X-Git-Url: https://git.armaanb.net/?p=opendoas.git;a=blobdiff_plain;f=doas.c;h=d348d2554b6f23a5c364ccccc8c8ce64cc09bf58;hp=6f644ece7a935b0b958bc8a8f06f2b52e07737db;hb=HEAD;hpb=09843fcf8876df1ab1728e9c2c49de4836b25626 diff --git a/doas.c b/doas.c index 6f644ec..d348d25 100644 --- a/doas.c +++ b/doas.c @@ -15,10 +15,16 @@ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ +#include "config.h" + #include #include +#include #include +#ifdef HAVE_LOGIN_CAP_H +#include +#endif #include #include #include @@ -28,40 +34,20 @@ #include #include #include +#include +#include -#include "includes.h" - +#include "openbsd.h" #include "doas.h" -static void __dead -version(void) -{ - fprintf(stderr, "doas: version %s built %s\n", VERSION, __DATE__); - exit(1); -} - static void __dead usage(void) { - fprintf(stderr, "usage: doas [-nsv] [-a style] [-C config] [-u user]" + fprintf(stderr, "usage: doas [-Lns] [-C config] [-u user]" " command [args]\n"); exit(1); } -size_t -arraylen(const char **arr) -{ - size_t cnt = 0; - - if (arr) { - while (*arr) { - cnt++; - arr++; - } - } - return cnt; -} - static int parseuid(const char *s, uid_t *uid) { @@ -70,9 +56,11 @@ parseuid(const char *s, uid_t *uid) if ((pw = getpwnam(s)) != NULL) { *uid = pw->pw_uid; + if (*uid == UID_MAX) + return -1; return 0; } - *uid = strtonum(s, 0, UID_MAX, &errstr); + *uid = strtonum(s, 0, UID_MAX - 1, &errstr); if (errstr) return -1; return 0; @@ -98,9 +86,11 @@ parsegid(const char *s, gid_t *gid) if ((gr = getgrnam(s)) != NULL) { *gid = gr->gr_gid; + if (*gid == GID_MAX) + return -1; return 0; } - *gid = strtonum(s, 0, GID_MAX, &errstr); + *gid = strtonum(s, 0, GID_MAX - 1, &errstr); if (errstr) return -1; return 0; @@ -147,10 +137,10 @@ match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd, } static int -permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr, +permit(uid_t uid, gid_t *groups, int ngroups, const struct rule **lastr, uid_t target, const char *cmd, const char **cmdargs) { - int i; + size_t i; *lastr = NULL; for (i = 0; i < nrules; i++) { @@ -190,112 +180,15 @@ parseconfig(const char *filename, int checkperms) exit(1); } -/* - * Copy the environment variables in safeset from oldenvp to envp. - */ -static int -copyenvhelper(const char **oldenvp, const char **safeset, size_t nsafe, - char **envp, int ei) -{ - size_t i; - - 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++; - } - } - return ei; -} - -static char ** -copyenv(const char **oldenvp, struct rule *rule) -{ - const char *safeset[] = { - "DISPLAY", "HOME", "LOGNAME", "MAIL", - "PATH", "TERM", "USER", "USERNAME", - NULL - }; - const char *badset[] = { - "ENV", - NULL - }; - char **envp; - const char **extra; - int ei; - size_t nsafe, nbad; - size_t nextras = 0; - - /* if there was no envvar whitelist, pass all except badset ones */ - nbad = arraylen(badset); - if ((rule->options & KEEPENV) && !rule->envlist) { - size_t iold, inew; - size_t oldlen = arraylen(oldenvp); - envp = reallocarray(NULL, oldlen + 1, sizeof(char *)); - if (!envp) - err(1, "reallocarray"); - for (inew = iold = 0; iold < oldlen; iold++) { - size_t ibad; - for (ibad = 0; ibad < nbad; ibad++) { - size_t len = strlen(badset[ibad]); - if (strncmp(oldenvp[iold], badset[ibad], len) == 0 && - oldenvp[iold][len] == '=') { - break; - } - } - if (ibad == nbad) { - if (!