Commit Graph
14 Commits
Author SHA1 Message Date
Marius CiepluchandClaude Opus 5 45cf43e625 fix(cpg): one method with no sources must not cost the whole batch its answers
`reachableByFlows` on an empty source list is not a no-op. Joern answers it by
logging

    [INFO ] Attempting to determine flows from empty list of sources.

to STDOUT -- while the script is running, so the line lands between the fence
markers, ahead of the payload. `json.loads` then fails on the whole document
and the driver reports `query_failed` for every request in the batch. One
method with nothing to trace from silently cost the answers for all 205 of
the others.

Fixed at both ends, because either alone leaves the seam brittle:

  * taint.sc skips the flow query when there is no source to trace from, which
    is also the correct thing to do with the question.
  * `extract_payload` starts a decode at each line that opens a document and
    keeps the first that parses. Trimming to the outermost brackets is the
    obvious approach and the wrong one -- `[INFO ]` brings its own bracket.

Found while testing whether `$this` belongs in parameter sources. It does not
belong there on the argument -- the receiver is the object, not request data --
and excluding it cuts Paid Memberships Pro's order class from 16 entailed
findings to 6, all sourced from a named parameter, and makes the 2.9.7/2.9.8
pair separate cleanly.

It also loses CVE-2023-6559: MW WP Form's `_delete_files()` takes no
parameters at all, and the attacker-controlled path arrives as
`$this->attachments`, assigned by another method. So the trade is a VERIFIED
CVE against findings merely suspected of being false, and it is refused. The
receiver stays, with the measurement written next to it. The real defect is
field-sensitivity -- a field should be tainted where it is assigned -- and
deleting the receiver removes the symptom by removing the evidence.

841 tests pass; gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 18:30:41 +02:00
Marius CiepluchandClaude Opus 5 e0442d146c fix(cpg): a graph the frontend emptied must not read as a clean repository
Scanning a two-file WordPress slice returned 64 regions examined, zero
findings and zero degradations. The graph it examined had no methods in it.

php2cpg 4.0.623 feeds several files to one `php-parse` process and reads its
stdout and stderr merged. php-parse writes a `====> File <next>:` banner to
stderr the moment it starts the next file, while the previous file's JSON --
megabytes of it -- is still draining from a block-buffered stdout. The banner
lands inside the JSON, ujson reports

    expected json value or } got "=" at index 5011645

and the frontend drops that file. Reproducible on real plugin code, and the
size that matters is one file's AST dump, not the repository's:

    class.memberorder.php alone (1834 lines)     -> 142KB CPG, no failures
    the same file + a two-line file              ->   5.7KB CPG, BOTH dropped

One oversized file empties the whole graph. `joern-parse` then does not
propagate any of the frontend's warnings: 13 lines of output, exit status 0,
"Successfully wrote graph". This is what made a 637-file plugin unscannable
and reported it as clean -- it was never a scale limit.

Two fixes, because the failure arrives on two different paths:

  * `_unparsed_files` reads the per-file warnings the frontend does emit, and
    the scan reports them as `files_unparsed`. This covers the direct-frontend
    path where the warnings are visible.

  * The batched query now carries a `__census__` of the graph -- method and
    file counts -- under a key no request id can collide with, and a scan over
    a graph with no methods degrades as `cpg_empty`. This covers joern-parse,
    which shows nothing. It rides the batch rather than costing its own
    invocation, because avoiding a JVM start is the entire reason batching
    exists.

Neither invents a verdict. There is no rung for "the graph was empty" because
the ladder labels verdicts and none was produced, which is exactly why it has
to be a degradation.

    pmpro two-file slice  before: 0 findings, degradations=[]
                          after:  0 findings, degradations=[cpg_empty]

Gates byte-identical; 840 tests pass.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 18:07:28 +02:00
Marius CiepluchandClaude Opus 5 92677136d7 fix(cpg): a batch goes through a file, not the command line
Scanning a 637-file WordPress plugin reported 500 regions examined, zero
findings, and a taint query time of **0.05 seconds** -- less than a JVM
takes to start. Dominance ran for 29.56s and config for 22.44s in the same
scan, so only taint had failed.

