfsm_chain_add_opaque_nopad(error, nmc_pre, tokbuf, toklen); nfsm_chain_build_done(error, nmc_pre); if (error) return (error); nfs_gss_append_chain(nmc_pre, results); // Append the results mbufs /* Encrypt the confounder + seqnum + results */ nfs_gss_encrypt_mchain(cp->gss_svc_skey, results, 0, reslen, DES_ENCRYPT); /* Add null XDR pad if the ASN.1 token misaligned the data */ pad = nfsm_pad(toklen + reslen); if (pad > 0) { nfsm_chain_add_opaque_nopad(error, nmc_pre, iv0, pad); nfsm_chain_build_done(error, nmc_pre); } } return (error); } /* * This function handles the context setup calls from the client. * Essentially, it implements the NFS null procedure calls when * an RPCSEC_GSS credential is used. * This is the context maintenance function. It creates and * destroys server contexts at the whim of the client. * During context creation, it receives GSS-API tokens from the * client, passes them up to gssd, and returns a received token * back to the client in the null procedure reply. */ int nfs_gss_svc_ctx_init(struct nfsrv_descript *nd, struct nfsrv_sock *slp, mbuf_t *mrepp) { struct nfs_gss_svc_ctx *cp = NULL; uint32_t handle = 0; int error = 0; int autherr = 0; struct nfsm_chain *nmreq, nmrep; int sz; nmreq = &nd->nd_nmreq; nfsm_chain_null(&nmrep); *mrepp = NULL; cp = nd->nd_gss_context; nd->nd_repstat = 0; switch (cp->gss_svc_proc) { case RPCSEC_GSS_INIT: /* * Give the client a random handle so that * if we reboot it's unlikely the client * will get a bad context match. * Make sure it's not zero, or already assigned. */ do { handle = random(); } while (nfs_gss_svc_ctx_find(handle) != NULL || handle == 0); cp->gss_svc_handle = handle; cp->gss_svc_mtx = lck_mtx_alloc_init(nfs_gss_svc_grp, LCK_ATTR_NULL); clock_interval_to_deadline(GSS_CTX_PEND, NSEC_PER_SEC, &cp->gss_svc_expiretime); nfs_gss_svc_ctx_insert(cp); /* FALLTHRU */ case RPCSEC_GSS_CONTINUE_INIT: /* Get the token from the request */ nfsm_chain_get_32(error, nmreq, cp->gss_svc_tokenlen); if (cp->gss_svc_tokenlen == 0) { autherr = RPCSEC_GSS_CREDPROBLEM; break; } MALLOC(cp->gss_svc_token, u_char *, cp->gss_svc_tokenlen, M_TEMP, M_WAITOK); if (cp->gss_svc_token == NULL) { autherr = RPCSEC_GSS_CREDPROBLEM; break; } nfsm_chain_get_opaque(error, nmreq, cp->gss_svc_tokenlen, cp->gss_svc_token); /* Use the token in a gss_accept_sec_context upcall */ error = nfs_gss_svc_gssd_upcall(cp); if (error) { autherr = RPCSEC_GSS_CREDPROBLEM; if (error == EAUTH) error = 0; break; } /* * If the context isn't complete, pass the new token * back to the client for another round. */ if (cp->gss_svc_major != GSS_S_COMPLETE) break; /* * Now the server context is complete. * Finish setup. */ clock_interval_to_deadline(GSS_CTX_EXPIRE, NSEC_PER_SEC, &cp->gss_svc_expiretime); cp->gss_svc_seqwin = GSS_SVC_SEQWINDOW; MALLOC(cp->gss_svc_seqbits, uint32_t *, nfsm_rndup((cp->gss_svc_seqwin + 7) / 8), M_TEMP, M_WAITOK|M_ZERO); if (cp->gss_svc_seqbits == NULL) { autherr = RPCSEC_GSS_CREDPROBLEM; break; } /* * Generate a key schedule from our shiny new DES key */ error = des_key_sched((des_cblock *) cp->gss_svc_skey, cp->gss_svc_sched); if (error) { autherr = RPCSEC_GSS_CREDPROBLEM; error = 0; break; } break; case RPCSEC_GSS_DATA: /* Just a nullproc ping - do nothing */ break; case RPCSEC_GSS_DESTROY: /* * Don't destroy the context immediately because * other active requests might still be using it. * Instead, schedule it for destruction after * GSS_CTX_PEND time has elapsed. */ cp = nfs_gss_svc_ctx_find(cp->gss_svc_handle); if (cp != NULL) { cp->gss_svc_handle = 0; // so it can't be found lck_mtx_lock(cp->gss_svc_mtx); clock_interval_to_deadline(GSS_CTX_PEND, NSEC_PER_SEC, &cp->gss_svc_expiretime); lck_mtx_unlock(cp->gss_svc_mtx); } break; default: autherr = RPCSEC_GSS_CREDPROBLEM; break; } /* Now build the reply */ if (nd->nd_repstat == 0) nd->nd_repstat = autherr ? (NFSERR_AUTHERR | autherr) : NFSERR_RETVOID; sz = 7 * NFSX_UNSIGNED + nfsm_rndup(cp->gss_svc_tokenlen); // size of results error = nfsrv_rephead(nd, slp, &nmrep, sz); *mrepp = nmrep.nmc_mhead; if (error || autherr) goto nfsmout; if (cp->gss_svc_proc == RPCSEC_GSS_INIT || cp->gss_svc_proc == RPCSEC_GSS_CONTINUE_INIT) { nfsm_chain_add_32(error, &nmrep, sizeof(cp->gss_svc_handle)); nfsm_chain_add_32(error, &nmrep, cp->gss_svc_handle); nfsm_chain_add_32(error, &nmrep, cp->gss_svc_major); nfsm_chain_add_32(error, &nmrep, cp->gss_svc_minor); nfsm_chain_add_32(error, &nmrep, cp->gss_svc_seqwin); nfsm_chain_add_32(error, &nmrep, cp->gss_svc_tokenlen); nfsm_chain_add_opaque(error, &nmrep, cp->gss_svc_token, cp->gss_svc_tokenlen); if (cp->gss_svc_token != NULL) { FREE(cp->gss_svc_token, M_TEMP); cp->gss_svc_token = NULL; } } nfsmout: if (autherr != 0) { LIST_REMOVE(cp, gss_svc_entries); if (cp->gss_svc_seqbits != NULL) FREE(cp->gss_svc_seqbits, M_TEMP); if (cp->gss_svc_token != NULL) FREE(cp->gss_svc_token, M_TEMP); lck_mtx_destroy(cp->gss_svc_mtx, nfs_gss_svc_grp); FREE(cp, M_TEMP); } nfsm_chain_build_done(error, &nmrep); if (error) { nfsm_chain_cleanup(&nmrep); *mrepp = NULL; } return (error); } /* * This is almost a mirror-image of the client side upcall. * It passes and receives a token, but invokes gss_accept_sec_context. * If it's the final call of the context setup, then gssd also returns * the session key and the user's UID. */ static int nfs_gss_svc_gssd_upcall(struct nfs_gss_svc_ctx *cp) { kern_return_t kr; mach_port_t mp; int retry_cnt = 0; byte_buffer okey = NULL; uint32_t skeylen = 0; vm_map_copy_t itoken = NULL; byte_buffer otoken = NULL; int error = 0; char svcname[] = "nfs"; kr = task_get_gssd_port(get_threadtask(current_thread()), &mp); if (kr != KERN_SUCCESS) { printf("nfs_gss_svc_gssd_upcall: can't get gssd port, status 0x%08x\n", kr); return (EAUTH); } if (!IPC_PORT_VALID(mp)) { printf("nfs_gss_svc_gssd_upcall: gssd port not valid\n"); return (EAUTH); } if (cp->gss_svc_tokenlen > 0) nfs_gss_mach_alloc_buffer(cp->gss_svc_token, cp->gss_svc_tokenlen, &itoken); retry: kr = mach_gss_accept_sec_context( mp, (byte_buffer) itoken, (mach_msg_type_number_t) cp->gss_svc_tokenlen, svcname, 0, &cp->gss_svc_gssd_verf, &cp->gss_svc_context, &cp->gss_svc_cred_handle, &cp->gss_svc_uid, cp->gss_svc_gids, &cp->gss_svc_ngroups, &okey, (mach_msg_type_number_t *) &skeylen, &otoken, (mach_msg_type_number_t *) &cp->gss_svc_tokenlen, &cp->gss_svc_major, &cp->gss_svc_minor); if (kr != KERN_SUCCESS) { printf("nfs_gss_svc_gssd_upcall failed: %d\n", kr); if (kr == MIG_SERVER_DIED && cp->gss_svc_context == 0 && retry_cnt++ < NFS_GSS_MACH_MAX_RETRIES) goto retry; task_release_special_port(mp); return (EAUTH); } task_release_special_port(mp); if (skeylen > 0) { if (skeylen != SKEYLEN) { printf("nfs_gss_svc_gssd_upcall: bad key length (%d)\n", skeylen); return (EAUTH); } error = nfs_gss_mach_vmcopyout((vm_map_copy_t) okey, skeylen, cp->gss_svc_skey); if (error) return (EAUTH); } if (cp->gss_svc_tokenlen > 0) { MALLOC(cp->gss_svc_token, u_char *, cp->gss_svc_tokenlen, M_TEMP, M_WAITOK); if (cp->gss_svc_token == NULL) return (ENOMEM); error = nfs_gss_mach_vmcopyout((vm_map_copy_t) otoken, cp->gss_svc_tokenlen, cp->gss_svc_token); if (error) return (EAUTH); } return (kr); } /* * Validate the sequence number in the credential as described * in RFC 2203 Section 5.3.3.1 * * Here the window of valid sequence numbers is represented by * a bitmap. As each sequence number is received, its bit is * set in the bitmap. An invalid sequence number lies below * the lower bound of the window, or is within the window but * has its bit already set. */ static int nfs_gss_svc_seqnum_valid(struct nfs_gss_svc_ctx *cp, uint32_t seq) { uint32_t *bits = cp->gss_svc_seqbits; uint32_t win = cp->gss_svc_seqwin; uint32_t i; lck_mtx_lock(cp->gss_svc_mtx); /* * If greater than the window upper bound, * move the window up, and set the bit. */ if (seq > cp->gss_svc_seqmax) { if (seq - cp->gss_svc_seqmax > win) bzero(bits, nfsm_rndup((win + 7) / 8)); else for (i = cp->gss_svc_seqmax + 1; i < seq; i++) win_resetbit(bits, i % win); win_setbit(bits, seq % win); cp->gss_svc_seqmax = seq; lck_mtx_unlock(cp->gss_svc_mtx); return (1); } /* * Invalid if below the lower bound of the window */ if (seq <= cp->gss_svc_seqmax - win) { lck_mtx_unlock(cp->gss_svc_mtx); return (0); } /* * In the window, invalid if the bit is already set */ if (win_getbit(bits, seq % win)) { lck_mtx_unlock(cp->gss_svc_mtx); return (0); } win_setbit(bits, seq % win); lck_mtx_unlock(cp->gss_svc_mtx); return (1); } /* * Called at NFS server shutdown - destroy all contexts */ void nfs_gss_svc_cleanup(void) { struct nfs_gss_svc_ctx_hashhead *head; struct nfs_gss_svc_ctx *cp, *ncp; int i; lck_mtx_lock(nfs_gss_svc_ctx_mutex); /* * Run through all the buckets */ for (i = 0; i < SVC_CTX_HASHSZ; i++) { /* * Remove and free all entries in the bucket */ head = &nfs_gss_svc_ctx_hashtbl[i]; LIST_FOREACH_SAFE(cp, head, gss_svc_entries, ncp) { LIST_REMOVE(cp, gss_svc_entries); if (cp->gss_svc_seqbits) FREE(cp->gss_svc_seqbits, M_TEMP); lck_mtx_destroy(cp->gss_svc_mtx, nfs_gss_svc_grp); FREE(cp, M_TEMP); } } lck_mtx_unlock(nfs_gss_svc_ctx_mutex); } #endif /* NFSSERVER */ /************* * The following functions are used by both client and server. */ /* * Release a task special port that was obtained by task_get_special_port * or one of its macros (task_get_gssd_port in this case). * This really should be in a public kpi. */ /* This should be in a public header if this routine is not */ extern void