/* gssd_proc.c Copyright (c) 2000-2004 The Regents of the University of Michigan. All rights reserved. Copyright (c) 2000 Dug Song . Copyright (c) 2001 Andy Adamson . Copyright (c) 2002 Marius Aamodt Eriksen . Copyright (c) 2002 Bruce Fields Copyright (c) 2004 Kevin Coffman All rights reserved, all wrongs reversed. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifdef HAVE_CONFIG_H #include #endif /* HAVE_CONFIG_H */ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "gssd.h" #include "err_util.h" #include "gss_util.h" #include "krb5_util.h" #include "context.h" #include "nfsrpc.h" #include "nfslib.h" /* * pollarray: * array of struct pollfd suitable to pass to poll. initialized to * zero - a zero struct is ignored by poll() because the events mask is 0. * * clnt_list: * linked list of struct clnt_info which associates a clntXXX directory * with an index into pollarray[], and other basic data about that client. * * Directory structure: created by the kernel * {rpc_pipefs}/{dir}/clntXX : one per rpc_clnt struct in the kernel * {rpc_pipefs}/{dir}/clntXX/krb5 : read uid for which kernel wants * a context, write the resulting context * {rpc_pipefs}/{dir}/clntXX/info : stores info such as server name * {rpc_pipefs}/{dir}/clntXX/gssd : pipe for all gss mechanisms using * a text-based string of parameters * * Algorithm: * Poll all {rpc_pipefs}/{dir}/clntXX/YYYY files. When data is ready, * read and process; performs rpcsec_gss context initialization protocol to * get a cred for that user. Writes result to corresponding krb5 file * in a form the kernel code will understand. * In addition, we make sure we are notified whenever anything is * created or destroyed in {rpc_pipefs} or in any of the clntXX directories, * and rescan the whole {rpc_pipefs} when this happens. */ struct pollfd * pollarray; int pollsize; /* the size of pollaray (in pollfd's) */ /* * convert a presentation address string to a sockaddr_storage struct. Returns * true on success or false on failure. * * Note that we do not populate the sin6_scope_id field here for IPv6 addrs. * gssd nececessarily relies on hostname resolution and DNS AAAA records * do not generally contain scope-id's. This means that GSSAPI auth really * can't work with IPv6 link-local addresses. * * We *could* consider changing this if we did something like adopt the * Microsoft "standard" of using the ipv6-literal.net domainname, but it's * not really feasible at present. */ static int addrstr_to_sockaddr(struct sockaddr *sa, const char *node, const char *port) { int rc; struct addrinfo *res; struct addrinfo hints = { .ai_flags = AI_NUMERICHOST | AI_NUMERICSERV }; #ifndef IPV6_SUPPORTED hints.ai_family = AF_INET; #endif /* IPV6_SUPPORTED */ rc = getaddrinfo(node, port, &hints, &res); if (rc) { printerr(0, "ERROR: unable to convert %s|%s to sockaddr: %s\n", node, port, rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc)); return 0; } #ifdef IPV6_SUPPORTED /* * getnameinfo ignores the scopeid. If the address turns out to have * a non-zero scopeid, we can't use it -- the resolved host might be * completely different from the one intended. */ if (res->ai_addr->sa_family == AF_INET6) { struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)res->ai_addr; if (sin6->sin6_scope_id) { printerr(0, "ERROR: address %s has non-zero " "sin6_scope_id!