Support using OpenSSL in FIPS mode

FIPS mode support needs to be enabled at compile time, by configuring
Erlang/OTP with --enable-fips option. In FIPS mode the non-FIPS
algorithms are disabled and raise error notsup.

The supported protocols list is properly updated in FIPS mode to
advertise only the enabled protocols.

FIPS mode is off by default even if Erlang/OTP was built with FIPS
support. It needs to be turned on at runtime.

The official approach is to set the fips_mode application environment
parameter of the crypto application to true. This would turn FIPS mode
on when the NIF is loaded and would prevent loading the module on
error.

Another method is provided via the crypto:enable_fips_mode/1
function, but it is not recommended to be used in production, as it
won't prevent the use of the crypto module in case of an error, and
would risk OpenSSL crashing the emulator. It is very useful for test
suites however that need to check both validated and non-validated
functionality.

This commit is based on commit
00b3a04d17a653b4abddeebd6dd8a2c38df532d0.

1 files changed, 115 insertions, 10 deletions

diff --git a/lib/crypto/c_src/crypto.c b/lib/crypto/c_src/crypto.c
index f9fa80c0c7..c881a17376 100644
--- a/lib/crypto/c_src/crypto.c
+++ b/lib/crypto/c_src/crypto.c
@@ -222,6 +222,8 @@ static void unload(ErlNifEnv* env, void* priv_data);
 
 /* The NIFs: */
 static ERL_NIF_TERM info_lib(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
+static ERL_NIF_TERM info_fips(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
+static ERL_NIF_TERM enable_fips_mode(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
 static ERL_NIF_TERM algorithms(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
 static ERL_NIF_TERM hash_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
 static ERL_NIF_TERM hash_init_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
@@ -291,6 +293,8 @@ static int library_refc = 0; /* number of users of this dynamic library */
 
 static ErlNifFunc nif_funcs[] = {
     {"info_lib", 0, info_lib},
+    {"info_fips", 0, info_fips},
+    {"enable_fips_mode", 1, enable_fips_mode},
     {"algorithms", 0, algorithms},
     {"hash_nif", 2, hash_nif},
     {"hash_init_nif", 1, hash_init_nif},
@@ -378,6 +382,12 @@ static ERL_NIF_TERM atom_unknown;
 static ERL_NIF_TERM atom_none;
 static ERL_NIF_TERM atom_notsup;
 static ERL_NIF_TERM atom_digest;
+#ifdef FIPS_SUPPORT
+static ERL_NIF_TERM atom_enabled;
+static ERL_NIF_TERM atom_not_enabled;
+#else
+static ERL_NIF_TERM atom_not_supported;
+#endif
 
 #if defined(HAVE_EC)
 static ERL_NIF_TERM atom_ec;
@@ -552,6 +562,13 @@ static int verify_lib_version(void)
     return 1;
 }
 
+#ifdef FIPS_SUPPORT
+/* In FIPS mode non-FIPS algorithms are disabled and return badarg. */
+#define CHECK_NO_FIPS_MODE() { if (FIPS_mode()) return atom_notsup; }
+#else
+#define CHECK_NO_FIPS_MODE()
+#endif
+
 #ifdef HAVE_DYNAMIC_CRYPTO_LIB
 
 # if defined(DEBUG)
@@ -602,11 +619,11 @@ static int init(ErlNifEnv* env, ERL_NIF_TERM load_info)
     if (!verify_lib_version())
 	return 0;
 
-    /* load_info: {301, <<"/full/path/of/this/library">>} */
+    /* load_info: {302, <<"/full/path/of/this/library">>,true|false} */
     if (!enif_get_tuple(env, load_info, &tpl_arity, &tpl_array)
-	|| tpl_arity != 2
+	|| tpl_arity != 3
 	|| !enif_get_int(env, tpl_array[0], &vernum)
-	|| vernum != 301
+	|| vernum != 302
 	|| !enif_inspect_binary(env, tpl_array[1], &lib_bin)) {
 
 	PRINTF_ERR1("CRYPTO: Invalid load_info '%T'", load_info);
@@ -650,6 +667,21 @@ static int init(ErlNifEnv* env, ERL_NIF_TERM load_info)
 
     atom_true  = enif_make_atom(env,"true");
     atom_false = enif_make_atom(env,"false");
+    /* Enter FIPS mode */
+    if (tpl_array[2] == atom_true) {
+#ifdef FIPS_SUPPORT
+        if (!FIPS_mode_set(1)) {
+#else
+        {
+#endif
+            PRINTF_ERR0("CRYPTO: Could not setup FIPS mode");
+            return 0;
+        }
+    } else if (tpl_array[2] != atom_false) {
+        PRINTF_ERR1("CRYPTO: Invalid load_info '%T'", load_info);
+        return 0;
+    }
+
     atom_sha = enif_make_atom(env,"sha");
     atom_error = enif_make_atom(env,"error");
     atom_rsa_pkcs1_padding = enif_make_atom(env,"rsa_pkcs1_padding");
@@ -683,6 +715,13 @@ static int init(ErlNifEnv* env, ERL_NIF_TERM load_info)
     atom_blowfish_ecb = enif_make_atom(env, "blowfish_ecb");
 #endif
 