ipc_port_release_send(ipc_port_t); extern ipc_port_t ipc_port_copy_send(ipc_port_t); static void task_release_special_port(mach_port_t mp) { ipc_port_release_send(mp); } static mach_port_t task_copy_special_port(mach_port_t mp) { return ipc_port_copy_send(mp); } /* * The token that is sent and received in the gssd upcall * has unbounded variable length. Mach RPC does not pass * the token in-line. Instead it uses page mapping to handle * these parameters. This function allocates a VM buffer * to hold the token for an upcall and copies the token * (received from the client) into it. The VM buffer is * marked with a src_destroy flag so that the upcall will * automatically de-allocate the buffer when the upcall is * complete. */ static void nfs_gss_mach_alloc_buffer(u_char *buf, uint32_t buflen, vm_map_copy_t *addr) { kern_return_t kr; vm_offset_t kmem_buf; vm_size_t tbuflen; *addr = NULL; if (buf == NULL || buflen == 0) return; tbuflen = round_page(buflen); kr = vm_allocate(ipc_kernel_map, &kmem_buf, tbuflen, VM_FLAGS_ANYWHERE); if (kr != 0) { printf("nfs_gss_mach_alloc_buffer: vm_allocate failed\n"); return; } kr = vm_map_wire(ipc_kernel_map, vm_map_trunc_page(kmem_buf), vm_map_round_page(kmem_buf + tbuflen), VM_PROT_READ|VM_PROT_WRITE, FALSE); bcopy(buf, (void *) kmem_buf, buflen); kr = vm_map_unwire(ipc_kernel_map, vm_map_trunc_page(kmem_buf), vm_map_round_page(kmem_buf + tbuflen), FALSE); if (kr != 0) { printf("nfs_gss_mach_alloc_buffer: vm_map_unwire failed\n"); return; } kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t) kmem_buf, (vm_map_size_t) buflen, TRUE, addr); if (kr != 0) { printf("nfs_gss_mach_alloc_buffer: vm_map_copyin failed\n"); return; } if (buflen != tbuflen) kmem_free(ipc_kernel_map, kmem_buf + buflen, tbuflen - buflen); } /* * Here we handle a token received from the gssd via an upcall. * The received token resides in an allocate VM buffer. * We copy the token out of this buffer to a chunk of malloc'ed * memory of the right size, then de-allocate the VM buffer. */ static int nfs_gss_mach_vmcopyout(vm_map_copy_t in, uint32_t len, u_char *out) { vm_map_offset_t map_data; vm_offset_t data; int error; error = vm_map_copyout(ipc_kernel_map, &map_data, in); if (error) return (error); data = CAST_DOWN(vm_offset_t, map_data); bcopy((void *) data, out, len); vm_deallocate(ipc_kernel_map, data, len); return (0); } /* * Encode an ASN.1 token to be wrapped in an RPCSEC_GSS verifier. * Returns the size of the token, since it contains a variable * length DER encoded size field. */ static int nfs_gss_token_put( des_key_schedule sched, u_char *alg, u_char *p, int initiator, int datalen, u_char *cksum) { static uint32_t seqnum = 0; u_char *psave = p; u_char plain[8]; int toklen, i; /* * Fill in the token header: 2 octets. * This is 0x06 - an ASN.1 tag for APPLICATION, 0, SEQUENCE * followed by the length of the token: 35 + 0 octets for a * MIC token, or 35 + encrypted octets for a wrap token; */ *p++ = 0x060; toklen = KRB5_SZ_MECH + KRB5_SZ_ALG + KRB5_SZ_SEQ + KRB5_SZ_CKSUM; nfs_gss_der_length_put(&p, toklen + datalen); /* * Fill in the DER encoded mech OID for Kerberos v5. * This represents the