Add ARMv7 build support

.github/workflows/build.yml

@@ -73,6 +73,29 @@ jobs:
         path: |
           target/*/release/avml
           target/*/release/avml-minimal
+  armv7:
+    permissions:
+        contents: read
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v7.0.1
+    - uses: Swatinem/rust-cache@a45951ff880207c249adf57334cf2e9bd81d6e1e # v2
+    - name: Cache ARMv7 build chain
+      uses: actions/cache@v6
+      with:
+        path: |
+          ~/.cache/avml/arm-linux-musleabihf-cross
+          ~/.cache/avml/musl-cross-make-armv7-227df8b99103f9c59f6570babf892978e293082f
+        key: armv7-build-chain-${{ runner.os }}-${{ hashFiles('eng/build-armv7.sh', 'eng/musl-cross-common.sh') }}
+    - name: build
+      run: eng/build-armv7.sh
+    - name: upload artifacts
+      uses: actions/upload-artifact@v7.0.1
+      with:
+        name: linux-armv7-artifacts
+        path: |
+          target/armv7-unknown-linux-musleabihf/release/avml
+          target/armv7-unknown-linux-musleabihf/release/avml-minimal
   armv6b:
     permissions:
         contents: read
@@ -86,7 +109,7 @@ jobs:
         path: |
           ~/.cache/avml/armeb-linux-musleabi-cross
           ~/.cache/avml/musl-cross-make-227df8b99103f9c59f6570babf892978e293082f
-        key: armv6b-build-chain-${{ runner.os }}-${{ hashFiles('eng/build-armv6b.sh') }}
+        key: armv6b-build-chain-${{ runner.os }}-${{ hashFiles('eng/build-armv6b.sh', 'eng/musl-cross-common.sh') }}
     - name: build
       run: |
         eng/build-armv6b.sh

README.md

@@ -4,11 +4,15 @@
 
 *A portable volatile memory acquisition tool for Linux.*
 
-AVML is an X86\_64 userland volatile memory acquisition tool written in
+AVML is a Linux userland volatile memory acquisition tool written in
 [Rust](https://www.rust-lang.org/), intended to be deployed as a static binary.
 AVML can be used to acquire memory without knowing the target OS distribution
 or kernel a priori.  No on-target compilation or fingerprinting is needed.
 
+Release builds are produced for x86-64, AArch64, ARMv7 little-endian hard-float,
+and legacy ARMv6-compatible big-endian systems. ARMv7 acquisition currently
+assumes 4096-byte memory pages.
+
 ## Features
 * Save recorded images to external locations via Azure Blob Store or HTTP PUT
 * Azure Blob Storage uploads retry transient failures via the Azure SDK's default exponential backoff policy (8 attempts, capped at one minute total elapsed).
@@ -197,6 +201,12 @@ Run `avml <COMMAND> --help` for per-command options.
     # Build without upload functionality
     cargo build --release --target x86_64-unknown-linux-musl --no-default-features
 
+ARMv7 hard-float artifacts require an ARM musl cross-toolchain. The repository
+build script creates the pinned toolchain and builds both full and minimal
+static binaries:
+
+    eng/build-armv7.sh
+
 # Testing on Azure
 
 The testing scripts will create, use, and cleanup a number of resource groups, virtual machines, and a storage account.

eng/build-armv6b.sh

@@ -8,6 +8,8 @@ set -euo pipefail
 
 cd "$(dirname "${BASH_SOURCE[0]}")/../"
 
+source eng/musl-cross-common.sh
+
 VERBOSE="${VERBOSE:-0}"
 