Linux caps a SINGLE argument at MAX_ARG_STRLEN (128KB) whatever ARG_MAX
says. Measured on that plugin:

  taint      2500 requests   1.49 MB   <- over the cap
  dominance    13 requests   0.04 MB
  config       13 requests   0.00 MB

As `--param requests=<json>` execve returned E2BIG, `_run` caught the
OSError, `query_batch` returned {} -- and {} reads as "no rows found". Only
taint crossed the cap, which is exactly why the failure looked like a
result rather than an error.

This is the quiet failure the rung ladder cannot catch. Every other honesty
mechanism in this codebase labels a verdict; here no verdict was produced
to label, and a scan of a vulnerable plugin reported it clean.

The payload is now staged to a file beside the CPG and the path is passed
instead; all three queries read `requestsFile` when it is set and keep
`requests` for the single-request forms and the tests. A test asserts no
argument approaches the cap, since the failure mode is invisible at the
scale the unit tests run at -- batching worked on every small tree it was
ever tried on.

Verified on vampi first: 4 entailed, unchanged, all three known
vulnerabilities still found.

Gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 16:27:58 +02:00
Marius CiepluchandClaude Opus 5 9221ba8e40 feat(model): a bound on the data lowers the rung, it does not clear it
contributor-scan 2.12. c/injection and c/memory carried zero sanitizers,
so no C flow could ever be discharged: every `argv -> strcpy` entailed
however carefully it was bounded.

Which sinks can be discharged this way is read from the sink fact's own
CWE rather than declared: CWE-121 is a stack buffer overflow, so
gets/sprintf/strcat/strcpy qualify. It is the only overflow CWE in the
fact tables and it is C-only, so no Python or JavaScript sink is touched
and the pair corpus is unaffected -- gates byte-identical.

Not a sanitizer list, because `strlen` appears in the guarded and the
unguarded case alike; the discharge is a guard, not a call.

**The first implementation required the bound to DOMINATE the sink, and it
found nothing.** libpng guards `strcpy(outname+len, ".png")` with
`(len = strlen(inname)) > 250`, but that check sits on an else-if chain
whose sibling branch skips it entirely, and the protection reaches the
sink through an `error` flag: `++error` in the guarded branch, `if
(!error)` around the copy. Joern's dominator set for that sink has 89
calls and correctly excludes the bound; `controlledBy` returns none
either. Verified against the CPG before the rule was changed rather than
after it failed.

So the bound is searched in the method, and the consequence is
corroborated rather than silence. That is the honest rung: a bound on this
variable means the graph has NOT shown the copy is unguarded, and it has
not shown it is guarded either -- off-by-one being how bounds fail. The
judge is asked. Proving the flag-mediated case needs path-sensitive
reasoning this arbiter does not do.

  libpng entailed   3 -> 1

The survivor is also a false positive: `strcpy(output + len, ".icc")` in
iccfrompng.c, where `output = malloc(len + 5)` makes it fit exactly. That
is a different discharge shape -- allocated to size, not bounds-checked --
and it is recorded as 2.13 rather than chased. Both shapes were found on
one repository, and extending a rule until that repository is clean is the
overfitting Req 8 exists to prevent; 2.13 requires a second C checkout
with a genuine CWE-121 so the change can be measured for what it silences
as well as what it clears.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 13:01:30 +02:00
Marius CiepluchandClaude Opus 5 67497c4d68 fix(cpg): a sink is matched as a word, not as a substring
`fgets` contains `gets`. The sink matcher's last clause was an unbounded
`methodFullName.contains(n)`, so every bounded read in libpng matched the
sink for the unbounded one. All 26 entailed findings on that repository
were the same false positive:

  *argv -> fgets(pnmline, 256, wpng_info.infile)   (line 335, 8 steps)

which is the safe API being reported as the dangerous one -- and `fgets`
is in the fact tables as a SOURCE, never a sink. Verified against the CPG:
methodFullName is exactly "fgets", and .contains("gets") is true.

