passwd: fix /etc/passwd support, ...

... rewrite parts to use libc functions (supported by musl and glibc).

passwd.c

@@ -25,29 +25,124 @@ usage(void)
 	eprintf("usage: %s [username]\n", argv0);
 }
 
-static int
+static FILE *
-gettempfile(char *template)
+spw_get_file(const char *user)
 {
-	int fd;
+	FILE *fp = NULL;
+	char file[PATH_MAX];
+	int r;
 
-	umask(077);
+	r = snprintf(file, sizeof(file), "/etc/tcb/%s/shadow", user);
-	fd = mkostemp(template, O_RDWR);
+	if (r < 0 || (size_t)r >= sizeof(file))
-	if (fd < 0)
+		eprintf("snprintf:");
-		weprintf("mkstemp:");
+	fp = fopen(file, "r+");
-	return fd;
+	if (!fp)
+		fp = fopen("/etc/shadow", "r+");
+	return fp;
+}
+
+static int
+spw_write_file(FILE *fp, const struct spwd *spw, char *pwhash)
+{
+	struct spwd *spwent;
+	int r = -1, w = 0;
+	FILE *tfp = NULL;
+
+	/* write to temporary file. */
+	tfp = tmpfile();
+	if (!tfp) {
+		weprintf("tmpfile:");
+		goto cleanup;
+	}
+	while ((spwent = fgetspent(fp))) {
+		/* update entry on name match */
+		if (strcmp(spwent->sp_namp, spw->sp_namp) == 0) {
+			spwent->sp_pwdp = pwhash;
+			w++;
+		}
+		errno = 0;
+		if (putspent(spwent, tfp) == -1) {
+			weprintf("putspent:");
+			goto cleanup;
+		}
+	}
+	if (!w) {
+		weprintf("shadow: no matching entry to write to\n");
+		goto cleanup;
+	}
+	fflush(tfp);
+
+	if (fseek(fp, 0, SEEK_SET) == -1 || fseek(tfp, 0, SEEK_SET) == -1) {
+		weprintf("fseek:");
+		goto cleanup;
+	}
+
+	/* write temporary file to (tcb) shadow file */
+	concat(tfp, "tmpfile", fp, "shadow");
+	ftruncate(fileno(fp), ftell(tfp));
+
+	r = 0; /* success */
+cleanup:
+	if (tfp)
+		fclose(tfp);
+	return r;
+}
+
+static
+int pw_write_file(FILE *fp, const struct passwd *pw, char *pwhash) {
+	struct passwd *pwent;
+	int r = -1, w = 0;
+	FILE *tfp = NULL;
+
+	/* write to temporary file. */
+	tfp = tmpfile();
+	if (!tfp) {
+		weprintf("tmpfile:");
+		goto cleanup;
+	}
+	while ((pwent = fgetpwent(fp))) {
+		/* update entry on name match */
+		if (strcmp(pwent->pw_name, pw->pw_name) == 0) {
+			pwent->pw_passwd = pwhash;
+			w++;
+		}
+		errno = 0;
+		if (putpwent(pwent, tfp) == -1) {
+			weprintf("putpwent:");
+			goto cleanup;
+		}
+	}
+	if (!w) {
+		weprintf("passwd: no matching entry to write to\n");
+		goto cleanup;
+	}
+	fflush(tfp);
+
+	if (fseek(fp, 0, SEEK_SET) == -1 || fseek(tfp, 0, SEEK_SET) == -1) {
+		weprintf("fseek:");
+		goto cleanup;
+	}
+
+	/* write to passwd file. */
+	concat(tfp, "tmpfile", fp, "passwd");
+	ftruncate(fileno(fp), ftell(tfp));
+
+	r = 0; /* success */
+cleanup:
+	if (tfp)
+		fclose(tfp);
+	return r;
 }
 
 int
 main(int argc, char *argv[])
 {
 	char *cryptpass1 = NULL, *cryptpass2 = NULL, *cryptpass3 = NULL;
-	char shadowfile[PATH_MAX], *inpass, *p, *pwd = NULL;
+	char *inpass, *p, *salt = PW_CIPHER, *prevhash = NULL;
-	char template[] = "/tmp/pw.XXXXXX";
 	struct passwd *pw;
-	struct spwd *spw = NULL, *spwent;
+	struct spwd *spw = NULL;
-	uid_t uid;
+	FILE *fp = NULL;
-	FILE *fp = NULL, *tfp = NULL;
+	int r = -1, status = EXIT_FAILURE;
-	int ffd = -1, tfd = -1, r, status = EXIT_FAILURE;
 
