roken: Add roken_get_username() and friends

We add roken_get_{shell, username, appdatadir, homedir}() functions.  These use
a combination of secure_getenv(), getpwuid_r(), getlogin_r(), or various WIN32
functions to get this information.

Use roken_get_appdatadir() instead of roken_get_homedir() when looking for
dotfiles.

lib/krb5/expand_path.c

@@ -311,17 +311,17 @@ _expand_euid(krb5_context context, PTYPE param, const char *postfix, char **str)
 static krb5_error_code
 _expand_username(krb5_context context, PTYPE param, const char *postfix, char **str)
 {
-    uid_t uid = geteuid();
+    char user[128];
-    struct passwd *pwd, pw;
+    const char *username = roken_get_username(user, sizeof(user));
-    char pwbuf[2048];
 
-    if (rk_getpwuid_r(uid, &pw, pwbuf, sizeof(pwbuf), &pwd) != 0) {
+    if (username == NULL) {
-	krb5_set_error_message(context, ENOENT,
+	krb5_set_error_message(context, ENOTTY,
-			       "Could not find username for UID '%ld'", (long)uid);
+			       N_("unable to figure out current principal",
-	return ENOENT;
+			       ""));
+	return ENOTTY; /* XXX */
     }
 
-    *str = strdup(pwd->pw_name);
+    *str = strdup(username);
     if (*str == NULL)
 	return krb5_enomem(context);
 

lib/roken/Makefile.am

@@ -31,6 +31,7 @@ check_PROGRAMS = 				\
 		getxxyyy-test			\
 		hex-test			\
 		test-auxval			\
+		test-getuserinfo		\
 		test-readenv			\
 		resolve-test			\
 		parse_bytes-test		\
@@ -54,6 +55,8 @@ parse_reply_test_CFLAGS  = -DTEST_RESOLVE
 
 test_readenv_SOURCES = test-readenv.c test-mem.c
 test_auxval_SOURCES = test-auxval.c
+test_getuserinfo_SOURCES = test-getuserinfo.c
+test_getuserinfo_LDADD = libtest.la $(LDADD)
 
 test_detach_SOURCES = test-detach.c
 
@@ -99,6 +102,7 @@ libroken_la_SOURCES =		\
 	getauxval.h		\
 	getnameinfo_verified.c	\
 	getprogname.c		\
+	getuserinfo.c		\
 	getxxyyy.c		\
 	h_errno.c		\
 	hex.c			\

lib/roken/NTMakefile

@@ -67,6 +67,7 @@ libroken_la_OBJS =			\
 	$(OBJ)\getopt.obj		\
 	$(OBJ)\getprogname.obj		\
 	$(OBJ)\gettimeofday.obj		\
+	$(OBJ)\getuserinfo.obj		\
 	$(OBJ)\hex.obj			\
 	$(OBJ)\hostent_find_fqdn.obj	\
 	$(OBJ)\inet_aton.obj		\
@@ -184,7 +185,7 @@ all:: $(INCFILES) $(LIBROKEN)
 clean::
 	-$(RM) $(LIBROKEN)
 
-TMP_PROGS = $(OBJ)\snprintf-test.exe $(OBJ)\resolve-test.exe
+TMP_PROGS = $(OBJ)\snprintf-test.exe $(OBJ)\resolve-test.exe $(OBJ)\test-getuserinfo.exe
 
 # Tests
 
@@ -194,6 +195,7 @@ TEST_PROGS =			    \
 	$(OBJ)\getifaddrs-test.exe  \
 	$(OBJ)\hex-test.exe	    \
 	$(OBJ)\test-detach.exe	    \
+	$(OBJ)\test-getuserinfo.exe \
 	$(OBJ)\test-readenv.exe	    \
 	$(OBJ)\parse_bytes-test.exe \
 	$(OBJ)\parse_reply-test.exe \
@@ -260,6 +262,9 @@ $(OBJ)\parse_bytes-test.exe: $(OBJ)\parse_bytes-test.obj $(LIBROKEN)
 $(OBJ)\test-detach.exe: $(OBJ)\test-detach.obj $(OBJ)\detach.obj $(LIBROKEN)
 	$(EXECONLINK)
 
