/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * Except as contained in this notice, the names of the authors or their * institutions shall not be used in advertising or otherwise to promote the * sale, use or other dealings in this Software without prior written * authorization from the authors. */ /* Authorization systems for the X protocol. */ #include <assert.h> #include <X11/Xauth.h> #include <sys/param.h> #include <unistd.h> #include <stdlib.h> #ifdef _WIN32 #include "xcb_windefs.h" #else #include <sys/socket.h> #include <netinet/in.h> #include <sys/un.h> #endif /* _WIN32 */ #include "xcb.h" #include "xcbint.h" #ifdef HASXDMAUTH #include <X11/Xdmcp.h> #endif enum auth_protos { #ifdef HASXDMAUTH AUTH_XA1, #endif AUTH_MC1, N_AUTH_PROTOS }; #define AUTH_PROTO_XDM_AUTHORIZATION "XDM-AUTHORIZATION-1" #define AUTH_PROTO_MIT_MAGIC_COOKIE "MIT-MAGIC-COOKIE-1" static char *authnames[N_AUTH_PROTOS] = { #ifdef HASXDMAUTH AUTH_PROTO_XDM_AUTHORIZATION, #endif AUTH_PROTO_MIT_MAGIC_COOKIE, }; static int authnameslen[N_AUTH_PROTOS] = { #ifdef HASXDMAUTH sizeof(AUTH_PROTO_XDM_AUTHORIZATION) - 1, #endif sizeof(AUTH_PROTO_MIT_MAGIC_COOKIE) - 1, }; static size_t memdup(char **dst, void *src, size_t len) { if(len) *dst = malloc(len); else *dst = 0; if(!*dst) return 0; memcpy(*dst, src, len); return len; } static int authname_match(enum auth_protos kind, char *name, size_t namelen) { if(authnameslen[kind] != namelen) return 0; if(memcmp(authnames[kind], name, namelen)) return 0; return 1; } #define SIN6_ADDR(s) (&((struct sockaddr_in6 *)s)->sin6_addr) static Xauth *get_authptr(struct sockaddr *sockname, int display) { char *addr = 0; int addrlen = 0; unsigned short family; char hostnamebuf[256]; /* big enough for max hostname */ char dispbuf[40]; /* big enough to hold more than 2^64 base 10 */ int dispbuflen; family = FamilyLocal; /* 256 */ switch(sockname->sa_family) { #ifdef AF_INET6 case AF_INET6: addr = (char *) SIN6_ADDR(sockname); addrlen = sizeof(*SIN6_ADDR(sockname)); if(!IN6_IS_ADDR_V4MAPPED(SIN6_ADDR(sockname))) { if(!IN6_IS_ADDR_LOOPBACK(SIN6_ADDR(sockname))) family = XCB_FAMILY_INTERNET_6; break; } addr += 12; /* if v4-mapped, fall through. */ #endif case AF_INET: if(!addr) addr = (char *) &((struct sockaddr_in *)sockname)->sin_addr; addrlen = sizeof(((struct sockaddr_in *)sockname)->sin_addr); if(*(in_addr_t *) addr != htonl(INADDR_LOOPBACK)) family = XCB_FAMILY_INTERNET; break; case AF_UNIX: break; default: return 0; /* cannot authenticate this family */ } dispbuflen = snprintf(dispbuf, sizeof(dispbuf), "%d", display); if(dispbuflen < 0) return 0; /* snprintf may have truncate our text */ dispbuflen = MIN(dispbuflen, sizeof(dispbuf) - 1); if (family == FamilyLocal) { if (gethostname(hostnamebuf, sizeof(hostnamebuf)) == -1) return 0; /* do not know own hostname */ addr = hostnamebuf; addrlen = strlen(addr); } return XauGetBestAuthByAddr (family, (unsigned short) addrlen, addr, (unsigned short) dispbuflen, dispbuf, N_AUTH_PROTOS, authnames, authnameslen); } #ifdef HASXDMAUTH static int next_nonce(void) { static int nonce = 0; static pthread_mutex_t nonce_mutex = PTHREAD_MUTEX_INITIALIZER; int ret; pthread_mutex_lock(&nonce_mutex); ret = nonce++; pthread_mutex_unlock(&nonce_mutex); return ret; } static void do_append(char *buf, int *idxp, void *val, size_t valsize) { memcpy(buf + *idxp, val, valsize); *idxp += valsize; } #endif static int compute_auth(xcb_auth_info_t *info, Xauth *authptr, struct sockaddr *sockname) { if (authname_match(AUTH_MC1, authptr->name, authptr->name_length)) { info->datalen = memdup(&info->data, authptr->data, authptr->data_length); if(!info->datalen) return 0; return 1; } #ifdef HASXDMAUTH #define APPEND(buf,idx,val) do_append((buf),&(idx),&(val),sizeof(val)) if (authname_match(AUTH_XA1, authptr->name, authptr->name_length)) { int j; info->data = malloc(192 / 8); if(!info->data) return 0; for (j = 0; j < 8; j++) info->data[j] = authptr->data[j]; switch(sockname->sa_family) { case AF_INET: /*block*/ { struct sockaddr_in *si = (struct