 TARGET_NAME="${TARGET_NAME:-armv5te-unknown-linux-musleabi}"
@@ -17,10 +19,6 @@ ARTIFACT_DIR="${ARTIFACT_DIR:-target/armeb-unknown-linux-musleabi/release}"
 CARGO_TOOLCHAIN="${CARGO_TOOLCHAIN:-nightly}"
 CROSS_COMPILE="${CROSS_COMPILE:-armeb-linux-musleabi-}"
 MUSL_TOOLCHAIN_DIR="${MUSL_TOOLCHAIN_DIR:-${HOME}/.cache/avml/armeb-linux-musleabi-cross}"
-MUSL_CROSS_MAKE_REV="${MUSL_CROSS_MAKE_REV:-227df8b99103f9c59f6570babf892978e293082f}"
-MUSL_CROSS_MAKE_URL="${MUSL_CROSS_MAKE_URL:-https://github.com/richfelker/musl-cross-make/archive/${MUSL_CROSS_MAKE_REV}.tar.gz}"
-MUSL_CROSS_MAKE_SHA256="${MUSL_CROSS_MAKE_SHA256:-bb3fc7851088e1e5e1274ee56a0ab6ae176043d160fdf0b71027934b091f208a}"
-MUSL_CROSS_MAKE_ARCHIVE="${MUSL_CROSS_MAKE_ARCHIVE:-}"
 MUSL_CROSS_MAKE_DIR="${MUSL_CROSS_MAKE_DIR:-${HOME}/.cache/avml/musl-cross-make-${MUSL_CROSS_MAKE_REV}}"
 BUILD_TOOLS_DIR="${BUILD_TOOLS_DIR:-target/armv6b-build-tools}"
 if [[ "$BUILD_TOOLS_DIR" != /* ]]; then
@@ -29,7 +27,6 @@ fi
 BUILD_LOG="${BUILD_LOG:-${BUILD_TOOLS_DIR}/build.log}"
 TARGET_ENV="${TARGET_NAME//-/_}"
 TARGET_ENV="${TARGET_ENV^^}"
-MUSL_CROSS_MAKE_DL_CMD="curl --fail --show-error --location --continue-at - --output"
 
 mkdir -p "$(dirname "$BUILD_LOG")"
 : > "$BUILD_LOG"
@@ -105,47 +102,8 @@ ensure_rust_toolchain() {
     rustup toolchain install "$CARGO_TOOLCHAIN" --profile minimal --component rust-src
 }
 
-verify_sha256() {
-    local archive="$1"
-    local expected_sha256="$2"
-
-    if ! echo "${expected_sha256}  ${archive}" | sha256sum --check --status; then
-        echo "${archive}: SHA-256 verification failed; expected ${expected_sha256}" >&2
-        exit 1
-    fi
-}
-
-download_verified() {
-    local url="$1"
-    local archive="$2"
-    local expected_sha256="$3"
-
-    log "Downloading musl-cross-make"
-    curl --fail --show-error --location --retry 5 --retry-delay 10 \
-        --output "$archive" "$url"
-    verify_sha256 "$archive" "$expected_sha256"
-}
-
 ensure_source_musl_toolchain() {
-    local archive="${BUILD_TOOLS_DIR}/musl-cross-make-${MUSL_CROSS_MAKE_REV}.tar.gz"
-
-    mkdir -p "$BUILD_TOOLS_DIR" "$MUSL_CROSS_MAKE_DIR"
-    if [[ -n "$MUSL_CROSS_MAKE_ARCHIVE" ]]; then
-        archive="$MUSL_CROSS_MAKE_ARCHIVE"
-        verify_sha256 "$archive" "$MUSL_CROSS_MAKE_SHA256"
-    elif [[ ! -f "$archive" ]]; then
-        download_verified "$MUSL_CROSS_MAKE_URL" "$archive" "$MUSL_CROSS_MAKE_SHA256"
-    else
-        verify_sha256 "$archive" "$MUSL_CROSS_MAKE_SHA256"
-    fi
-
-    if [[ ! -f "${MUSL_CROSS_MAKE_DIR}/Makefile" ]]; then
-        log "Extracting musl-cross-make"
-        rm -rf "$MUSL_CROSS_MAKE_DIR"
-        mkdir -p "$MUSL_CROSS_MAKE_DIR"
-        tar --extract --gzip --directory "$MUSL_CROSS_MAKE_DIR" --strip-components=1 \
-            --file "$archive"
-    fi
+    avml_ensure_musl_cross_make_source "$BUILD_TOOLS_DIR" "$MUSL_CROSS_MAKE_DIR"
 