+#ifdef FIPS_SUPPORT
+    atom_enabled = enif_make_atom(env,"enabled");
+    atom_not_enabled = enif_make_atom(env,"not_enabled");
+#else
+    atom_not_supported = enif_make_atom(env,"not_supported");
+#endif
+
     init_digest_types(env);
     init_cipher_types(env);
     init_algorithms_types(env);
@@ -766,15 +805,16 @@ static void unload(ErlNifEnv* env, void* priv_data)
     --library_refc;
 }
 
-static int algo_hash_cnt;
+static int algo_hash_cnt, algo_hash_fips_cnt;
 static ERL_NIF_TERM algo_hash[8];   /* increase when extending the list */
-static int algo_pubkey_cnt;
+static int algo_pubkey_cnt, algo_pubkey_fips_cnt;
 static ERL_NIF_TERM algo_pubkey[7]; /* increase when extending the list */
-static int algo_cipher_cnt;
+static int algo_cipher_cnt, algo_cipher_fips_cnt;
 static ERL_NIF_TERM algo_cipher[23]; /* increase when extending the list */
 
 static void init_algorithms_types(ErlNifEnv* env)
 {
+    // Validated algorithms first
     algo_hash_cnt = 0;
     algo_hash[algo_hash_cnt++] = atom_sha;
 #ifdef HAVE_SHA224
@@ -789,6 +829,8 @@ static void init_algorithms_types(ErlNifEnv* env)
 #ifdef HAVE_SHA512
     algo_hash[algo_hash_cnt++] = enif_make_atom(env, "sha512");
 #endif
+    // Non-validated algorithms follow
+    algo_hash_fips_cnt = algo_hash_cnt;
     algo_hash[algo_hash_cnt++] = enif_make_atom(env, "md4");
     algo_hash[algo_hash_cnt++] = enif_make_atom(env, "md5");
     algo_hash[algo_hash_cnt++] = enif_make_atom(env, "ripemd160");
@@ -804,8 +846,11 @@ static void init_algorithms_types(ErlNifEnv* env)
     algo_pubkey[algo_pubkey_cnt++] = enif_make_atom(env, "ecdsa");
     algo_pubkey[algo_pubkey_cnt++] = enif_make_atom(env, "ecdh");
 #endif
+    // Non-validated algorithms follow
+    algo_pubkey_fips_cnt = algo_pubkey_cnt;
     algo_pubkey[algo_pubkey_cnt++] = enif_make_atom(env, "srp");
 
+    // Validated algorithms first
     algo_cipher_cnt = 0;
 #ifndef OPENSSL_NO_DES
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env, "des3_cbc");
@@ -822,6 +867,11 @@ static void init_algorithms_types(ErlNifEnv* env)
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env, "aes_cbc256");
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env, "aes_ctr");
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env, "aes_ecb");
+#if defined(HAVE_GCM)
+    algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"aes_gcm");
+#endif
+    // Non-validated algorithms follow
+    algo_cipher_fips_cnt = algo_cipher_cnt;
 #ifdef HAVE_AES_IGE
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"aes_ige256");
 #endif
@@ -836,9 +886,6 @@ static void init_algorithms_types(ErlNifEnv* env)
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"blowfish_ecb");
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"rc2_cbc");
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"rc4");
-#if defined(HAVE_GCM)
-    algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"aes_gcm");
-#endif
 #if defined(HAVE_CHACHA20_POLY1305)
     algo_cipher[algo_cipher_cnt++] = enif_make_atom(env,"chacha20_poly1305");
 #endif
@@ -850,9 +897,16 @@ static void init_algorithms_types(ErlNifEnv* env)
 
 static ERL_NIF_TERM algorithms(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
+#ifdef FIPS_SUPPORT
+    int fips_mode  = FIPS_mode();
+    int hash_cnt   = fips_mode ? algo_hash_fips_cnt   : algo_hash_cnt;
+    int pubkey_cnt = fips_mode ? algo_pubkey_fips_cnt : algo_pubkey_cnt;
+    int cipher_cnt = fips_mode ? algo_cipher_fips_cnt : algo_cipher_cnt;
+#else
     int hash_cnt   = algo_hash_cnt;
     int pubkey_cnt = algo_pubkey_cnt;
     int cipher_cnt = algo_cipher_cnt;
+#endif
     return enif_make_tuple3(env,
 			    enif_make_list_from_array(env, algo_hash,   hash_cnt),
 			    enif_make_list_from_array(env, algo_pubkey, pubkey_cnt),
@@ -886,6 +940,37 @@ static ERL_NIF_TERM info_lib(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]
 						 ver_term));
 }
 
