/* SAMHAIN file system integrity testing */ /* Copyright (C) 1999, 2000 Rainer Wichmann */ /* */ /* This program is free software; you can redistribute it */ /* and/or modify */ /* it under the terms of the GNU General Public License as */ /* published by */ /* the Free Software Foundation; either version 2 of the License, or */ /* (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU General Public License for more details. */ /* */ /* You should have received a copy of the GNU General Public License */ /* along with this program; if not, write to the Free Software */ /* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "config_xor.h" #include #include #include #ifdef HAVE_MEMORY_H #include #endif #if TIME_WITH_SYS_TIME #include #include #else #if HAVE_SYS_TIME_H #include #else #include #endif #endif #include #include #include #include #include #include #include #include #ifdef HAVE_SYS_SELECT_H #include #endif #include #include "samhain.h" #include "sh_utils.h" #include "sh_unix.h" #include "sh_tiger.h" #include "sh_calls.h" #undef FIL__ #define FIL__ _("sh_entropy.c") #if defined (HAVE_EGD_RANDOM) /* rndegd.c - interface to the EGD * Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc. */ #include #include #include static int do_write( int fd, void *buf, size_t nbytes ) { size_t nleft = nbytes; int nwritten; while( nleft > 0 ) { nwritten = write( fd, buf, nleft); if( nwritten < 0 ) { if( errno == EINTR ) continue; return -1; } nleft -= nwritten; buf = (char*)buf + nwritten; } return 0; } static int do_read( int fd, void *buf, int nbytes ) { int n, nread = 0; if (nbytes < 0) return 0; do { do { n = read(fd, (char*)buf + nread, nbytes ); } while( n == -1 && errno == EINTR ); if( n == -1 ) return -1; nread += n; } while( nread < nbytes ); return nbytes; } int sh_entropy(int getbytes, char * nbuf) { static int fd = -1; int n; byte buffer[256+2]; int nbytes; int do_restart = 0; int myerror = 0; int length; char * p = nbuf; int i; SL_ENTER(_("sh_entropy")); if( getbytes <= 0) SL_RETURN( -1, _("sh_entropy")); if (getbytes > KEY_BYT) getbytes = KEY_BYT; length = getbytes; restart: if( do_restart ) { if( fd != -1 ) { close( fd ); fd = -1; } } if( fd == -1 ) { const char *bname = NULL; char *name; struct sockaddr_un addr; int addr_len; #ifdef EGD_SOCKET_NAME bname = EGD_SOCKET_NAME; #endif if ( !bname || !*bname ) bname = _("=entropy"); if ( *bname == '=' && bname[1] ) name = sh_util_strconcat ( DEFAULT_DATAROOT, "/", bname+1 , NULL ); else name = sh_util_strconcat ( bname , NULL ); if ( strlen(name)+1 >= sizeof(addr.sun_path) ) { sh_error_handle ((-1), FIL__, __LINE__, ENAMETOOLONG, MSG_E_SUBGEN, _("EGD socketname is too long"), _("sh_entropy") ); SH_FREE(name); SL_RETURN( -1, _("sh_entropy") ); } memset( &addr, 0, sizeof(addr) ); addr.sun_family = AF_UNIX; sl_strlcpy( addr.sun_path, name, sizeof(addr.sun_path) ); addr_len = offsetof( struct sockaddr_un, sun_path ) + strlen( addr.sun_path ); fd = socket(AF_UNIX, SOCK_STREAM, 0); if( fd == -1 ) { myerror = errno; sh_error_handle ((-1), FIL__, __LINE__, myerror, MSG_E_SUBGEN, _("cannot create unix domain socket"), _("sh_entropy") ); SH_FREE(name); SL_RETURN( -1, _("sh_entropy") ); } if( connect( fd, (struct sockaddr*)&addr, addr_len) == -1 ) { myerror = errno; sh_error_handle ((-1), FIL__, __LINE__, myerror, MSG_E_SUBGEN, _("cannot connect