Kerberos OID 1.2.840.113554.1.2.2 * described in RFC 2623, section 4.2 */ bcopy(krb5_mech, p, sizeof(krb5_mech)); p += sizeof(krb5_mech); /* * Now at the token described in RFC 1964, section 1.2.1 * Fill in the token ID, integrity algorithm indicator, * for DES MAC MD5, and four filler octets. * The alg string encodes the bytes to represent either * a MIC token or a WRAP token for Kerberos. */ bcopy(alg, p, KRB5_SZ_ALG); p += KRB5_SZ_ALG; /* * Now encode the sequence number according to * RFC 1964, section 1.2.1.2 which dictates 4 octets * of sequence number followed by 4 bytes of direction * indicator: 0x00 for initiator or 0xff for acceptor. * We DES CBC encrypt the sequence number using the first * 8 octets of the checksum field as an initialization * vector. * Note that this sequence number is not at all related * to the RPCSEC_GSS protocol sequence number. This * number is private to the ASN.1 token. The only * requirement is that it not be repeated in case the * server has replay detection on, which normally should * not be the case, since RFC 2203 section 5.2.3 says that * replay detection and sequence checking must be turned off. */ seqnum++; for (i = 0; i < 4; i++) plain[i] = (u_char) ((seqnum >> (i * 8)) & 0xff); for (i = 4; i < 8; i++) plain[i] = initiator ? 0x00 : 0xff; des_cbc_encrypt((des_cblock *) plain, (des_cblock *) p, 8, sched, (des_cblock *) cksum, NULL, DES_ENCRYPT); p += 8; /* * Finally, append 8 octets of DES MAC MD5 * checksum of the alg + plaintext data. * The plaintext could be an RPC call header, * the window value, or a sequence number. */ bcopy(cksum, p, 8); p += 8; return (p - psave); } /* * Determine size of ASN.1 DER length */ static int nfs_gss_der_length_size(int len) { return len < (1 << 7) ? 1 : len < (1 << 8) ? 2 : len < (1 << 16) ? 3 : len < (1 << 24) ? 4 : 5; } /* * Encode an ASN.1 DER length field */ static void nfs_gss_der_length_put(u_char **pp, int len) { int sz = nfs_gss_der_length_size(len); u_char *p = *pp; if (sz == 1) { *p++ = (u_char) len; } else { *p++ = (u_char) ((sz-1) | 0x80); sz -= 1; while (sz--) *p++ = (u_char) ((len >> (sz * 8)) & 0xff); } *pp = p; } /* * Decode an ASN.1 DER length field */ static int nfs_gss_der_length_get(u_char **pp) { u_char *p = *pp; uint32_t flen, len = 0; flen = *p & 0x7f; if ((*p++ & 0x80) == 0) len = flen; else { if (flen > sizeof(uint32_t)) return (-1); while (flen--) len = (len << 8) + *p++; } *pp = p; return (len); } /* * Decode an ASN.1 token from an RPCSEC_GSS verifier. */ static int nfs_gss_token_get( des_key_schedule sched, u_char *alg, u_char *p, int initiator, uint32_t *len, u_char *cksum) { u_char d, plain[8]; u_char *psave = p; int seqnum, i; /* * Check that we have a valid token header */ if (*p++ != 0x60) return (AUTH_BADCRED); (void) nfs_gss_der_length_get(&p); // ignore the size /* * Check that we have the DER encoded Kerberos v5 mech OID */ if (bcmp(p, krb5_mech, sizeof(krb5_mech) != 0)) return (AUTH_BADCRED); p += sizeof(krb5_mech); /* * Now check the token ID, DES MAC MD5 algorithm * indicator, and filler octets. */ if (bcmp(p, alg, KRB5_SZ_ALG) != 0) return (AUTH_BADCRED); p += KRB5_SZ_ALG; /* * Now