adduser: safe username passing to passwd/addgroup

passwd: support creating SHA passwords
random code shrink

function                                             old     new   delta
crypt_make_pw_salt                                     -      87     +87
adduser_main                                         883     904     +21
...
crypt_make_salt                                       99      89     -10
chpasswd_main                                        329     312     -17
packed_usage                                       28731   28691     -40
passwd_main                                         1070    1000     -70
cryptpw_main                                         310     224     -86
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/12 up/down: 154/-288)        Total: -134 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

7 files changed, 88 insertions, 77 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 4232c38f4..89e8e4452 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1259,14 +1259,19 @@ extern int correct_password(const struct passwd *pw) FAST_FUNC;
 #endif
 extern char *pw_encrypt(const char *clear, const char *salt, int cleanup) FAST_FUNC;
 extern int obscure(const char *old, const char *newval, const struct passwd *pwdp) FAST_FUNC;
-/* rnd is additional random input. New one is returned.
+/*
+ * rnd is additional random input. New one is returned.
  * Useful if you call crypt_make_salt many times in a row:
  * rnd = crypt_make_salt(buf1, 4, 0);
  * rnd = crypt_make_salt(buf2, 4, rnd);
  * rnd = crypt_make_salt(buf3, 4, rnd);
  * (otherwise we risk having same salt generated)
  */
-extern int crypt_make_salt(char *p, int cnt, int rnd) FAST_FUNC;
+extern int crypt_make_salt(char *p, int cnt /*, int rnd*/) FAST_FUNC;
+/* "$N$" + sha_salt_16_bytes + NUL */
+#define MAX_PW_SALT_LEN (3 + 16 + 1)
+extern char* crypt_make_pw_salt(char p[MAX_PW_SALT_LEN], const char *algo) FAST_FUNC;
+
 
 /* Returns number of lines changed, or -1 on error */
 #if !(ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP)
diff --git a/libbb/pw_encrypt.c b/libbb/pw_encrypt.c
index c6c04d44a..39ffa084f 100644
--- a/libbb/pw_encrypt.c
+++ b/libbb/pw_encrypt.c
@@ -27,9 +27,10 @@ static int i64c(int i)
 	return ('a' - 38 + i);
 }
 
-int FAST_FUNC crypt_make_salt(char *p, int cnt, int x)
+int FAST_FUNC crypt_make_salt(char *p, int cnt /*, int x */)
 {
-	x += getpid() + time(NULL);
+	/* was: x += ... */
+	int x = getpid() + monotonic_us();
 	do {
 		/* x = (x*1664525 + 1013904223) % 2^32 generator is lame
 		 * (low-order bit is not "random", etc...),
@@ -47,6 +48,26 @@ int FAST_FUNC crypt_make_salt(char *p, int cnt, int x)
 	return x;
 }
 
+char* FAST_FUNC crypt_make_pw_salt(char salt[MAX_PW_SALT_LEN], const char *algo)
+{
+	int len = 2/2;
+	char *salt_ptr = salt;
+	if (algo[0] != 'd') { /* not des */
+		len = 8/2; /* so far assuming md5 */
+		*salt_ptr++ = '$';
+		*salt_ptr++ = '1';
+		*salt_ptr++ = '$';
+#if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
+		if (algo[0] == 's') { /* sha */
+			salt[1] = '5' + (strcmp(algo, "sha512") == 0);
+			len = 16/2;
+		}
+#endif
+	}
+	crypt_make_salt(salt_ptr, len);
+	return salt_ptr;
+}
+
 #if ENABLE_USE_BB_CRYPT
 
 static char*
diff --git a/loginutils/adduser.c b/loginutils/adduser.c
index 1944d9d56..a05b72158 100644
--- a/loginutils/adduser.c
+++ b/loginutils/adduser.c
@@ -82,21 +82,23 @@ static void passwd_study(struct passwd *p)
 
 static void addgroup_wrapper(struct passwd *p, const char *group_name)
 {
-	char *argv[5];
+	char *argv[6];
 
 	argv[0] = (char*)"addgroup";
 	if (group_name) {
 		/* Add user to existing group */
-		argv[1] = p->pw_name;
-		argv[2] = (char*)group_name;
-		argv[3] = NULL;
+		argv[1] = (char*)"--";
+		argv[2] = p->pw_name;
+		argv[3] = (char*)group_name;
+		argv[4] = NULL;
 	} else {
 		/* Add user to his own group with the first free gid found in passwd_study */
 //TODO: to be compatible with external addgroup programs we should use --gid instead...
 		argv[1] = (char*)"-g";
 		argv[2] = utoa(p->pw_gid);
-		argv[3] = p->pw_name;
-		argv[4] = NULL;
+		argv[3] = (char*)"--";
+		argv[4] = p->pw_name;
+		argv[5] = NULL;
 	}
 
