Fix: SBO in CIccTagNum<(icTagTypeSignature)>::GetValues()

[ChrisCoxArt]

And check that the output size is less than or equal to the input
Fixes #618

Pull Request Checklist

• Have you followed the guidelines in Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you built your Pull Request locally with the Build Instructions?
• Have you added or updated relevant tests?
• Have you added or updated relevant docs?

[xsscx]

Maintainer Review

2026-03-01 03:14:08 UTC

mkdir pr-638
cd pr-638
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV
git fetch origin pull/638/head:pr-638
git checkout pr-638
cd Build
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_BUILD_TYPE=Debug -Wno-dev -DCMAKE_CXX_FLAGS="-g -fsanitize=address,undefined -fno-sanitize=leak -fno-omit-frame-pointer -Wall" -DENABLE_TOOLS=ON -DENABLE_STATIC_LIBS=ON -DENABLE_SHARED_LIBS=ON Cmake > cmake.log 2>&1
make -j32
wget https://github.com/xsscx/fuzz/raw/refs/heads/master/graphics/icc/sbo-CIccTagStruct-GetElemNumberValue-IccTagComposite_cpp-Line737.icc
printf "'RGB '\nicEncodeFloat\n0.5 0.5 0.5\n" | ASAN_OPTIONS=detect_leaks=0,print_scariness=1 Tools/IccApplyNamedCmm/iccApplyNamedCmm /dev/stdin 3 0 sbo-CIccTagStruct-GetElemNumberValue-IccTagComposite_cpp-Line737.icc 0

Expected Output

Error 2 - Unable to begin profile application - Possibly invalid or incompatible profiles