\n", node); freeaddrinfo(res); return 0; } } #endif /* IPV6_SUPPORTED */ memcpy(sa, res->ai_addr, res->ai_addrlen); freeaddrinfo(res); return 1; } /* * convert a sockaddr to a hostname */ static char * sockaddr_to_hostname(const struct sockaddr *sa, const char *addr) { socklen_t addrlen; int err; char *hostname; char hbuf[NI_MAXHOST]; switch (sa->sa_family) { case AF_INET: addrlen = sizeof(struct sockaddr_in); break; #ifdef IPV6_SUPPORTED case AF_INET6: addrlen = sizeof(struct sockaddr_in6); break; #endif /* IPV6_SUPPORTED */ default: printerr(0, "ERROR: unrecognized addr family %d\n", sa->sa_family); return NULL; } err = getnameinfo(sa, addrlen, hbuf, sizeof(hbuf), NULL, 0, NI_NAMEREQD); if (err) { printerr(0, "ERROR: unable to resolve %s to hostname: %s\n", addr, err == EAI_SYSTEM ? strerror(err) : gai_strerror(err)); return NULL; } hostname = strdup(hbuf); return hostname; } /* XXX buffer problems: */ static int read_service_info(char *info_file_name, char **servicename, char **servername, int *prog, int *vers, char **protocol, struct sockaddr *addr) { #define INFOBUFLEN 256 char buf[INFOBUFLEN + 1]; static char dummy[128]; int nbytes; static char service[128]; static char address[128]; char program[16]; char version[16]; char protoname[16]; char port[128]; char *p; int fd = -1; int numfields; *servicename = *servername = *protocol = NULL; if ((fd = open(info_file_name, O_RDONLY)) == -1) { printerr(0, "ERROR: can't open %s: %s\n", info_file_name, strerror(errno)); goto fail; } if ((nbytes = read(fd, buf, INFOBUFLEN)) == -1) goto fail; close(fd); buf[nbytes] = '\0'; numfields = sscanf(buf,"RPC server: %127s\n" "service: %127s %15s version %15s\n" "address: %127s\n" "protocol: %15s\n", dummy, service, program, version, address, protoname); if (numfields == 5) { strcpy(protoname, "tcp"); } else if (numfields != 6) { goto fail; } port[0] = '\0'; if ((p = strstr(buf, "port")) != NULL) sscanf(p, "port: %127s\n", port); /* check service, program, and version */ if (memcmp(service, "nfs", 3) != 0) return -1; *prog = atoi(program + 1); /* skip open paren */ *vers = atoi(version); if (strlen(service) == 3 ) { if ((*prog != 100003) || ((*vers != 2) && (*vers != 3) && (*vers != 4))) goto fail; } else if (memcmp(service, "nfs4_cb", 7) == 0) { if (*vers != 1) goto fail; } if (!addrstr_to_sockaddr(addr, address, port)) goto fail; *servername = sockaddr_to_hostname(addr, address); if (*servername == NULL) goto fail; nbytes = snprintf(buf, INFOBUFLEN, "%s@%s", service, *servername); if (nbytes > INFOBUFLEN) goto fail; if (!(*servicename = calloc(strlen(buf) + 1, 1))) goto fail; memcpy(*servicename, buf, strlen(buf)); if (!(*protocol = strdup(protoname))) goto fail; return 0; fail: printerr(0, "ERROR: failed to read service info\n"); if (fd != -1) close(fd); free(*servername); free(*servicename); free(*protocol); *servicename = *servername = *protocol = NULL; return -1; } static void destroy_client(struct clnt_info *clp) { if (clp->krb5_poll_index != -1) memset(&pollarray[clp->krb5_poll_index], 0, sizeof(struct pollfd)); if (clp->gssd_poll_index != -1) memset(&pollarray[clp->gssd_poll_index], 0, sizeof(struct pollfd)); if (clp->dir_fd != -1) close(clp->dir_fd); if (clp->krb5_fd != -1) close(clp->krb5_fd); if (clp->gssd_fd != -1) close(clp->gssd_fd); free(clp->dirname); free(clp->servicename); free(clp->servername); free(clp->protocol); free(clp); } static struct clnt_info * insert_new_clnt(void) { struct clnt_info *clp = NULL; if (!