crypt: remove dubious validator.

The validate_salt function was introduced in commit
c3a0ceb2cea1a9d43f2baf5a2e63d0d712c8df19, February 2020.
I cannot reproduce the internal crash in crypt which
it alleges, and I neglected to mention the bad inputs
in the commit or add tests. I'm not able to reproduce
the alleged behavior in spite of trying all sorts of bad
inputs; and looking at the crypt source in glibc, I
don't see any obvious problem.

And so, on this Halowe'en, we exorcise the ghost
that has been haunting the crypt.

* sysif.c (salt_char_p, validate_salt): Static functions
removed.
(crypt_wrap): Don't call validate_salt, and so cwsalt
need not be tested for null.

* tests/018/crypt.tl: New file.

* txr.1: Mention that crypt_r is used if available, which
avoids static storage.

1 files changed, 12 insertions, 69 deletions

diff --git a/sysif.c b/sysif.c
index 339d9962..2043354d 100644
--- a/sysif.c
+++ b/sysif.c
@@ -2064,82 +2064,25 @@ static val getgrnam_wrap(val wname)
 
 #if HAVE_CRYPT || HAVE_CRYPT_R
 
-static int salt_char_p(wchar_t ch)
-{
-  return ((ch >= 'a' && ch <= 'z') ||
-          (ch >= 'A' && ch <= 'Z') ||
-          (ch >= '0' && ch <= '9') ||
-          (ch == '.') || (ch == '/'));
-}
-
-static const wchar_t *validate_salt(const wchar_t *salt)
-{
-  const wchar_t *s = salt;
-
-  if (salt_char_p(*s)) {
-    if (salt_char_p(*++s))
-      return salt;
-    else
-      goto badsalt;
-  }
-
-  if (*s++ != '$')
-    goto badsalt;
-
-  switch (*s++) {
-  case '1': case '5': case '6':
-    break;
-  case '2':
-    if (*s >= 'a' && *s++ <= 'z')
-      break;
-    /* fallthrough */
-  default:
-    goto badsalt;
-  }
-
-  if (*s++ != '$')
-    goto badsalt;
-
-  if (wcsncmp(s, L"rounds=", 7) == 0) {
-    size_t ispn = wcsspn(s += 7, L"0123456789");
-    s += ispn;
-    if (*s++ != '$')
-      goto badsalt;
-  }
-
-  while (salt_char_p(*s))
-    s++;
-
-  if (*s && *s != '$')
-    goto badsalt;
-
-  return salt;
-
-badsalt:
-  errno = EINVAL;
-  return 0;
-}
-
 static val crypt_wrap(val wkey, val wsalt)
 {
   val self = lit("crypt");
   const wchar_t *cwkey = c_str(wkey, self);
-  const wchar_t *cwsalt = validate_salt(c_str(wsalt, self));
-
-  if (cwsalt != 0) {
-    char *key = utf8_dup_to(cwkey);
-    char *salt = utf8_dup_to(cwsalt);
+  const wchar_t *cwsalt = c_str(wsalt, self);
+  char *key = utf8_dup_to(cwkey);
+  char *salt = utf8_dup_to(cwsalt);
 #if HAVE_CRYPT_R
-    struct crypt_data cd;
-    char *hash = (cd.initialized = 0, crypt_r(key, salt, &cd));
+  struct crypt_data cd;
+  char *hash = (cd.initialized = 0, crypt_r(key, salt, &cd));
 #else
-    char *hash = crypt(key, salt);
+  char *hash = crypt(key, salt);
 #endif
-    free(key);
-    free(salt);
-    if (hash != 0)
-      return string_utf8(hash);
-  }
+
+  free(key);
+  free(salt);
+
+  if (hash != 0)
+    return string_utf8(hash);
 
   uw_ethrowf(error_s, lit("crypt failed: ~d/~s"), num(errno),
              errno_to_str(errno), nao);