     cat > "${MUSL_CROSS_MAKE_DIR}/config.mak" <<EOF
 TARGET = armeb-linux-musleabi
@@ -158,6 +116,7 @@ GCC_CONFIG += --disable-libquadmath --disable-decimal-float --disable-libitm
 GCC_CONFIG += --disable-fixed-point --disable-lto --enable-languages=c,c++
 EOF
 
+    avml_ensure_musl_source "$MUSL_CROSS_MAKE_DIR"
     log "Building musl cross toolchain"
     make -C "$MUSL_CROSS_MAKE_DIR"
     make -C "$MUSL_CROSS_MAKE_DIR" install

eng/build-armv7.sh

@@ -0,0 +1,140 @@
+#!/usr/bin/bash
+#
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+#
+
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/../"
+
+source eng/musl-cross-common.sh
+
+TARGET_NAME="${TARGET_NAME:-armv7-unknown-linux-musleabihf}"
+CROSS_COMPILE="${CROSS_COMPILE:-arm-linux-musleabihf-}"
+MUSL_TOOLCHAIN_DIR="${MUSL_TOOLCHAIN_DIR:-${HOME}/.cache/avml/arm-linux-musleabihf-cross}"
+MUSL_CROSS_MAKE_DIR="${MUSL_CROSS_MAKE_DIR:-${HOME}/.cache/avml/musl-cross-make-armv7-${MUSL_CROSS_MAKE_REV}}"
+BUILD_TOOLS_DIR="${BUILD_TOOLS_DIR:-target/armv7-build-tools}"
+TARGET_ENV="${TARGET_NAME//-/_}"
+TARGET_ENV="${TARGET_ENV^^}"
+
+log() {
+    echo "==> $*"
+}
+
+require_command() {
+    local command_name="$1"
+
+    if ! command -v "$command_name" >/dev/null 2>&1; then
+        echo "Missing required command: $command_name" >&2
+        exit 1
+    fi
+}
+
+install_apt_packages() {
+    local missing_packages=("$@")
+
+    if [[ "${#missing_packages[@]}" -eq 0 ]]; then
+        return
+    fi
+
+    require_command sudo
+    log "Installing missing host packages: ${missing_packages[*]}"
+    sudo apt-get update
+    sudo apt-get install --no-install-recommends --yes "${missing_packages[@]}"
+}
+
+ensure_host_tools() {
+    local packages=()
+
+    command -v curl >/dev/null 2>&1 || packages+=("curl")
+    command -v make >/dev/null 2>&1 || packages+=("make")
+    command -v perl >/dev/null 2>&1 || packages+=("perl")
+    command -v sha256sum >/dev/null 2>&1 || packages+=("coreutils")
+    command -v gcc >/dev/null 2>&1 || packages+=("build-essential")
+    command -v bzip2 >/dev/null 2>&1 || packages+=("bzip2")
+    command -v xz >/dev/null 2>&1 || packages+=("xz-utils")
+
+    if [[ "${#packages[@]}" -gt 0 ]]; then
+        if command -v apt-get >/dev/null 2>&1; then
+            install_apt_packages "${packages[@]}"
+        else
+            echo "Install these host tools before running $0: ${packages[*]}" >&2
+            exit 1
+        fi
+    fi
+}
+
+ensure_musl_toolchain() {
+    if command -v "${CROSS_COMPILE}gcc" >/dev/null 2>&1; then
+        return
+    fi
+    if [[ -x "${MUSL_TOOLCHAIN_DIR}/bin/arm-linux-musleabihf-gcc" ]]; then