Third instance of one bug class in this codebase, after the sanitizer that
matched `resolve` inside `resolveUrl` and the discharger that matched
`user` inside `users`. The sink matcher had never been given the same
treatment. All four of its clauses now run through the shared bounded
matcher, and that matcher is the punctuation-tolerant version written for
task 2.6 -- so `input(`, which an unconditional lookahead had made
unmatchable in `input(x)`, works for the first time as well.

  libpng entailed   26 -> 0

Zero is the right answer for a PNG library whose only known CVE is out of
family. Gates byte-identical, so no pair outcome depended on the substring
match.

What remains on that scan is recorded, not claimed: 113 `c-unsafe-*` rows
assert an API is present rather than misused, and 50 overlay-coverage rows
are annotations rather than findings. 82 of the 113 are under `contrib/`.
Task 2.11 covers whether that band is worth putting in front of a
contributor at all; 2.10 already covers not scanning example code.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 11:43:00 +02:00
Marius CiepluchandClaude Opus 5 0fcd5feade feat(model): a region for the code that is in no function
contributor-scan 2.5. VAmPI's `host='0.0.0.0'` is now reported exactly
once, at app.py:17:<module>. Before task 2.2 it was reported eight times
in eight files that do not contain it; after 2.2 it was reported nowhere.

Two causes, one shape: nothing could ask about module-level code.

**The main-guard marker is not a function.** `__main__` is what the mapper
emits for `if __name__ == '__main__':`. Sent to the engine as a function
name it matched nothing, because a CPG calls a file's top-level code
`<module>` -- verified against the VAmPI CPG rather than assumed. The
region model translates the marker, which is the one place that turns what
the mapper meant into what the scanner asks.

**A function-scoped file had no region for its module body.** Settings,
route registration and globals live in no function, and every region's
query filters by function name. A file-level region beside the handlers
would report each handler's findings a second time, which is why the
earlier rule dropped it as "a second full-file pass". A module-scope region
PARTITIONS the file instead of overlapping it. That only became cheap after
batching: before it, a region was a JVM.

Two things this needed to be correct rather than merely present:

- A module method spans its whole file, so the taint query's line-range
  containment made `<module>` the parent of every function in it. Under
  module scope, membership is direct -- otherwise the module region reports
  every handler's sinks again, which is the duplication the old rule was
  avoiding.
- A module body is not a handler. The marker-derived region inherited the
  handler families and entailed a missing authorization check on the main
  guard: a finding with no possible remediation. Caught by the first
  repository run that had the region, and now covered by a test.

  bind address   8 wrong files -> 0 -> 1, at app.py:17:<module>
  regions        22 -> 25
  entailed       8 -> 9
  query time     37.4s -> 41.3s
  peak RSS       827MB -> 823MB
  cost           $0.0067 -> $0.0068

Three more regions for four seconds and no more model calls: the budget is
a total and was already spent, so regions_unasked rose 17 -> 20 -- those
regions got the free pass and are reported as unasked, not as clean.

`<module>` is Joern's Python name for a module body; JavaScript uses
`:program`, so this is verified for Python only.

Gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 09:43:53 +02:00
Marius CiepluchandClaude Opus 5 ca7b5ba370 feat(model): a region that spans the flow, not just a function
contributor-scan 2.4, closing the no-go task 2.2 recorded.

VAmPI's SQL injection is a request parameter reaching `get_by_username`
in api_views/users.py, passed to `User.get_user` in models/user_model.py,
interpolated into a query string and executed there. Source and sink are
in different functions and different modules. Regions were per-function,
so neither region saw both ends and the engine was silent on the most
ordinary shape a real injection bug has.