sockaddr_in *) sockname; APPEND(info->data, j, si->sin_addr.s_addr); APPEND(info->data, j, si->sin_port); } break; #ifdef AF_INET6 case AF_INET6: /*block*/ { struct sockaddr_in6 *si6 = (struct sockaddr_in6 *) sockname; if(IN6_IS_ADDR_V4MAPPED(SIN6_ADDR(sockname))) { do_append(info->data, &j, &si6->sin6_addr.s6_addr[12], 4); APPEND(info->data, j, si6->sin6_port); } else { /* XDM-AUTHORIZATION-1 does not handle IPv6 correctly. Do the same thing Xlib does: use all zeroes for the 4-byte address and 2-byte port number. */ uint32_t fakeaddr = 0; uint16_t fakeport = 0; APPEND(info->data, j, fakeaddr); APPEND(info->data, j, fakeport); } } break; #endif case AF_UNIX: /*block*/ { uint32_t fakeaddr = htonl(0xffffffff - next_nonce()); uint16_t fakeport = htons(getpid()); APPEND(info->data, j, fakeaddr); APPEND(info->data, j, fakeport); } break; default: free(info->data); return 0; /* do not know how to build this */ } { uint32_t now = htonl(time(0)); APPEND(info->data, j, now); } assert(j <= 192 / 8); while (j < 192 / 8) info->data[j++] = 0; info->datalen = j; XdmcpWrap ((unsigned char *) info->data, (unsigned char *) authptr->data + 8, (unsigned char *) info->data, info->datalen); return 1; } #undef APPEND #endif return 0; /* Unknown authorization type */ } /* `sockaddr_un.sun_path' typical size usually ranges between 92 and 108 */ #define INITIAL_SOCKNAME_SLACK 108 #ifndef WIN32 typedef int (*LPFN_GETPEERNAME)(int,struct sockaddr *,socklen_t *); #endif /* Return a dynamically allocated socket address structure according to the value returned by either getpeername() or getsockname() (according to POSIX, applications should not assume a particular length for `sockaddr_un.sun_path') */ static struct sockaddr *get_peer_sock_name(LPFN_GETPEERNAME socket_func, int fd) { socklen_t socknamelen = sizeof(struct sockaddr) + INITIAL_SOCKNAME_SLACK; socklen_t actual_socknamelen = socknamelen; struct sockaddr *sockname = malloc(socknamelen), *new_sockname = NULL; if (sockname == NULL) return NULL; /* Both getpeername() and getsockname() truncates sockname if there is not enough space and set the required length in actual_socknamelen */ if (socket_func(fd, sockname, &actual_socknamelen) == -1) goto sock_or_realloc_error; if (actual_socknamelen > socknamelen) { socknamelen = actual_socknamelen; if ((new_sockname = realloc(sockname, actual_socknamelen)) == NULL || socket_func(fd, new_sockname, &actual_socknamelen) == -1 || actual_socknamelen > socknamelen) goto sock_or_realloc_error; sockname = new_sockname; } return sockname; sock_or_realloc_error: free(sockname); return NULL; } int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display) { /* code adapted from Xlib/ConnDis.c, xtrans/Xtranssocket.c, xtrans/Xtransutils.c */ struct sockaddr *sockname = NULL; int gotsockname = 0; Xauth *authptr = 0; int ret = 1; /* Some systems like hpux or Hurd do not expose peer names * for UNIX Domain Sockets, but this is irrelevant, * since compute_auth() ignores the peer name in this * case anyway.*/ if ((sockname = get_peer_sock_name(getpeername, fd)) == NULL) { if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL) return 0; /* can only authenticate sockets */ if (sockname->sa_family != AF_UNIX) { free(sockname); return 0; /* except for AF_UNIX, sockets should have peernames */ } gotsockname = 1; } authptr = get_authptr(sockname, display); if (authptr == 0) { free(sockname); return 0; /* cannot find good auth data */ } info->namelen = memdup(&info->name, authptr->name, authptr->name_length); if (!info->namelen) goto no_auth; /* out of memory */ if (!gotsockname) { free(sockname); if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL) { free(info->name); goto no_auth; /* can only authenticate sockets */ } } ret = compute_auth(info, authptr, sockname); if(!ret) { free(info->name); goto no_auth; /* cannot build auth record */ } free(sockname); sockname = NULL; XauDisposeAuth(authptr); return ret; no_auth: free(sockname); info->name = 0; info->namelen = 0; XauDisposeAuth(authptr); return 0; }