[bitcoin-core] Add differential cryptography fuzzer (#5717)

* [bitcoin-core] Support AFL builds

* [bitcoin-core] Add differential cryptography fuzzer

* [bitcoin-core] Update secp256k1 build procedure

* [bitcoin-core] Build libsecp256k1 without schnorrsig support

* [bitcoin-core] Cryptofuzz: Build 3 versions of libsecp256k1

3 files changed, 140 insertions, 1 deletions

diff --git a/projects/bitcoin-core/Dockerfile b/projects/bitcoin-core/Dockerfile
index 734470e3..8556c892 100644
--- a/projects/bitcoin-core/Dockerfile
+++ b/projects/bitcoin-core/Dockerfile
@@ -27,5 +27,12 @@ RUN apt-get update && apt-get install -y \
 
 RUN git clone --depth=1 https://github.com/bitcoin/bitcoin.git bitcoin-core
 RUN git clone --depth=1 https://github.com/bitcoin-core/qa-assets bitcoin-core/assets
+RUN git clone --depth 1 https://github.com/guidovranken/cryptofuzz
+RUN git clone --depth 1 https://github.com/bitcoin-core/secp256k1.git
+RUN git clone --depth 1 https://github.com/randombit/botan.git
+RUN git clone --depth 1 https://github.com/trezor/trezor-firmware.git
+RUN git clone --depth 1 https://github.com/google/wycheproof.git
+RUN wget https://boostorg.jfrog.io/artifactory/main/release/1.74.0/source/boost_1_74_0.tar.bz2
 WORKDIR bitcoin-core
 COPY build.sh $SRC/
+COPY build_cryptofuzz.sh $SRC/
diff --git a/projects/bitcoin-core/build.sh b/projects/bitcoin-core/build.sh
index db965479..f2a2cb0d 100755
--- a/projects/bitcoin-core/build.sh
+++ b/projects/bitcoin-core/build.sh
@@ -15,6 +15,10 @@
 #
 ################################################################################
 