`reachableByFlows` was never the limitation -- it follows calls already.
The limitation was the QUESTION. Sinks were filtered to the labeled
function's own body, so a crossing flow had no sink to end at.

Three changes, each with a reason it is sound rather than convenient:

**An entry point is the trust boundary.** parameter_sources was off for
repository scans because a repository's parameters are not all attacker
input. An entry point's are, by definition -- that is what makes it an
entry point. The driver turns it on only for regions the mapper found and
named, and leaves it off for walker fallbacks and for named functions that
are not entry points.

**Sinks may sit below the handler.** taint.sc admits sinks in methods
reachable from the labeled method through the call graph, bounded at
ENTRY_POINT_CALL_DEPTH = 3: handler -> service -> data access, which is
where these bugs live. Unbounded would make the question about most of the
repository rather than about this entry point, and make it unaffordable.

**The finding names the sink, not the asker.** A crossing flow ends in
another file and another function, so Verdict carries the evidence's own
`path:line:function` and the site uses it. Reporting
`models/user_model.py:73:get_by_username` would name a place that does not
exist: line 73 is inside get_user.

Also: labeled methods are now resolved by name AND file. `get_user` exists
in more than one module of a real repository, which a corpus of one-file
excerpts could never surface.

Measured on the same checkout and budget as 2.2:

  VAmPI-SQLI    missed -> model_entailed at models/user_model.py:73:get_user
  known found   0 of 2 before 2.2's fixes, 1 of 2 in 2.2, 2 of 2 now
  entailed      7 -> 8
  query time    40.9s -> 37.4s
  peak RSS      869MB -> 827MB
  cost          $0.0067, unchanged

Asking the bigger question cost nothing measurable here: file scoping and
call-graph following pull in opposite directions and roughly cancel at this
size. That is one 520-line repository, and VAmPI is now the repository this
change was developed against -- the exact overfitting shape Req 8 exists to
catch. The depth bound and the entry-point rule mean nothing general until
a checkout nobody tuned against says so.

Gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 09:27:19 +02:00
Marius CiepluchandClaude Opus 5 177c7f3719 feat(model): first repository measurement, and the four things it found
contributor-scan 2.2. VAmPI at a pinned commit, scanned whole rather than
as excerpts, with benchmarks/repos/measure.py recording build time, query
time, arbitration time, peak memory, cost, unjudged regions, and whether
each known vulnerability was found and at which rung.

The corpus could not have found any of this. Every defect below needs a
repository to become visible, and three of them were invisible behind a
passing test suite.

**The batch path was unreachable.** query_batch was implemented, tested and
committed while CpgResult exposed only `run`, so the driver's capability
check found nothing and fell back to one JVM per region-family: the first
attempt at this measurement ran eighteen minutes on 520 lines, issuing
`--param function=` one at a time. Every test called query_batch directly,
so none of them noticed. CpgResult now carries run_batch and a test asserts
the capability is reachable through the object the driver is handed.
The earlier 275s->106s improvement attributed to batching came from region
deduplication alone.

**The budget stopped free work.** It bounds model calls, but was enforced
by breaking the region loop -- spending a paid limit to stop unpaid CPG
arbitration. 6 of 22 regions were examined and VAmPI's BOLA, which the
graph entails for nothing, was never reached. It now withholds the judge
only. 22 of 22 regions arbitrated, 17 counted as regions_unasked (silent
because unaffordable is not silent because decided), and the BOLA is
entailed by the model layer.

**A region with no function asked about the whole repository.** Sending
function="" matched every hit in the tree and the driver attributed that
answer to whoever asked: one `host='0.0.0.0'` in app.py became eight
identical entailed findings in eight files that do not contain it. Queries
now carry the region's file. Entailed findings 14 -> 7, query time
70.9s -> 40.9s. The single-request form stays unscoped so the committed
pair measurements remain reproducible.

