fips: More elaborate way of getting FIPS pk flags indicators.

* src/fips.c (_gcry_fips_indicator_pk_flags): List more allowed string
in the S-expression.
* doc/gcrypt.texi: Add document for the FIPS service indicator
GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS with example.

--

GnuPG-bug-id: 6417
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

2 files changed, 76 insertions, 7 deletions

diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi
index 750b6718..752f64d6 100644
--- a/doc/gcrypt.texi
+++ b/doc/gcrypt.texi
@@ -1007,9 +1007,45 @@ FIPS 140-3 certification. If the algorithm is approved, this function returns
 
 @item GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS; Arguments: const char *
 
-Check if the given public key operation flag is approved under the current
-FIPS 140-3 certification. If the flag is approved, this function returns
-@code{GPG_ERR_NO_ERROR}. Otherwise @code{GPG_ERR_NOT_SUPPORTED} is returned.
+Check if the given public key operation flag or s-expression object name is
+approved under the current FIPS 140-3 certification.  If the flag is
+approved, this function returns @code{GPG_ERR_NO_ERROR}.
+
+Otherwise @code{GPG_ERR_NOT_SUPPORTED} is returned.
+
+For compound s-expression objects, if the object name is allowed, the user
+is responsible to check also the internal members.  For example:
+
+@example
+  gcry_sexp_t s_sig = NULL;
+  gcry_md_hd_t hd = NULL;
+  gcry_sexp_t s_sk = NULL;
+  const char *data_tmpl = "(data(flags pss)(hash %s %b)(salt-length 1:0))";
+
+  if (err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_FUNCTION, "gcry_md_open") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_MD, GCRY_MD_SHA512) &&
+      err = gcry_md_open (&hd, GCRY_MD_SHA512, 0))
+    @{
+      printf ("gcry_md_open failed: %s", gpg_strerror (err));
+      return;
+    @}
+  gcry_md_write (hd, buffer, buflen);
+
+  /* initialize the key in s_sk */
+
+  if (err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_FUNCTION, "gcry_pk_hash_sign") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS, "data") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS, "flags") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS, "pss") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS, "hash") &&
+      err = gcry_control(GCRYCTL_FIPS_SERVICE_INDICATOR_PK_FLAGS, "salt-length")
+      err = gcry_pk_hash_sign (&s_sig, data_tmpl, s_sk, hd, NULL))
+    @{
+      printf ("gcry_pk_hash_sign failed: %s", gpg_strerror (err));
+      return;
+    @}
+  /* ok */
+@end example
 
 @end table
 
diff --git a/src/fips.c b/src/fips.c
index a7342030..669cfd0e 100644
--- a/src/fips.c
+++ b/src/fips.c
@@ -457,16 +457,49 @@ _gcry_fips_indicator_function (va_list arg_ptr)
   return GPG_ERR_NO_ERROR;
 }
 
+/* Note: the array should be sorted.  */
+static const char *valid_string_in_sexp[] = {
+  "curve",
+  "d",
+  "data",
+  "e",
+  "ecdsa",
+  "flags",
+  "genkey",
+  "hash",
+  "n",
+  "nbits",
+  "pkcs1",
+  "private-key",
+  "pss",
+  "public-key",
+  "q",
+  "r",
+  "raw",
+  "rsa",
+  "rsa-use-e",
+  "s",
+  "salt-length",
+  "sig-val",
+  "value"
+};
+
+static int
+compare_string (const void *v1, const void *v2)
+{
+  const char * const *p_str1 = v1;
+  const char * const *p_str2 = v2;
+
+  return strcmp (*p_str1, *p_str2);
+}
 
 int
 _gcry_fips_indicator_pk_flags (va_list arg_ptr)
 {
   const char *flag = va_arg (arg_ptr, const char *);
 
-  if (strcmp (flag, "param") == 0 ||
-      strcmp (flag, "raw") == 0 ||
-      strcmp (flag, "no-blinding") == 0 ||
-      strcmp (flag, "pss") == 0)
+  if (bsearch (&flag, valid_string_in_sexp, DIM (valid_string_in_sexp),
+               sizeof (char *), compare_string))
     return GPG_ERR_NO_ERROR;
 
   return GPG_ERR_NOT_SUPPORTED;