 	spawn_and_wait(argv);
@@ -106,7 +108,7 @@ static void passwd_wrapper(const char *login_name) NORETURN;
 
 static void passwd_wrapper(const char *login_name)
 {
-	BB_EXECLP("passwd", "passwd", login_name, NULL);
+	BB_EXECLP("passwd", "passwd", "--", login_name, NULL);
 	bb_error_msg_and_die("can't execute passwd, you must set password manually");
 }
 
diff --git a/loginutils/chpasswd.c b/loginutils/chpasswd.c
index 6c4296faa..f4718c829 100644
--- a/loginutils/chpasswd.c
+++ b/loginutils/chpasswd.c
@@ -37,9 +37,8 @@ int chpasswd_main(int argc UNUSED_PARAM, char **argv)
 	char *name, *pass;
 	char salt[sizeof("$N$XXXXXXXX")];
 	int opt, rc;
-	int rnd = rnd; /* we *want* it to be non-initialized! */
 
-	if (getuid())
+	if (getuid() != 0)
 		bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
 
 	opt_complementary = "m--e:e--m";
@@ -55,10 +54,12 @@ int chpasswd_main(int argc UNUSED_PARAM, char **argv)
 		xuname2uid(name); /* dies if there is no such user */
 
 		if (!(opt & OPT_ENC)) {
-			rnd = crypt_make_salt(salt, 1, rnd);
+			crypt_make_salt(salt, 1);
 			if (opt & OPT_MD5) {
-				strcpy(salt, "$1$");
-				rnd = crypt_make_salt(salt + 3, 4, rnd);
+				salt[0] = '$';
+				salt[1] = '1';
+				salt[2] = '$';
+				crypt_make_salt(salt + 3, 4);
 			}
 			pass = pw_encrypt(pass, salt, 0);
 		}
diff --git a/loginutils/cryptpw.c b/loginutils/cryptpw.c
index bbaa858da..b25a39ac9 100644
--- a/loginutils/cryptpw.c
+++ b/loginutils/cryptpw.c
@@ -19,7 +19,7 @@
 //usage:	IF_LONG_OPTS(
 //usage:     "\n	-P,--password-fd=N	Read password from fd N"
 /* //usage:  "\n	-s,--stdin		Use stdin; like -P0" */
-//usage:     "\n	-m,--method=TYPE	Encryption method TYPE"
+//usage:     "\n	-m,--method=TYPE	Encryption method"
 //usage:     "\n	-S,--salt=SALT"
 //usage:	)
 //usage:	IF_NOT_LONG_OPTS(
@@ -39,7 +39,7 @@
 //usage:	IF_LONG_OPTS(
 //usage:     "\n	-P,--password-fd=N	Read password from fd N"
 /* //usage:  "\n	-s,--stdin		Use stdin; like -P0" */
-//usage:     "\n	-m,--method=TYPE	Encryption method TYPE"
+//usage:     "\n	-m,--method=TYPE	Encryption method"
 //usage:     "\n	-S,--salt=SALT"
 //usage:	)
 //usage:	IF_NOT_LONG_OPTS(
@@ -92,11 +92,9 @@ to cryptpw. -a option (alias for -m) came from cryptpw.
 int cryptpw_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int cryptpw_main(int argc UNUSED_PARAM, char **argv)
 {
-	/* $N$ + sha_salt_16_bytes + NUL */
-	char salt[3 + 16 + 1];
+	char salt[MAX_PW_SALT_LEN];
 	char *salt_ptr;
 	const char *opt_m, *opt_S;
-	int len;
 	int fd;
 
 #if ENABLE_LONG_OPTS
@@ -121,24 +119,9 @@ int cryptpw_main(int argc UNUSED_PARAM, char **argv)
 	if (argv[0] && !opt_S)
 		opt_S = argv[1];
 