 	ARGBEGIN {
 	default:
@@ -55,6 +150,7 @@ main(int argc, char *argv[])
 	} ARGEND;
 
 	pw_init();
+	umask(077);
 
 	errno = 0;
 	if (argc == 0)
@@ -69,7 +165,7 @@ main(int argc, char *argv[])
 	}
 
 	/* is using shadow entry ? */
-	if (pw->pw_passwd[0] == 'x') {
+	if (pw->pw_passwd[0] == 'x' && pw->pw_passwd[1] == '\0') {
 		errno = 0;
 		spw = getspnam(pw->pw_name);
 		if (!spw) {
@@ -78,55 +174,46 @@ main(int argc, char *argv[])
 			else
 				eprintf("who are you?\n");
 		}
-		pwd = spw->sp_pwdp;
-	} else {
-		pwd = pw->pw_passwd;
 	}
 
-	uid = getuid();
+	/* Flush pending input */
-	if (uid == 0) {
+	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
-		if (pw->pw_passwd[0] == '!' ||
+
-		    pw->pw_passwd[0] == 'x' ||
+	if (getuid() == 0) {
-		    pw->pw_passwd[0] == '*' ||
-		    pw->pw_passwd[0] == '\0')
-			pw->pw_passwd = PW_CIPHER;
 		goto newpass;
 	} else {
 		if (pw->pw_passwd[0] == '!' ||
 		    pw->pw_passwd[0] == '*')
 			eprintf("denied\n");
 		if (pw->pw_passwd[0] == '\0') {
-			pw->pw_passwd = PW_CIPHER;
 			goto newpass;
 		}
+		if (pw->pw_passwd[0] == 'x')
+			prevhash = salt = spw->sp_pwdp;
+		else
+			prevhash = salt = pw->pw_passwd;
 	}
 
-	/* Flush pending input */
-	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
-
 	printf("Changing password for %s\n", pw->pw_name);
 	inpass = getpass("Old password: ");
 	if (!inpass)
 		eprintf("getpass:");
 	if (inpass[0] == '\0')
 		eprintf("no password supplied\n");
-	p = crypt(inpass, pwd);
+	p = crypt(inpass, salt);
 	if (!p)
 		eprintf("crypt:");
 	cryptpass1 = estrdup(p);
-	if (strcmp(cryptpass1, pwd) != 0)
+	if (strcmp(cryptpass1, prevhash) != 0)
 		eprintf("incorrect password\n");
 
 newpass:
-	/* Flush pending input */
-	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
-
 	inpass = getpass("Enter new password: ");
 	if (!inpass)
 		eprintf("getpass:");
 	if (inpass[0] == '\0')
 		eprintf("no password supplied\n");
-	p = crypt(inpass, pwd);
+	p = crypt(inpass, salt);
 	if (!p)
 		eprintf("crypt:");
 	cryptpass2 = estrdup(p);
@@ -141,88 +228,28 @@ newpass:
 		eprintf("getpass:");
 	if (inpass[0] == '\0')
 		eprintf("no password supplied\n");
-	p = crypt(inpass, pwd);
+	p = crypt(inpass, salt);
 	if (!p)
 		eprintf("crypt:");
 	cryptpass3 = estrdup(p);
 	if (strcmp(cryptpass2, cryptpass3) != 0)
 		eprintf("passwords don't match\n");
 
-	r = snprintf(shadowfile, sizeof(shadowfile), "/etc/tcb/%s/shadow", pw->pw_name);
+	fp = spw_get_file(pw->pw_name);
-	if (r < 0 || (size_t)r >= sizeof(shadowfile))
-		eprintf("snprintf:");
-	fp = fopen(shadowfile, "r+");
-	if (!fp) {
-		strlcpy(shadowfile, "/etc/shadow", sizeof(shadowfile));
-		fp = fopen(shadowfile, "r+");
-	}
 	if (fp) {
-		if ((tfd = gettempfile(template)) == -1)
+		r = spw_write_file(fp, spw, cryptpass3);
-			goto cleanup;
-
-		/* write to (tcb) shadow file. */
-		if (!(tfp = fdopen(tfd, "w+"))) {
-			weprintf("fdopen:");
-			goto cleanup;
-		}
-		while ((spwent = fgetspent(fp))) {
-			/* update entry on name match */
-			if (strcmp(spwent->sp_namp, spw->sp_namp) == 0)
-				spwent->sp_pwdp = cryptpass3;
-			errno = 0;
-			if (putspent(spwent, tfp) == -1) {
-				weprintf("putspent:");
-				goto cleanup;
-			}
-		}
-		fflush(tfp);
-
-		if (fseek(fp, 0, SEEK_SET) == -1 || fseek(tfp, 0, SEEK_SET) == -1) {
-			weprintf("rewind:");
-			goto cleanup;
-		}
-
-		/* old shadow file with temporary file data. */
-		concat(tfp, template, fp, shadowfile);
-		ftruncate(tfd, ftell(tfp));
 	} else {
-		/* write to /etc/passwd file. */
+		fp = fopen("/etc/passwd", "r+");
-		ffd = open("/etc/passwd", O_RDWR);
+		if (fp)
-		if (ffd < 0) {
+			r = pw_write_file(fp, pw, cryptpass3);
-			weprintf("open %s:", "/etc/passwd");
+		else
-			goto cleanup;
+			weprintf("fopen:");
-		}
-		pw->pw_passwd = cryptpass3;
-
-		if ((tfd = gettempfile(template)) == -1)
-			goto cleanup;
-
-		r = pw_copy(ffd, tfd, pw);
-		if (r < 0)
-			goto cleanup;
-		r = lseek(ffd, 0, SEEK_SET);
-		if (r < 0)
-			goto cleanup;
-		r = lseek(tfd, 0, SEEK_SET);
-		if (r < 0)
-			goto cleanup;
-		r = pw_copy(tfd, ffd, NULL);
-		if (r < 0)
-			goto cleanup;
 	}
-	status = EXIT_SUCCESS;
+	if (!r)
+		status = EXIT_SUCCESS;
 
