X-Git-Url: https://git.armaanb.net/?p=opendoas.git;a=blobdiff_plain;f=doas.c;h=1fd0e9a9c455ab62e32b738019cc2f3fbb14a947;hp=a712bc3799970a2f6096d82ac16ed9ef1c3fd1ec;hb=dbc7d06b5bbf01652744423bd8825ea7b5e92f73;hpb=8fcb0f4187e02ff1c2cd4fcf2b92cb79c6251a54 diff --git a/doas.c b/doas.c index a712bc3..1fd0e9a 100644 --- a/doas.c +++ b/doas.c @@ -1,4 +1,4 @@ -/* $OpenBSD: doas.c,v 1.13 2015/07/20 01:00:48 tedu Exp $ */ +/* $OpenBSD: doas.c,v 1.52 2016/04/28 04:48:56 tedu Exp $ */ /* * Copyright (c) 2015 Ted Unangst * @@ -17,10 +17,13 @@ #include #include +#include #include -#include -#include +#if __OpenBSD__ +# include +# include +#endif #include #include #include @@ -31,27 +34,21 @@ #include #include +#include "includes.h" + #include "doas.h" static void __dead usage(void) { - fprintf(stderr, "usage: doas [-s] [-u user] command [args]\n"); + fprintf(stderr, "usage: doas [-Lns] " +#ifdef __OpenBSD__ + "[-a style] " +#endif + "[-C config] [-u user] command [args]\n"); exit(1); } -size_t -arraylen(const char **arr) -{ - size_t cnt = 0; - - while (*arr) { - cnt++; - arr++; - } - return cnt; -} - static int parseuid(const char *s, uid_t *uid) { @@ -80,30 +77,31 @@ uidcheck(const char *s, uid_t desired) return 0; } -static gid_t -strtogid(const char *s) +static int +parsegid(const char *s, gid_t *gid) { struct group *gr; const char *errstr; - gid_t gid; - if ((gr = getgrnam(s)) != NULL) - return gr->gr_gid; - gid = strtonum(s, 0, GID_MAX, &errstr); + if ((gr = getgrnam(s)) != NULL) { + *gid = gr->gr_gid; + return 0; + } + *gid = strtonum(s, 0, GID_MAX, &errstr); if (errstr) return -1; - return gid; + return 0; } static int match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd, - struct rule *r) + const char **cmdargs, struct rule *r) { int i; if (r->ident[0] == ':') { - gid_t rgid = strtogid(r->ident + 1); - if (rgid == -1) + gid_t rgid; + if (parsegid(r->ident + 1, &rgid) == -1) return 0; for (i = 0; i < ngroups; i++) { if (rgid == groups[i]) @@ -117,20 +115,34 @@ match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd, } if (r->target && uidcheck(r->target, target) != 0) return 0; - if (r->cmd && strcmp(r->cmd, cmd) != 0) - return 0; + if (r->cmd) { + if (strcmp(r->cmd, cmd)) + return 0; + if (r->cmdargs) { + /* if arguments were given, they should match explicitly */ + for (i = 0; r->cmdargs[i]; i++) { + if (!cmdargs[i]) + return 0; + if (strcmp(r->cmdargs[i], cmdargs[i])) + return 0; + } + if (cmdargs[i]) + return 0; + } + } return 1; } static int -permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr, - uid_t target, const char *cmd) +permit(uid_t uid, gid_t *groups, int ngroups, const struct rule **lastr, + uid_t target, const char *cmd, const char **cmdargs) { int i; *lastr = NULL; for (i = 0; i < nrules; i++) { - if (match(uid, groups, ngroups, target, cmd, rules[i])) + if (match(uid, groups, ngroups, target, cmd, + cmdargs, rules[i])) *lastr = rules[i]; } if (!*lastr) @@ -139,156 +151,176 @@ permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr, } static void -parseconfig(const char *filename) +parseconfig(const char *filename, int checkperms) { extern FILE *yyfp; extern int yyparse(void); struct stat sb; yyfp = fopen(filename, "r"); - if (!yyfp) { - fprintf(stderr, "doas is not enabled.