From 4a8512750710b7abda17c63c7bf837df14d167c2 Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Tue, 8 Jun 2021 09:55:56 -0700
Subject: [PATCH] Improve `wc_DhKeyToDer` for public key size calculation.
 Fixes bug with the output too (was missing 1 byte in length for the unused
 bits byte in bit string).

---
 certs/statickeys/dh-ffdhe2048-pub.der | Bin 552 -> 552 bytes
 certs/statickeys/gen-static.sh        |   5 ++---
 wolfcrypt/src/asn.c                   |   2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/certs/statickeys/dh-ffdhe2048-pub.der b/certs/statickeys/dh-ffdhe2048-pub.der
index e7b3393d1e9a9133310539b3083a8f762569ce93..6a817a526ff4b30701cdf0322881d5d550c1e24f 100644
GIT binary patch
delta 13
UcmZ3%vVw)hpovLkBZ~?X02wg@5C8xG

delta 13
UcmZ3%vVw)hpovL&BZ~?X02wR;4*&oF

diff --git a/certs/statickeys/gen-static.sh b/certs/statickeys/gen-static.sh
index f81e52709..dc92757db 100644
--- a/certs/statickeys/gen-static.sh
+++ b/certs/statickeys/gen-static.sh
@@ -10,7 +10,6 @@ openssl ec -inform pem -in certs/statickeys/ecc-secp256r1.pem -outform der -out
 # Using one generated and capture with wolfSSL using wc_DhGenerateKeyPair (openssl generates DH keys with 2048-bits... based on the DH "p" prime size)
 #openssl genpkey -paramfile certs/statickeys/dh-ffdhe2048-params.pem -out certs/statickeys/dh-ffdhe2048.der
 openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048.der -outform pem -out certs/statickeys/dh-ffdhe2048.pem
-openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048.der -outform der -out certs/statickeys/dh-ffdhe2048-pub.der -pubout
 # Export DH public key as DER and convert to PEM
-openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048-pub.der -outform pem -out certs/statickeys/dh-ffdhe2048-pub.pem
-openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048-pub.der -outform pem -out certs/statickeys/dh-ffdhe2048-pub.pem -pubin
+openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048.der -outform der -out certs/statickeys/dh-ffdhe2048-pub.der -pubout
+openssl pkey -inform der -in certs/statickeys/dh-ffdhe2048.der -outform pem -out certs/statickeys/dh-ffdhe2048-pub.pem -pubout
diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c
index 94ea32a28..a02a6d5a5 100644
--- a/wolfcrypt/src/asn.c
+++ b/wolfcrypt/src/asn.c
@@ -4811,7 +4811,7 @@ int wc_DhKeyToDer(DhKey* key, byte* output, word32* outSz, int exportPriv)
     else {
         /* bit string: public */
         pubSz = SetASNIntMP(&key->pub, -1, NULL);
-        idx = 1 + SetLength(pubSz, NULL) + pubSz; /* +1 for ASN_BIT_STRING */
+        idx = SetBitString(pubSz, 0, NULL) + pubSz;
     }
     keySz = idx;