**The JVM had no heap bound.** Joern claimed a quarter of physical RAM and
runs were killed under memory pressure at different points, so the numbers
described the host rather than the engine. -J-Xmx2048m by default,
OPENULTRASAST_CPG_HEAP_MB to raise it.

Also: arbitrated findings carried `function:line` where the report layer
read `path:line`, so every entailed finding reached a contributor with a
function name where its file belonged; and the witness line was parsed by
splitting on a comma, which produced sites like
`config.py:17): permissive literal '0.0.0.0':?`.

Reading: GO on one CPG per repository -- 6.2s to build, 177s end to end,
869MB, $0.0067, nothing infeasible. NO-GO on region-scoped taint as the
only shape: VAmPI's SQL injection runs from a handler parameter into a
function in another module, and a per-function region sees neither end.
That is the ordinary shape of a real injection bug, so it is recorded as
task 2.4 along with three smaller defects this run exposed.

Gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 08:46:21 +02:00
Marius CiepluchandClaude Opus 5 c35426e186 perf(model): one Joern invocation per query kind, not one per region
JVM startup dominated a scan: a call per region per family put a ten-line
file at 275s over three regions, and would have put a thousand regions at
roughly fifty hours. The queries themselves are milliseconds once the CPG
is loaded, so the cost was almost entirely process starts.

scan_repository() is now collect -> batch -> arbitrate. The three .sc
scripts accept a `requests` JSON map and answer all of them in one run,
keeping the single-request form so the committed measurements stay
reproducible byte-for-byte. Arbiters are untouched: each is handed a
CpgResult whose `run` returns its own prefetched rows.

The batcher builds parameters by calling request_params() extracted from
taint.py, dominance.py and config_value.py rather than reconstructing
them. A second copy that drifts from the arbiter's is the exact shape of
the five family-assumption bugs the predecessor spec spent a session
finding; there is now one definition per family and the batcher borrows
it.

Regions are also deduplicated by (path, function), collapsing the
nameless entry-point rows that were producing `model:injection:?:10`.

Measured on the same ten-line file: 275s -> 106s, three duplicate
findings -> one `model:injection:ping:10`, rung unchanged at
model_entailed. Gates byte-identical.

Server mode is recorded as task 2.3, deliberately sequenced after the
repository measurement: whether the remaining ~100s floor is worth a
process model, a weakened subprocess seam and a Scala-evaluating HTTP
endpoint depends on a build-time-to-query-time ratio only 2.2 produces.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-09 07:57:35 +02:00
Marius CiepluchandClaude Opus 5 d651455d23 fix(model-grounded-detection): closure scoping, and the three bugs it uncovered
The group-4 finding: JavaScript is callback-heavy, so the method containing a
sink routinely is not the labeled function. `fs.readFileSync` inside the
callback passed to `fs.stat` has enclosing method `<lambda>0`, and filtering on
`sinkMethod == function` dropped it -- the whole path family measured 0/8.

Scope is now decided by line-range containment within the same file
(astParentFullName is empty for lambdas, so nesting is not readable there), and
reported as `inLabeledScope`; the Python side trusts that flag and keeps the
name comparison only as a fallback, so an engine that cannot report scope never
has its sinks silently treated as scoped. Parameter sources stay bound to the
labeled function's OWN parameters -- a callback's `err`/`stats` are not
attacker input.

Fixing the scope exposed three further bugs, each of which would have raised
the number while making the answer untrue:

  * Shortest-flow-wins picked the wrong witness. With closures in scope the
    same sink has flows from `req.url...` (10 steps, the vulnerability), `res`
    (3) and `this` (7). A flow whose source matches the source model now
    outranks a shorter one from a bare captured name; shortest still breaks
    ties, so the order stays total and the verdict deterministic.
  * The JS fact file had NO sanitizers at all, so no JavaScript fix of any
    family could ever be recognised. Added the documented path-normalisation
    and HTML-escaping APIs, with provenance.
  * Adding them regressed the witness, because `resolveUrl` CONTAINS `resolve`
    and the substring test marked the vulnerable flow sanitized. This is the
    same bug class already fixed in dominance.sc and not carried across -- the
    exact fix-the-instance-miss-the-class failure. taint.sc now matches on word
    boundaries too.