+$(OBJ)\test-getuserinfo.exe: $(OBJ)\test-getuserinfo.obj $(OBJ)\getuserinfo.obj $(LIBROKEN)
+	$(EXECONLINK) Secur32.lib Shell32.lib
+
 $(OBJ)\dirent-test.exe: $(OBJ)\dirent-test.obj $(LIBROKEN)
 	$(EXECONLINK)
 

lib/roken/getuserinfo.c

@@ -0,0 +1,334 @@
+/*
+ * Copyright (c) 2017 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * 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 Institute 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 BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE 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.
+ */
+
+#include <config.h>
+#include "roken.h"
+
+#ifdef WIN32
+#include <Shlobj.h>  // need to include definitions of constants
+#define SECURITY_WIN32
+#include <security.h>
+#else
+#include <sys/types.h>
+#include <pwd.h>
+#include <unistd.h>
+#endif
+
+/**
+ * Returns the user's SHELL.
+ */
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_shell(char *shell, size_t shellsz)
+{
+    char *p;
+
+#ifndef WIN32
+    char user[128];
+    const char *username = roken_get_username(user, sizeof(user));
+    size_t buflen = 2048;
+
+    if (sysconf(_SC_GETPW_R_SIZE_MAX) > 0)
+        buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+
+    if (issuid())
+        return "/bin/sh";
+
+    p = secure_getenv("SHELL");
+    if (p != NULL && p[0] != '\0') {
+        if (strlcpy(shell, p, shellsz) < shellsz)
+            return shell;
+        errno = ERANGE;
+        return NULL;
+    }
+
+#ifdef HAVE_GETPWNAM_R
+    {
+        struct passwd pwd;
+        struct passwd *pwdp;
+        char buf[buflen];
+
+        if (getpwnam_r(username, &pwd, buf, buflen, &pwdp) == 0 &&
+            pwdp != NULL && pwdp->pw_shell != NULL) {
+            if (strlcpy(shell, pwdp->pw_shell, shellsz) < shellsz)
+                return shell;
+            errno = ERANGE;
+            return NULL;
+        }
+    }
+#endif
+    return "/bin/sh";
+#else
+    /* Windows */
+    p = getenv("SHELL");
+    if (p != NULL && p[0] != '\0') {
+        if (strlcpy(shell, p, shellsz) < shellsz)
+            return shell;
+        errno = ERANGE;
+        return NULL;
+    }
+#endif
+    errno = 0;
+    return NULL;
+}
+
+/**
+ * Returns the home directory.
+ */
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_homedir(char *home, size_t homesz)
+{
+    char *p;
+
+#ifdef WIN32
+    if (homesz < MAX_PATH) {
+        errno = ERANGE;
+        return NULL;
+    }
+
+    if (SUCCEEDED(SHGetFolderPath(NULL, CSIDL_PROFILE, NULL,
+                                  SHGFP_TYPE_CURRENT, home)))
+        return home;
+
+    if ((p = getenv("HOMEDRIVE")) != NULL && p[0] != '\0') {
+        if (strlcpy(home, p, homesz) >= homesz) {
+            errno = ERANGE;
+            return NULL;
+        }
+        if ((p = getenv("HOMEPATH")) != NULL) {
+            if (strlcat(home, p, homesz) < homesz)
+                return home;
+            errno = ERANGE;
+            return NULL;
+        }
+        return home;
+    }
+    /* Fallthru to return NULL */
+#else
+    char user[128];
+    const char *username = roken_get_username(user, sizeof(user));
+    size_t buflen = 2048;
+
+    if (sysconf(_SC_GETPW_R_SIZE_MAX) > 0)
+        buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+
+    if (issuid()) {
+        errno = 0;
+        return NULL;
+    }
+
+    p = secure_getenv("HOME");
+    if (p != NULL && p[0] != '\0') {
+        if (strlcpy(home, p, homesz) < homesz)
+            return home;
+        errno = ERANGE;
+        return NULL;
+    }
+
+#ifdef HAVE_GETPWNAM_R
+    {
+        struct passwd pwd;
+        struct passwd *pwdp;
+        char buf[buflen];
+
+        if (getpwnam_r(username, &pwd, buf, buflen, &pwdp) == 0 &&
+            pwdp != NULL && pwdp->pw_dir != NULL) {
+            if (strlcpy(home, pwdp->pw_dir, homesz) < homesz)
+                return home;
+            errno = ERANGE;
+            return NULL;
+        }
+    }
+#endif
+#endif
+    errno = 0;
+    return NULL;
+}
+
+/**
+ * Returns the home directory on Unix, or the AppData directory on
+ * Windows.
+ */
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_appdatadir(char *appdata, size_t appdatasz)
+{
+#ifdef WIN32
+    char *p;