decrypt the sequence number. * Note that the DES CBC decryption uses the first 8 octets * of the checksum field as an initialization vector (p + 8). * Per RFC 2203 section 5.2.2 we don't check the sequence number * in the ASN.1 token because the RPCSEC_GSS protocol has its * own sequence number described in section 5.3.3.1 */ seqnum = 0; des_cbc_encrypt((des_cblock *) p, (des_cblock *) plain, 8, sched, (des_cblock *) (p + 8), NULL, DES_DECRYPT); p += 8; for (i = 0; i < 4; i++) seqnum |= plain[i] << (i * 8); /* * Make sure the direction * indicator octets are correct. */ d = initiator ? 0x00 : 0xff; for (i = 4; i < 8; i++) if (plain[i] != d) return (AUTH_BADCRED); /* * Finally, get the checksum */ bcopy(p, cksum, 8); p += 8; if (len != NULL) *len = p - psave; return (0); } /* * Return the number of bytes in an mbuf chain. */ static int nfs_gss_mchain_length(mbuf_t mhead) { mbuf_t mb; int len = 0; for (mb = mhead; mb; mb = mbuf_next(mb)) len += mbuf_len(mb); return (len); } /* * Append an args or results mbuf chain to the header chain */ static int nfs_gss_append_chain(struct nfsm_chain *nmc, mbuf_t mc) { int error = 0; mbuf_t mb, tail; /* Connect the mbuf chains */ error = mbuf_setnext(nmc->nmc_mcur, mc); if (error) return (error); /* Find the last mbuf in the chain */ tail = NULL; for (mb = mc; mb; mb = mbuf_next(mb)) tail = mb; nmc->nmc_mcur = tail; nmc->nmc_ptr = (caddr_t) mbuf_data(tail) + mbuf_len(tail); nmc->nmc_left = mbuf_trailingspace(tail); return (0); } /* * Convert an mbuf chain to an NFS mbuf chain */ static void nfs_gss_nfsm_chain(struct nfsm_chain *nmc, mbuf_t mc) { mbuf_t mb, tail; /* Find the last mbuf in the chain */ tail = NULL; for (mb = mc; mb; mb = mbuf_next(mb)) tail = mb; nmc->nmc_mhead = mc; nmc->nmc_mcur = tail; nmc->nmc_ptr = (caddr_t) mbuf_data(tail) + mbuf_len(tail); nmc->nmc_left = mbuf_trailingspace(tail); nmc->nmc_flags = 0; } /* * Compute a checksum over an mbuf chain. * Start building an MD5 digest at the given offset and keep * going until the end of data in the current mbuf is reached. * Then convert the 16 byte MD5 digest to an 8 byte DES CBC * checksum. */ static void nfs_gss_cksum_mchain( des_key_schedule sched, mbuf_t mhead, u_char *alg, int offset, int len, u_char *cksum) { mbuf_t mb; u_char *ptr; int left, bytes; MD5_CTX context; u_char digest[16]; MD5Init(&context); /* * Logically prepend the first 8 bytes of the algorithm * field as required by RFC 1964, section 1.2.1.1 */ MD5Update(&context, alg, KRB5_SZ_ALG); /* * Move down the mbuf chain until we reach the given * byte offset, then start MD5 on the mbuf data until * we've done len bytes. */ for (mb = mhead; mb && len > 0; mb = mbuf_next(mb)) { ptr = mbuf_data(mb); left = mbuf_len(mb); if (offset >= left) { /* Offset not yet reached */ offset -= left; continue; } /* At or beyond offset - checksum data */ ptr += offset; left -= offset; offset = 0; bytes = left < len ? left : len; if (bytes > 0) MD5Update(&context, ptr, bytes); len -= bytes; } MD5Final(digest, &context); /* * Now get the DES CBC checksum for the digest. */ (void) des_cbc_cksum((des_cblock *) digest, (des_cblock *) cksum, sizeof(digest), sched, (des_cblock *) iv0); } /* * Compute a checksum over an NFS mbuf chain. * Start building an MD5 digest at the given offset and keep * going until the end of data in the current mbuf is reached. * Then convert the 16 byte MD5 digest to an 8 byte DES CBC * checksum. */ static void nfs_gss_cksum_chain( des_key_schedule sched, struct nfsm_chain *nmc, u_char *alg, int offset, int len, u_char *cksum) { /* * If the length parameter is zero, then we need * to use the length from the offset to the current * encode/decode offset. */ if (len == 0) len = nfsm_chain_offset(nmc) - offset; return (nfs_gss_cksum_mchain(sched, nmc->nmc_mhead, alg, offset, len, cksum)); } /* * Compute a checksum of the sequence number (or sequence window) * of an RPCSEC_GSS reply. */ static void nfs_gss_cksum_rep(des_key_schedule sched, uint32_t seqnum, u_char *cksum) { MD5_CTX context; u_char digest[16]; uint32_t val = htonl(seqnum); MD5Init(&context); /* * Logically prepend the first 8 bytes of the MIC * token as required by RFC 1964, section 1.2.1.1 */ MD5Update(&context, krb5_mic, KRB5_SZ_ALG); /* * Compute the digest of the seqnum in network order */ MD5Update(&context, (u_char *) &val, 4); MD5Final(digest, &context); /* * Now get the DES CBC checksum for the digest. */ (void) des_cbc_cksum((des_cblock *) digest, (des_cblock *) cksum, sizeof(digest), sched, (des_cblock *) iv0); } /* * Encrypt or decrypt data in an mbuf chain with des-cbc. */ static void nfs_gss_encrypt_mchain( u_char *key, mbuf_t mhead, int offset, int len, int encrypt) { des_key_schedule sched; mbuf_t mb, mbn; u_char *ptr, *nptr; u_char tmp[8], ivec[8]; int i, left, left8, remain; /* * Make the key schedule per RFC 1964 section 1.2.2.3 */ for (i = 0; i < 8; i++) tmp[i] = key[i] ^ 0xf0; bzero(ivec, 8); (void) des_key_sched((des_cblock *) tmp, sched); /* * Move down the mbuf chain until we reach the given * byte offset, then start encrypting the mbuf data until * we've done len bytes. */ for (mb = mhead; mb && len > 0; mb = mbn) { mbn = mbuf_next(mb); ptr = mbuf_data(mb); left = mbuf_len(mb); if (offset >= left) { /* Offset not yet reached */ offset -= left; continue; } /* At or beyond offset - encrypt data */ ptr += offset; left -= offset; offset = 0; /* * DES CBC has to encrypt 8 bytes at a time. * If the number of bytes to be encrypted in this * mbuf isn't some multiple of 8 bytes, encrypt all * the 8 byte blocks, then combine the remaining * bytes with enough from the next mbuf to make up * an 8 byte block and encrypt that block separately, * i.e. that block is split across two mbufs. */ remain = left % 8; left8 = left - remain; left = left8 < len ? left8 : len; if (left > 0) { des_cbc_encrypt((des_cblock *) ptr, (des_cblock *) ptr, left, sched, (des_cblock *) ivec, (des_cblock *) ivec, encrypt); len -= left; } if (mbn && remain > 0) { nptr = mbuf_data(mbn); offset = 8 - remain; bcopy(ptr + left, tmp, remain); // grab from this mbuf bcopy(nptr, tmp + remain, offset); // grab from next mbuf des_cbc_encrypt((des_cblock *) tmp, (des_cblock *) tmp, 8, sched, (des_cblock *) ivec, (des_cblock *) ivec, encrypt); bcopy(tmp, ptr + left, remain); // return to this mbuf