(clp = (struct clnt_info *)calloc(1,sizeof(struct clnt_info)))) { printerr(0, "ERROR: can't malloc clnt_info: %s\n", strerror(errno)); goto out; } clp->krb5_poll_index = -1; clp->gssd_poll_index = -1; clp->krb5_fd = -1; clp->gssd_fd = -1; clp->dir_fd = -1; TAILQ_INSERT_HEAD(&clnt_list, clp, list); out: return clp; } static int process_clnt_dir_files(struct clnt_info * clp) { char name[PATH_MAX]; char gname[PATH_MAX]; char info_file_name[PATH_MAX]; if (clp->gssd_fd == -1) { snprintf(gname, sizeof(gname), "%s/gssd", clp->dirname); clp->gssd_fd = open(gname, O_RDWR); } if (clp->gssd_fd == -1) { if (clp->krb5_fd == -1) { snprintf(name, sizeof(name), "%s/krb5", clp->dirname); clp->krb5_fd = open(name, O_RDWR); } /* If we opened a gss-specific pipe, let's try opening * the new upcall pipe again. If we succeed, close * gss-specific pipe(s). */ if (clp->krb5_fd != -1) { clp->gssd_fd = open(gname, O_RDWR); if (clp->gssd_fd != -1) { if (clp->krb5_fd != -1) close(clp->krb5_fd); clp->krb5_fd = -1; } } } if ((clp->krb5_fd == -1) && (clp->gssd_fd == -1)) return -1; snprintf(info_file_name, sizeof(info_file_name), "%s/info", clp->dirname); if ((clp->servicename == NULL) && read_service_info(info_file_name, &clp->servicename, &clp->servername, &clp->prog, &clp->vers, &clp->protocol, (struct sockaddr *) &clp->addr)) return -1; return 0; } static int get_poll_index(int *ind) { int i; *ind = -1; for (i=0; igssd_fd != -1) && (clp->gssd_poll_index == -1)) { if (get_poll_index(&clp->gssd_poll_index)) { printerr(0, "ERROR: Too many gssd clients\n"); return -1; } pollarray[clp->gssd_poll_index].fd = clp->gssd_fd; pollarray[clp->gssd_poll_index].events |= POLLIN; } if ((clp->krb5_fd != -1) && (clp->krb5_poll_index == -1)) { if (get_poll_index(&clp->krb5_poll_index)) { printerr(0, "ERROR: Too many krb5 clients\n"); return -1; } pollarray[clp->krb5_poll_index].fd = clp->krb5_fd; pollarray[clp->krb5_poll_index].events |= POLLIN; } return 0; } static void process_clnt_dir(char *dir, char *pdir) { struct clnt_info * clp; if (!(clp = insert_new_clnt())) goto fail_destroy_client; /* An extra for the '/', and an extra for the null */ if (!(clp->dirname = calloc(strlen(dir) + strlen(pdir) + 2, 1))) { goto fail_destroy_client; } sprintf(clp->dirname, "%s/%s", pdir, dir); if ((clp->dir_fd = open(clp->dirname, O_RDONLY)) == -1) { printerr(0, "ERROR: can't open %s: %s\n", clp->dirname, strerror(errno)); goto fail_destroy_client; } fcntl(clp->dir_fd, F_SETSIG, DNOTIFY_SIGNAL); fcntl(clp->dir_fd, F_NOTIFY, DN_CREATE | DN_DELETE | DN_MULTISHOT); if (process_clnt_dir_files(clp)) goto fail_keep_client; if (insert_clnt_poll(clp)) goto fail_destroy_client; return; fail_destroy_client: if (clp) { TAILQ_REMOVE(&clnt_list, clp, list); destroy_client(clp); } fail_keep_client: /* We couldn't find some subdirectories, but we keep the client * around in case we get a notification on the directory when the * subdirectories are created. */ return; } void init_client_list(void) { TAILQ_INIT(&clnt_list); /* Eventually plan to grow/shrink poll array: */ pollsize = FD_ALLOC_BLOCK; pollarray = calloc(pollsize, sizeof(struct pollfd)); } /* * This is run after a DNOTIFY signal, and should clear up any * directories that are no longer around, and re-scan any existing * directories, since the DNOTIFY could have been in there. */ static void update_old_clients(struct dirent **namelist, int size, char *pdir) { struct clnt_info *clp; void *saveprev; int i, stillhere; char fname[PATH_MAX]; for (clp = clnt_list.tqh_first; clp != NULL; clp = clp->list.tqe_next) { /* only compare entries in the global list that are from the * same pipefs parent directory as "pdir" */ if (strncmp(clp->dirname, pdir, strlen(pdir)) != 0) continue; stillhere = 0; for (i=0; i < size; i++) { snprintf(fname, sizeof(fname), "%s/%s", pdir, namelist[i]->d_name); if (strcmp(clp->dirname, fname) == 0) { stillhere = 1; break; } } if (!stillhere) { printerr(2, "destroying client %s\n", clp->dirname); saveprev = clp->list.tqe_prev; TAILQ_REMOVE(&clnt_list, clp, list); destroy_client(clp); clp = saveprev; } } for (clp = clnt_list.tqh_first; clp != NULL; clp = clp->list.tqe_next) { if (!process_clnt_dir_files(clp)) insert_clnt_poll(clp); } } /* Search for a client by directory name, return 1 if found, 0 otherwise */ static int find_client(char *dirname, char *pdir) { struct clnt_info *clp; char fname[PATH_MAX]; for (clp = clnt_list.tqh_first; clp != NULL; clp = clp->list.tqe_next) { snprintf(fname, sizeof(fname), "%s/%s", pdir, dirname); if (strcmp(clp->dirname, fname) == 0) return 1; } return 0; } static int process_pipedir(char *pipe_name) { struct dirent **namelist; int i, j; if (chdir(pipe_name) < 0) { printerr(0, "ERROR: can't chdir to %s: %s\n", pipe_name, strerror(errno)); return -1; } j = scandir(pipe_name, &namelist, NULL, alphasort); if (j < 0) { printerr(0, "ERROR: can't scandir %s: %s\n", pipe_name, strerror(errno)); return -1; } update_old_clients(namelist, j, pipe_name); for (i=0; i < j; i++) { if (i < FD_ALLOC_BLOCK && !strncmp(namelist[i]->d_name, "clnt", 4) && !find_client(namelist[i]->d_name, pipe_name)) process_clnt_dir(namelist[i]->d_name, pipe_name); free(namelist[i]); } free(namelist); return 0; } /* Used to read (and re-read) list of clients, set up poll array. */ int update_client_list(void) { int retval = -1; struct topdirs_info *tdi; TAILQ_FOREACH(tdi, &topdirs_list, list) { retval = process_pipedir(tdi->dirname); if (retval) printerr(1, "WARNING: error processing %s\n", tdi->dirname); } return retval; } /* Encryption types supported by the kernel rpcsec_gss code */ int num_krb5_enctypes = 0; krb5_enctype *krb5_enctypes = NULL; /* * Parse the supported encryption type information */ static int parse_enctypes(char *enctypes) { int n = 0; char *curr, *comma; int i; static char *cached_types; if (cached_types && strcmp(cached_types, enctypes) == 0) return 0; free(cached_types); if (krb5_enctypes != NULL) { free(krb5_enctypes); krb5_enctypes = NULL; num_krb5_enctypes = 0; } /* count the number of commas */ for (curr = enctypes; curr && *curr != '\0'; curr = ++comma) { comma = strchr(curr, ','); if (comma != NULL) n++; else break; } /* If no more commas and we're not at the end, there's one more value */ if (*curr != '\0') n++; /* Empty string, return an error */ if (n == 0) return ENOENT; /* Allocate space for enctypes array */ if ((krb5_enctypes = (int *) calloc(n, sizeof(int))) == NULL) { return ENOMEM; } /* Now parse each value into the array */ for (curr = enctypes, i = 0; curr && *curr != '\0'; curr = ++comma) { krb5_enctypes[i++] = atoi(curr); comma = strchr(curr, ','); if (comma == NULL) break; } num_krb5_enctypes = n; if ((cached_types = malloc(strlen(enctypes)+1))) strcpy(cached_types, enctypes); return 0; } static int do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd, gss_buffer_desc *context_token) { char *buf = NULL, *p = NULL, *end = NULL; unsigned int timeout = context_timeout; unsigned int buf_size = 0; printerr(1, "doing downcall\n"); buf_size = sizeof(uid) + sizeof(timeout) + sizeof(pd->pd_seq_win) + sizeof(pd->pd_ctx_hndl.length) + pd->pd_ctx_hndl.length + sizeof(context_token->length) + context_token->length; p = buf = malloc(buf_size); end = buf + buf_size; if (WRITE_BYTES(&p, end, uid)) goto out_err; if (WRITE_BYTES(&p, end, timeout)) goto out_err; if (WRITE_BYTES(&p, end, pd->pd_seq_win)) goto out_err; if (write_buffer(&p, end, &pd->pd_ctx_hndl)) goto out_err; if (write_buffer(&p, end, context_token)) goto out_err; if (write(k5_fd, buf, p - buf) < p - buf) goto out_err; if (buf) free(buf); return 0; out_err: if (buf) free(buf); printerr(1, "Failed to write downcall!