read what the binary says about itself: names, signatures, prototypes; gen v2

fuzz/fuzz_targets/fuzz_concmd.rs

@@ -0,0 +1,45 @@
+#![no_main]
+//! Console-command extraction decodes every function in the image and does arithmetic on values the
+//! FILE controls at every step: `lea` displacements are added to tracked register contents, member
+//! offsets are added to a symbolic base, and the accessor window walks `arg3 + k*8` looking for a stored
+//! pointer. A crafted (or truncated) `.so` can make any of those wrap, point outside every section, or
+//! nest arbitrarily deep — and the reader must answer with fewer commands, never a panic.
+//!
+//! It also exercises the two indirections that resolve a callback (a static object's first virtual, and
+//! a constructor-stored member) against pointers the file chose, which is the same untrusted-chase shape
+//! the Valve table readers had to be hardened for.
+use libfuzzer_sys::fuzz_target;
+use source2rosetta::concmd;
+use source2rosetta::elf::CodeImage;
+
+fuzz_target!(|data: &[u8]| {
+    let Ok(img) = CodeImage::from_bytes(data.to_vec()) else {
+        return;
+    };
+    let cmds = concmd::console_commands(&img);
+    for c in &cmds {
+        // A recovered handler is only ever accepted because it lands in executable code, so the reader
+        // must never hand back one that does not — a caller treats this as a locator.
+        assert!(
+            img.is_code(c.handler),
+            "a non-executable handler was recorded for {:?}",
+            c.name
+        );
+        // The name gate is what stops prose and format strings being read as commands.
+        assert!(
+            !c.name.is_empty() && c.name.len() <= 64,
+            "an implausible command name was recorded: {:?}",
+            c.name
+        );
+        // Flag decoding is a pure bit test and must stay within the bits it claims to know.
+        let named = concmd::flag_names(c.flags);
+        assert!(named.len() <= 12, "more flag names than there are flag bits");
+        let _ = (c.description.len(), c.form.describe(), c.flags);
+    }
+    // Commands are deduped on (name, address), so no pair may survive twice.
+    let mut seen: Vec<(&str, u64)> = cmds.iter().map(|c| (c.name.as_str(), c.handler)).collect();
+    let before = seen.len();
+    seen.sort_unstable();
+    seen.dedup();
+    assert_eq!(before, seen.len(), "a duplicate (name, handler) survived");
+});

fuzz/fuzz_targets/fuzz_pulse.rs

@@ -0,0 +1,34 @@
+#![no_main]
+//! A Pulse binding's typed signature is reconstructed by DECODING the accessor that returns its
+//! descriptor: the reader follows arbitrary control flow, constant-propagates through it, and then
+//! dereferences whatever addresses that produced — a returned element count, a base pointer, a name
+//! pointer per element, and a receiver it chases one call deep. Every one of those is whatever the file
+//! says it is, so a crafted (or truncated) `.so` can aim them anywhere, into non-code, off the end of a
+//! section, or into a cycle. The reader must answer with fewer signatures, never a panic and never a
+//! runaway. Also exercises the invariant the whole stage rests on: a recovered list has exactly as many
+//! parameters as the accessor's own count says, so a shifted layout cannot ship as a short signature.
+use libfuzzer_sys::fuzz_target;
+use source2rosetta::elf::CodeImage;
+use source2rosetta::{pulse, valvetab};
+
+fuzz_target!(|data: &[u8]| {
+    let Ok(img) = CodeImage::from_bytes(data.to_vec()) else {
+        return;
+    };
+    let bindings = valvetab::pulse_bindings(&img);
+    let pairs: Vec<(u64, u64)> = bindings
+        .iter()
+        .take(64)
+        .map(|b| (b.descriptor, b.arg_descriptor))
+        .collect();
+    let (sigs, stride, votes, _) = pulse::read_all(&img, &pairs, 1);
+    assert_eq!(sigs.len(), pairs.len(), "one verdict per binding");
+    assert!(votes == 0 || stride > 0, "a voted-for stride is never zero");
+    for s in sigs.into_iter().flatten() {
+        for p in s.args.iter().chain(&s.returns) {
+            // A parameter that survived is fully formed: the name gate and the type gate both passed.
+            assert!(!p.name.is_empty(), "shipped a nameless parameter");
+            assert!(p.ty >= -1, "shipped a type below PVAL_VOID");
+        }
+    }
+});

