libbb: move crypt_make_salt() to pw_encrypt.c, reuse

bin-to-ascii64 conversion which does not require an array.

function                                             old     new   delta
to64                                                  29      33      +4
to64_msb_first                                        63      62      -1
ascii64                                               65       -     -65

1 files changed, 46 insertions, 9 deletions

diff --git a/libbb/pw_encrypt.c b/libbb/pw_encrypt.c
index 572591ea9..6fc0ba87c 100644
--- a/libbb/pw_encrypt.c
+++ b/libbb/pw_encrypt.c
@@ -1,6 +1,6 @@
 /* vi: set sw=4 ts=4: */
 /*
- * Utility routine.
+ * Utility routines.
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
@@ -9,25 +9,62 @@
 
 #include "libbb.h"
 
-#if ENABLE_USE_BB_CRYPT
-
-/*
- * DES and MD5 crypt implementations are taken from uclibc.
- * They were modified to not use static buffers.
+/* static const uint8_t ascii64[] =
+ * "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  */
 
-/* Used by pw_encrypt_XXX.c */
-static const uint8_t ascii64[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+static int i64c(int i)
+{
+	i &= 0x3f;
+	if (i == 0)
+		return '.';
+	if (i == 1)
+		return '/';
+	if (i < 12)
+		return ('0' - 2 + i);
+	if (i < 38)
+		return ('A' - 12 + i);
+	return ('a' - 38 + i);
+}
+
+int FAST_FUNC crypt_make_salt(char *p, int cnt, int x)
+{
+	x += getpid() + time(NULL);
+	do {
+		/* x = (x*1664525 + 1013904223) % 2^32 generator is lame
+		 * (low-order bit is not "random", etc...),
+		 * but for our purposes it is good enough */
+		x = x*1664525 + 1013904223;
+		/* BTW, Park and Miller's "minimal standard generator" is
+		 * x = x*16807 % ((2^31)-1)
+		 * It has no problem with visibly alternating lowest bit
+		 * but is also weak in cryptographic sense + needs div,
+		 * which needs more code (and slower) on many CPUs */
+		*p++ = i64c(x >> 16);
+		*p++ = i64c(x >> 22);
+	} while (--cnt);
+	*p = '\0';
+	return x;
+}
+
+#if ENABLE_USE_BB_CRYPT
+
 static char*
 to64(char *s, unsigned v, int n)
 {
 	while (--n >= 0) {
-		*s++ = ascii64[v & 0x3f];
+		/* *s++ = ascii64[v & 0x3f]; */
+		*s++ = i64c(v);
 		v >>= 6;
 	}
 	return s;
 }
 
+/*
+ * DES and MD5 crypt implementations are taken from uclibc.
+ * They were modified to not use static buffers.
+ */
+
 #include "pw_encrypt_des.c"
 #include "pw_encrypt_md5.c"
 #if ENABLE_USE_BB_CRYPT_SHA