Cross-compile OpenSSL 3.X for Android

build-openssl.sh

#!/bin/bash

# This script builds openSSL from source for the Android platform
# while patching some hand-written assembly that fails on Android
# It's useful when trying to use OpenSSL in Rust which tries to
# from the official sources and will therefore fail when launching
# your crate on Android

# Link to the main PR that fixes the sources:

# https://github.com/openssl/openssl/pull/22181

# Set the ANDROID_NDK_HOME environment variable for this script to work

set -ex

export OPENSSL_VERSION="openssl-3.1.4"
rm -rf ${OPENSSL_VERSION}
# Uncommment this lines to try to download the file, however this URL might have changed, you can just download it yourself
# curl -O "https://www.openssl.org/source/${OPENSSL_VERSION}.tar.gz"
# tar xfz "${OPENSSL_VERSION}.tar.gz"

PROJECT_HOME=`pwd`
PATH_ORG=$PATH
OUTPUT_DIR="libs"

# Clean output
rm -rf $OUTPUT_DIR
mkdir $OUTPUT_DIR

build_android_clang() {
	echo ""
	echo "----- Build libcrypto & libssl.so for "$1" -----"
	echo ""

	ARCHITECTURE=$1
	TOOLCHAIN=$2
	stl="libc++"

	# Set toolchain
	export TOOLCHAIN_ROOT=$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/darwin-x86_64
	export SYSROOT=$TOOLCHAIN_ROOT/sysroot
	export CC=${TOOLCHAIN}21-clang
	export CXX=${TOOLCHAIN}21-clang++
	export CXXFLAGS="-fPIC"
	export CPPFLAGS="-DANDROID -fPIC"

	export PATH=$TOOLCHAIN_ROOT/bin:$SYSROOT/usr/local/bin:$PATH

	cd "${OPENSSL_VERSION}"

	./Configure $ARCHITECTURE no-asm no-shared -D__ANDROID_API__=21

	make clean
	# Apply patch that fixes the armcap instruction
	# Linux version
	# sed -e '/[.]hidden.*OPENSSL_armcap_P/d; /[.]extern.*OPENSSL_armcap_P/ {p; s/extern/hidden/ }' -i -- crypto/*arm*pl crypto/*/asm/*arm*pl
	# macOS version
	sed -E -i '' -e '/[.]hidden.*OPENSSL_armcap_P/d' -e '/[.]extern.*OPENSSL_armcap_P/ {p; s/extern/hidden/; }' crypto/*arm*pl crypto/*/asm/*arm*pl

	make

	mkdir -p ../$OUTPUT_DIR/${ARCHITECTURE}/lib
	mkdir -p ../$OUTPUT_DIR/${ARCHITECTURE}/include

	cp libcrypto.a ../$OUTPUT_DIR/${ARCHITECTURE}/lib/libcrypto.a
	cp libssl.a ../$OUTPUT_DIR/${ARCHITECTURE}/lib/libssl.a

	cp -R include/openssl ../$OUTPUT_DIR/${ARCHITECTURE}/include

	cd ..
}

build_android_clang "android-arm" "armv7a-linux-androideabi"
build_android_clang "android-x86" "i686-linux-android"
build_android_clang "android-x86_64" "x86_64-linux-android"
build_android_clang "android-arm64" "aarch64-linux-android"

export PATH=$PATH_ORG

Thanks for the explanation.

Forgot to mention that your script is still needed with openssl branch 3.4.

Yeah, as long as the hand-crafted assembly code is not patched and released it will be necessary.

Main discussion here:

openssl/openssl#22181

Spent entire day to build openssl v3.4.1 with NDK r29-beta but kept failing.
This script worked like a charm!

Thanks a zillion ton!!!