Remove libubsan CI workaround (#24782)

It seems that this was added to allow rustc to load proc macros that had
been compiled with UBSan enabled, which zig does for debug and
`ReleaseSafe` builds. When zig drives the link of the final binary it
knows to include the ubsan runtime, but our zig-built artifacts are
being linked into a binary whose linking rustc drives. This removes the
libubsan workaround we have and replaces it with
`-fno-sanitize=undefined` passed to zig.

The new argument is passed at the end of zig's args so should take
precedence over any earlier arguments from the script's caller.

.github/scripts/install-musl-build-tools.sh

@@ -150,7 +150,9 @@ for arg in "\$@"; do
   args+=("\${arg}")
 done
 
-exec "${zig_bin}" cc -target "${zig_target}" "\${args[@]}"
+# Zig enables UBSan for debug C builds by default. Rust links these objects
+# without Zig's sanitizer runtime, so keep native dependencies uninstrumented.
+exec "${zig_bin}" cc -target "${zig_target}" "\${args[@]}" -fno-sanitize=undefined
 EOF
   cat >"${cxx}" <<EOF
 #!/usr/bin/env bash
@@ -207,7 +209,9 @@ for arg in "\$@"; do
   args+=("\${arg}")
 done
 
-exec "${zig_bin}" c++ -target "${zig_target}" "\${args[@]}"
+# Zig enables UBSan for debug C++ builds by default. Rust links these objects
+# without Zig's sanitizer runtime, so keep native dependencies uninstrumented.
+exec "${zig_bin}" c++ -target "${zig_target}" "\${args[@]}" -fno-sanitize=undefined
 EOF
   chmod +x "${cc}" "${cxx}"
 
@@ -270,6 +274,11 @@ echo "PKG_CONFIG_PATH=${pkg_config_path}" >> "$GITHUB_ENV"
 pkg_config_path_var="PKG_CONFIG_PATH_${TARGET}"
 pkg_config_path_var="${pkg_config_path_var//-/_}"
 echo "${pkg_config_path_var}=${libcap_pkgconfig_dir}" >> "$GITHUB_ENV"
+pkg_config_libdir_var="PKG_CONFIG_LIBDIR_${TARGET}"
+pkg_config_libdir_var="${pkg_config_libdir_var//-/_}"
+# Do not let musl cross-builds resolve native libraries from the host glibc
+# pkg-config directories. libcap is the only target package provided here.
+echo "${pkg_config_libdir_var}=${libcap_pkgconfig_dir}" >> "$GITHUB_ENV"
 
 if [[ -n "${sysroot}" && "${sysroot}" != "/" ]]; then
   echo "PKG_CONFIG_SYSROOT_DIR=${sysroot}" >> "$GITHUB_ENV"

.github/workflows/rust-ci-full.yml

@@ -260,11 +260,7 @@ jobs:
           set -euo pipefail
           if command -v apt-get >/dev/null 2>&1; then
             sudo apt-get update -y
-            packages=(pkg-config libcap-dev)
-            if [[ "${{ matrix.target }}" == 'x86_64-unknown-linux-musl' || "${{ matrix.target }}" == 'aarch64-unknown-linux-musl' ]]; then
-              packages+=(libubsan1)
-            fi
-            sudo DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends "${packages[@]}"
+            sudo DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends pkg-config libcap-dev
           fi
       - uses: dtolnay/rust-toolchain@e081816240890017053eacbb1bdf337761dc5582 # 1.95.0
         with:
@@ -348,14 +344,6 @@ jobs:
             sccache-${{ matrix.runner }}-${{ matrix.target }}-${{ matrix.profile }}-${{ steps.lockhash.outputs.hash }}-
             sccache-${{ matrix.runner }}-${{ matrix.target }}-${{ matrix.profile }}-
 
-      - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
-        name: Disable sccache wrapper (musl)
-        shell: bash
-        run: |
-          set -euo pipefail
-          echo "RUSTC_WRAPPER=" >> "$GITHUB_ENV"
-          echo "RUSTC_WORKSPACE_WRAPPER=" >> "$GITHUB_ENV"
-
       - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
         name: Prepare APT cache directories (musl)
         shell: bash
@@ -389,58 +377,6 @@ jobs:
         shell: bash
         run: bash "${GITHUB_WORKSPACE}/.github/scripts/install-musl-build-tools.sh"
 
