[Qemu-devel] [PATCH V2 0/6] tests: Add the image fuzzer with qcow2 support

[Qemu-devel] [PATCH V2 0/6] tests: Add the image fuzzer with qcow2 support

[Maria Kustova]

This patch series introduces the image fuzzer, a tool for stability and
reliability testing.
Its approach is to run large amount of tests in background. During every test a
program (e.g. qemu-img) is called to read or modify an invalid test image.
A test image has valid inner structure defined by its format specification with
some fields having random invalid values.

Patch 1 contains documentation for the image fuzzer, patch 2 is the test runner
and remaining ones relate to the image generator for qcow2 format.

This patch series was created for the 'block-next' branch.

v1 -> v2:
* refactored qcow2/layout module
* added support of external fuzzer configurations
* fixed wrong string truncation in qcow2/fuzz module
* fixed documentation typos and ambiguities (based on Eric Blake comments)
* updated documentation with the fuzzer configuration
* add LICENSE file (based on Eric Blake comments)


Maria Kustova (6):
  docs: Specification for the image fuzzer
  runner: Tool for fuzz tests execution
  fuzz: Fuzzing functions for qcow2 images
  layout: Generator of fuzzed qcow2 images
  package: Public API for image-fuzzer/runner/runner.py
  image-fuzzer: GPLv2 license file

 tests/image-fuzzer/LICENSE               | 339 +++++++++++++++++++++++++++++++
 tests/image-fuzzer/docs/fuzzer.conf      |  37 ++++
 tests/image-fuzzer/docs/image-fuzzer.txt | 216 ++++++++++++++++++++
 tests/image-fuzzer/qcow2/__init__.py     |   1 +
 tests/image-fuzzer/qcow2/fuzz.py         | 328 ++++++++++++++++++++++++++++++
 tests/image-fuzzer/qcow2/layout.py       | 319 +++++++++++++++++++++++++++++
 tests/image-fuzzer/runner/runner.py      | 290 ++++++++++++++++++++++++++
 7 files changed, 1530 insertions(+)
 create mode 100644 tests/image-fuzzer/LICENSE
 create mode 100644 tests/image-fuzzer/docs/fuzzer.conf
 create mode 100644 tests/image-fuzzer/docs/image-fuzzer.txt
 create mode 100644 tests/image-fuzzer/qcow2/__init__.py
 create mode 100644 tests/image-fuzzer/qcow2/fuzz.py
 create mode 100644 tests/image-fuzzer/qcow2/layout.py
 create mode 100755 tests/image-fuzzer/runner/runner.py

-- 
1.9.3

[Qemu-devel] [PATCH V2 1/6] docs: Specification for the image fuzzer

[Maria Kustova]

'Overall fuzzer requirements' chapter contains the current product vision and
features done and to be done. This chapter is still in progress.

v1 -> v2:
 * added description for fuzzer configuration files
 * added the example fuzzer.conf file
 * various fixes based on the Eric's review

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/docs/fuzzer.conf      |  37 ++++++
 tests/image-fuzzer/docs/image-fuzzer.txt | 216 +++++++++++++++++++++++++++++++
 2 files changed, 253 insertions(+)
 create mode 100644 tests/image-fuzzer/docs/fuzzer.conf
 create mode 100644 tests/image-fuzzer/docs/image-fuzzer.txt