And the principled rule the fix turns on: parameter sources are a FALLBACK,
never an override. When a modelled source reaches the sink, those flows are the
evidence; otherwise a captured `res` reaching a sanitized sink reports the fix
as still vulnerable on a flow that names no attacker input.

Also recorded: req.url was NOT wrong as a diagnosis, it was untestable in
isolation -- the scoping bug masked it. Both were needed. On the pair that
motivated all of this:

  vuln   model_entailed      req.url.split('?')[0] -> readFileSync(possibleFilename)
  fixed  model_corroborated  same flow, sanitized by path.normalize
  distinguished: true

700 passing, mypy/ruff clean, gates byte-identical.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-08 16:24:23 +02:00
Marius CiepluchandClaude Opus 5 e127e430ed feat(model-grounded-detection): parameter sources, so the measurement is like-for-like
Only 11 of the 50 injection pairs contain a framework source token at all. The
other 39 receive untrusted input as a FUNCTION PARAMETER, because SVEN-style
pairs are function-level extractions:

    def add_user(username, password):
        os.system("useradd ... -p " + encPass + " " + username)

A framework-anchored source model finds nothing there, which caps entailment on
this slice near 22% by construction -- a property of the source model, not of
the engine. More to the point, the flat-IR baseline this feature is measured
against already counted these (source_kinds: ["parameter"]), so a run without
them is not comparable to the 2.2% it is supposed to beat.

The flag is opt-in and off by default, because the two settings are right in
different places: in a function-level pair the function boundary IS the trust
boundary, while across a whole repository most parameters carry internal
values and treating them all as untrusted is not sound. The corpus harness
opts in; a repository scan does not.

On the pair that exposed this the model now resolves both flows, including one
through an intermediate binding:
    username -> os.system(...)                       2 steps
    password -> crypt.crypt(...) -> encPass -> ...   7 steps

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-08 12:56:13 +02:00
Marius CiepluchandClaude Opus 5 1765e51da1 feat(model-grounded-detection): the safe-shape test, without which the model arbitrates nothing
The first live run produced the finding that shapes this design: taint
reachability alone does not distinguish a fix from a bug. On the canonical SQL
pair the flow request.args["name"] -> name -> execute exists on BOTH sides --

  vuln   db.execute("select ... '" + name + "'")   one argument, interpolated
  fixed  db.execute("select ... = %s", (name,))    two arguments, bound

-- so the model entailed the fixed twin exactly as readily as the vulnerable
one, and arbitrated nothing. What separates them is the SHAPE of the sink call,
which is precisely what safe_shape_sinks preserved from the earlier sanitizer
fix. The query now reports sinkArity and sinkArg0Literal, and a flow ending at
a sink written in its declared-safe form is not a vulnerability.

Two bugs in that shape test, both found only against the real engine:
Joern's `call.argument` includes the RECEIVER at argumentIndex 0, so `db` was
counted as an argument -- making a one-argument interpolated call look like a
two-argument bound one, the exact inversion of the test -- and the "first
argument" whose literalness decides a format-string sink was the receiver
rather than the format. Both fixed with argumentIndexGt(0).

The rule is narrow on purpose: only sinks named in safe_shape_sinks are subject
to it (os.system(x) is not safe merely because it takes one argument), and a
row carrying no shape fields is judged on the flow alone -- an unknown shape
must never be read as a safe one.

