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Chimera GFX release export
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# PS5 payload loader contract audit
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Audit date: 2026-07-17. Scope: pinned public PS5 Payload SDK v0.41 at
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`d2e2e585740362976a39fdd5ccf390f199a7bc37`, inspected offline. No PS5 was
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contacted and no ELF was built, transferred, or executed.
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## Available primary evidence
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The SDK README names three external loader families: `ps5-payload-dev/elfldr`,
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`cryonumb/elfloader` through `ps5-jar-loader`, and
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`shahrilnet/remote_lua_loader`. None of those caller repositories is present in
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the pinned local evidence set. A `git grep` of every other local primary-source
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checkout found no `payload_args_t` or `payloadout` caller implementation. The
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only available contract is therefore the SDK callee side:
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- `include/ps5/payload.h` defines the six-field `payload_args_t`;
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- `crt/crt.c` defines `int _start(payload_args_t *args)` and labels it as the
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entry invoked by the ELF loader;
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- `crt1.o` disassembly shows the first argument consumed from `RDI` and
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`payloadout` read at offset `0x28`;
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- the SDK linker script defines image, BSS, constructor, destructor, and
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dynamic-section boundaries.
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These facts prove the callee layout. They do not prove how a particular loader
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constructs the argument, stack, return address, or post-return state.
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## Argument layout
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For the audited x86-64 target the public fields are six eight-byte values in
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this order:
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| Offset | Field | Callee use |
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|---:|---|---|
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| `0x00` | `sys_dynlib_dlsym` | SDK syscall/symbol bootstrap |
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| `0x08` | `rwpipe` | existing kernel read/write transport descriptors |
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| `0x10` | `rwpair` | existing kernel read/write transport descriptors |
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| `0x18` | `kpipe_addr` | existing kernel pipe address |
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| `0x20` | `kdata_base_addr` | existing kernel data-base address |
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| `0x28` | `payloadout` | result location written by the SDK CRT |
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The 48-byte layout is `SAFE` as a source and disassembly fact. The lifetime,
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writability, ownership, nullability, and post-return consumption of every
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pointer are `UNPROVEN` because the caller is absent.
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## Entry ABI and stack
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The compiled SDK `_start` has a normal x86-64 function prologue, consumes the
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argument from `RDI`, makes further calls without dynamically realigning `RSP`,
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and ends one path with `ret`. This establishes what the callee expects, not what
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the loader guarantees. In particular, the following remain `UNPROVEN`:
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- the exact stack alignment at entry;
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- whether a valid return address is present;
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- which registers or floating-point state the loader expects preserved;
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- whether the loader calls the entry as an ordinary function or transfers
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control by another mechanism;
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- whether the memory behind `payload_args_t` remains valid until return.
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## BSS and image initialization
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The SDK linker script provides `__bss_start` and `__bss_end`. The stock `_start`
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explicitly zeros that range byte-by-byte before accessing its own BSS state.
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The loop itself is freestanding and has no import, so a comparable loop is
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technically possible. It is not evidence that the loader maps every segment
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with the permissions, alignment, relocation state, or zero-fill behavior a new
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artifact would require. Those caller/mapper properties are `UNPROVEN`.
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## Return, exit, crash, and cleanup
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The stock CRT does not define one universal return rule. Its
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`payload_terminate()` first tries to detect a hijacked process with
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`kernel_dynlib_dlsym(-1, 0x2001, "sceKernelDlsym")`. In that branch it returns
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from `_start`. Otherwise it resolves and invokes `exit`; if that fails it
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executes a trap. This heuristic itself depends on the syscall/kernel/rtld stack
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that Phase 0.5 forbids.
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Consequently, a custom `_start` that simply executes `ret` cannot be claimed
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safe from the SDK callee alone. No local primary evidence proves:
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- who consumes the integer return value;
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- whether return resumes a hijacked process or exits a dedicated process;
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- which mappings, descriptors, credentials, or signal state are restored;
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- what happens after an invalid argument, fault, trap, or partial BSS clear;
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- whether any cleanup exists after a crash.
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All five are `UNPROVEN` and are build blockers.
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## Loader state versus artifact-caused state
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The argument fields show that kernel read/write descriptors and kernel
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addresses already exist when the SDK entry is called. That is a fact about the
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incoming state, not proof of how the loader created it. The exact loader may
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have changed credentials, syscall bounds, mappings, modules, or other process
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state before entry; the available callee source cannot distinguish those
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possibilities.
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The stock SDK artifact then independently causes additional writes through
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`__patch_init`; those writes are attributable to `crt1.o` and are `UNSAFE`.
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No Phase-0.5 candidate artifact exists, so it caused no new state changes.
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## Contract decision
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The public callee contract is insufficient for a safe-return artifact.
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Decision: **BLOCKED**. The minimal missing evidence is the exact loader used for
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firmware 9.60 at a pinned public commit, including its entry call site,
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argument ownership, return path, pre-entry changes, cleanup, and crash path.
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Machine evidence: `manifests/runtime/phase-0.5-startup-audit.json`.