-cleanup:
 	if (fp)
 		fclose(fp);
-	if (tfp)
-		fclose(tfp);
-	if (tfd != -1) {
-		close(tfd);
-		unlink(template);
-	}
-	if (ffd != -1)
-		close(ffd);
 	free(cryptpass3);
 	free(cryptpass2);
 	free(cryptpass1);

passwd.h

@@ -1,6 +1,4 @@
 /* See LICENSE file for copyright and license details. */
 /* passwd.c */
-int pw_check(struct passwd *, const char *);
+int pw_check(const struct passwd *, const char *);
-int pw_copy(int, int, const struct passwd *);
 int pw_init(void);
-int pw_scan(char *, struct passwd *);

util/passwd.c

@@ -17,7 +17,7 @@
 /* Returns -1 on error, 0 for incorrect password
  * and 1 if all went OK */
 int
-pw_check(struct passwd *pw, const char *pass)
+pw_check(const struct passwd *pw, const char *pass)
 {
 	char *cryptpass, *p;
 	struct spwd *spw;
@@ -64,53 +64,6 @@ pw_check(struct passwd *pw, const char *pass)
 	return 1;
 }
 
-int
-pw_copy(int ffd, int tfd, const struct passwd *newpw)
-{
-	struct passwd pw;
-	char *buf = NULL, *p;
-	size_t size = 0;
-	FILE *from, *to;
-
-	from = fdopen(ffd, "r");
-	if (!from) {
-		weprintf("fdopen:");
-		return -1;
-	}
-	to = fdopen(tfd, "w");
-	if (!to) {
-		weprintf("fdopen:");
-		return -1;
-	}
-	while (agetline(&buf, &size, from) != -1) {
-		p = strdup(buf);
-		if (!p) {
-			weprintf("strdup:");
-			return -1;
-		}
-		if (newpw) {
-			if (pw_scan(p, &pw) < 0)
-				return -1;
-			if (strcmp(pw.pw_name, newpw->pw_name) == 0) {
-				fprintf(to, "%s:%s:%u:%u:%s:%s:%s\n",
-					newpw->pw_name,
-					newpw->pw_passwd,
-					newpw->pw_uid,
-					newpw->pw_gid,
-					newpw->pw_gecos,
-					newpw->pw_dir,
-					newpw->pw_shell);
-					continue;
-			}
-		}
-		fprintf(to, "%s", buf);
-		free(p);
-	}
-	fflush(to);
-	free(buf);
-	return 0;
-}
-
 int
 pw_init(void)
 {
@@ -122,63 +75,3 @@ pw_init(void)
 		eprintf("setrlimit:");
 	return 0;
 }
-
-int
-pw_scan(char *bp, struct passwd *pw)
-{
-	char *p;
-
-	memset(pw, 0, sizeof(*pw));
-
-	/* login name */
-	p = strsep(&bp, ":");
-	if (!p || *p == '\0')
-		goto corrupt;
-	pw->pw_name = p;
-
-	/* passwd */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_passwd = p;
-
-	/* uid */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_uid = estrtol(p, 10);
-
-	/* gid */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_gid = estrtol(p, 10);
-
-	/* user name or comment */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_gecos = p;
-
-	/* home directory */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_dir = p;
-
-	/* optional shell */
-	p = strsep(&bp, ":");
-	if (!p)
-		goto corrupt;
-	pw->pw_shell = p;
-
-	/* look for redundant entries */
-	p = strsep(&bp, ":");
-	if (p)
-		goto corrupt;
-
-	return 0;
-corrupt:
-	weprintf("corrupted passwd entry\n");
-	return -1;
-}