+static ERL_NIF_TERM info_fips(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+#ifdef FIPS_SUPPORT
+    return FIPS_mode() ? atom_enabled : atom_not_enabled;
+#else
+    return atom_not_supported;
+#endif
+}
+
+static ERL_NIF_TERM enable_fips_mode(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{/* (Boolean) */
+    if (argv[0] == atom_true) {
+#ifdef FIPS_SUPPORT
+        if (FIPS_mode_set(1)) {
+            return atom_true;
+        }
+#endif
+        PRINTF_ERR0("CRYPTO: Could not setup FIPS mode");
+        return atom_false;
+    } else if (argv[0] == atom_false) {
+#ifdef FIPS_SUPPORT
+        if (!FIPS_mode_set(0)) {
+            return atom_false;
+        }
+#endif
+        return atom_true;
+    } else {
+        return enif_make_badarg(env);
+    }
+}
+
 static ERL_NIF_TERM make_badarg_maybe(ErlNifEnv* env)
 {
     ERL_NIF_TERM reason;
@@ -1442,7 +1527,11 @@ static ERL_NIF_TERM block_crypt_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM
     }
 
     if ((argv[0] == atom_aes_cfb8 || argv[0] == atom_aes_cfb128)
-        && (key.size == 24 || key.size == 32)) {
+        && (key.size == 24 || key.size == 32)
+#ifdef FIPS_SUPPORT
+	&& !FIPS_mode()
+#endif
+	) {
         /* Why do EVP_CIPHER_CTX_set_key_length() fail on these key sizes?
          * Fall back on low level API
          */
@@ -1504,6 +1593,8 @@ static ERL_NIF_TERM aes_cfb_8_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM
      int new_ivlen = 0;
      ERL_NIF_TERM ret;
 
+     CHECK_NO_FIPS_MODE();
+
      if (!enif_inspect_iolist_as_binary(env, argv[0], &key)
          || !(key.size == 16 || key.size == 24 || key.size == 32)
          || !enif_inspect_binary(env, argv[1], &ivec) || ivec.size != 16
@@ -1531,6 +1622,8 @@ static ERL_NIF_TERM aes_ige_crypt_nif(ErlNifEnv* env, int argc, const ERL_NIF_TE
     unsigned char* ret_ptr;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
        || (key_bin.size != 16 && key_bin.size != 32)
        || !enif_inspect_binary(env, argv[1], &ivec_bin)
@@ -2385,6 +2478,8 @@ static ERL_NIF_TERM rc4_encrypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM arg
     RC4_KEY rc4_key;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!enif_inspect_iolist_as_binary(env,argv[0], &key)
 	|| !enif_inspect_iolist_as_binary(env,argv[1], &data)) {
 	return enif_make_badarg(env);
@@ -2401,6 +2496,8 @@ static ERL_NIF_TERM rc4_set_key(ErlNifEnv* env, int argc, const ERL_NIF_TERM arg
     ErlNifBinary key;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!enif_inspect_iolist_as_binary(env,argv[0], &key)) {
 	return enif_make_badarg(env);
     }
@@ -2416,6 +2513,8 @@ static ERL_NIF_TERM rc4_encrypt_with_state(ErlNifEnv* env, int argc, const ERL_N
     RC4_KEY* rc4_key;
     ERL_NIF_TERM new_state, new_data;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!enif_inspect_iolist_as_binary(env,argv[0], &state)
 	|| state.size != sizeof(RC4_KEY)
 	|| !enif_inspect_iolist_as_binary(env,argv[1], &data)) {
@@ -2844,6 +2943,8 @@ static ERL_NIF_TERM srp_value_B_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM
     unsigned dlen;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!get_bn_from_bin(env, argv[0], &bn_multiplier)
 	|| !get_bn_from_bin(env, argv[1], &bn_verifier)
 	|| !get_bn_from_bin(env, argv[2], &bn_generator)
@@ -2904,6 +3005,8 @@ static ERL_NIF_TERM srp_user_secret_nif(ErlNifEnv* env, int argc, const ERL_NIF_
     unsigned dlen;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!get_bn_from_bin(env, argv[0], &bn_a)
 	|| !get_bn_from_bin(env, argv[1], &bn_u)
 	|| !get_bn_from_bin(env, argv[2], &bn_B)
@@ -2983,6 +3086,8 @@ static ERL_NIF_TERM srp_host_secret_nif(ErlNifEnv* env, int argc, const ERL_NIF_
     unsigned dlen;
     ERL_NIF_TERM ret;
 
+    CHECK_NO_FIPS_MODE();
+
     if (!get_bn_from_bin(env, argv[0], &bn_verifier)
 	|| !get_bn_from_bin(env, argv[1], &bn_b)
 	|| !get_bn_from_bin(env, argv[2], &bn_u)