From 9b1f3e665308ee2ddd5b3f35a078219b5c509cdb Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Sat, 7 Mar 2020 13:12:35 +0100 Subject: prog: control program length We have _some_ limits on program length, but they are really soft. When we ask to generate a program with 10 calls, sometimes we get 100-150 calls. There are also no checks when we accept external programs from corpus/hub. Issue #1630 contains an example where this crashes VM (executor limit on number of 1000 resources is violated). Larger programs also harm the process overall (slower, consume more memory, lead to monster reproducers, etc). Add a set of measure for hard control over program length. Ensure that generated/mutated programs are not too long; drop too long programs coming from corpus/hub in manager; drop too long programs in hub. As a bonus ensure that mutation don't produce programs with 0 calls (which is currently possible and happens). Fixes #1630 --- syz-hub/state/state.go | 44 +++++++++++++++++++++++++++++++------------- 1 file changed, 31 insertions(+), 13 deletions(-) (limited to 'syz-hub') diff --git a/syz-hub/state/state.go b/syz-hub/state/state.go index a8a1b36ea..dd722d80c 100644 --- a/syz-hub/state/state.go +++ b/syz-hub/state/state.go @@ -58,8 +58,15 @@ func Make(dir string) (*State, error) { } osutil.MkdirAll(st.dir) - st.Corpus, st.corpusSeq = loadDB(filepath.Join(st.dir, "corpus.db"), "corpus") - st.Repros, st.reproSeq = loadDB(filepath.Join(st.dir, "repro.db"), "repro") + var err error + st.Corpus, st.corpusSeq, err = loadDB(filepath.Join(st.dir, "corpus.db"), "corpus") + if err != nil { + log.Fatal(err) + } + st.Repros, st.reproSeq, err = loadDB(filepath.Join(st.dir, "repro.db"), "repro") + if err != nil { + log.Fatal(err) + } managersDir := filepath.Join(st.dir, "manager") osutil.MkdirAll(managersDir) @@ -80,20 +87,26 @@ func Make(dir string) (*State, error) { return st, err } -func loadDB(file, name string) (*db.DB, uint64) { +func loadDB(file, name string) (*db.DB, uint64, error) { log.Logf(0, "reading %v...", name) db, err := db.Open(file) if err != nil { - log.Fatalf("failed to open %v database: %v", name, err) + return nil, 0, fmt.Errorf("failed to open %v database: %v", name, err) } log.Logf(0, "read %v programs", len(db.Records)) var maxSeq uint64 for key, rec := range db.Records { - if _, err := prog.CallSet(rec.Val); err != nil { + _, ncalls, err := prog.CallSet(rec.Val) + if err != nil { log.Logf(0, "bad file: can't parse call set: %v", err) db.Delete(key) continue } + if ncalls > prog.MaxCalls { + log.Logf(0, "bad file: too many calls: %v", ncalls) + db.Delete(key) + continue + } if sig := hash.Hash(rec.Val); sig.String() != key { log.Logf(0, "bad file: hash %v, want hash %v", key, sig.String()) db.Delete(key) @@ -104,9 +117,9 @@ func loadDB(file, name string) (*db.DB, uint64) { } } if err := db.Flush(); err != nil { - log.Fatalf("failed to flush corpus database: %v", err) + return nil, 0, fmt.Errorf("failed to flush corpus database: %v", err) } - return db, maxSeq + return db, maxSeq, nil } func (st *State) createManager(name string) (*Manager, error) { @@ -130,11 +143,11 @@ func (st *State) createManager(name string) (*Manager, error) { if st.reproSeq < mgr.reproSeq { st.reproSeq = mgr.reproSeq } - var err error - mgr.Corpus, err = db.Open(mgr.corpusFile) + corpus, _, err := loadDB(mgr.corpusFile, name) if err != nil { return nil, fmt.Errorf("failed to open manager corpus %v: %v", mgr.corpusFile, err) } + mgr.Corpus = corpus log.Logf(0, "created manager %v: corpus=%v, corpusSeq=%v, reproSeq=%v", mgr.name, len(mgr.Corpus.Records), mgr.corpusSeq, mgr.reproSeq) st.Managers[name] = mgr @@ -202,7 +215,7 @@ func (st *State) AddRepro(name string, repro []byte) error { if mgr == nil || mgr.Connected.IsZero() { return fmt.Errorf("unconnected manager %v", name) } - if _, err := prog.CallSet(repro); err != nil { + if _, _, err := prog.CallSet(repro); err != nil { log.Logf(0, "manager %v: failed to extract call set: %v, program:\n%v", mgr.name, err, string(repro)) return nil @@ -242,7 +255,7 @@ func (st *State) PendingRepro(name string) ([]byte, error) { if mgr.ownRepros[key] { continue } - calls, err := prog.CallSet(rec.Val) + calls, _, err := prog.CallSet(rec.Val) if err != nil { return nil, fmt.Errorf("failed to extract call set: %v\nprogram: %s", err, rec.Val) } @@ -277,7 +290,7 @@ func (st *State) pendingInputs(mgr *Manager) ([][]byte, int, error) { if _, ok := mgr.Corpus.Records[key]; ok { continue } - calls, err := prog.CallSet(rec.Val) + calls, _, err := prog.CallSet(rec.Val) if err != nil { return nil, 0, fmt.Errorf("failed to extract call set: %v\nprogram: %s", err, rec.Val) } @@ -338,10 +351,15 @@ func (st *State) addInputs(mgr *Manager, inputs [][]byte) { } func (st *State) addInput(mgr *Manager, input []byte) { - if _, err := prog.CallSet(input); err != nil { + _, ncalls, err := prog.CallSet(input) + if err != nil { log.Logf(0, "manager %v: failed to extract call set: %v, program:\n%v", mgr.name, err, string(input)) return } + if want := prog.MaxCalls; ncalls > want { + log.Logf(0, "manager %v: too long program, ignoring (%v/%v)", mgr.name, ncalls, want) + return + } sig := hash.String(input) mgr.Corpus.Save(sig, nil, 0) if _, ok := st.Corpus.Records[sig]; !ok { -- cgit mrf-deployment