\n"); return -1; } static int do_error_downcall(int k5_fd, uid_t uid, int err) { char buf[1024]; char *p = buf, *end = buf + 1024; unsigned int timeout = 0; int zero = 0; printerr(1, "doing error downcall\n"); if (WRITE_BYTES(&p, end, uid)) goto out_err; if (WRITE_BYTES(&p, end, timeout)) goto out_err; /* use seq_win = 0 to indicate an error: */ if (WRITE_BYTES(&p, end, zero)) goto out_err; if (WRITE_BYTES(&p, end, err)) goto out_err; if (write(k5_fd, buf, p - buf) < p - buf) goto out_err; return 0; out_err: printerr(1, "Failed to write error downcall!\n"); return -1; } /* * If the port isn't already set, do an rpcbind query to the remote server * using the program and version and get the port. * * Newer kernels send the value of the port= mount option in the "info" * file for the upcall or '0' for NFSv2/3. For NFSv4 it sends the value * of the port= option or '2049'. The port field in a new sockaddr should * reflect the value that was sent by the kernel. */ static int populate_port(struct sockaddr *sa, const socklen_t salen, const rpcprog_t program, const rpcvers_t version, const unsigned short protocol) { struct sockaddr_in *s4 = (struct sockaddr_in *) sa; #ifdef IPV6_SUPPORTED struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) sa; #endif /* IPV6_SUPPORTED */ unsigned short port; /* * Newer kernels send the port in the upcall. If we already have * the port, there's no need to look it up. */ switch (sa->sa_family) { case AF_INET: if (s4->sin_port != 0) { printerr(2, "DEBUG: port already set to %d\n", ntohs(s4->sin_port)); return 1; } break; #ifdef IPV6_SUPPORTED case AF_INET6: if (s6->sin6_port != 0) { printerr(2, "DEBUG: port already set to %d\n", ntohs(s6->sin6_port)); return 1; } break; #endif /* IPV6_SUPPORTED */ default: printerr(0, "ERROR: unsupported address family %d\n", sa->sa_family); return 0; } /* * Newer kernels that send the port in the upcall set the value to * 2049 for NFSv4 mounts when one isn't specified. The check below is * only for kernels that don't send the port in the upcall. For those * we either have to do an rpcbind query or set it to the standard * port. Doing a query could be problematic (firewalls, etc), so take * the latter approach. */ if (program == 100003 && version == 4) { port = 2049; goto set_port; } port = nfs_getport(sa, salen, program, version, protocol); if (!port) { printerr(0, "ERROR: unable to obtain port for prog %ld " "vers %ld\n", program, version); return 0; } set_port: printerr(2, "DEBUG: setting port to %hu for prog %lu vers %lu\n", port, program, version); switch (sa->sa_family) { case AF_INET: s4->sin_port = htons(port); break; #ifdef IPV6_SUPPORTED case AF_INET6: s6->sin6_port = htons(port); break; #endif /* IPV6_SUPPORTED */ } return 1; } /* * Create an RPC connection and establish an authenticated * gss context with a server. */ int create_auth_rpc_client(struct clnt_info *clp, CLIENT **clnt_return, AUTH **auth_return, uid_t uid, int authtype) { CLIENT *rpc_clnt = NULL; struct rpc_gss_sec sec; AUTH *auth = NULL; uid_t save_uid = -1; int retval = -1; OM_uint32 min_stat; char rpc_errmsg[1024]; int protocol; struct timeval timeout = {5, 0}; struct sockaddr *addr = (struct sockaddr *) &clp->addr; socklen_t salen; /* Create the context as the user (not as root) */ save_uid = geteuid(); if (setfsuid(uid) != 0) { printerr(0, "WARNING: Failed to setfsuid for " "user with uid %d\n", uid); goto out_fail; } printerr(2, "creating context using fsuid %d (save_uid %d)\n", uid, save_uid); sec.qop = GSS_C_QOP_DEFAULT; sec.svc = RPCSEC_GSS_SVC_NONE; sec.cred = GSS_C_NO_CREDENTIAL; sec.req_flags = 0; if (authtype == AUTHTYPE_KRB5) { sec.mech = (gss_OID)&krb5oid; sec.req_flags = GSS_C_MUTUAL_FLAG; } else { printerr(0, "ERROR: Invalid authentication type (%d) " "in create_auth_rpc_client\n", authtype); goto out_fail; } if (authtype == AUTHTYPE_KRB5) { #ifdef HAVE_SET_ALLOWABLE_ENCTYPES /* * Do this before creating rpc connection since we won't need * rpc connection if it fails! */ if (limit_krb5_enctypes(&sec)) { printerr(1, "WARNING: Failed while limiting krb5 " "encryption types for user with uid %d\n", uid); goto out_fail; } #endif } /* create an rpc connection to the nfs server */ printerr(2, "creating %s client for server %s\n", clp->protocol, clp->servername); if ((strcmp(clp->protocol, "tcp")) == 0) { protocol = IPPROTO_TCP; } else if ((strcmp(clp->protocol, "udp")) == 0) { protocol = IPPROTO_UDP; } else { printerr(0, "WARNING: unrecognized protocol, '%s', requested " "for connection to server %s for user with uid %d\n", clp->protocol, clp->servername, uid); goto out_fail; } switch (addr->sa_family) { case AF_INET: salen = sizeof(struct sockaddr_in); break; #ifdef IPV6_SUPPORTED case AF_INET6: salen = sizeof(struct sockaddr_in6); break; #endif /* IPV6_SUPPORTED */ default: printerr(1, "ERROR: Unknown address family %d\n", addr->sa_family); goto out_fail; } if (!populate_port(addr, salen, clp->prog, clp->vers, protocol)) goto out_fail; rpc_clnt = nfs_get_rpcclient(addr, salen, protocol, clp->prog, clp->vers, &timeout); if (!rpc_clnt) { snprintf(rpc_errmsg, sizeof(rpc_errmsg), "WARNING: can't create %s rpc_clnt to server %s for " "user with uid %d", protocol == IPPROTO_TCP ? "tcp" : "udp", clp->servername, uid); printerr(0, "%s\n", clnt_spcreateerror(rpc_errmsg)); goto out_fail; } printerr(2, "creating context with server %s\n", clp->servicename); auth = authgss_create_default(rpc_clnt, clp->servicename, &sec); if (!auth) { /* Our caller should print appropriate message */ printerr(2, "WARNING: Failed to create krb5 context for " "user with uid %d for server %s\n", uid, clp->servername); goto out_fail; } /* Success !!! */ rpc_clnt->cl_auth = auth; *clnt_return = rpc_clnt; *auth_return = auth; retval = 0; out: if (sec.cred != GSS_C_NO_CREDENTIAL) gss_release_cred(&min_stat, &sec.cred); /* Restore euid to original value */ if (((int)save_uid != -1) && (setfsuid(save_uid) != (int)uid)) { printerr(0, "WARNING: Failed to restore fsuid" " to uid %d from %d\n", save_uid, uid); } return retval; out_fail: /* Only destroy here if failure. Otherwise, caller is responsible */ if (rpc_clnt) clnt_destroy(rpc_clnt); goto out; } static char * user_cachedir(char *dirname, uid_t uid) { struct passwd *pw; char *ptr; if ((pw = getpwuid(uid)) == NULL) { printerr(0, "user_cachedir: Failed to find '%d' uid" " for cache directory\n"); return NULL; } ptr = malloc(strlen(dirname)+strlen(pw->pw_name)+2); if (ptr) sprintf(ptr, "%s/%s", dirname, pw->pw_name); return ptr; } /* * this code uses the userland rpcsec gss library to create a krb5 * context on behalf of the kernel */ static void process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname, char *service) { CLIENT *rpc_clnt = NULL; AUTH *auth = NULL; struct authgss_private_data pd; gss_buffer_desc token; char **credlist = NULL; char **ccname; char **dirname, *dir, *userdir; int create_resp = -1; int err, downcall_err = -EACCES; printerr(1, "handling krb5 