diff --git a/tests/image-fuzzer/docs/fuzzer.conf b/tests/image-fuzzer/docs/fuzzer.conf
new file mode 100644
index 0000000..856cec7
--- /dev/null
+++ b/tests/image-fuzzer/docs/fuzzer.conf
@@ -0,0 +1,37 @@
+# Python version < 2.7 doesn't support empty options
+# Option values will not be interpreted
+[header]
+magic=True
+version=True
+backing_file_offset=True
+backing_file_size=True
+cluster_bits=True
+size=True
+crypt_method=True
+l1_size=True
+l1_table_offset=True
+refcount_table_offset=True
+refcount_table_clusters=True
+nb_snapshots=True
+snapshots_offset=True
+incompatible_features=True
+compatible_features=True
+autoclear_features=True
+refcount_order=True
+header_length=True
+
+[backing_file_format_ext]
+ext_magic=True
+ext_length=True
+bf_data=True
+
+[feature_name_table_ext]
+ext_magic=True
+ext_length=True
+feat_type=True
+feat_bit_number=True
+feat_name=True
+
+[end_ext]
+ext_magic=True
+ext_length=True
\ No newline at end of file
diff --git a/tests/image-fuzzer/docs/image-fuzzer.txt b/tests/image-fuzzer/docs/image-fuzzer.txt
new file mode 100644
index 0000000..0ebd0f7
--- /dev/null
+++ b/tests/image-fuzzer/docs/image-fuzzer.txt
@@ -0,0 +1,216 @@
+Image fuzzer
+============
+
+Description
+-----------
+
+The goal of the image fuzzer is to catch crashes of qemu-io/qemu-img
+by providing to them randomly corrupted images.
+Test images are generated from scratch and have valid inner structure with some
+elements, e.g. L1/L2 tables, having random invalid values.
+
+
+Test runner
+-----------
+
+The test runner generates test images, executes tests utilizing generated
+images, indicates their results and collects all test related artifacts (logs,
+core dumps, test images).
+The test means one start of a system under test (SUT), e.g. qemu-io, with
+specified arguments and one test image.
+By default, the test runner generates new tests and executes them until
+keyboard interruption. But if a test seed is specified via the '-s' runner
+parameter, then only one test with this seed will be executed, after its finish
+the runner will exit.
+
+The runner uses an external image fuzzer to generate test images. An image
+generator should be specified as a mandatory parameter of the test runner.
+Details about interactions between the runner and fuzzers see "Module
+interfaces".
+
+The runner activates generation of core dumps during test executions, but it
+assumes that core dumps will be generated in the current working directory.
+For comprehensive test results, please, set up your test environment
+properly.
+
+Path to a SUT can be specified via the '--binary' parameter of the test runner.
+If no SUT is provided, then the runner tries to get it from environment
+variables (now only qemu_img).If the environment check fails the runner will
+use qemu-img installed in system paths.
+For details about environment variables see qemu-iotests/check.
+
+The runner accepts files with lists of fields expected to be fuzzed. The file
+has the same structure as regular *.conf or *.ini file. Complex image elements
+having multiple fields should be specified as sections, individual fields as
+options for the sections.
+Example,
+        [header]
+        l1_table_offset=True
+        nb_snapshots=True
+
+        [feature_name_table_ext]
+
+If all fields in a section are expected to be fuzzed, leave the section empty.
+Option values play no role and added just for compatibility.
+The full list of supported fields are available in
+image-fuzzer/docs/fuzzer.conf.
+
+
+Qcow2 image generator
+---------------------
+
+The 'qcow2' generator is a Python package providing 'create_image' method as
+a single public API. See details in 'Test runner/image fuzzer' in 'Module
+interfaces'.
+
+Qcow2 contains two submodules: fuzz.py and layout.py.
+
+'fuzz.py' contains all fuzzing functions, one per image field. It's assumed
+that
+after code analysis every field will have own constraints for its value. For
+now only universal potentially dangerous values are used, e.g. type limits for
+integers or unsafe symbols as '%s' for strings. For bitmasks random amount of
+bits are set to ones. All fuzzed values are checked on non-equality to the
+current valid value of the field. In case of equality the value will be
+regenerated.
+
+'layout.py' creates a random valid image, fuzzes a random subset of the image
+fields by 'fuzz.py' module and writes a fuzzed image to the file specified.
+If a fuzzer configuration is specified, then it has the next interpretation:
+
+    1. If a section has no options, then some random portion of fields of
+    the image element specified as the section name will be fuzzed every test.
+    The same behavior is applied for the entire image if no configuration is
+    used. This case is useful for the test specialization.
+
+    2. When a section has options, then all fields specified in these options
+    are always fuzzed for every test. This case is useful for regression
+    testing.
+
+For now only header fields and header extensions are generated, the remaining
+file is filled with zeros.
+
+
+Module interfaces
+-----------------
+
+* Test runner/image fuzzer
+
+The runner calls an image generator specifying the path to a test image file.
+An image generator is expected to provide a
+   'create_image(test_img_path, fuzz_config=None)'
+method that creates a test image and writes it to the specified file. The file
+should be created if it doesn't exist or overwritten otherwise.
+'fuzz_config' has a form of a list of lists. Every sublist can have one
+or two elements: the first element is a name of a parent image element,
+the second one if exists is a name of a field in this element.
+Example,
+        [['header', 'l1_table_offset'],
+         ['header', 'nb_snapshots'],
+         ['feature_name_table_ext']]
+
+The full list of available names can be found in docs/fuzzer.conf.
+
+Random seed is set by the runner at every test execution for the regression
+purpose, so an image generator is not recommended to modify it internally.
+
+* Test runner/SUT
+
+A full test command is composed from the SUT, its arguments specified
+via '-c' runner parameter and the name of generated image. To indicate where
+a test image name should be placed TEST_IMG placeholder can be used.
+For example, for the next test command
+
+ qemu-img convert -O vmdk fuzzed_image test.vmdk
+
+a call of the image fuzzer will be following:
+
+ ./runner.py -b qemu-img -c 'convert -O vmdk TEST_IMG test.vmdk' work_dir qcow2
+
+
+Overall fuzzer requirements
+===========================
+
+Input data:
+----------
+
+ - image template (generator)
+ - work directory
+ - test run duration (optional)
+ - action vector (optional)
+ - seed (optional)
+ - SUT and its arguments (optional)
+
+
+Fuzzer requirements:
+-------------------
+
+1.  Should be able to inject random data
+2.  Should be able to select a random value from the manually pregenerated
+    vector (boundary values, e.g. max/min cluster size)
+3.  Image template should describe a general structure invariant for all
+    test images (image format description)
+4.  Image template should be autonomous and other fuzzer parts should not
+    rely on it
+5.  Image template should contain reference rules (not only block+size
+    description)
+6.  Should generate the test image with the correct structure based on an image
+    template
+7.  Should accept a seed as an argument (for regression purpose)
+8.  Should generate a seed if it is not specified as an input parameter.
+9.  The same seed should generate the same image for the same action vector,
+    specified or generated.
+10. Should accept a vector of actions as an argument (for test reproducing and
+    for test case specification, e.g. group of tests for header structure,
+    group of test for snapshots, etc)
+11. Action vector should be randomly generated from the pool of available
+    actions, if it is not specified as an input parameter
+12. Pool of actions should be defined automatically based on an image template
+13. Should accept a SUT and its call parameters as an argument or select them
+    randomly otherwise. As far as it's expected to be rarely changed, the list
+    of all possible test commands can be available in the test runner
+    internally.
+14. Should accept a test run duration as an argument. Tests should be executed
+    during a minimum period from a test run duration and time while fuzzer can
+    generate different test images
+15. Should support an external cancellation of a test run
+16. Seed and action vector should be logged (for regression purpose)
+17. All files related to test result should be collected: a test image,
+    SUT logs, fuzzer logs and crash dumps
+18. Should be compatible with python version 2.4-2.7
+19. Usage of external libraries should be limited as much as possible.
+
+
+Image formats:
+-------------
+
+Main target image format is qcow2, but support of image templates should
+provide an ability to add any other image format.
+
+
+Effectiveness:
+-------------
+
+Fuzzer can be controlled via template, seed and action vector;
+it makes the fuzzer itself invariant to an image format and test logic.
+It should be able to perform rather complex and precise tests, that can be
+specified via action vector. Otherwise, knowledge about an image structure
+allows the fuzzer to generate the pool of all available areas can be fuzzed
+and randomly select some of them and so compose its own action vector.
+Also complexity of a template defines complexity of the fuzzer, so its
+functionality can be varied from simple model-independent fuzzing to smart
+model-based one.
+
+
+Glossary:
+--------
+
+Action vector is a sequence of structure elements retrieved from an image
+format, each of them will be fuzzed for the test image. It's a subset of
+elements of the action pool. Example: header, refcount table, etc.
+Action pool is all available elements of an image structure that generated
+automatically from an image template.
+Image template is a formal description of an image structure and relations
+between image blocks.
+Test image is an output image of the fuzzer defined by the current seed and
+action vector.
-- 
1.9.3