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## Phase 0.6 exact-loader addendum
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The Phase-0.5 conclusion above is preserved as the evidence available at that
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time. Phase 0.6 identified the installed loader exactly through the read-only
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Payload Manager inventory and a byte-for-byte public release match:
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- Payload Manager v0.3.1, commit
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`cfbc70f30f419b09bf2b52283f7409e2d3117ee1`, SHA-256
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`518740adbacccb9094fadb07dd424c53ee290f38306449ccc9d6957fdf813c0b`;
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- `ps5-payload-dev/elfldr` v0.23, commit
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`699e8bcff03e91e8d6ca6eba281af25c5a58d8c2`, SHA-256
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`092d16ee0ede0c494947efd38d1a17bbd7cc4b022d3858ea898833c188c703e8`.
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The proposed `itsPLK/ps5-elfldr` v0.23.2 candidate is not installed: its
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release hash is
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`2c28f847c859d3126b0f089ee23b72b84a733548da222ceafd91ae2f3df8f933`.
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The exact exploit/autoloader that originally starts the first-stage loader
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remains unidentified.
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### Proven entry setup
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The exact v0.23 source creates a new process using
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`rfork_thread(RFPROC | RFCFDG | RFMEM)`. The child enables tracing and executes
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`/system/vsh/app/NPXS40112/eboot.bin` (`SceSpZeroConf`). The parent stops at an
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INT3 placed 58 bytes after the mapped eboot entry, restores that byte, maps the
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payload, and then sets:
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| Register/state | Exact loader operation | Status |
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|---|---|---|
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| `RSP` | writes observed `RIP` at `RSP - 8`, then subtracts 8 | `SAFE` source fact |
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| `RIP` | payload ELF entry | `SAFE` source fact |
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| `RDI` | loader-created `payload_args_t` page | `SAFE` source fact |
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| breakpoint byte | original byte restored before injection | `RESTORED_BY_LOADER` |
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| breakpoint page permission | changed to RWX and not restored | `PAYLOAD_PROCESS_LOCAL` |
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This is a synthetic function-call frame. The public source does not establish
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the meaning of the observed trap `RIP`, the exact original instruction
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boundary, or the validity of resuming there after payload return. Therefore
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the continuation is still `UNPROVEN`.
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### Argument ownership and lifetime
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`elfldr_payload_args()` maps one page into the child, creates two IPv6 sockets
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and a pipe, overlaps the sockets through the SDK kernel helper, and populates
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the six public fields. On successful detach the loader does not unmap that
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page or close those child descriptors. They are process-local, but cleanup
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depends on the child terminating. That termination and reaping path is not
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bounded or proven.
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### Return, exit, crash, and hang
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The stock SDK v0.41 `_start` may return, resolve and call `exit`, or trap,
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depending on `payload_terminate()`. Which branch applies to this injected
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SceSpZeroConf child is not proven. Separately, elfldr:
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- has no payload wall-clock deadline after `PT_DETACH`;
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- has unbounded single-step loops in both `pt_call()` and `pt_syscall()`;
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- ignores `SIGCHLD` in the service and documents no post-detach reaping
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contract;
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- kills the child on some preparation errors, but does not supervise normal
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runtime, return, crash, or hang.
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These are `UNBOUNDED_OR_UNKNOWN`, not objections to the mere presence of
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temporary kernel/process writes. They block the requested controlled
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two-second lifecycle.
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### Existing loader state versus artifact-caused state
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The first-stage loader enables QA flag bits and temporarily changes
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credentials before the candidate payload exists. Those are existing-loader
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effects. For each ptrace operation the service temporarily changes its authid
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and normally restores it. The child receives process-local credentials,
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mappings, sockets, pipes, executable permissions, and SDK `__patch_init`
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changes. The artifact would cause SDK startup only after entry; it would not
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cause the loader bootstrap.
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The separation does not make the chain ready: UID restoration is absent,
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authid restoration has an unrecovered failure path, and child lifetime is
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unbounded. Full evidence is in
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`manifests/runtime/phase-0.6-loader-runtime-audit.json`.
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## Phase 0.7 hardened loader contract
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Phase 0.7 does not depend on safely returning from `main`. The lifecycle
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probe calls `_exit` after exactly one notification, so the unresolved SDK
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`payload_terminate` return/exit/trap branch is outside the reachable
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application path.
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The hardened elfldr preserves the public `payload_args_t *` entry convention
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and adds a controlled versioned transport header with exact artifact ID,
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firmware 9.60, size, SHA-256, 2000 ms timeout, and no-retry fields. Both sender
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and receiver validate the metadata; the receiver hashes the actual received
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bytes and rejects the permanent denylist.
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The loader's process mutations are exact and bounded:
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- the initial QA flag change is an existing volatile bootstrap effect;
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- ptrace service auth-ID and all child UID/jail/root/caps/auth fields are
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backed up, restored, and checked;
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- breakpoint byte and page protection are restored;
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- single-step loops have independent time and step limits;
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- every incomplete launch path terminates and reaps the child;
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- the detached success path is replaced with a two-second supervised wait,
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bounded termination escalation, and reap;
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- an auth restoration failure permanently disables further ptrace work and
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stops the service.
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This is sufficient for the offline
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`READY_FOR_HARDENED_RUNTIME_DEPLOYMENT` decision. Loader behavior on firmware
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9.60 remains `UNPROVEN` until separately authorized installation and execution
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produce on-device evidence.
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