openssl/0084-pbkdf2-Set-minimum-password-length-of-8-bytes.patch

From 915990e450e769e370fcacbfd8ed58ab6afaf2bf Mon Sep 17 00:00:00 2001
From: Dmitry Belyavskiy <dbelyavs@redhat.com>
Date: Mon, 21 Aug 2023 15:47:55 +0200
Subject: [PATCH 39/48] 
 0084-pbkdf2-Set-minimum-password-length-of-8-bytes.patch

Patch-name: 0084-pbkdf2-Set-minimum-password-length-of-8-bytes.patch
Patch-id: 84
---
 providers/implementations/kdfs/pbkdf2.c | 27 ++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/providers/implementations/kdfs/pbkdf2.c b/providers/implementations/kdfs/pbkdf2.c
index 349c3dd657..11820d1e69 100644
--- a/providers/implementations/kdfs/pbkdf2.c
+++ b/providers/implementations/kdfs/pbkdf2.c
@@ -35,6 +35,21 @@
 #define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF
 #define KDF_PBKDF2_MIN_ITERATIONS 1000
 #define KDF_PBKDF2_MIN_SALT_LEN   (128 / 8)
+/* The Implementation Guidance for FIPS 140-3 says in section D.N
+ * "Password-Based Key Derivation for Storage Applications" that "the vendor
+ * shall document in the module’s Security Policy the length of
+ * a password/passphrase used in key derivation and establish an upper bound
+ * for the probability of having this parameter guessed at random. This
+ * probability shall take into account not only the length of the
+ * password/passphrase, but also the difficulty of guessing it. The decision on
+ * the minimum length of a password used for key derivation is the vendor’s,
+ * but the vendor shall at a minimum informally justify the decision."
+ *
+ * We are choosing a minimum password length of 8 bytes, because NIST's ACVP
+ * testing uses passwords as short as 8 bytes, and requiring longer passwords
+ * combined with an implicit indicator (i.e., returning an error) would cause
+ * the module to fail ACVP testing. */
+#define KDF_PBKDF2_MIN_PASSWORD_LEN (8)
 
 static OSSL_FUNC_kdf_newctx_fn kdf_pbkdf2_new;
 static OSSL_FUNC_kdf_dupctx_fn kdf_pbkdf2_dup;
@@ -219,9 +234,15 @@ static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])
         ctx->lower_bound_checks = pkcs5 == 0;
     }
 
-    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
+    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL) {
+        if (ctx->lower_bound_checks != 0
+            && p->data_size < KDF_PBKDF2_MIN_PASSWORD_LEN) {
+            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
+            return 0;
+        }
         if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p))
             return 0;
+    }
 
     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) {
         if (ctx->lower_bound_checks != 0
@@ -331,6 +352,10 @@ static int pbkdf2_derive(const char *pass, size_t passlen,
     }
 
     if (lower_bound_checks) {
+        if (passlen < KDF_PBKDF2_MIN_PASSWORD_LEN) {
+            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
+            return 0;
+        }
         if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
             ERR_raise(ERR_LIB_PROV, PROV_R_KEY_SIZE_TOO_SMALL);
             return 0;
-- 
2.41.0