\n"); - exit(1); + if (!yyfp) + err(1, checkperms ? "doas is not enabled, %s" : + "could not open config file %s", filename); + + if (checkperms) { + if (fstat(fileno(yyfp), &sb) != 0) + err(1, "fstat(\"%s\")", filename); + if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) + errx(1, "%s is writable by group or other", filename); + if (sb.st_uid != 0) + errx(1, "%s is not owned by root", filename); } - if (fstat(fileno(yyfp), &sb) != 0) - err(1, "fstat(\"%s\")", filename); - if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) - errx(1, "%s is writable by group or other", filename); - if (sb.st_uid != 0) - errx(1, "%s is not owned by root", filename); - yyparse(); fclose(yyfp); + if (parse_errors) + exit(1); } -static int -copyenvhelper(const char **oldenvp, const char **safeset, int nsafe, - char **envp, int ei) +static void __dead +checkconfig(const char *confpath, int argc, char **argv, + uid_t uid, gid_t *groups, int ngroups, uid_t target) { - int i; + const struct rule *rule; - for (i = 0; i < nsafe; i++) { - const char **oe = oldenvp; - while (*oe) { - size_t len = strlen(safeset[i]); - if (strncmp(*oe, safeset[i], len) == 0 && - (*oe)[len] == '=') { - if (!(envp[ei++] = strdup(*oe))) - err(1, "strdup"); - break; - } - oe++; - } + if (setresuid(uid, uid, uid) != 0) + err(1, "setresuid"); + + parseconfig(confpath, 0); + if (!argc) + exit(0); + + if (permit(uid, groups, ngroups, &rule, target, argv[0], + (const char **)argv + 1)) { + printf("permit%s\n", (rule->options & NOPASS) ? " nopass" : ""); + exit(0); + } else { + printf("deny\n"); + exit(1); } - return ei; } -static char ** -copyenv(const char **oldenvp, struct rule *rule) +#ifdef USE_BSD_AUTH +static void +authuser(char *myname, char *login_style, int persist) { - const char *safeset[] = { - "DISPLAY", "HOME", "LOGNAME", "MAIL", - "PATH", "TERM", "USER", "USERNAME", - NULL - }; - const char *badset[] = { - "ENV", - NULL - }; - char **envp; - const char **extra; - int ei; - int nsafe, nbad; - int nextras = 0; - - nbad = arraylen(badset); - if ((rule->options & KEEPENV) && !rule->envlist) { - size_t i, ii; - size_t oldlen = arraylen(oldenvp); - envp = reallocarray(NULL, oldlen + 1, sizeof(char *)); - if (!envp) - err(1, "reallocarray"); - for (ii = i = 0; i < oldlen; i++) { - size_t j; - for (j = 0; j < nbad; j++) { - size_t len = strlen(badset[j]); - if (strncmp(oldenvp[i], badset[j], len) == 0 && - oldenvp[i][len] == '=') { - break; - } - } - if (j == nbad) { - if (!(envp[ii] = strdup(oldenvp[i]))) - err(1, "strdup"); - ii++; - } - } - envp[ii] = NULL; - return envp; + char *challenge = NULL, *response, rbuf[1024], cbuf[128]; + auth_session_t *as; + int fd = -1; + + if (persist) + fd = open("/dev/tty", O_RDWR); + if (fd != -1) { + if (ioctl(fd, TIOCCHKVERAUTH) == 0) + goto good; } - nsafe = arraylen(safeset); - if ((extra = rule->envlist)) { - size_t i; - nextras = arraylen(extra); - for (i = 0; i < nsafe; i++) { - size_t j; - for (j = 0; j < nextras; j++) { - if (strcmp(extra[j], safeset[i]) == 0) { - extra[j--] = extra[nextras--]; - extra[nextras] = NULL; - } - } - } + if (!(as = auth_userchallenge(myname, login_style, "auth-doas", + &challenge))) + errx(1, "Authorization failed"); + if (!challenge) { + char host[HOST_NAME_MAX + 1]; + if (gethostname(host, sizeof(host))) + snprintf(host, sizeof(host), "?"); + snprintf(cbuf, sizeof(cbuf), + "\rdoas (%.32s@%.32s) password: ", myname, host); + challenge = cbuf; + } + response = readpassphrase(challenge, rbuf, sizeof(rbuf), + RPP_REQUIRE_TTY); + if (response == NULL && errno == ENOTTY) { + syslog(LOG_AUTHPRIV | LOG_NOTICE, + "tty required for %s", myname); + errx(1, "a tty is required"); + } + if (!auth_userresponse(as, response, 0)) { + explicit_bzero(rbuf, sizeof(rbuf)); + syslog(LOG_AUTHPRIV | LOG_NOTICE, + "failed auth for %s", myname); + errx(1, "Authorization failed"); + } + explicit_bzero(rbuf, sizeof(rbuf)); +good: + if (fd != -1) { + int secs = 5 * 