Add crypt_checkpass(3) and crypt_newhash(3).

libc/Makefile

@@ -578,6 +578,7 @@ unistd/chroot.o \
 unistd/closefrom.o \
 unistd/close.o \
 unistd/confstr.o \
+unistd/crypt_newhash.o \
 unistd/dup2.o \
 unistd/dup3.o \
 unistd/dup.o \

libc/include/unistd.h

@@ -548,6 +548,8 @@ size_t getpagesize(void);
 #if __USE_SORTIX
 int chroot(const char*);
 int closefrom(int);
+int crypt_checkpass(const char*, const char*);
+int crypt_newhash(const char*, const char*, char*, size_t);
 int dup3(int, int, int);
 int execvpe(const char*, char* const [], char* const []);
 char* get_current_dir_name(void);

libc/unistd/crypt_newhash.cpp

@@ -0,0 +1,90 @@
+/* $OpenBSD: cryptutil.c,v 1.12 2015/09/13 15:33:48 guenther Exp $ */
+/*
+ * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <errno.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+extern "C"
+int
+crypt_checkpass(const char *pass, const char *goodhash)
+{
+	char dummy[128];
+
+	if (goodhash == NULL) {
+		/* fake it */
+		goto fake;
+	}
+
+	/* empty password */
+	if (strlen(goodhash) == 0 && strlen(pass) == 0)
+		return 0;
+
+	if (goodhash[0] == '$' && goodhash[1] == '2') {
+		if (bcrypt_checkpass(pass, goodhash))
+			goto fail;
+		return 0;
+	}
+
+	/* unsupported. fake it. */
+fake:
+	bcrypt_newhash(pass, 8, dummy, sizeof(dummy));
+fail:
+	errno = EACCES;
+	return -1;
+}
+
+extern "C"
+int
+crypt_newhash(const char *pass, const char *pref, char *hash, size_t hashlen)
+{
+	int rv = -1;
+	const char *defaultpref = "blowfish,8";
+	int rounds;
+
+	if (pref == NULL)
+		pref = defaultpref;
+	if (strncmp(pref, "blowfish", 8) == 0)
+		pref += 8;
+	else if (strncmp(pref, "bcrypt", 6) == 0)
+		pref += 6;
+	else {
+		errno = EINVAL;
+		goto err;
+	}
+	if (!*pref)
+		rounds = -1; /* auto */
+	else if (*pref++ != ',') {
+		errno = EINVAL;
+		goto err;
+	} else if (strcmp(pref, "a") == 0)
+		rounds = -1; /* auto */
+	else {
+		const char* pref_end;
+		long rounds_long = strtol((char*) pref, (char**) &pref_end, 10);
+		if (*pref_end || rounds_long < 4 || 31 < rounds_long) {
+			errno = EINVAL;
+			goto err;
+		}
+		rounds = rounds_long;
+	}
+	rv = bcrypt_newhash(pass, rounds, hash, hashlen);
+
+err:
+	return rv;
+}