+#endif
+
+#ifndef WIN32
+    return roken_get_homedir(appdata, appdatasz);
+#else
+    if (appdatasz < MAX_PATH) {
+        errno = ERANGE;
+        return NULL;
+    }
+
+    if (SUCCEEDED(SHGetFolderPath(NULL, CSIDL_APPDATA, NULL,
+                                  SHGFP_TYPE_CURRENT, appdata)))
+        return appdata;
+
+    if ((p = getenv("APPDATA")) != NULL && p[0] != '\0') {
+        if (strlcpy(appdata, p, appdatasz) < appdatasz)
+            return appdata;
+        errno = ERANGE;
+        return NULL;
+    }
+
+    errno = 0;
+    return NULL;
+#endif
+}
+
+/**
+ * Return a bare username.  This is used for, e.g., constructing default
+ * principal names.
+ */
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_username(char *user, size_t usersz)
+{
+    char *p;
+
+#ifdef WIN32
+    ULONG sz = usersz;
+
+    if (GetUserNameEx(NameSamCompatible, user, &sz)) {
+        /*
+         * There's no EXTENDED_NAME_FORMAT for "bare username".  We we
+         * have to parse one.
+         */
+        p = strchr(user, '\\');
+        if (p != NULL) {
+            p++;
+            memmove(user, p, strlen(p));
+        }
+        return user;
+    } else {
+        DWORD err = GetLastError();
+        if (err == ERROR_MORE_DATA) {
+            errno = ERANGE;
+            return NULL;
+        }
+        /* %USERNAME% is generally bare */
+        p = getenv("USERNAME");
+        if (p != NULL && p[0] != '\0') {
+            if (strchr(p, '\\') != NULL)
+                p = strchr(p, '\\') + 1;
+            if (strlcpy(user, p, usersz) < usersz)
+                return user;
+            errno = ERANGE;
+            return NULL;
+        }
+    }
+#else
+    size_t buflen = 2048;
+
+    if (issuid())
+        return NULL;
+
+    if (getuid() == 0) {
+        /*
+         * NOTE: When the running process was not the result of executing a
+         * set-uid or set-gid executable, and it is running as root, then the
+         * username will preferentially be taken from the wtmp if at all
+         * possible.  This is depended on by _krb5_get_default_principal_local()
+         * in order to produce <username>/root@DEFAULT_REALM as the default
+         * principal.
+         */
+#ifdef HAVE_GETLOGIN_R
+        if ((errno = getlogin_r(user, usersz)) == 0)
+            return user;
+        if (errno != ENOENT)
+            return NULL;
+#else
+#ifdef HAVE_GETLOGIN
+        if ((p = getlogin()) != NULL && p[0] != '\0') {
+            if strlcpy(user, p, usersz) < usersz)
+                return user;
+            errno = ERANGE;
+            return NULL;
+        }
+        if (errno != ENOENT)
+            return NULL;
+#endif
+#endif
+    }
+
+    p = secure_getenv("USER");
+    if (p == NULL || p[0] == '\0')
+        p = secure_getenv("LOGNAME");
+    if (p != NULL && p[0] != '\0') {
+        if (strlcpy(user, p, usersz) < usersz)
+            return user;
+        errno = ERANGE;
+        return NULL;
+    }
+
+#ifdef HAVE_GETPWUID_R
+    if (sysconf(_SC_GETPW_R_SIZE_MAX) > 0)
+        buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+
+    {
+        struct passwd pwd;
+        struct passwd *pwdp;
+        char buf[buflen];
+
+        if (getpwuid_r(getuid(), &pwd, buf, buflen, &pwdp) == 0 &&
+            pwdp != NULL && pwdp->pw_name != NULL) {
+            if (strlcpy(user, pwdp->pw_name, usersz) < usersz)
+                return user;
+            errno = ERANGE;
+            return NULL;
+        }
+    }
+#endif
+#ifdef HAVE_GETLOGIN_R
+    if ((errno = getlogin_r(user, usersz)) == 0)
+        return user;
+    if (errno != ENOENT)
+        return NULL;
+#else
+#ifdef HAVE_GETLOGIN
+    if ((p = getlogin()) != NULL && p[0] != '\0') {
+        if (strlcpy(user, p, usersz) < usersz)
+            return user;
+        errno = ERANGE;
+        return NULL;
+    }
+    if (errno != ENOENT)
+        return NULL;
+#endif
+#endif
+#endif
+    errno = 0;
+    return NULL;
+}

lib/roken/roken.h.in

@@ -1010,6 +1010,15 @@ roken_getaddrinfo_hostspec(const char *, int, struct addrinfo **);
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 roken_getaddrinfo_hostspec2(const char *, int, int, struct addrinfo **);
 
