# FORTIFY Clang port for msm-4.14 (LOS sunfish)

Based on Kees Cook *fortify: Add Clang support* (upstream ~2022), adapted
to 4.14’s in-`string.h` FORTIFY (no `fortify-string.h` yet).

**Not** AXP `0004` (strict-string). **Not** `BUG()` link stubs.

See `docs/009-fortify-clang-port.md`.

## Apply

```bash
# on rom-dev01, after git reset of msm-4.14:
python3 apply_fortify_clang.py /path/to/msm-4.14
patch -p1 -d /path/to/msm-4.14 < 0001-driver-bounds-rtac-fils.patch
```

`ksync-one.sh` with `CONFIG_FORTIFY_SOURCE` runs both automatically.

Then enable `CONFIG_FORTIFY_SOURCE=y` and build **without**
`ALLOW_FORTIFY_BUG_STUBS`.

## Nested strlen (required)

With Clang `__pass_object_size`, fortified `strlcpy`/`strcpy` must call
`__underlying_strlen(q)`, not fortified `strlen(q)`. Otherwise a known
source object size makes `strlen` panic at boot (LAB: `strlen+strlcpy`
fail; `strlen+strncpy` OK). `apply_fortify_clang.py` rewrites both.

## Diag capture (v4)

`apply_fortify_diag.py` — `early_ioremap` before `parse_early_param`, ordinary
`ioremap` only after `mm_init`, never map from the failure handler; failure
and milestone zones separated. See `docs/009-fortify-diag-capture-plan.md`
and `docs/009-fortify-diag-v3-review-20260927.md`. Control:
`PSTORE_ALT_PLAIN=1` / `scripts/009-bisect-ksync-pstore-alt-plain.sh`.