+        CROSS_COMPILE="${MUSL_TOOLCHAIN_DIR}/bin/arm-linux-musleabihf-"
+        return
+    fi
+
+    avml_ensure_musl_cross_make_source "$BUILD_TOOLS_DIR" "$MUSL_CROSS_MAKE_DIR"
+
+    cat > "${MUSL_CROSS_MAKE_DIR}/config.mak" <<EOF
+TARGET = arm-linux-musleabihf
+OUTPUT = ${MUSL_TOOLCHAIN_DIR}
+DL_CMD = ${MUSL_CROSS_MAKE_DL_CMD}
+COMMON_CONFIG += CFLAGS="-g0 -Os" CXXFLAGS="-g0 -Os" LDFLAGS="-s"
+COMMON_CONFIG += --disable-nls --with-debug-prefix-map=\$(CURDIR)=
+GCC_CONFIG += --with-arch=armv7-a --with-fpu=vfpv3-d16 --with-float=hard
+GCC_CONFIG += --disable-libquadmath --disable-decimal-float --disable-libitm
+GCC_CONFIG += --disable-lto --enable-languages=c,c++
+EOF
+
+    avml_ensure_musl_source "$MUSL_CROSS_MAKE_DIR"
+    log "Building ARMv7 musl cross toolchain"
+    make -C "$MUSL_CROSS_MAKE_DIR"
+    make -C "$MUSL_CROSS_MAKE_DIR" install
+    CROSS_COMPILE="${MUSL_TOOLCHAIN_DIR}/bin/arm-linux-musleabihf-"
+}
+
+verify_binary() {
+    local binary="$1"
+    local readelf="${CROSS_COMPILE}readelf"
+
+    "$readelf" -h "$binary" | grep -q "Class:.*ELF32"
+    "$readelf" -h "$binary" | grep -q "Data:.*little endian"
+    "$readelf" -h "$binary" | grep -q "Machine:.*ARM"
+    "$readelf" -h "$binary" | grep -q "Flags:.*hard-float ABI"
+    "$readelf" -A "$binary" | grep -q "Tag_CPU_arch: v7"
+    ! "$readelf" -l "$binary" | grep -q "INTERP"
+    ! "$readelf" -d "$binary" | grep -q "(NEEDED)"
+}
+
+ensure_host_tools
+require_command rustup
+log "Ensuring Rust target ${TARGET_NAME} is installed"
+rustup +stable target add "$TARGET_NAME"
+ensure_musl_toolchain
+
+LINKER="${CROSS_COMPILE}gcc"
+STRIP="${CROSS_COMPILE}strip"
+TARGET_VARIABLE="${TARGET_NAME//-/_}"
+
+export "CARGO_TARGET_${TARGET_ENV}_LINKER=${LINKER}"
+export "CC_${TARGET_VARIABLE}=${LINKER}"
+export "AR_${TARGET_VARIABLE}=${CROSS_COMPILE}ar"
+export "RANLIB_${TARGET_VARIABLE}=${CROSS_COMPILE}ranlib"
+export "CFLAGS_${TARGET_VARIABLE}=-march=armv7-a -mfpu=vfpv3-d16 -mfloat-abi=hard"
+export OPENSSL_STATIC="${OPENSSL_STATIC:-1}"
+
+log "Building minimal AVML for ${TARGET_NAME}"
+cargo +stable build --release --no-default-features --target "$TARGET_NAME" --locked
+cp "target/${TARGET_NAME}/release/avml" "target/${TARGET_NAME}/release/avml-minimal"
+
+log "Building default AVML for ${TARGET_NAME}"
+cargo +stable build --release --target "$TARGET_NAME" --locked
+
+for binary in \
+    "target/${TARGET_NAME}/release/avml" \
+    "target/${TARGET_NAME}/release/avml-minimal"; do
+    log "Verifying ${binary}"
+    "$STRIP" "$binary"
+    verify_binary "$binary"
+done

