Fix: UB in CIccOpDefEnvVar::Exec()

[ChrisCoxArt]

so UB doesn't happen when we read bad values
Fixes #670

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[xsscx]

Maintainer Review

2026-03-15 00:50:41 UTC

Repro

mkdir pr-685
cd pr-685
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV/Build
git fetch origin pull/685/head:pr-685
git checkout pr-685
export CXX=clang++ && export CXXFLAGS="-fsanitize=address,undefined -fno-omit-frame-pointer -g -O1 -fprofile-arcs -ftest-coverage" && export LDFLAGS="-fsanitize=address,undefined -fprofile-arcs" && cmake Cmake -DCMAKE_BUILD_TYPE=Debug -DENABLE_ASAN=ON -DENABLE_UBSAN=ON -DENABLE_COVERAGE=ON
make -j$(nproc)
        cd ../Testing/
        echo "=== Updating PATH ==="
         for d in ../Build/Tools/*; do
          [ -d "$d" ] && export PATH="$(realpath "$d"):$PATH"
         done
wget https://github.com/xsscx/fuzz/raw/refs/heads/master/graphics/icc/ub-nan-outside-range-iccApplyProfiles_cpp-Line560.icc
wget https://github.com/xsscx/fuzz/raw/refs/heads/master/graphics/tif/test_rgb.tif
ASAN_OPTIONS=detect_leaks=0 iccApplyProfiles test_rgb.tif ub-out.tif 1 0 0 0 0 ub-nan-outside-range-iccApplyProfiles_cpp-Line560.icc 0 

PR Application Output

100%