fix(appsec): use length-aware libddwaf bindings to prevent NUL byte truncation

[KowalskiThomas]

Description

This updates ddwaf_object_map_addl to take a new string length parameter. Previously, due to using raw strlen to detect the string length, it would stop at the first null byte in the input, even if the string was actually longer.

Depends on: DataDog/libddwaf#493

[cit-pr-commenter-54b7da]

Codeowners resolved as

ddtrace/appsec/_ddwaf/ddwaf_types.py                                    @DataDog/asm-python

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-05-18 08:54:31

Comparing candidate commit 564f5de in PR branch kowalski/fix-appsec-use-length-aware-libddwaf-bindings-to-prevent-nul-byte-truncation with baseline commit fe1f0ac in branch main.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 78 metrics, 0 unstable metrics.

scenario:iastaspectsospath-ospathbasename_aspect

• 🟥 execution_time [+79.333µs; +88.810µs] or [+18.460%; +20.666%]

[christophe-papazian]

This is currently not an issue for our product, this PR should be closed.