(envp[inew] = strdup(oldenvp[iold]))) - err(1, "strdup"); - inew++; - } - } - envp[inew] = NULL; - return envp; - } - - nsafe = arraylen(safeset); - if ((extra = rule->envlist)) { - size_t isafe; - nextras = arraylen(extra); - for (isafe = 0; isafe < nsafe; isafe++) { - size_t iextras; - for (iextras = 0; iextras < nextras; iextras++) { - if (strcmp(extra[iextras], safeset[isafe]) == 0) { - nextras--; - extra[iextras] = extra[nextras]; - extra[nextras] = NULL; - iextras--; - } - } - } - } - - 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 checkconfig(const char *confpath, int argc, char **argv, uid_t uid, gid_t *groups, int ngroups, uid_t target) { - struct rule *rule; + const struct rule *rule; + + if (setresuid(uid, uid, uid) != 0) + err(1, "setresuid"); - setresuid(uid, uid, uid); parseconfig(confpath, 0); if (!argc) exit(0); @@ -311,57 +204,97 @@ checkconfig(const char *confpath, int argc, char **argv, } int -main(int argc, char **argv, char **envp) +mygetpwuid_r(uid_t uid, struct passwd *pwd, struct passwd **result) +{ + int rv; + char *buf; + static long pwsz = 0; + size_t buflen; + + *result = NULL; + + if (pwsz == 0) + pwsz = sysconf(_SC_GETPW_R_SIZE_MAX); + + buflen = pwsz > 0 ? pwsz : 1024; + + buf = malloc(buflen); + if (buf == NULL) + return errno; + + while ((rv = getpwuid_r(uid, pwd, buf, buflen, result)) == ERANGE) { + size_t newsz; + newsz = buflen * 2; + if (newsz < buflen) + return rv; + buflen = newsz; + buf = realloc(buf, buflen); + if (buf == NULL) + return errno; + } + + return rv; +} + +void +authfail(int opt) +{ + +#ifdef DOAS_INSULTS + if (opt) + printf("%s\n", getinsult()); +#endif + + errx(1, "Authentication failed"); +} + +int +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 *p; const char *cmd; char cmdline[LINE_MAX]; - char myname[_PW_NAME_LEN + 1]; - struct passwd *pw; - struct rule *rule; + 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; - int vflag = 0; char cwdpath[PATH_MAX]; const char *cwd; -#ifdef HAVE_BSD_AUTH_H - char *login_style = NULL; -#endif + char **envp; - setprogname("doas"); + if (argc <= 0 || argv == NULL || argv[0] == NULL) { + fprintf(stderr, "doas: executed without argv\n"); + exit(1); + } - if (pledge("stdio rpath getpw tty proc exec id", NULL) == -1) - err(1, "pledge"); + setprogname("doas"); - /* closefrom(STDERR_FILENO + 1); */ + closefrom(STDERR_FILENO + 1); uid = getuid(); -#ifdef HAVE_BSD_AUTH_H -# define OPTSTRING "a:C:nsu:v" -#else -# define OPTSTRING "C:nsu:v" -#endif - - while ((ch = getopt(argc, argv, OPTSTRING)) != -1) { + while ((ch = getopt(argc, argv, "+C:Lnsu:")) != -1) { switch (ch) { -#ifdef HAVE_BSD_AUTH_H - case 'a': - login_style = optarg; - break; -#endif case 'C': confpath = optarg; break; + case 'L': +#if defined(USE_TIMESTAMP) + exit(timestamp_clear() == -1); +#else + exit(0); +#endif case 'u': if (parseuid(optarg, &target) != 0) errx(1, "unknown user"); @@ -372,9 +305,6 @@ main(int argc, char **argv, char **envp) case 's': sflag = 1; break; - case 'v': - vflag = 1; - break; default: usage(); break; @@ -383,20 +313,17 @@ main(int argc, char **argv, char **envp) argv += optind; argc -= optind; - if (vflag) - version(); - if (confpath) { if (sflag) usage(); } else if ((!sflag && !argc) || (sflag && argc)) usage(); - 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"); + rv = mygetpwuid_r(uid, &mypwstore, &mypw); + if (rv != 0) + err(1, "getpwuid_r failed"); + if (mypw == NULL) + errx(1, "no passwd entry for self"); ngroups = getgroups(NGROUPS_MAX, groups); if (ngroups == -1) err(1, "can't get groups"); @@ -404,9 +331,9 @@ 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; @@ -418,10 +345,13 @@ main(int argc, char **argv, char **envp) exit(1); /* fail safe */ } - parseconfig("/etc/doas.conf", 1); + if (geteuid()) + errx(1, "not installed setuid"); + + parseconfig(DOAS_CONF, 1); /* cmdline is used only for logging, no need to abort on truncate */ - (void) strlcpy(cmdline, argv[0], sizeof(cmdline)); + (void)strlcpy(cmdline, argv[0], sizeof(cmdline)); for (i = 1; i < argc; i++) { if (strlcat(cmdline, " ", sizeof(cmdline)) >= sizeof(cmdline)) break; @@ -431,87 +361,74 @@ main(int argc, char **argv, char **envp) cmd = argv[0]; if (!permit(uid, groups, ngroups, &rule, target, cmd, - (const char**)argv + 1)) { + (const char **)argv + 1)) { syslog(LOG_AUTHPRIV | LOG_NOTICE, - "failed command for %s: %s", myname, cmdline); + "command not permitted for %s: %s", mypw->pw_name, cmdline); errc(1, EPERM, NULL); } -#ifdef HAVE_BSD_AUTH_H if (!(rule->options & NOPASS)) { if (nflag) - errx(1, "Authorization required"); - - char *challenge = NULL, *response, rbuf[1024], cbuf[128]; - auth_session_t *as; - - 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)) { - syslog(LOG_AUTHPRIV | LOG_NOTICE, - "failed auth for %s", myname); - errc(1, EPERM, NULL); - } - explicit_bzero(rbuf, sizeof(rbuf)); - } -#elif HAVE_PAM_APPL_H - if (!doas_pam(myname, !nflag, rule->options & NOPASS)) { - syslog(LOG_AUTHPRIV | LOG_NOTICE, - "failed auth for %s", myname); - errc(1, EPERM, NULL); + errx(1, "Authentication required"); + + int ret = shadowauth(mypw->pw_name, rule->options & PERSIST); + if (ret == 5) + authfail(rule->options & INSULT); } -#else - if (!(rule->options & NOPASS)) { - errx(1, "Authorization required"); -#endif /* HAVE_BSD_AUTH_H */ - if (pledge("stdio rpath getpw exec id", NULL) == -1) - err(1, "pledge"); + if ((p = getenv("PATH")) != NULL) + formerpath = strdup(p); + if (formerpath == NULL) + formerpath = ""; - pw = getpwuid(target); - if (!pw) + if (rule->cmd) { + if (setenv("PATH", safepath, 1) == -1) + err(1, "failed to set PATH '%s'", safepath); + } + + rv = mygetpwuid_r(target, &targpwstore, &targpw); + if (rv != 0) + err(1, "getpwuid_r failed"); + if (targpw == NULL) errx(1, "no passwd entry for target"); - if (setusercontext(NULL, pw, target, LOGIN_SETGROUP | +#ifdef HAVE_LOGIN_CAP_H + if (setusercontext(NULL, targpw, target, LOGIN_SETGROUP | + LOGIN_SETPATH | LOGIN_SETPRIORITY | LOGIN_SETRESOURCES | LOGIN_SETUMASK | LOGIN_SETUSER) != 0) errx(1, "failed to set user context for target"); - - if (pledge("stdio rpath exec", NULL) == -1) - err(1, "pledge"); +#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"); + if (setenv("PATH", safepath, 1) == -1) + err(1, "failed to set PATH '%s'", safepath); +#endif if (getcwd(cwdpath, sizeof(cwdpath)) == NULL) cwd = "(failed)"; else cwd = cwdpath; - if (pledge("stdio exec", NULL) == -1) - err(1, "pledge"); - - syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command %s as %s from %s", - myname, cmdline, pw->pw_name, cwd); + if (!(rule->options & NOLOG)) { + syslog(LOG_AUTHPRIV | LOG_INFO, + "%s ran command %s as %s from %s", + mypw->pw_name, cmdline, targpw->pw_name, cwd); + } - envp = copyenv((const char **)envp, rule); + envp = prepenv(rule, mypw, targpw); + /* setusercontext set path for the next process, so reset it for us */ if (rule->cmd) { if (setenv("PATH", safepath, 1) == -1) err(1, "failed to set PATH '%s'", safepath); + } else { + if (setenv("PATH", formerpath, 1) == -1) + err(1, "failed to set PATH '%s'", formerpath); } execvpe(cmd, argv, envp); if (errno == ENOENT)