+bash $SRC/build_cryptofuzz.sh
+
+cd $SRC/bitcoin-core/
+
 # Build dependencies
 # This will also force static builds
 if [ "$ARCHITECTURE" = "i386" ]; then
@@ -67,4 +71,4 @@ for fuzz_target in ${FUZZ_TARGETS[@]}; do
     cd assets/fuzz_seed_corpus
     zip --recurse-paths --quiet --junk-paths "$OUT/${fuzz_target}_seed_corpus.zip" "${fuzz_target}"
   )
-done
+done
\ No newline at end of file
diff --git a/projects/bitcoin-core/build_cryptofuzz.sh b/projects/bitcoin-core/build_cryptofuzz.sh
new file mode 100644
index 00000000..c69d419d
--- /dev/null
+++ b/projects/bitcoin-core/build_cryptofuzz.sh
@@ -0,0 +1,128 @@
+#!/bin/bash -eu
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+export CXXFLAGS="$CXXFLAGS -DCRYPTOFUZZ_NO_OPENSSL"
+export LIBFUZZER_LINK="$LIB_FUZZING_ENGINE"
+
+# Install Boost headers
+cd $SRC/
+tar jxf boost_1_74_0.tar.bz2
+cd boost_1_74_0/
+CFLAGS="" CXXFLAGS="" ./bootstrap.sh
+CFLAGS="" CXXFLAGS="" ./b2 headers
+export CXXFLAGS="$CXXFLAGS -I $SRC/boost_1_74_0/"
+
+# Prevent Boost compilation error with -std=c++17
+export CXXFLAGS="$CXXFLAGS -D_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR"
+
+# Preconfigure libsecp256k1
+cd $SRC/secp256k1/
+autoreconf -ivf
+export CXXFLAGS="$CXXFLAGS -DCRYPTOFUZZ_SECP256K1"
+
+function build_libsecp256k1() {
+    # Build libsecp256k1
+    cd $SRC/secp256k1/
+
+    if test -f "Makefile"; then
+        # Remove old configuration if it exists
+        make clean
+    fi
+
+    if [[ $CFLAGS = *sanitize=memory* ]]
+    then
+        ./configure --enable-static --disable-tests --disable-benchmark --disable-exhaustive-tests --enable-module-recovery --enable-experimental --with-asm=no "$@"
+    else
+        ./configure --enable-static --disable-tests --disable-benchmark --disable-exhaustive-tests --enable-module-recovery --enable-experimental "$@"
+    fi
+    make
+
+    export SECP256K1_INCLUDE_PATH=$(realpath include)
+    export LIBSECP256K1_A_PATH=$(realpath .libs/libsecp256k1.a)
+
+    # Build libsecp256k1 Cryptofuzz module
+    cd $SRC/cryptofuzz/modules/secp256k1/
+    make -B -j$(nproc)
+}
+
+# Build Trezor firmware
+cd $SRC/trezor-firmware/crypto/
+# Rename blake2b_* functions to avoid symbol collisions with other libraries
+sed -i "s/\<blake2b_\([A-Za-z_]\)/trezor_blake2b_\1/g" *.c *.h
+sed -i 's/\<blake2b(/trezor_blake2b(/g' *.c *.h
+cd ../../
+export TREZOR_FIRMWARE_PATH=$(realpath trezor-firmware)
+export CXXFLAGS="$CXXFLAGS -DCRYPTOFUZZ_TREZOR_FIRMWARE"
+
+# Build Botan
+cd $SRC/botan
+if [[ $CFLAGS != *-m32* ]]
+then
+    ./configure.py --cc-bin=$CXX --cc-abi-flags="$CXXFLAGS" --disable-shared --disable-modules=locking_allocator --build-targets=static --without-documentation
+else
+    ./configure.py --cpu=x86_32 --cc-bin=$CXX --cc-abi-flags="$CXXFLAGS" --disable-shared --disable-modules=locking_allocator --build-targets=static --without-documentation
+fi
+make -j$(nproc)
+
+export CXXFLAGS="$CXXFLAGS -DCRYPTOFUZZ_BOTAN -DCRYPTOFUZZ_BOTAN_IS_ORACLE"
+export LIBBOTAN_A_PATH="$SRC/botan/libbotan-3.a"
+export BOTAN_INCLUDE_PATH="$SRC/botan/build/include"
+
+# Build Cryptofuzz
+cd $SRC/cryptofuzz
+python gen_repository.py
+rm extra_options.h
+echo -n '"' >>extra_options.h
+echo -n '--operations=Digest,HMAC,KDF_HKDF,SymmetricEncrypt,SymmetricDecrypt,ECC_PrivateToPublic,ECC_ValidatePubkey,ECDSA_Sign,ECDSA_Verify,ECDSA_Recover,BignumCalc_Mod_2Exp256 ' >>extra_options.h
+echo -n '--curves=secp256k1 ' >>extra_options.h
+echo -n '--digests=NULL,SHA1,SHA256,SHA512,RIPEMD160,SHA3-256,SIPHASH64 ' >>extra_options.h
+echo -n '--ciphers=CHACHA20,AES_256_CBC ' >>extra_options.h
+echo -n '--calcops=Add,And,Div,IsEq,IsGt,IsGte,IsLt,IsLte,IsOdd,Mul,NumBits,Or,Set,Sub,Xor ' >>extra_options.h
+echo -n '"' >>extra_options.h
+cd modules/bitcoin/
+make -B -j$(nproc)
+cd ../trezor/
+make -B -j$(nproc)
+cd ../botan/
+make -B -j$(nproc)
+cd ../../
+
+# Build with 3 configurations of libsecp256k1
+# Discussion: https://github.com/google/oss-fuzz/pull/5717#issuecomment-842765383
+
+build_libsecp256k1 "--with-ecmult-window=2" "--with-ecmult-gen-precision=2"
+cd $SRC/cryptofuzz/
+make -B -j$(nproc)
+cp cryptofuzz $OUT/cryptofuzz-bitcoin-cryptography-w2-p2
+
+build_libsecp256k1 "--with-ecmult-window=15" "--with-ecmult-gen-precision=4"
+cd $SRC/cryptofuzz/
+rm cryptofuzz
+make
+cp cryptofuzz $OUT/cryptofuzz-bitcoin-cryptography-w15-p4
+
+build_libsecp256k1 "--with-ecmult-window=24" "--with-ecmult-gen-precision=8"
+cd $SRC/cryptofuzz/
+rm cryptofuzz
+make
+cp cryptofuzz $OUT/cryptofuzz-bitcoin-cryptography-w24-p8
+
+# Convert Wycheproof test vectors to Cryptofuzz corpus format
+mkdir $SRC/corpus-cryptofuzz-wycheproof/
+find $SRC/wycheproof/testvectors/ -type f -name 'ecdsa_secp256k1_*' -exec $SRC/cryptofuzz/cryptofuzz --from-wycheproof={},$SRC/corpus-cryptofuzz-wycheproof/ \;
+# Pack it and use it as seed corpus
+zip -j $OUT/cryptofuzz-bitcoin-cryptography_seed_corpus.zip $SRC/corpus-cryptofuzz-wycheproof/*