-      - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
-        name: Configure rustc UBSan wrapper (musl host)
-        shell: bash
-        run: |
-          set -euo pipefail
-          ubsan=""
-          if command -v ldconfig >/dev/null 2>&1; then
-            ubsan="$(ldconfig -p | grep -m1 'libubsan\.so\.1' | sed -E 's/.*=> (.*)$/\1/')"
-          fi
-          wrapper_root="${RUNNER_TEMP:-/tmp}"
-          wrapper="${wrapper_root}/rustc-ubsan-wrapper"
-          cat > "${wrapper}" <<EOF
-          #!/usr/bin/env bash
-          set -euo pipefail
-          if [[ -n "${ubsan}" ]]; then
-            export LD_PRELOAD="${ubsan}\${LD_PRELOAD:+:\${LD_PRELOAD}}"
-          fi
-          exec "\$1" "\${@:2}"
-          EOF
-          chmod +x "${wrapper}"
-          echo "RUSTC_WRAPPER=${wrapper}" >> "$GITHUB_ENV"
-          echo "RUSTC_WORKSPACE_WRAPPER=" >> "$GITHUB_ENV"
-
-      - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
-        name: Clear sanitizer flags (musl)
-        shell: bash
-        run: |
-          set -euo pipefail
-          # Clear global Rust flags so host/proc-macro builds don't pull in UBSan.
-          echo "RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_ENCODED_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "RUSTDOCFLAGS=" >> "$GITHUB_ENV"
-          # Override any runner-level Cargo config rustflags as well.
-          echo "CARGO_BUILD_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_RUSTFLAGS=" >> "$GITHUB_ENV"
-
-          sanitize_flags() {
-            local input="$1"
-            input="${input//-fsanitize=undefined/}"
-            input="${input//-fno-sanitize-recover=undefined/}"
-            input="${input//-fno-sanitize-trap=undefined/}"
-            echo "$input"
-          }
-
-          cflags="$(sanitize_flags "${CFLAGS-}")"
-          cxxflags="$(sanitize_flags "${CXXFLAGS-}")"
-          echo "CFLAGS=${cflags}" >> "$GITHUB_ENV"
-          echo "CXXFLAGS=${cxxflags}" >> "$GITHUB_ENV"
-
       - if: ${{ !contains(matrix.target, 'windows') }}
         name: Configure rusty_v8 artifact overrides and verify checksums
         uses: ./.github/actions/setup-rusty-v8

.github/workflows/rust-release.yml

@@ -245,15 +245,6 @@ jobs:
           set -euo pipefail
           sudo apt-get update -y
           sudo DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends pkg-config libcap-dev
-      - name: Install UBSan runtime (musl)
-        if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl' }}
-        shell: bash
-        run: |
-          set -euo pipefail
-          if command -v apt-get >/dev/null 2>&1; then
-            sudo apt-get update -y
-            sudo DEBIAN_FRONTEND=noninteractive apt-get install -y libubsan1
-          fi
       - uses: dtolnay/rust-toolchain@e081816240890017053eacbb1bdf337761dc5582 # 1.95.0
         with:
           targets: ${{ matrix.target }}
@@ -283,30 +274,7 @@ jobs:
         run: bash "${GITHUB_WORKSPACE}/.github/scripts/install-musl-build-tools.sh"
 
       - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
-        name: Configure rustc UBSan wrapper (musl host)
-        shell: bash
-        run: |
-          set -euo pipefail
-          ubsan=""
-          if command -v ldconfig >/dev/null 2>&1; then
-            ubsan="$(ldconfig -p | grep -m1 'libubsan\.so\.1' | sed -E 's/.*=> (.*)$/\1/')"
-          fi
-          wrapper_root="${RUNNER_TEMP:-/tmp}"
-          wrapper="${wrapper_root}/rustc-ubsan-wrapper"
-          cat > "${wrapper}" <<EOF
-          #!/usr/bin/env bash
-          set -euo pipefail
-          if [[ -n "${ubsan}" ]]; then
-            export LD_PRELOAD="${ubsan}\${LD_PRELOAD:+:\${LD_PRELOAD}}"
-          fi
-          exec "\$1" "\${@:2}"
-          EOF
-          chmod +x "${wrapper}"
-          echo "RUSTC_WRAPPER=${wrapper}" >> "$GITHUB_ENV"
-          echo "RUSTC_WORKSPACE_WRAPPER=" >> "$GITHUB_ENV"
-
-      - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
-        name: Clear sanitizer flags (musl)
+        name: Disable aws-lc jitter entropy (musl)
         shell: bash
         run: |
           set -euo pipefail
@@ -316,30 +284,6 @@ jobs:
           target_no_jitter="${target_no_jitter//-/_}"
           echo "${target_no_jitter}=1" >> "$GITHUB_ENV"
 
-          # Clear global Rust flags so host/proc-macro builds don't pull in UBSan.
-          echo "RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_ENCODED_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "RUSTDOCFLAGS=" >> "$GITHUB_ENV"
-          # Override any runner-level Cargo config rustflags as well.
-          echo "CARGO_BUILD_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUSTFLAGS=" >> "$GITHUB_ENV"
-          echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_RUSTFLAGS=" >> "$GITHUB_ENV"
-
-          sanitize_flags() {
-            local input="$1"
-            input="${input//-fsanitize=undefined/}"
-            input="${input//-fno-sanitize-recover=undefined/}"
-            input="${input//-fno-sanitize-trap=undefined/}"
-            echo "$input"
-          }
-
-          cflags="$(sanitize_flags "${CFLAGS-}")"
-          cxxflags="$(sanitize_flags "${CXXFLAGS-}")"
-          echo "CFLAGS=${cflags}" >> "$GITHUB_ENV"
-          echo "CXXFLAGS=${cxxflags}" >> "$GITHUB_ENV"
-
       - name: Configure rusty_v8 artifact overrides and verify checksums
         uses: ./.github/actions/setup-rusty-v8
         with: