Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add RedHatProductSecurity/prodsec-skills --skill compiler-hardeninggit clone --depth 1 https://github.com/RedHatProductSecurity/prodsec-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/compiler-hardening)<a href="https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/compiler-hardening"><img src="https://agentmods.dev/badge/skills/redhatproductsecurity/prodsec-skills/compiler-hardening/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/compiler-hardening"><img src="https://agentmods.dev/badge/skills/redhatproductsecurity/prodsec-skills/compiler-hardening.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00038 | $0.01139 |
| Opus 5 | $0.00019 | $0.00570 |
| Sonnet 5 | $0.00008 | $0.00228 |
| Haiku 4.5 | $0.00004 | $0.00114 |
Grade A, and why
compiler-hardening scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Compiler Hardening
Common Vulnerability Classes
| Category | Examples |
|---|---|
| Memory errors | Buffer overflow, use-after-free (UAF), buffer over-read |
| Dependency attacks | Library hijacking, library sideloading, supply chain compromise |
Hardening Flags
When building with Fedora/RPM toolchains, hardened flags are often applied automatically. For other build systems, explicitly add hardening options.
The OpenSSF Compiler Hardening Guide is the canonical reference. Key flags include:
| Flag | Purpose |
|---|---|
-fstack-protector-strong |
Stack buffer overflow detection |
-D_FORTIFY_SOURCE=2 |
Runtime buffer overflow checks for standard library functions |
-fPIE / -pie |
Position-independent executable for ASLR |
-Wl,-z,relro,-z,now |
Full RELRO -- makes GOT read-only after relocation |
-Wl,-z,noexecstack |
Non-executable stack |
-fno-strict-overflow |
Prevent undefined behavior optimizations on signed overflow |
GCC 14+ provides -fhardened as a convenience flag that enables a recommended set of hardening options.
The Fedora Security Features Matrix provides an overview of security features available in a modern Linux system.
Sanitizers
Sanitizers add runtime instrumentation that catches errors during testing that would otherwise go undetected. They increase binary size and resource consumption but provide significantly better error detection and debug information than traditional tooling.
| Sanitizer | Flag | Detects |
|---|---|---|
| AddressSanitizer | -fsanitize=address |
Memory access violations (buffer overflow, UAF, stack overflow) |
| ThreadSanitizer | -fsanitize=thread |
Data races and race conditions |
| LeakSanitizer | -fsanitize=leak |
Memory leaks |
| UndefinedBehaviorSanitizer | -fsanitize=undefined |
Undefined behavior at runtime |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 11d ago First seen · 88 lines · 38 tokens per session scan A abf15e04fe51
compiler-hardening is a skill published in the GitHub repository RedHatProductSecurity/prodsec-skills (52 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 38 tokens to every session and 1,139 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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