From 52b347703ba2b98a0efee86c1a483c2f0f9f73d6 Mon Sep 17 00:00:00 2001
From: Clemens Lang <[email protected]>
Date: Wed, 11 Jan 2023 12:52:59 +0100
Subject: [PATCH] rsa: Disallow SHAKE in OAEP and PSS in FIPS prov

According to FIPS 140-3 IG, section C.C, the SHAKE digest algorithms
must not be used in higher-level algorithms (such as RSA-OAEP and
RSASSA-PSS):

"To be used in an approved mode of operation, the SHA-3 hash functions
may be implemented either as part of an approved higher-level algorithm,
for example, a digital signature algorithm, or as the standalone
functions. The SHAKE128 and SHAKE256 extendable-output functions may
only be used as the standalone algorithms."

Add a check to prevent their use as message digest in PSS signatures and
as MGF1 hash function in both OAEP and PSS.

Signed-off-by: Clemens Lang <[email protected]>
---
 crypto/rsa/rsa_oaep.c | 28 ++++++++++++++++++++++++++++
 crypto/rsa/rsa_pss.c  | 16 ++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/crypto/rsa/rsa_oaep.c b/crypto/rsa/rsa_oaep.c
index d9be1a4f98..dfe9c9f0e8 100644
--- a/crypto/rsa/rsa_oaep.c
+++ b/crypto/rsa/rsa_oaep.c
@@ -73,9 +73,23 @@ int ossl_rsa_padding_add_PKCS1_OAEP_mgf1_ex(OSSL_LIB_CTX *libctx,
         return 0;
 #endif
     }
+
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(md, "SHAKE-128") || EVP_MD_is_a(md, "SHAKE-256")) {
+        ERR_raise(ERR_LIB_RSA, RSA_R_DIGEST_NOT_ALLOWED);
+        return 0;
+    }
+#endif
     if (mgf1md == NULL)
         mgf1md = md;
 
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(mgf1md, "SHAKE-128") || EVP_MD_is_a(mgf1md, "SHAKE-256")) {
+        ERR_raise(ERR_LIB_RSA, RSA_R_DIGEST_NOT_ALLOWED);
+        return 0;
+    }
+#endif
+
     mdlen = EVP_MD_get_size(md);
     if (mdlen <= 0) {
         ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_LENGTH);
@@ -181,9 +195,23 @@ int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
 #endif
     }
 
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(md, "SHAKE-128") || EVP_MD_is_a(md, "SHAKE-256")) {
+        ERR_raise(ERR_LIB_RSA, RSA_R_DIGEST_NOT_ALLOWED);
+        return -1;
+    }
+#endif
+
     if (mgf1md == NULL)
         mgf1md = md;
 
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(mgf1md, "SHAKE-128") || EVP_MD_is_a(mgf1md, "SHAKE-256")) {
+        ERR_raise(ERR_LIB_RSA, RSA_R_DIGEST_NOT_ALLOWED);
+        return -1;
+    }
+#endif
+
     mdlen = EVP_MD_get_size(md);
 
     if (tlen <= 0 || flen <= 0)
diff --git a/crypto/rsa/rsa_pss.c b/crypto/rsa/rsa_pss.c
index 33874bfef8..e8681b0351 100644
--- a/crypto/rsa/rsa_pss.c
+++ b/crypto/rsa/rsa_pss.c
@@ -53,6 +53,14 @@ int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
     if (mgf1Hash == NULL)
         mgf1Hash = Hash;
 
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(Hash, "SHAKE-128") || EVP_MD_is_a(Hash, "SHAKE-256"))
+        goto err;
+
+    if (EVP_MD_is_a(mgf1Hash, "SHAKE-128") || EVP_MD_is_a(mgf1Hash, "SHAKE-256"))
+        goto err;
+#endif
+
     hLen = EVP_MD_get_size(Hash);
     if (hLen < 0)
         goto err;
@@ -164,6 +172,14 @@ int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
     if (mgf1Hash == NULL)
         mgf1Hash = Hash;
 
+#ifdef FIPS_MODULE
+    if (EVP_MD_is_a(Hash, "SHAKE-128") || EVP_MD_is_a(Hash, "SHAKE-256"))
+        goto err;
+
+    if (EVP_MD_is_a(mgf1Hash, "SHAKE-128") || EVP_MD_is_a(mgf1Hash, "SHAKE-256"))
+        goto err;
+#endif
+
     hLen = EVP_MD_get_size(Hash);
     if (hLen < 0)
         goto err;
-- 
2.39.0