-	len = 2/2;
-	salt_ptr = salt;
-	if (opt_m[0] != 'd') { /* not des */
-		len = 8/2; /* so far assuming md5 */
-		*salt_ptr++ = '$';
-		*salt_ptr++ = '1';
-		*salt_ptr++ = '$';
-#if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
-		if (opt_m[0] == 's') { /* sha */
-			salt[1] = '5' + (strcmp(opt_m, "sha512") == 0);
-			len = 16/2;
-		}
-#endif
-	}
+	salt_ptr = crypt_make_pw_salt(salt, opt_m);
 	if (opt_S)
-		safe_strncpy(salt_ptr, opt_S, sizeof(salt) - 3);
-	else
-		crypt_make_salt(salt_ptr, len, 0);
+		safe_strncpy(salt_ptr, opt_S, sizeof(salt) - (sizeof("$N$")-1));
 
 	xmove_fd(fd, STDIN_FILENO);
 
diff --git a/loginutils/passwd.c b/loginutils/passwd.c
index 810644e61..8c47e65ff 100644
--- a/loginutils/passwd.c
+++ b/loginutils/passwd.c
@@ -9,7 +9,7 @@
 //usage:       "Change USER's password. If no USER is specified,\n"
 //usage:       "changes the password for the current user.\n"
 //usage:     "\nOptions:"
-//usage:     "\n	-a ALG	Algorithm to use for password (des, md5)" /* ", sha1)" */
+//usage:     "\n	-a ALG	Encryption method"
 //usage:     "\n	-d	Delete password for the account"
 //usage:     "\n	-l	Lock (disable) account"
 //usage:     "\n	-u	Unlock (re-enable) account"
@@ -22,15 +22,15 @@ static void nuke_str(char *str)
 	if (str) memset(str, 0, strlen(str));
 }
 
-static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
+static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
 {
-	char salt[sizeof("$N$XXXXXXXX")]; /* "$N$XXXXXXXX" or "XX" */
+	char salt[MAX_PW_SALT_LEN];
 	char *orig = (char*)"";
 	char *newp = NULL;
 	char *cp = NULL;
 	char *ret = NULL; /* failure so far */
 
-	if (myuid && pw->pw_passwd[0]) {
+	if (myuid != 0 && pw->pw_passwd[0]) {
 		char *encrypted;
 
 		orig = bb_ask_stdin("Old password: "); /* returns ptr to static */
@@ -38,13 +38,13 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
 			goto err_ret;
 		encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
 		if (strcmp(encrypted, pw->pw_passwd) != 0) {
-			syslog(LOG_WARNING, "incorrect password for %s",
-				pw->pw_name);
+			syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
 			bb_do_delay(LOGIN_FAIL_DELAY);
 			puts("Incorrect password");
 			goto err_ret;
 		}
-		if (ENABLE_FEATURE_CLEAN_UP) free(encrypted);
+		if (ENABLE_FEATURE_CLEAN_UP)
+			free(encrypted);
 	}
 	orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */
 	newp = bb_ask_stdin("New password: "); /* returns ptr to static */
@@ -52,22 +52,22 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
 		goto err_ret;
 	newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */
 	if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
-	 && obscure(orig, newp, pw) && myuid)
+	 && obscure(orig, newp, pw)
+	 && myuid != 0
+	) {
 		goto err_ret; /* non-root is not allowed to have weak passwd */
+	}
 
 	cp = bb_ask_stdin("Retype password: ");
 	if (!cp)
 		goto err_ret;
-	if (strcmp(cp, newp)) {
+	if (strcmp(cp, newp) != 0) {
 		puts("Passwords don't match");
 		goto err_ret;
 	}
 
-	crypt_make_salt(salt, 1, 0); /* des */
-	if (algo) { /* MD5 */
-		strcpy(salt, "$1$");
-		crypt_make_salt(salt + 3, 4, 0);
-	}
+	crypt_make_pw_salt(salt, algo);
+
 	/* pw_encrypt returns malloced str */
 	ret = pw_encrypt(newp, salt, 1);
 	/* whee, success! */
@@ -75,8 +75,10 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
  err_ret:
 	nuke_str(orig);
 	if (ENABLE_FEATURE_CLEAN_UP) free(orig);
+
 	nuke_str(newp);
 	if (ENABLE_FEATURE_CLEAN_UP) free(newp);
+
 	nuke_str(cp);
 	return ret;
 }
@@ -85,17 +87,15 @@ int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int passwd_main(int argc UNUSED_PARAM, char **argv)
 {
 	enum {
-		OPT_algo = 0x1, /* -a - password algorithm */
-		OPT_lock = 0x2, /* -l - lock account */
-		OPT_unlock = 0x4, /* -u - unlock account */
-		OPT_delete = 0x8, /* -d - delete password */
-		OPT_lud = 0xe,
-		STATE_ALGO_md5 = 0x10,
-		//STATE_ALGO_des = 0x20, not needed yet
+		OPT_algo   = (1 << 0), /* -a - password algorithm */
+		OPT_lock   = (1 << 1), /* -l - lock account */
+		OPT_unlock = (1 << 2), /* -u - unlock account */
+		OPT_delete = (1 << 3), /* -d - delete password */
+		OPT_lud    = OPT_lock | OPT_unlock | OPT_delete,
 	};
 	unsigned opt;
 	int rc;
-	const char *opt_a = "";
+	const char *opt_a = "d"; /* des */
 	const char *filename;
 	char *myname;
 	char *name;
@@ -116,13 +116,9 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
 	//argc -= optind;
 	argv += optind;
 