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_homedir(char *, size_t);
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_appdatadir(char *, size_t);
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_username(char *, size_t);
+ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
+roken_get_shell(char *, size_t);
+
 #ifndef HAVE_STRFTIME
 #define strftime rk_strftime
 ROKEN_LIB_FUNCTION size_t ROKEN_LIB_CALL

lib/roken/test-getuserinfo.c

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2017 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * 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 Institute 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 BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE 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.
+ */
+
+#ifndef WIN32
+#include <err.h>
+#endif
+#include "roken.h"
+
+int
+main(void)
+{
+    char buf[MAX_PATH * 2];
+    char buf2[MAX_PATH * 2];
+#ifndef WIN32
+    int ret = 0;
+    if (!issuid() && getuid() != 0) {
+        if (getenv("USER") != NULL && strlen(getenv("USER")) != 0 &&
+            strcmp(getenv("USER"),
+                   roken_get_username(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_username() != getenv(\"USER\")");
+            ret++;
+        }
+        if (getenv("HOME") != NULL && strlen(getenv("HOME")) != 0 &&
+            strcmp(getenv("HOME"), roken_get_homedir(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_homedir() != getenv(\"HOME\")");
+            ret++;
+        }
+        if (getenv("HOME") != NULL && strlen(getenv("HOME")) != 0 &&
+            strcmp(roken_get_appdatadir(buf, sizeof(buf)),
+                   roken_get_homedir(buf2, sizeof(buf2))) != 0) {
+            warnx("roken_get_homedir() != roken_get_appdatadir()");
+            ret++;
+        }
+        if (getenv("SHELL") != NULL && strlen(getenv("SHELL")) != 0 &&
+            strcmp(getenv("SHELL"), roken_get_shell(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_shell() != getenv(\"SHELL\")");
+            ret++;
+        }
+    }
+#endif
+    printf("Username:\t%s\n", roken_get_username(buf, sizeof(buf)));
+    printf("Home:\t\t%s\n", roken_get_homedir(buf, sizeof(buf)));
+    printf("Appdatadir:\t%s\n", roken_get_appdatadir(buf, sizeof(buf)));
+    printf("Shell:\t\t%s\n", roken_get_shell(buf, sizeof(buf)));
+
+#ifndef WIN32
+    if (!issuid() && getuid() != 0) {
+        putenv("USER=h5lfoouser");
+        putenv("HOME=/no/such/dir/h5lfoouser");
+        putenv("SHELL=/no/such/shell");
+        if (strcmp("h5lfoouser", roken_get_username(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_username() (%s) did not honor $USER",
+                  roken_get_username(buf, sizeof(buf)));
+            ret++;
+        }
+        if (strcmp("/no/such/dir/h5lfoouser",
+                   roken_get_homedir(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_homedir() (%s) did not honor $HOME",
+                  roken_get_homedir(buf, sizeof(buf)));
+            ret++;
+        }
+        if (strcmp(roken_get_appdatadir(buf, sizeof(buf)),
+                   roken_get_homedir(buf2, sizeof(buf2))) != 0) {
+            warnx("roken_get_homedir() != roken_get_appdatadir() (%s)",
+                  roken_get_appdatadir(buf, sizeof(buf)));
+            ret++;
+        }
+        if (strcmp("/no/such/shell", roken_get_shell(buf, sizeof(buf))) != 0) {
+            warnx("roken_get_shell() (%s) did not honor $SHELL",
+                  roken_get_shell(buf, sizeof(buf)));
+            ret++;
+        }
+    }
+    return ret;
+#endif
+    return 0;
+}

lib/roken/version-script.map

@@ -179,6 +179,10 @@ HEIMDAL_ROKEN_1.0 {
 		roken_gethostby_setup;
 		roken_gethostbyaddr;
 		roken_gethostbyname;
+		roken_get_appdatadir;
+		roken_get_homedir;
+		roken_get_shell;
+		roken_get_username;
 		roken_mconcat;
 		roken_vconcat;
 		roken_vmconcat;