eng/musl-cross-common.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/bash
+#
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+#
+
+: "${MUSL_CROSS_MAKE_REV:=227df8b99103f9c59f6570babf892978e293082f}"
+: "${MUSL_CROSS_MAKE_URL:=https://github.com/richfelker/musl-cross-make/archive/${MUSL_CROSS_MAKE_REV}.tar.gz}"
+: "${MUSL_CROSS_MAKE_SHA256:=bb3fc7851088e1e5e1274ee56a0ab6ae176043d160fdf0b71027934b091f208a}"
+: "${MUSL_CROSS_MAKE_ARCHIVE:=}"
+: "${MUSL_VERSION:=1.2.6}"
+: "${MUSL_SOURCE_URL:=https://sources.buildroot.net/musl/musl-${MUSL_VERSION}.tar.gz}"
+: "${MUSL_SOURCE_SHA256:=d585fd3b613c66151fc3249e8ed44f77020cb5e6c1e635a616d3f9f82460512a}"
+: "${MUSL_CROSS_MAKE_DL_CMD:=curl --fail --show-error --location --continue-at - --retry 5 --retry-delay 10 --output}"
+
+avml_verify_sha256() {
+    local archive="$1"
+    local expected_sha256="$2"
+
+    if ! echo "${expected_sha256}  ${archive}" | sha256sum --check --status; then
+        echo "${archive}: SHA-256 verification failed; expected ${expected_sha256}" >&2
+        exit 1
+    fi
+}
+
+avml_download_verified() {
+    local name="$1"
+    local url="$2"
+    local archive="$3"
+    local expected_sha256="$4"
+    local temporary_archive="${archive}.download"
+
+    log "Downloading ${name}"
+    curl --fail --show-error --location --retry 5 --retry-delay 10 \
+        --output "$temporary_archive" "$url"
+    avml_verify_sha256 "$temporary_archive" "$expected_sha256"
+    mv "$temporary_archive" "$archive"
+}
+
+avml_ensure_musl_cross_make_source() {
+    local build_tools_dir="$1"
+    local source_dir="$2"
+    local archive="${build_tools_dir}/musl-cross-make-${MUSL_CROSS_MAKE_REV}.tar.gz"
+
+    mkdir -p "$build_tools_dir" "$source_dir"
+    if [[ -n "$MUSL_CROSS_MAKE_ARCHIVE" ]]; then
+        archive="$MUSL_CROSS_MAKE_ARCHIVE"
+        avml_verify_sha256 "$archive" "$MUSL_CROSS_MAKE_SHA256"
+    elif [[ -f "$archive" ]]; then
+        avml_verify_sha256 "$archive" "$MUSL_CROSS_MAKE_SHA256"
+    else
+        avml_download_verified \
+            "musl-cross-make" \
+            "$MUSL_CROSS_MAKE_URL" \
+            "$archive" \
+            "$MUSL_CROSS_MAKE_SHA256"
+    fi
+
+    if [[ ! -f "${source_dir}/Makefile" ]]; then
+        log "Extracting musl-cross-make"
+        rm -rf "$source_dir"
+        mkdir -p "$source_dir"
+        tar --extract --gzip --directory "$source_dir" --strip-components=1 \
+            --file "$archive"
+    fi
+}
+
+avml_ensure_musl_source() {
+    local source_dir="${1}/sources"
+    local archive="${source_dir}/musl-${MUSL_VERSION}.tar.gz"
+
+    mkdir -p "$source_dir"
+    if [[ -f "$archive" ]]; then
+        avml_verify_sha256 "$archive" "$MUSL_SOURCE_SHA256"
+        return
+    fi
+
+    avml_download_verified \
+        "musl ${MUSL_VERSION}" \
+        "$MUSL_SOURCE_URL" \
+        "$archive" \
+        "$MUSL_SOURCE_SHA256"
+}