File libcryptopp-CVE-2024-28285.patch of Package libcryptopp
commit 2472be710f8518caab1f62999c50970b475f162f
Author: Angel Yankov <angel.yankov@suse.com>
Date: Wed May 28 16:17:10 2025 +0300
Fix ElGamal side channel issue
Index: cryptopp-CRYPTOPP_8_9_0/pubkey.h
===================================================================
--- cryptopp-CRYPTOPP_8_9_0.orig/pubkey.h
+++ cryptopp-CRYPTOPP_8_9_0/pubkey.h
@@ -1855,7 +1855,14 @@ public:
SecByteBlock derivedKey(encAlg.GetSymmetricKeyLength(encAlg.GetMaxSymmetricPlaintextLength(ciphertextLength)));
derivAlg.Derive(params, derivedKey, derivedKey.size(), z, q, parameters);
- return encAlg.SymmetricDecrypt(derivedKey, ciphertext, ciphertextLength, plaintext, parameters);
+ DecodingResult res = encAlg.SymmetricDecrypt(derivedKey, ciphertext, ciphertextLength, plaintext, parameters);
+ Element z2 = agreeAlg.AgreeWithStaticPrivateKey(params, q, true, key.GetPrivateExponent());
+ if (z == z2) {
+ } else {
+ return DecodingResult();
+ }
+ return res;
+
}
catch (DL_BadElement &)
{