upcall (%s)\n", clp->dirname); if (tgtname) { if (clp->servicename) { free(clp->servicename); clp->servicename = strdup(tgtname); } } token.length = 0; token.value = NULL; memset(&pd, 0, sizeof(struct authgss_private_data)); /* * If "service" is specified, then the kernel is indicating that * we must use machine credentials for this request. (Regardless * of the uid value or the setting of root_uses_machine_creds.) * If the service value is "*", then any service name can be used. * Otherwise, it specifies the service name that should be used. * (For now, the values of service will only be "*" or "nfs".) * * Restricting gssd to use "nfs" service name is needed for when * the NFS server is doing a callback to the NFS client. In this * case, the NFS server has to authenticate itself as "nfs" -- * even if there are other service keys such as "host" or "root" * in the keytab. * * Another case when the kernel may specify the service attribute * is when gssd is being asked to create the context for a * SETCLIENT_ID operation. In this case, machine credentials * must be used for the authentication. However, the service name * used for this case is not important. * */ printerr(2, "%s: service is '%s'\n", __func__, service ? service : ""); if (uid != 0 || (uid == 0 && root_uses_machine_creds == 0 && service == NULL)) { /* Tell krb5 gss which credentials cache to use */ for (dirname = ccachesearch; *dirname != NULL; dirname++) { /* See if the user name is needed */ if (strncmp(*dirname, GSSD_USER_CRED_DIR, strlen(GSSD_USER_CRED_DIR)) == 0) { userdir = user_cachedir(*dirname, uid); if (userdir == NULL) continue; dir = userdir; } else dir = *dirname; err = gssd_setup_krb5_user_gss_ccache(uid, clp->servername, dir); if (userdir) { free(userdir); userdir = NULL; } if (err == -EKEYEXPIRED) downcall_err = -EKEYEXPIRED; else if (!err) create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid, AUTHTYPE_KRB5); if (create_resp == 0) break; } } if (create_resp != 0) { if (uid == 0 && (root_uses_machine_creds == 1 || service != NULL)) { int nocache = 0; int success = 0; do { gssd_refresh_krb5_machine_credential(clp->servername, NULL, service); /* * Get a list of credential cache names and try each * of them until one works or we've tried them all */ if (gssd_get_krb5_machine_cred_list(&credlist)) { printerr(0, "ERROR: No credentials found " "for connection to server %s\n", clp->servername); goto out_return_error; } for (ccname = credlist; ccname && *ccname; ccname++) { gssd_setup_krb5_machine_gss_ccache(*ccname); if ((create_auth_rpc_client(clp, &rpc_clnt, &auth, uid, AUTHTYPE_KRB5)) == 0) { /* Success! */ success++; break; } printerr(2, "WARNING: Failed to create machine krb5 context " "with credentials cache %s for server %s\n", *ccname, clp->servername); } gssd_free_krb5_machine_cred_list(credlist); if (!success) { if(nocache == 0) { nocache++; printerr(2, "WARNING: Machine cache is prematurely expired or corrupted " "trying to recreate cache for server %s\n", clp->servername); } else { printerr(1, "WARNING: Failed to create machine krb5 context " "with any credentials cache for server %s\n", clp->servername); goto out_return_error; } } } while(!success); } else { printerr(1, "WARNING: Failed to create krb5 context " "for user with uid %d for server %s\n", uid, clp->servername); goto out_return_error; } } if (!authgss_get_private_data(auth, &pd)) { printerr(1, "WARNING: Failed to obtain authentication " "data for user with uid %d for server %s\n", uid, clp->servername); goto out_return_error; } if (serialize_context_for_kernel(pd.pd_ctx, &token, &krb5oid, NULL)) { printerr(0, "WARNING: Failed to serialize krb5 context for " "user with uid %d for server %s\n", uid, clp->servername); goto out_return_error; } do_downcall(fd, uid, &pd, &token); out: if (token.value) free(token.value); #ifndef HAVE_LIBTIRPC if (pd.pd_ctx_hndl.length != 0) authgss_free_private_data(&pd); #endif if (auth) AUTH_DESTROY(auth); if (rpc_clnt) clnt_destroy(rpc_clnt); return; out_return_error: do_error_downcall(fd, uid, downcall_err); goto out; } void handle_krb5_upcall(struct clnt_info *clp) { uid_t uid; if (read(clp->krb5_fd, &uid, sizeof(uid)) < (ssize_t)sizeof(uid)) { printerr(0, "WARNING: failed reading uid from krb5 " "upcall pipe: %s\n", strerror(errno)); return; } return process_krb5_upcall(clp, uid, clp->krb5_fd, NULL, NULL); } void handle_gssd_upcall(struct clnt_info *clp) { uid_t uid; char *lbuf = NULL; int lbuflen = 0; char *p; char *mech = NULL; char *target = NULL; char *service = NULL; char *enctypes = NULL; printerr(1, "handling gssd upcall (%s)\n", clp->dirname); if (readline(clp->gssd_fd, &lbuf, &lbuflen) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed reading request\n"); return; } printerr(2, "%s: '%s'\n", __func__, lbuf); /* find the mechanism name */ if ((p = strstr(lbuf, "mech=")) != NULL) { mech = malloc(lbuflen); if (!mech) goto out; if (sscanf(p, "mech=%s", mech) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed to parse gss mechanism name " "in upcall string '%s'\n", lbuf); goto out; } } else { printerr(0, "WARNING: handle_gssd_upcall: " "failed to find gss mechanism name " "in upcall string '%s'\n", lbuf); goto out; } /* read uid */ if ((p = strstr(lbuf, "uid=")) != NULL) { if (sscanf(p, "uid=%d", &uid) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed to parse uid " "in upcall string '%s'\n", lbuf); goto out; } } else { printerr(0, "WARNING: handle_gssd_upcall: " "failed to find uid " "in upcall string '%s'\n", lbuf); goto out; } /* read supported encryption types if supplied */ if ((p = strstr(lbuf, "enctypes=")) != NULL) { enctypes = malloc(lbuflen); if (!enctypes) goto out; if (sscanf(p, "enctypes=%s", enctypes) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed to parse encryption types " "in upcall string '%s'\n", lbuf); goto out; } if (parse_enctypes(enctypes) != 0) { printerr(0, "WARNING: handle_gssd_upcall: " "parsing encryption types failed: errno %d\n", errno); } } /* read target name */ if ((p = strstr(lbuf, "target=")) != NULL) { target = malloc(lbuflen); if (!target) goto out; if (sscanf(p, "target=%s", target) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed to parse target name " "in upcall string '%s'\n", lbuf); goto out; } } /* * read the service name * * The presence of attribute "service=" indicates that machine * credentials should be used for this request. If the value * is "*", then any machine credentials available can be used. * If the value is anything else, then machine credentials for * the specified service name (always "nfs" for now) should be * used. */ if ((p = strstr(lbuf, "service=")) != NULL) { service = malloc(lbuflen); if (!service) goto out; if (sscanf(p, "service=%s", service) != 1) { printerr(0, "WARNING: handle_gssd_upcall: " "failed to parse service type " "in upcall string '%s'\n", lbuf); goto out; } } if (strcmp(mech, "krb5") == 0) process_krb5_upcall(clp, uid, clp->gssd_fd, target, service); else printerr(0, "WARNING: handle_gssd_upcall: " "received unknown gss mech '%s'\n", mech); out: free(lbuf); free(mech); free(enctypes); free(target); free(service); return; }