-	if (strcasecmp(opt_a, "des") != 0) /* -a */
-		opt |= STATE_ALGO_md5;
-	//else
-	//	opt |= STATE_ALGO_des;
 	myuid = getuid();
 	/* -l, -u, -d require root priv and username argument */
-	if ((opt & OPT_lud) && (myuid || !argv[0]))
+	if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
 		bb_show_usage();
 
 	/* Will complain and die if username not found */
@@ -130,7 +126,7 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
 	name = argv[0] ? argv[0] : myname;
 
 	pw = xgetpwnam(name);
-	if (myuid && pw->pw_uid != myuid) {
+	if (myuid != 0 && pw->pw_uid != myuid) {
 		/* LOGMODE_BOTH */
 		bb_error_msg_and_die("%s can't change password for %s", myname, name);
 	}
@@ -164,27 +160,29 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
 	newp = NULL;
 	c = pw->pw_passwd[0] - '!';
 	if (!(opt & OPT_lud)) {
-		if (myuid && !c) { /* passwd starts with '!' */
+		if (myuid != 0 && !c) { /* passwd starts with '!' */
 			/* LOGMODE_BOTH */
 			bb_error_msg_and_die("can't change "
 					"locked password for %s", name);
 		}
 		printf("Changing password for %s\n", name);
-		newp = new_password(pw, myuid, opt & STATE_ALGO_md5);
+		newp = new_password(pw, myuid, opt_a);
 		if (!newp) {
 			logmode = LOGMODE_STDIO;
 			bb_error_msg_and_die("password for %s is unchanged", name);
 		}
 	} else if (opt & OPT_lock) {
-		if (!c) goto skip; /* passwd starts with '!' */
+		if (!c)
+			goto skip; /* passwd starts with '!' */
 		newp = xasprintf("!%s", pw->pw_passwd);
 	} else if (opt & OPT_unlock) {
-		if (c) goto skip; /* not '!' */
+		if (c)
+			goto skip; /* not '!' */
 		/* pw->pw_passwd points to static storage,
 		 * strdup'ing to avoid nasty surprizes */
 		newp = xstrdup(&pw->pw_passwd[1]);
 	} else if (opt & OPT_delete) {
-		newp = (char*)""; //xstrdup("");
+		newp = (char*)"";
 	}
 
 	rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
@@ -202,7 +200,7 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
 	rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
 	if (rc > 0)
 		/* password in /etc/shadow was updated */
-		newp = (char*) "x"; //xstrdup("x");
+		newp = (char*) "x";
 	if (rc >= 0)
 		/* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
 #endif
@@ -212,16 +210,17 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
 	}
 	/* LOGMODE_BOTH */
 	if (rc < 0)
-		bb_error_msg_and_die("can't update password file %s",
-				filename);
+		bb_error_msg_and_die("can't update password file %s", filename);
 	bb_info_msg("Password for %s changed by %s", name, myname);
 
-	//if (ENABLE_FEATURE_CLEAN_UP) free(newp);
+	/*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
  skip:
 	if (!newp) {
 		bb_error_msg_and_die("password for %s is already %slocked",
 			name, (opt & OPT_unlock) ? "un" : "");
 	}
-	if (ENABLE_FEATURE_CLEAN_UP) free(myname);
+
+	if (ENABLE_FEATURE_CLEAN_UP)
+		free(myname);
 	return 0;
 }
diff --git a/networking/httpd.c b/networking/httpd.c
index d6157aca2..d77342a2a 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -2424,7 +2424,7 @@ int httpd_main(int argc UNUSED_PARAM, char **argv)
 		salt[0] = '$';
 		salt[1] = '1';
 		salt[2] = '$';
-		crypt_make_salt(salt + 3, 4, 0);
+		crypt_make_salt(salt + 3, 4);
 		puts(pw_encrypt(pass, salt, 1));
 		return 0;
 	}