Add fuzzer for codecs module

Makefile

@@ -1,8 +1,8 @@
-all : fuzzer-html fuzzer-email fuzzer-httpclient fuzzer-json fuzzer-difflib fuzzer-csv fuzzer-decode fuzzer-ast fuzzer-tarfile fuzzer-tarfile-hypothesis fuzzer-zipfile fuzzer-zipfile-hypothesis fuzzer-re fuzzer-configparser fuzzer-tomllib fuzzer-plistlib fuzzer-xml fuzzer-zoneinfo
+all : fuzzer-html fuzzer-email fuzzer-httpclient fuzzer-json fuzzer-difflib fuzzer-csv fuzzer-decode fuzzer-ast fuzzer-tarfile fuzzer-tarfile-hypothesis fuzzer-zipfile fuzzer-zipfile-hypothesis fuzzer-re fuzzer-configparser fuzzer-tomllib fuzzer-plistlib fuzzer-xml fuzzer-zoneinfo fuzzer-codecs
 
 PYTHON_CONFIG_PATH=$(CPYTHON_INSTALL_PATH)/bin/python3-config
 CXXFLAGS += $(shell $(PYTHON_CONFIG_PATH) --cflags)
-LDFLAGS += -rdynamic $(shell $(PYTHON_CONFIG_PATH) --ldflags --embed)
+LDFLAGS += -rdynamic $(shell $(PYTHON_CONFIG_PATH) --ldflags --embed) $(CPYTHON_MODLIBS) -Wl,--allow-multiple-definition
 
 fuzzer-html:
 	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"html.py\"" -ldl $(LDFLAGS) -o fuzzer-html
@@ -40,3 +40,6 @@ fuzzer-xml:
 	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"xml.py\"" -ldl $(LDFLAGS) -o fuzzer-xml
 fuzzer-zoneinfo:
 	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"zoneinfo.py\"" -ldl $(LDFLAGS) -o fuzzer-zoneinfo
+
+fuzzer-codecs:
+	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"codecs.py\"" -ldl $(LDFLAGS) -o fuzzer-codecs

codecs.py

@@ -0,0 +1,92 @@
+from fuzzeddataprovider import FuzzedDataProvider
+import codecs
+import io
+
+DECODERS = [
+    "utf-7", "shift_jis", "euc-jp", "gb2312", "big5", "iso-2022-jp",
+    "euc-kr", "gb18030", "big5hkscs", "charmap", "ascii", "latin-1",
+    "cp1252", "unicode_escape", "raw_unicode_escape", "utf-16", "utf-32",
+]
+
+ENCODERS = [
+    "shift_jis", "euc-jp", "gb2312", "big5", "iso-2022-jp", "euc-kr",
+    "gb18030", "big5hkscs", "unicode_escape", "raw_unicode_escape",
+    "utf-7", "utf-8", "utf-16", "utf-16-le", "utf-16-be", "utf-32",
+    "latin-1", "ascii", "charmap",
+]
+
+INC_DEC_CODECS = ["shift_jis", "gb18030", "utf-16"]
+INC_ENC_CODECS = ["shift_jis", "utf-8"]
+
+OP_DECODE = 0
+OP_ENCODE = 1
+OP_INCREMENTAL_DECODE = 2
+OP_INCREMENTAL_ENCODE = 3
+OP_STREAM_READ = 4
+
+def op_decode(fdp):
+    codec = fdp.PickValueInList(DECODERS)
+    data = fdp.ConsumeBytes(fdp.remaining_bytes())
+    codecs.decode(data, codec, 'replace')
+
+def op_encode(fdp):
+    codec = fdp.PickValueInList(ENCODERS)
+    n = fdp.ConsumeIntInRange(1, min(fdp.remaining_bytes(), 10000)) if fdp.remaining_bytes() > 0 else 0
+    if n == 0:
+        return
+    s = fdp.ConsumeUnicode(n)
+    codecs.encode(s, codec, 'replace')
+
+def op_incremental_decode(fdp):
+    codec = fdp.PickValueInList(INC_DEC_CODECS)
+    chunk1_size = fdp.ConsumeIntInRange(0, 10000)
+    chunk1 = fdp.ConsumeBytes(chunk1_size)
+    chunk2 = fdp.ConsumeBytes(fdp.remaining_bytes())
+    decoder = codecs.getincrementaldecoder(codec)('replace')
+    decoder.decode(chunk1)
+    decoder.decode(chunk2, True)
+    decoder.getstate()
+    decoder.reset()
+
+def op_incremental_encode(fdp):
+    codec = fdp.PickValueInList(INC_ENC_CODECS)
+    n = fdp.ConsumeIntInRange(1, min(fdp.remaining_bytes(), 10000)) if fdp.remaining_bytes() > 0 else 0
+    if n == 0:
+        return
+    s = fdp.ConsumeUnicode(n)
+    split = fdp.ConsumeIntInRange(0, len(s))
+    encoder = codecs.getincrementalencoder(codec)('replace')
+    encoder.encode(s[:split])
+    encoder.reset()
+    encoder.encode(s[split:])
+    encoder.getstate()
+
+def op_stream(fdp):
+    data = fdp.ConsumeBytes(fdp.remaining_bytes())
+    bio = io.BytesIO(data)
+    reader = codecs.getreader('utf-8')(bio, 'replace')
+    reader.read()
+
+# Fuzzes CPython's codec infrastructure (Modules/cjkcodecs/, Python/codecs.c).
+# Exercises full and incremental encode/decode for CJK codecs (Shift-JIS,
+# EUC-JP, GB2312, Big5, ISO-2022-JP, EUC-KR, GB18030, Big5-HKSCS) and
+# Western/Unicode codecs (UTF-7/16/32, charmap, unicode_escape, latin-1).
+# Also tests stream-based reading via codecs.getreader().
+def FuzzerRunOne(FuzzerInput):
+    if len(FuzzerInput) < 1 or len(FuzzerInput) > 0x100000:
+        return
+    fdp = FuzzedDataProvider(FuzzerInput)
+    op = fdp.ConsumeIntInRange(OP_DECODE, OP_STREAM_READ)
+    try:
+        if op == OP_DECODE:
+            op_decode(fdp)
+        elif op == OP_ENCODE:
+            op_encode(fdp)
+        elif op == OP_INCREMENTAL_DECODE:
+            op_incremental_decode(fdp)
+        elif op == OP_INCREMENTAL_ENCODE:
+            op_incremental_encode(fdp)
+        else:
+            op_stream(fdp)
+    except Exception:
+        pass

fuzz_targets.txt

@@ -1,4 +1,5 @@
 ast ast.py
+codecs codecs.py
 configparser configparser.py
 csv csv.py
 decode decode.py