fuzz/fuzz_targets/fuzz_schema.rs

@@ -11,6 +11,16 @@ fuzz_target!(|data: &[u8]| {
     let Ok(img) = CodeImage::from_bytes(data.to_vec()) else {
         return;
     };
+    // The enum bindings are a SECOND table read the same reloc-driven way: a name pointer, a
+    // width/count word, and an enumerator array whose length that word supplies. A crafted count is the
+    // sharp edge — it drives the per-enumerator read loop — so the reader must bound it rather than
+    // trust it.
+    for e in schema::enumerate_enums(&img) {
+        let _ = (e.name.len(), e.size, e.align);
+        for (n, v) in &e.values {
+            let _ = (n.len(), *v);
+        }
+    }
     for c in schema::enumerate_schema(&img) {
         let _ = c.primary_base();
         for f in &c.fields {

fuzz/fuzz_targets/fuzz_valvetab.rs

@@ -0,0 +1,64 @@
+#![no_main]
+//! Valve's in-binary name tables are read by walking every writable data section in 8-byte steps and
+//! treating each position as a candidate record — chasing a name pointer, two code pointers and, for the
+//! entity-IO table, an input-name pointer. Every one of those fields is whatever the file says it is, so a
+//! crafted (or truncated) `.so` can aim them anywhere; the readers must answer with fewer records, never a
+//! panic. Also exercises the accessors the derivation reads off each record, and the ambiguity rule that
+//! decides which names are safe to ship as locators.
+use libfuzzer_sys::fuzz_target;
+use source2rosetta::elf::CodeImage;
+use source2rosetta::valvetab;
+
+fuzz_target!(|data: &[u8]| {
+    let Ok(img) = CodeImage::from_bytes(data.to_vec()) else {
+        return;
+    };
+    let pulse = valvetab::pulse_bindings(&img);
+    for b in &pulse {
+        let _ = (
+            b.name.len(),
+            b.display.as_ref().map(String::len),
+            b.description.as_ref().map(String::len),
+            b.descriptor,
+            b.arg_descriptor,
+            b.flags.raw,
+        );
+    }
+    let inputs = valvetab::datadesc_inputs(&img);
+    for i in &inputs {
+        let _ = (i.handler.len(), i.io_name.len(), i.func);
+    }
+    // Array segmentation walks BACKWARD and forward from a confirmed input over addresses the file
+    // controls, so every step is arithmetic on untrusted values — the same shape as the `r.base + 8`
+    // overflow the Pulse reader had to be hardened against. It must yield fewer arrays, never a panic.
+    let arrays = valvetab::datadesc_arrays(&img);
+    for a in &arrays {
+        // An array is only recorded because it holds an input, and a field descriptor's offset is read
+        // as a u32 — so neither list may come back as something the caller has to re-validate.
+        assert!(!a.inputs.is_empty(), "an array with no inputs was recorded");
+        for (n, o) in &a.fields {
+            let _ = (n.len(), *o);
+        }
+    }
+    // Every input the array walk finds must also be one the direct reader finds: the two disagree only
+    // if one of them is reading a record the other rejects, which is a contradiction worth catching.
+    assert!(
+        arrays.iter().map(|a| a.inputs.len()).sum::<usize>() <= inputs.len(),
+        "the array walk claimed more inputs than the record reader accepts"
+    );
+    // The shipping gate: a name reaches gamedata only through here, so it is the part that must never
+    // panic AND never over-claim — no name may survive with more than one address behind it.
+    let (names, _dropped) = valvetab::names(&inputs);
+    for n in &names {
+        assert_eq!(
+            inputs
+                .iter()
+                .filter(|i| i.handler == n.name)
+                .map(|i| i.func)
+                .collect::<std::collections::BTreeSet<_>>()
+                .len(),
+            1,
+            "shipped an ambiguous handler name"
+        );
+    }
+});