to unix domain socket"), _("sh_entropy") ); SH_FREE(name); SL_RETURN( -1, _("sh_entropy") ); } SH_FREE(name); } do_restart = 0; nbytes = length < 255? length : 255; /* first time we do it with a non blocking request */ buffer[0] = 1; /* non blocking */ buffer[1] = nbytes; if( do_write( fd, buffer, 2 ) == -1 ) { myerror = errno; sh_error_handle ((-1), FIL__, __LINE__, myerror, MSG_E_SUBGEN, _("cannot write to EGD"), _("sh_entropy") ); SL_RETURN( -1, _("sh_entropy") ); } n = do_read( fd, buffer, 1 ); if( n == -1 ) { myerror = errno; sh_error_handle (SH_ERR_ALL, FIL__, __LINE__, myerror, MSG_E_SUBGEN, _("read error on EGD"), _("sh_entropy") ); do_restart = 1; goto restart; } n = buffer[0]; if( n ) { n = do_read( fd, buffer, n ); if( n == -1 ) { myerror = errno; sh_error_handle (SH_ERR_ALL, FIL__, __LINE__, myerror,MSG_E_SUBGEN, _("read error on EGD"), _("sh_entropy") ); do_restart = 1; goto restart; } for (i = 0; i < n; ++i) { if (getbytes >= 0) { *p = buffer[i]; ++p; --getbytes; } } length -= n; } while( length ) { nbytes = length < 255? length : 255; buffer[0] = 2; /* blocking */ buffer[1] = nbytes; if( do_write( fd, buffer, 2 ) == -1 ) { myerror = errno; sh_error_handle ((-1), FIL__, __LINE__, myerror, MSG_E_SUBGEN, _("cannot write to EGD"), _("sh_entropy") ); SL_RETURN( -1, _("sh_entropy") ); } n = do_read( fd, buffer, nbytes ); if( n == -1 ) { myerror = errno; sh_error_handle (SH_ERR_ALL, FIL__, __LINE__, myerror,MSG_E_SUBGEN, _("read error on EGD"), _("sh_entropy") ); do_restart = 1; goto restart; } for (i = 0; i < n; ++i) { if (getbytes >= 0) { *p = buffer[i]; ++p; --getbytes; } } length -= n; } memset(buffer, 0, sizeof(buffer) ); SL_RETURN( 0, _("sh_entropy") ); /* success */ } /* HAVE_EGD_RANDOM */ #endif #if defined (HAVE_URANDOM) #include static jmp_buf entropy_timeout; static void sh_entropy_alarmhandle (int mysignal) { (void) mysignal; /* avoid compiler warning */ longjmp (entropy_timeout, 1); } int read_mbytes(int timeout_val, char * path, char * nbuf, int nbytes) { int count, m_count; int fd2; struct sigaction new_act; sigset_t unblock; struct sigaction old_act; volatile unsigned int old_alarm = 0; new_act.sa_handler = sh_entropy_alarmhandle; sigemptyset( &new_act.sa_mask ); /* set an empty mask */ new_act.sa_flags = 0; /* init sa_flags */ sigemptyset(&unblock); sigaddset (&unblock, SIGALRM); SL_ENTER(_("read_mbytes")); if ((fd2 = aud_open (FIL__, __LINE__, SL_NOPRIV, path, O_RDONLY, 0)) >= 0) { /* Test whether file is a character device, and is * not world writeable. */ if (0 == sh_unix_file_exists(fd2)) { /* alarm was triggered */ if (setjmp(entropy_timeout) != 0) { alarm(0); sigaction (SIGALRM, &old_act, NULL); alarm(old_alarm); sigprocmask(SIG_UNBLOCK, &unblock, NULL); TPT((0,FIL__,__LINE__, _("msg=\n"))); close (fd2); SL_RETURN(0, _("read_mbytes")); } /* timeout after 30 seconds */ old_alarm = alarm(0); sigaction (SIGALRM, &new_act, &old_act); alarm(timeout_val); m_count = 0; while (m_count < nbytes) { errno = 0; /* paranoia */ count = read (fd2, &nbuf[m_count], nbytes-m_count); switch (count) { case -1: #ifdef EWOULDBLOCK if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) #else if (errno == EINTR || errno == EAGAIN) #endif continue; /* if errno == -1 && no continue: fallthrough to this */ case 0: break; default: m_count += count; } } close (fd2); alarm(0); sigaction (SIGALRM, &old_act, NULL); alarm(old_alarm); sigprocmask(SIG_UNBLOCK, &unblock, NULL); } else m_count = 0; } else m_count = 0; TPT((0, FIL__, __LINE__, _("msg=\n"))); SL_RETURN(m_count, _("read_mbytes")); } /* Read nbytes bytes from /dev/random, mix them with * previous reads using a hash function, and give out * nbytes bytes from the result. */ int sh_entropy(int nbytes, char * nbuf) { int i, m_count = 0; char * keybuf; char addbuf[2 * KEY_BYT]; SL_ENTER(_("sh_entropy")); ASSERT((nbytes <= KEY_BYT), _("nbytes <= KEY_BYT")) if (nbytes > KEY_BYT) nbytes = KEY_BYT; memset(nbuf, '\0', nbytes); #ifdef NAME_OF_DEV_URANDOM m_count = read_mbytes (30, NAME_OF_DEV_RANDOM, nbuf, nbytes); #else m_count = read_mbytes (300, NAME_OF_DEV_RANDOM, nbuf, nbytes); #endif if (m_count == 0) { #ifdef NAME_OF_DEV_URANDOM sh_error_handle (SH_ERR_NOTICE, FIL__, __LINE__, EIO, MSG_NODEV, (long) sh.real.uid, NAME_OF_DEV_RANDOM); #else sh_error_handle ((-1), FIL__, __LINE__, EIO, MSG_NODEV, (long) sh.real.uid, NAME_OF_DEV_RANDOM); #endif } #ifdef NAME_OF_DEV_URANDOM if (m_count < nbytes) { i = read_mbytes(30, NAME_OF_DEV_URANDOM, &nbuf[m_count], nbytes-m_count); if (i == 0) sh_error_handle ((-1), FIL__, __LINE__, EIO, MSG_NODEV, (long) sh.real.uid, NAME_OF_DEV_URANDOM); else m_count += i; } #endif if (m_count > 0) { /* -- Add previous entropy into the new pool. -- */ memset(addbuf, '\0', sizeof(addbuf)); for (i = 0; i < m_count; ++i) addbuf[i] = nbuf[i]; for (i = 0; i < KEY_BYT; ++i) addbuf[i+KEY_BYT] = skey->poolv[i]; keybuf = (char *) sh_tiger_hash_uint32 (addbuf, TIGER_DATA, 2 * KEY_BYT); memset(addbuf, '\0', sizeof(addbuf)); /* -- Give out nbytes bytes from the new pool. -- */ for (i = 0; i < KEY_BYT; ++i) { skey->poolv[i] = keybuf[i]; if (i < nbytes) nbuf[i] = keybuf[i]; } memset (keybuf, '\0', KEY_BYT); SL_RETURN(0, _("sh_entropy")); } else { SL_RETURN((-1), _("sh_entropy")); } } /* HAVE_URANDOM */ #endif #ifdef HAVE_UNIX_RANDOM #ifndef FD_SET #define NFDBITS 32 #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS))) #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS))) #endif /* !FD_SET */ #ifndef FD_SETSIZE #define FD_SETSIZE 32 #endif #ifndef FD_ZERO #define FD_ZERO(p) memset((char *)(p), '\0', sizeof(*(p))) #endif #include "sh_static.h" static char * com_path[] = { N_("/usr/ucb/"), N_("/bin/"), N_("/sbin/"), N_("/usr/bin/"), N_("/usr/sbin/"), N_("/usr/local/bin/"), NULL }; typedef struct { char * command; char * arg; int pipeFD; pid_t pid; int isset; FILE * pipe; } sourcetable_t; static sourcetable_t source[] = { { N_("w"), N_("w"), 0, 0, 0, NULL }, { N_("netstat"), N_("netstat -n"), 0, 0, 0, NULL }, { N_("ps"), N_("ps -ef"), 0, 0, 0, NULL }, { N_("arp"), N_("arp -a"), 0, 0, 0, NULL }, { N_("free"), N_("free"), 0, 0, 0, NULL }, { N_("uptime"), N_("uptime"), 0, 0, 0, NULL }, { N_("procinfo"), N_("procinfo -a"), 0, 0, 0, NULL }, { N_("vmstat"), N_("vmstat"), 0, 0, 0, NULL }, { N_("w"), /* Play it again, Sam. */ N_("w"), 0, 0, 0, NULL }, { NULL, NULL, 0, 0, 0, NULL } }; static FILE * sh_popen (sourcetable_t *source, char * command) { int i; int pipedes[2]; FILE *outf = NULL; struct passwd * tempres; char * arg[4]; char * envp[2]; size_t len; SL_ENTER(_("sh_popen")); arg[0] = _("/bin/sh"); arg[1] = _("-c"); arg[2] = command; arg[3] = NULL; if (sh.timezone != NULL) { len = sl_strlen(sh.timezone) + 