From 0a18868475fd6fc80c484c5a4ebdcc5cfc694788 Mon Sep 17 00:00:00 2001
From: Justin Traglia <95511699+jtraglia@users.noreply.github.com>
Date: Wed, 25 Jan 2023 21:07:15 +0100
Subject: [PATCH] Upgrade blst & remove sha256 patch (#85)

---
 .gitmodules              |  1 -
 bindings/csharp/Makefile |  6 +-----
 blst                     |  2 +-
 blst_sha.patch           | 31 -------------------------------
 src/Makefile             |  3 ---
 src/c_kzg_4844.c         | 28 +++-------------------------
 6 files changed, 5 insertions(+), 66 deletions(-)
 delete mode 100644 blst_sha.patch

diff --git a/.gitmodules b/.gitmodules
index 6f7ff08..bed358c 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,4 +1,3 @@
 [submodule "blst"]
 	path = blst
 	url = https://github.com/supranational/blst
-	ignore = dirty # because we apply a patch
diff --git a/bindings/csharp/Makefile b/bindings/csharp/Makefile
index 1364efa..b94e455 100644
--- a/bindings/csharp/Makefile
+++ b/bindings/csharp/Makefile
@@ -27,11 +27,7 @@ CLANG_FLAGS += -DFIELD_ELEMENTS_PER_BLOB=$(FIELD_ELEMENTS_PER_BLOB)
 TARGETS=ckzg.c ../../src/c_kzg_4844.c ../../blst/$(BLST_OBJ)
 
 .blst:
-	cd ../../blst &&\
-	git apply ../blst_sha.patch &&\
-	$(BLST_BUILDSCRIPT) &&\
-	git apply -R ../blst_sha.patch &&\
-	cd ../bindings/csharp
+	cd ../../blst && $(BLST_BUILDSCRIPT)
 
 .ckzg:
 	$(CLANG_EXECUTABLE) -O -Wall -shared $(CLANG_FLAGS) ${addprefix -I,${INCLUDE_DIRS}} -o $(CKZG_LIBRARY_PATH) $(TARGETS)
diff --git a/blst b/blst
index 6382d67..ca03e11 160000
--- a/blst
+++ b/blst
@@ -1 +1 @@
-Subproject commit 6382d67c72119d563975892ed49ba32e92d3d0da
+Subproject commit ca03e11a3ff24d818ae390a1e7f435f15bf72aee
diff --git a/blst_sha.patch b/blst_sha.patch
deleted file mode 100644
index a4a975c..0000000
--- a/blst_sha.patch
+++ /dev/null
@@ -1,31 +0,0 @@
-diff --git a/src/sha256.h b/src/sha256.h
-index 77ddb6d..67ccf7a 100644
---- a/src/sha256.h
-+++ b/src/sha256.h
-@@ -49,7 +49,7 @@ static void sha256_init_h(unsigned int h[8])
-     h[7] = 0x5be0cd19U;
- }
- 
--static void sha256_init(SHA256_CTX *ctx)
-+void sha256_init(SHA256_CTX *ctx)
- {
-     sha256_init_h(ctx->h);
-     ctx->N = 0;
-@@ -57,7 +57,7 @@ static void sha256_init(SHA256_CTX *ctx)
-     ctx->off = 0;
- }
- 
--static void sha256_update(SHA256_CTX *ctx, const void *_inp, size_t len)
-+void sha256_update(SHA256_CTX *ctx, const void *_inp, size_t len)
- {
-     size_t n;
-     const unsigned char *inp = _inp;
-@@ -116,7 +116,7 @@ static void sha256_emit(unsigned char md[32], const unsigned int h[8])
- }
- #endif
- 
--static void sha256_final(unsigned char md[32], SHA256_CTX *ctx)
-+void sha256_final(unsigned char md[32], SHA256_CTX *ctx)
- {
-     unsigned long long bits = ctx->N * 8;
-     size_t n = ctx->off;
diff --git a/src/Makefile b/src/Makefile
index 527dd8f..4512e0c 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -16,11 +16,8 @@ all: c_kzg_4844.o lib
 c_kzg_4844.o: c_kzg_4844.c Makefile
 	${CLANG_EXECUTABLE} -Wall -I$(INCLUDE_DIRS) -DFIELD_ELEMENTS_PER_BLOB=$(FIELD_ELEMENTS_PER_BLOB) $(CFLAGS) -c $<
 
-# Will fail with "patch does not apply" if it has already been patched.
-# Safe to ignore.
 blst:
 	cd ../blst; \
-	git apply < ../blst_sha.patch; \
 	${BLST_BUILD_SCRIPT} && \
 	cp libblst.a ../lib && \
 	cp bindings/*.h ../inc
diff --git a/src/c_kzg_4844.c b/src/c_kzg_4844.c
index 4319958..6291f96 100644
--- a/src/c_kzg_4844.c
+++ b/src/c_kzg_4844.c
@@ -527,28 +527,6 @@ static void bytes_of_uint64(uint8_t out[8], uint64_t n) {
     }
 }
 
-///////////////////////////////////////////////////////////////////////////////
-// SHA-256 Hash Functions
-///////////////////////////////////////////////////////////////////////////////
-
-typedef struct {
-    unsigned int h[8];
-    unsigned long long N;
-    unsigned char buf[64];
-    size_t off;
-} SHA256_CTX;
-
-void sha256_init(SHA256_CTX *ctx);
-void sha256_update(SHA256_CTX *ctx, const void *_inp, size_t len);
-void sha256_final(unsigned char md[32], SHA256_CTX *ctx);
-
-static void hash(uint8_t md[32], const uint8_t *input, size_t n) {
-    SHA256_CTX ctx;
-    sha256_init(&ctx);
-    sha256_update(&ctx, input, n);
-    sha256_final(md, &ctx);
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 // Bit-reversal Permutation Functions
 ///////////////////////////////////////////////////////////////////////////////
@@ -724,7 +702,7 @@ static C_KZG_RET compute_challenges(fr_t *eval_challenge_out, fr_t *r_powers_out
 
     /* Now let's create challenges! */
     uint8_t hashed_data[32] = {0};
-    hash(hashed_data, bytes, nb);
+    blst_sha256(hashed_data, bytes, nb);
 
     /* We will use hash_input in the computation of both challenges */
     uint8_t hash_input[33];
@@ -733,7 +711,7 @@ static C_KZG_RET compute_challenges(fr_t *eval_challenge_out, fr_t *r_powers_out
     Bytes32 r_bytes;
     memcpy(hash_input, hashed_data, 32);
     hash_input[32] = 0x0;
-    hash(r_bytes.bytes, hash_input, 33);
+    blst_sha256(r_bytes.bytes, hash_input, 33);
 
     /* Compute r_powers */
     fr_t r;
@@ -743,7 +721,7 @@ static C_KZG_RET compute_challenges(fr_t *eval_challenge_out, fr_t *r_powers_out
     /* Compute eval_challenge */
     Bytes32 eval_challenge;
     hash_input[32] = 0x1;
-    hash(eval_challenge.bytes, hash_input, 33);
+    blst_sha256(eval_challenge.bytes, hash_input, 33);
     hash_to_bls_field(eval_challenge_out, &eval_challenge);
 
     free(bytes);