Add fuzzer for datetime module

Makefile

@@ -1,4 +1,4 @@
-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-binascii
+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-binascii fuzzer-datetime
 
 PYTHON_CONFIG_PATH=$(CPYTHON_INSTALL_PATH)/bin/python3-config
 CXXFLAGS += $(shell $(PYTHON_CONFIG_PATH) --cflags)
@@ -43,3 +43,6 @@ fuzzer-zoneinfo:
 
 fuzzer-binascii:
 	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"binascii.py\"" -ldl $(LDFLAGS) -o fuzzer-binascii
+
+fuzzer-datetime:
+	clang++ $(CXXFLAGS) $(LIB_FUZZING_ENGINE) -std=c++17 fuzzer.cpp -DPYTHON_HARNESS_PATH="\"datetime.py\"" -ldl $(LDFLAGS) -o fuzzer-datetime

datetime.py

@@ -0,0 +1,86 @@
+from fuzzeddataprovider import FuzzedDataProvider
+from datetime import date, time, datetime
+
+# Parse target constants (op_parse)
+PARSE_DATE_FROMISOFORMAT = 0
+PARSE_TIME_FROMISOFORMAT = 1
+PARSE_DATETIME_FROMISOFORMAT = 2
+PARSE_DATETIME_STRPTIME = 3
+
+# Format target constants (op_format)
+FORMAT_DATE = 0
+FORMAT_TIME = 1
+FORMAT_DATETIME = 2
+
+OP_PARSE = 0
+OP_FORMAT = 1
+
+STRPTIME_FORMATS = [
+    "%Y-%m-%d",
+    "%Y-%m-%d %H:%M:%S",
+    "%d/%m/%Y",
+    "%m/%d/%Y",
+    "%Y%m%d",
+    "%H:%M:%S",
+    "%I:%M %p",
+    "%Y-%m-%dT%H:%M:%S",
+    "%a %b %d %H:%M:%S %Y",
+    "%c",
+]
+
+
+def op_parse(fdp):
+    s = fdp.ConsumeUnicode(fdp.ConsumeIntInRange(1, 100))
+    if not s:
+        return
+    target = fdp.ConsumeIntInRange(PARSE_DATE_FROMISOFORMAT)
+    if target == PARSE_DATE_FROMISOFORMAT:
+        date.fromisoformat(s)
+    elif target == PARSE_TIME_FROMISOFORMAT:
+        time.fromisoformat(s)
+    elif target == PARSE_DATETIME_FROMISOFORMAT:
+        datetime.fromisoformat(s)
+
+
+def op_format(fdp):
+    fmt = fdp.ConsumeUnicode(fdp.ConsumeIntInRange(1, 100))
+    if not fmt:
+        return
+    target = fdp.ConsumeIntInRange(FORMAT_DATE, FORMAT_DATETIME)
+    if target == FORMAT_DATE:
+        year = fdp.ConsumeIntInRange(1, 9999)
+        month = fdp.ConsumeIntInRange(1, 12)
+        day = fdp.ConsumeIntInRange(1, 28)
+        date(year, month, day).strftime(fmt)
+    elif target == FORMAT_TIME:
+        hour = fdp.ConsumeIntInRange(0, 23)
+        minute = fdp.ConsumeIntInRange(0, 59)
+        second = fdp.ConsumeIntInRange(0, 59)
+        time(hour, minute, second).strftime(fmt)
+    elif target == FORMAT_DATETIME:
+        year = fdp.ConsumeIntInRange(1, 9999)
+        month = fdp.ConsumeIntInRange(1, 12)
+        day = fdp.ConsumeIntInRange(1, 28)
+        hour = fdp.ConsumeIntInRange(0, 23)
+        minute = fdp.ConsumeIntInRange(0, 59)
+        second = fdp.ConsumeIntInRange(0, 59)
+        datetime(year, month, day, hour, minute, second).strftime(fmt)
+
+
+# Fuzzes the _datetime C module (Modules/_datetimemodule.c).
+# Exercises ISO format parsing (date/time/datetime.fromisoformat),
+# strptime with multiple predefined format strings, and strftime with
+# fuzz-generated format strings. Only operations that pass fuzzed
+# text into the C parser are included.
+def FuzzerRunOne(FuzzerInput):
+    if len(FuzzerInput) < 1 or len(FuzzerInput) > 0x10000:
+        return
+    fdp = FuzzedDataProvider(FuzzerInput)
+    op = fdp.ConsumeIntInRange(OP_PARSE, OP_FORMAT)
+    try:
+        if op == OP_PARSE:
+            op_parse(fdp)
+        elif op == OP_FORMAT:
+            op_format(fdp)
+    except Exception:
+        pass

fuzz_targets.txt

@@ -2,6 +2,7 @@ ast ast.py
 binascii binascii.py
 configparser configparser.py
 csv csv.py
+datetime datetime.py
 decode decode.py
 difflib difflib.py
 email email.py