4; envp[0] = malloc (len); /* free() ok */ if (envp[0] != NULL) sl_snprintf (envp[0], len, "TZ=%s", sh.timezone); else envp[0] = NULL; envp[1] = NULL; } else { envp[0] = NULL; } /* Create the pipe */ if (aud_pipe(FIL__, __LINE__, pipedes) < 0) { if (envp[0] != NULL) free(envp[0]); SL_RETURN(NULL, _("sh_popen")); } source->pid = aud_fork(FIL__, __LINE__); /* Failure */ if (source->pid == (pid_t) - 1) { close(pipedes[0]); close(pipedes[1]); if (envp[0] != NULL) free(envp[0]); SL_RETURN(NULL, _("sh_popen")); } if (source->pid == (pid_t) 0) { /* child - make read side of the pipe stdout */ if (retry_aud_dup2(FIL__, __LINE__, pipedes[STDOUT_FILENO], STDOUT_FILENO) < 0) aud__exit(FIL__, __LINE__, EXIT_FAILURE); /* close the pipe descriptors */ close (pipedes[STDIN_FILENO]); close (pipedes[STDOUT_FILENO]); /* don't leak file descriptors */ sh_unix_closeall (3, -1); /* in child process */ /* zero priv info */ memset(skey, 0, sizeof(sh_key_t)); /* drop root privileges */ i = 0; if (0 == geteuid()) { tempres = sh_getpwnam(DEFAULT_IDENT); if (NULL != tempres) { i = aud_setgid(FIL__, __LINE__, tempres->pw_gid); if (i == 0) i = sh_unix_initgroups(DEFAULT_IDENT ,tempres->pw_gid); if (i == 0) i = aud_setuid(FIL__, __LINE__, tempres->pw_uid); /* make sure we cannot get root again */ if ((tempres->pw_uid != 0) && (aud_setuid(FIL__, __LINE__, 0) >= 0)) i = -1; } else { i = -1; } } /* some problem ... */ if (i == -1) { aud__exit(FIL__, __LINE__, EXIT_FAILURE); } freopen (_("/dev/null"), "r+", stderr); /* exec the program */ retry_aud_execve (FIL__, __LINE__, _("/bin/sh"), arg, envp); /* failed */ aud__exit(FIL__, __LINE__, EXIT_FAILURE); } /* parent */ if (envp[0] != NULL) free(envp[0]); close (pipedes[STDOUT_FILENO]); retry_fcntl (FIL__, __LINE__, pipedes[STDIN_FILENO], F_SETFD, FD_CLOEXEC); outf = fdopen (pipedes[STDIN_FILENO], "r"); if (outf == NULL) { aud_kill (FIL__, __LINE__, source->pid, SIGKILL); close (pipedes[STDOUT_FILENO]); waitpid (source->pid, NULL, 0); source->pid = 0; SL_RETURN(NULL, _("sh_popen")); } SL_RETURN(outf, _("sh_popen")); } static int sh_pclose (sourcetable_t *source) { int status = 0; SL_ENTER(_("sh_pclose")); status = fclose(source->pipe); if (status) { SL_RETURN((-1), _("sh_pclose")); } if (waitpid(source->pid, NULL, 0) != source->pid) status = -1; source->pipe = NULL; source->pid = 0; SL_RETURN(status, _("sh_pclose")); } #define BUF_ENT 32766 /* Poll the system for randomness, mix results with * previous reads using a hash function, and give out * nbytes bytes from the result. */ int sh_entropy(int nbytes, char * nbuf) { int caperr; char combuf[80]; char * buffer; int i, j, icount; int bufcount = 0; int count; char * keybuf; char addbuf[2 * KEY_BYT]; struct timeval tv; fd_set fds; unsigned long select_now = 0; int maxFD = 0; int imax, selcount; SL_ENTER(_("sh_entropy")); ASSERT((nbytes <= KEY_BYT), _("nbytes <= KEY_BYT")) if (nbytes > KEY_BYT) nbytes = KEY_BYT; /* --- If there is entropy in the pool, return it. --- */ if (skey->poolc >= nbytes) { j = KEY_BYT - skey->poolc; for (i = 0; i < nbytes; ++i) { nbuf[i] = skey->poolv[i+j]; --skey->poolc; } SL_RETURN(0, _("sh_entropy")); } FD_ZERO(&fds); i = 0; icount = 0; buffer = SH_ALLOC(BUF_ENT+2); if (0 != (caperr = sl_get_cap_sub())) { sh_error_handle((-1), FIL__, __LINE__, caperr, MSG_E_SUBGEN, sh_error_message (caperr), _("sl_get_cap_sub")); } while (source[i].command != NULL) { j = 0; while (com_path[j] != NULL) { sl_strlcpy(combuf, _(com_path[j]), 80); sl_strlcat(combuf, _(source[i].command), 80); /* flawfinder: ignore */ if ( access (combuf, X_OK) == 0) { sl_strlcpy(combuf, _(com_path[j]), 80); sl_strlcat(combuf, _(source[i].arg), 80); sh_error_handle ((-1), FIL__, __LINE__, 0, MSG_ENSTART, combuf); break; } ++j; } /* Not found, try next command. */ if (com_path[j] == NULL) { ++i; continue; } /* Source exists */ source[i].pipe = sh_popen ( &source[i], combuf ); if (NULL != source[i].pipe) { source[i].pipeFD = fileno ( source[i].pipe ); sh_error_handle ((-1), FIL__, __LINE__, 0, MSG_ENEXEC, combuf, (long) source[i].pipeFD); maxFD = (source[i].pipeFD > maxFD) ? source[i].pipeFD : maxFD; retry_fcntl( FIL__, __LINE__, source[i].pipeFD, F_SETFL, O_NONBLOCK); FD_SET( source[i].pipeFD, &fds ); source[i].isset = 1; ++icount; } else { sh_error_handle ((-1), FIL__, __LINE__, EIO, MSG_ENFAIL, combuf); } ++i; } imax = i; tv.tv_sec = 1; tv.tv_usec = 0; bufcount = 0; while ( (icount > 0) && (bufcount < BUF_ENT) ) { if ( (selcount = select (maxFD+1, &fds, NULL, NULL, &tv)) == -1) break; /* reset timeout for select() */ tv.tv_sec = 1; tv.tv_usec = 0; /* timeout - let's not hang on forever */ if (selcount == 0) { ++select_now; sh_error_handle ((-1), FIL__, __LINE__, 0, MSG_ENTOUT, (unsigned long) select_now); if ( select_now > 9 ) break; } for (i = 0; i < imax; ++i) { if ( FD_ISSET (source[i].pipeFD, &fds) ) { count = fread (&buffer[bufcount], 1, BUF_ENT-bufcount, source[i].pipe ); if (count == 0) { if (0 != feof(source[i].pipe)) sh_error_handle ((-1), FIL__, __LINE__, EIO, MSG_ENCLOS, (long) source[i].pipeFD); else sh_error_handle ((-1), FIL__, __LINE__, EIO, MSG_ENCLOS1, (long) source[i].pipeFD); source[i].isset = 0; sh_pclose ( &source[i] ); --icount; } else { sh_error_handle ((-1), FIL__, __LINE__, 0, MSG_ENREAD, (long) source[i].pipeFD, (long) count); } bufcount += count; } } maxFD = 0; FD_ZERO(&fds); for (i = 0; i < imax; ++i) { if (source[i].isset == 1) { FD_SET( source[i].pipeFD, &fds ); maxFD = (source[i].pipeFD > maxFD) ? source[i].pipeFD : maxFD; } } } for (i = 0; i < imax; ++i) { if (source[i].isset == 1) { sh_error_handle ((-1), FIL__, __LINE__, 0, MSG_ENCLOS1, (long) source[i].pipeFD); sh_pclose ( &source[i] ); } } buffer[bufcount] = '\0'; if (0 != (caperr = sl_drop_cap_sub())) { sh_error_handle((-1), FIL__, __LINE__, caperr, MSG_E_SUBGEN, sh_error_message (caperr), _("sl_drop_cap_sub")); } if (bufcount > 0) { keybuf = (char *) sh_tiger_hash_uint32 (buffer, TIGER_DATA, sl_strlen(buffer)); /* add previous entropy into the new pool */ memset(addbuf, '\0', sizeof(addbuf)); for (i = 0; i < KEY_BYT; ++i) { addbuf[i] = keybuf[i]; addbuf[i+KEY_BYT] = skey->poolv[i]; } keybuf = (char *) sh_tiger_hash_uint32 (addbuf, TIGER_DATA, sizeof(addbuf)); memset(addbuf, '\0', sizeof(addbuf)); /* store in system pool */ for (i = 0; i < KEY_BYT; ++i) skey->poolv[i] = keybuf[i]; skey->poolc = KEY_BYT; memset (buffer, '\0', BUF_ENT+2); memset (keybuf, '\0', KEY_BYT); SH_FREE(buffer); } else { SH_FREE(buffer); SL_RETURN((-1), _("sh_entropy")); } /* give out nbytes Bytes from the entropy pool */ for (i = 0; i < nbytes; ++i) { nbuf[i] = skey->poolv[i]; --skey->poolc; } SL_RETURN(0, _("sh_entropy")); } /* HAVE_UNIX_RANDOM */ #endif