bcopy(tmp + remain, nptr, offset); // return to next mbuf len -= 8; } } } /* * Encrypt or decrypt data in an NFS mbuf chain with des-cbc. */ static void nfs_gss_encrypt_chain( u_char *key, struct nfsm_chain *nmc, int offset, int len, int encrypt) { /* * If the length parameter is zero, then we need * to use the length from the offset to the current * encode/decode offset. */ if (len == 0) len = nfsm_chain_offset(nmc) - offset; return (nfs_gss_encrypt_mchain(key, nmc->nmc_mhead, offset, len, encrypt)); } /* * XXX This function borrowed from OpenBSD. * It will likely be moved into kernel crypto. */ static DES_LONG des_cbc_cksum(input, output, length, schedule, ivec) des_cblock (*input); des_cblock (*output); long length; des_key_schedule schedule; des_cblock (*ivec); { register unsigned long tout0,tout1,tin0,tin1; register long l=length; unsigned long tin[2]; unsigned char *in,*out,*iv; in=(unsigned char *)input; out=(unsigned char *)output; iv=(unsigned char *)ivec; c2l(iv,tout0); c2l(iv,tout1); for (; l>0; l-=8) { if (l >= 8) { c2l(in,tin0); c2l(in,tin1); } else c2ln(in,tin0,tin1,l); tin0^=tout0; tin[0]=tin0; tin1^=tout1; tin[1]=tin1; des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT); /* fix 15/10/91 eay - thanks to keithr@sco.COM */ tout0=tin[0]; tout1=tin[1]; } if (out != NULL) { l2c(tout0,out); l2c(tout1,out); } tout0=tin0=tin1=tin[0]=tin[1]=0; return(tout1); } /* * XXX This function borrowed from OpenBSD. * It will likely be moved into kernel crypto. */ static void des_cbc_encrypt(input, output, length, schedule, ivec, retvec, encrypt) des_cblock (*input); des_cblock (*output); long length; des_key_schedule schedule; des_cblock (*ivec); des_cblock (*retvec); int encrypt; { register unsigned long tin0,tin1; register unsigned long tout0,tout1,xor0,xor1; register unsigned char *in,*out,*retval; register long l=length; unsigned long tin[2]; unsigned char *iv; tin0 = tin1 = 0; in=(unsigned char *)input; out=(unsigned char *)output; retval=(unsigned char *)retvec; iv=(unsigned char *)ivec; if (encrypt) { c2l(iv,tout0); c2l(iv,tout1); for (l-=8; l>=0; l-=8) { c2l(in,tin0); c2l(in,tin1); tin0^=tout0; tin[0]=tin0; tin1^=tout1; tin[1]=tin1; des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT); tout0=tin[0]; l2c(tout0,out); tout1=tin[1]; l2c(tout1,out); } if (l != -8) { c2ln(in,tin0,tin1,l+8); tin0^=tout0; tin[0]=tin0; tin1^=tout1; tin[1]=tin1; des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT); tout0=tin[0]; l2c(tout0,out); tout1=tin[1]; l2c(tout1,out); } if (retval) { l2c(tout0,retval); l2c(tout1,retval); } } else { c2l(iv,xor0); c2l(iv,xor1); for (l-=8; l>=0; l-=8) { c2l(in,tin0); tin[0]=tin0; c2l(in,tin1); tin[1]=tin1; des_encrypt1((DES_LONG *)tin,schedule,DES_DECRYPT); tout0=tin[0]^xor0; tout1=tin[1]^xor1; l2c(tout0,out); l2c(tout1,out); xor0=tin0; xor1=tin1; } if (l != -8) { c2l(in,tin0); tin[0]=tin0; c2l(in,tin1); tin[1]=tin1; des_encrypt1((DES_LONG *)tin,schedule,DES_DECRYPT); tout0=tin[0]^xor0; tout1=tin[1]^xor1; l2cn(tout0,tout1,out,l+8); /* xor0=tin0; xor1=tin1; */ } if (retval) { l2c(tin0,retval); l2c(tin1,retval); } } tin0=tin1=tout0=tout1=xor0=xor1=0; tin[0]=tin[1]=0; }