End to end on the pair, deterministic and with no model call:
  vuln  -> model_entailed  request.args["name"] -> db.execute(...) (line 4)
  fixed -> None

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-08 12:51:42 +02:00
Marius CiepluchandClaude Opus 5 f59e0f5b5a fix(model-grounded-detection): two modelling bugs the first live Joern run exposed
Both were found by running the real engine, and neither was visible offline.

1. A sink was its own sanitizer. The shipped facts mark some sanitizers with a
   *shape* qualifier -- parameterized ("execute(sql, params) binds rather than
   interpolates") and literal_format_arg ("printf with a constant format string
   is safe"). These describe a safe FORM OF THE SINK CALL, not a call that
   cleans a value on the path. Flattening them into the sanitizer list made
   `execute` both the injection sink and its own sanitizer, so every SQL flow
   would have reported as already-clean and nothing could ever be entailed.
   Fixed as a class, not an instance: any fact carrying a shape qualifier is
   excluded from `sanitizers` and kept in `safe_shape_sinks` for the shape test
   task 4.2 will model properly. Fixing only the Python `parameterized` case
   would have left C's entire printf family -- which the generalised test then
   caught immediately.

2. labeled_family lost its deterministic derivation in group 1. The deleted
   classifier resolved a pair's family by declared label, else obligation, else
   mechanism, else CWE, and only asked an LLM when every link failed -- which
   for a labeled corpus was never. Group 1 reduced this to the declared label
   alone, which silently emptied every family whose pairs are labeled by CWE:
   the injection slice went to zero pairs. The chain is restored, still with no
   model call, and the family census again matches the committed entailment
   ceiling exactly (injection 50, memory 176, access_control 8, ...).

Also: the Joern seam now runs in the CPG's own scratch directory, because
`joern --script` writes a `workspace/` beside the working directory and would
otherwise leave one inside the repository being analysed.

The taint query itself was corrected against the live engine: the sink is the
call's ARGUMENTS (data flows into arguments, not into the call node) and
reachableByFlows is called on the sink with the source. With that, the
three-hop chain our flat IR could not resolve is found:
  request.args["cmd"] -> cmd -> "echo " + cmd -> full -> os.system(full)

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-08 12:45:42 +02:00
Marius CiepluchandClaude Opus 5 2b973dc0db feat(model-grounded-detection): tasks 2.1-2.2, the Joern seam and the taint verdict
The whole engine integration is one subprocess boundary: joern-parse builds a
cpg.bin, joern --script runs a shipped CPGQL query that prints its JSON between
fence markers, because Joern's stdout carries a banner and a REPL prompt around
whatever a script emits. Nothing is imported in-process, so the core install
keeps dependencies = [] -- a test walks the seam's AST to assert it imports
only the standard library and names no JVM binding.

Fail closed everywhere. A build or query that errors, times out, or prints
something unparseable yields no verdict and the caller reports suspicion. The
taint verdict distinguishes this from absence deliberately: a query returning
None means "the engine could not decide", which is not "there is no flow", and
conflating them is how a missing engine silently becomes a clean bill of health.

The verdict is where the ladder earns its keep. An unsanitized source->sink
path is model_entailed -- the graph establishes it and the LLM's claim is no
longer load-bearing. A path a sanitizer may break is model_corroborated: the
flow is real, but whether the sanitizer suffices is the semantic residual the
LLM answers, checked against this verdict rather than averaged over runs. The
chosen flow is picked by a total order (shortest, then lexicographic), so two
runs over one CPG cannot disagree -- Req 6.4 asserted directly.

The query itself is the part our flat IR could not do: reachableByFlows walks
the PDG, so `q = "..." + request.args["x"]; execute(q)` is found, which is
exactly the one-hop limit that held measured entailment at 2.2%.

Capability detection reuses semantic/engines.joern_available rather than
growing a second notion of "installed". The audit manifest is regenerated; the
new modules are named by Req 4/5/6 rather than counted as orphans.

Task 2.3, the go/no-go measurement, needs Joern installed and has not run.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
2026-09-08 12:23:40 +02:00