60; + ioctl(fd, TIOCSETVERAUTH, &secs); + close(fd); } - - envp = reallocarray(NULL, nsafe + nextras + 1, sizeof(char *)); - if (!envp) - err(1, "can't allocate new environment"); - - ei = 0; - ei = copyenvhelper(oldenvp, safeset, nsafe, envp, ei); - ei = copyenvhelper(oldenvp, rule->envlist, nextras, envp, ei); - envp[ei] = NULL; - - return envp; -} - -static void __dead -fail(void) -{ - fprintf(stderr, "Permission denied\n"); - exit(1); } +#endif int -main(int argc, char **argv, char **envp) +main(int argc, char **argv) { const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:" "/usr/local/bin:/usr/local/sbin"; + const char *confpath = NULL; char *shargv[] = { NULL, NULL }; char *sh; const char *cmd; char cmdline[LINE_MAX]; - char myname[_PW_NAME_LEN + 1]; - struct passwd *pw; - struct rule *rule; +#ifdef __OpenBSD__ + char mypwbuf[_PW_BUF_LEN], targpwbuf[_PW_BUF_LEN]; +#else + char *mypwbuf = NULL, *targpwbuf = NULL; +#endif + struct passwd mypwstore, targpwstore; + struct passwd *mypw, *targpw; + const struct rule *rule; uid_t uid; uid_t target = 0; gid_t groups[NGROUPS_MAX + 1]; int ngroups; - int i, ch; + int i, ch, rv; int sflag = 0; + int nflag = 0; + char cwdpath[PATH_MAX]; + const char *cwd; + char **envp; +#ifdef USE_BSD_AUTH + char *login_style = NULL; +#endif + + setprogname("doas"); + + closefrom(STDERR_FILENO + 1); + + uid = getuid(); - parseconfig("/etc/doas.conf"); +#ifdef USE_BSD_AUTH +# define OPTSTRING "a:C:Lnsu:" +#else +# define OPTSTRING "+C:Lnsu:" +#endif - while ((ch = getopt(argc, argv, "su:")) != -1) { + while ((ch = getopt(argc, argv, OPTSTRING)) != -1) { switch (ch) { +#ifdef USE_BSD_AUTH + case 'a': + login_style = optarg; + break; +#endif + case 'C': + confpath = optarg; + break; + case 'L': +#if defined(USE_BSD_AUTH) + i = open("/dev/tty", O_RDWR); + if (i != -1) + ioctl(i, TIOCCLRVERAUTH); + exit(i == -1); +#elif defined(USE_TIMESTAMP) + exit(timestamp_clear() == -1); +#else + exit(0); +#endif case 'u': if (parseuid(optarg, &target) != 0) errx(1, "unknown user"); break; + case 'n': + nflag = 1; + break; case 's': sflag = 1; break; @@ -300,15 +332,30 @@ main(int argc, char **argv, char **envp) argv += optind; argc -= optind; - if ((!sflag && !argc) || (sflag && argc)) + if (confpath) { + if (sflag) + usage(); + } else if ((!sflag && !argc) || (sflag && argc)) usage(); - uid = getuid(); - pw = getpwuid(uid); - if (!pw) - err(1, "getpwuid failed"); - if (strlcpy(myname, pw->pw_name, sizeof(myname)) >= sizeof(myname)) - errx(1, "pw_name too long"); +#ifdef __OpenBSD__ + rv = getpwuid_r(uid, &mypwstore, mypwbuf, sizeof(mypwbuf), &mypw); + if (rv != 0) + err(1, "getpwuid_r failed"); +#else + for (size_t sz = 1024; sz <= 16*1024; sz *= 2) { + mypwbuf = reallocarray(mypwbuf, sz, sizeof (char)); + if (mypwbuf == NULL) + errx(1, "can't allocate mypwbuf"); + rv = getpwuid_r(uid, &mypwstore, mypwbuf, sz, &mypw); + if (rv != ERANGE) + break; + } + if (rv != 0) + err(1, "getpwuid_r failed"); +#endif + if (mypw == NULL) + errx(1, "no passwd entry for self"); ngroups = getgroups(NGROUPS_MAX, groups); if (ngroups == -1) err(1, "can't get groups"); @@ -316,51 +363,128 @@ main(int argc, char **argv, char **envp) if (sflag) { sh = getenv("SHELL"); - if (sh == NULL || *sh == '\0') - shargv[0] = pw->pw_shell; - else + if (sh == NULL || *sh == '\0') { + shargv[0] = mypw->pw_shell; + } else shargv[0] = sh; argv = shargv; argc = 1; } - cmd = argv[0]; - if (strlcpy(cmdline, argv[0], sizeof(cmdline)) >= sizeof(cmdline)) - errx(1, "command line too long"); + if (confpath) { + checkconfig(confpath, argc, argv, uid, groups, ngroups, + target); + exit(1); /* fail safe */ + } + + if (geteuid()) + errx(1, "not installed setuid"); + + parseconfig("/etc/doas.conf", 1); + + /* cmdline is used only for logging, no need to abort on truncate */ + (void)strlcpy(cmdline, argv[0], sizeof(cmdline)); for (i = 1; i < argc; i++) { if (strlcat(cmdline, " ", sizeof(cmdline)) >= sizeof(cmdline)) - errx(1, "command line too long"); + break; if (strlcat(cmdline, argv[i], sizeof(cmdline)) >= sizeof(cmdline)) - errx(1, "command line too long"); + break; } - if (!permit(uid, groups, ngroups, &rule, target, cmd)) { + cmd = argv[0]; + if (!permit(uid, groups, ngroups, &rule, target, cmd, + (const char **)argv + 1)) { syslog(LOG_AUTHPRIV | LOG_NOTICE, - "failed command for %s: %s", myname, cmdline); - fail(); + "failed command for %s: %s", mypw->pw_name, cmdline); + errc(1, EPERM, NULL); } +#if defined(__OpenBSD__) || defined(USE_SHADOW) if (!(rule->options & NOPASS)) { - if (!auth_userokay(myname, NULL, NULL, NULL)) { - syslog(LOG_AUTHPRIV | LOG_NOTICE, - "failed password for %s", myname); - fail(); - } + if (nflag) + errx(1, "Authorization required"); + +# ifdef __OpenBSD__ + authuser(mypw->pw_name, login_style, rule->options & PERSIST); +# else + shadowauth(mypw->pw_name, rule->options & PERSIST); +# endif + } + +# ifdef __OpenBSD__ + if (pledge("stdio rpath getpw exec id", NULL) == -1) + err(1, "pledge"); +# endif + +#elif !defined(USE_PAM) + (void) nflag; + if (!(rule->options & NOPASS)) { + errx(1, "Authorization required"); } - envp = copyenv((const char **)envp, rule); +#endif /* !(__OpenBSD__ || USE_SHADOW) && !USE_PAM */ - pw = getpwuid(target); - if (!pw) +#ifdef __OpenBSD__ + rv = getpwuid_r(target, &targpwstore, targpwbuf, sizeof(targpwbuf), &targpw); + if (rv != 0) errx(1, "no passwd entry for target"); - if (setusercontext(NULL, pw, target, LOGIN_SETGROUP | +#else + for (size_t sz = 1024; sz <= 16*1024; sz *= 2) { + targpwbuf = reallocarray(targpwbuf, sz, sizeof (char)); + if (targpwbuf == NULL) + errx(1, "can't allocate targpwbuf"); + rv = getpwuid_r(target, &targpwstore, targpwbuf, sz, &targpw); + if (rv != ERANGE) + break; + } + if (rv != 0) + err(1, "getpwuid_r failed"); +#endif + if (targpw == NULL) + err(1, "getpwuid_r failed"); + +#if defined(USE_PAM) + pamauth(targpw->pw_name, mypw->pw_name, !nflag, rule->options & NOPASS, + rule->options & PERSIST); +#endif + +#ifdef HAVE_SETUSERCONTEXT + if (setusercontext(NULL, targpw, target, LOGIN_SETGROUP | LOGIN_SETPRIORITY | LOGIN_SETRESOURCES | LOGIN_SETUMASK | LOGIN_SETUSER) != 0) errx(1, "failed to set user context for target"); - - syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s", - myname, pw->pw_name, cmdline); - if (setenv("PATH", safepath, 1) == -1) - err(1, "failed to set PATH '%s'", safepath); +#else + if (setresgid(targpw->pw_gid, targpw->pw_gid, targpw->pw_gid) != 0) + err(1, "setresgid"); + if (initgroups(targpw->pw_name, targpw->pw_gid) != 0) + err(1, "initgroups"); + if (setresuid(target, target, target) != 0) + err(1, "setresuid"); +#endif + +#ifdef __OpenBSD__ + if (pledge("stdio rpath exec", NULL) == -1) + err(1, "pledge"); +#endif + + if (getcwd(cwdpath, sizeof(cwdpath)) == NULL) + cwd = "(failed)"; + else + cwd = cwdpath; + +#ifdef __OpenBSD__ + if (pledge("stdio exec", NULL) == -1) + err(1, "pledge"); +#endif + + syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command %s as %s from %s", + mypw->pw_name, cmdline, targpw->pw_name, cwd); + + envp = prepenv(rule); + + if (rule->cmd) { + if (setenv("PATH", safepath, 1) == -1) + err(1, "failed to set PATH '%s'", safepath); + } execvpe(cmd, argv, envp); if (errno == ENOENT) errx(1, "%s: command not found", cmd);