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>

1 files changed, 23 insertions, 2 deletions

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*