[Qemu-devel] [PATCH V2 2/6] runner: Tool for fuzz tests execution

[Maria Kustova]

The purpose of the test runner is to prepare test environment (e.g. create a
work directory, a test image, etc), execute the program under test with
parameters, indicate a test failure if the program was killed during test
execution and collect core dumps, logs and other test artifacts.

The test runner doesn't depend on image format or a program will be tested, so
it can be used with any external image generator and program under test.

v1 -> v2:
Added parameter for a fuzzer configuration file

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/runner/runner.py | 290 ++++++++++++++++++++++++++++++++++++
 1 file changed, 290 insertions(+)
 create mode 100755 tests/image-fuzzer/runner/runner.py

diff --git a/tests/image-fuzzer/runner/runner.py b/tests/image-fuzzer/runner/runner.py
new file mode 100755
index 0000000..bf28300
--- /dev/null
+++ b/tests/image-fuzzer/runner/runner.py
@@ -0,0 +1,290 @@
+#!/usr/bin/env python
+
+# Tool for running fuzz tests
+#
+# Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import sys, os, signal
+from time import time
+import subprocess
+import random
+from itertools import count
+from shutil import rmtree
+import getopt
+import ConfigParser
+import resource
+resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
+
+
+def multilog(msg, *output):
+    """ Write an object to all of specified file descriptors
+    """
+
+    for fd in output:
+        fd.write(msg)
+        fd.flush()
+
+
+def str_signal(sig):
+    """ Convert a numeric value of a system signal to the string one
+    defined by the current operational system
+    """
+
+    for k, v in signal.__dict__.items():
+        if v == sig:
+            return k
+
+
+class TestException(Exception):
+    """Exception for errors risen by TestEnv objects"""
+    pass
+
+
+class TestEnv(object):
+    """ Trivial test object
+
+    The class sets up test environment, generates a test image and executes
+    application under tests with specified arguments and a test image provided.
+    All logs are collected.
+    Summary log will contain short descriptions and statuses of tests in
+    a run.
+    Test log will include application (e.g. 'qemu-img') logs besides info sent
+    to the summary log.
+    """
+
+    def __init__(self, test_id, seed, work_dir, run_log, exec_bin=None,
+                 cleanup=True, log_all=False, fuzz_config=None):
+        """Set test environment in a specified work directory.
+
+        Path to qemu_img will be retrieved from 'QEMU_IMG' environment
+        variable, if a test binary is not specified.
+        """
+
+        if seed is not None:
+            self.seed = seed
+        else:
+            self.seed = hash(time())
+
+        self.init_path = os.getcwd()
+        self.work_dir = work_dir
+        self.current_dir = os.path.join(work_dir, 'test-' + test_id)
+        if exec_bin is not None:
+            self.exec_bin = exec_bin.strip().split(' ')
+        else:
+            self.exec_bin = \
+                os.environ.get('QEMU_IMG', 'qemu-img').strip().split(' ')
+
+        try:
+            os.makedirs(self.current_dir)
+        except OSError:
+            e = sys.exc_info()[1]
+            print >>sys.stderr, \
+                "Error: The working directory '%s' cannot be used. Reason: %s"\
+                % (self.work_dir, e[1])
+            raise TestException
+        self.log = open(os.path.join(self.current_dir, "test.log"), "w")
+        self.parent_log = open(run_log, "a")
+        self.result = False
+        self.cleanup = cleanup
+        self.log_all = log_all
+        self.fuzz_config = fuzz_config
+
+    def _test_app(self, q_args):
+        """ Start application under test with specified arguments and return
+        an exit code or a kill signal depending on result of an execution.
+        """
+        devnull = open('/dev/null', 'r+')
+        return subprocess.call(self.exec_bin + q_args,
+                               stdin=devnull, stdout=self.log, stderr=self.log)
+
+    def execute(self, q_args):
+        """ Execute a test.
+
+        The method creates a test image, runs the test app and analyzes
+        its exit status. If the application was killed by a signal,
+        the test is marked as failed.
+        """
+        os.chdir(self.current_dir)
+        # Seed initialization should be as close to an image generation call
+        # as posssible to avoid a corruption of the random sequence
+        random.seed(self.seed)
+        image_generator.create_image('test_image', self.fuzz_config)
+        test_summary = "Seed: %s\nCommand: %s\nTest directory: %s\n" \
+                       % (self.seed, " ".join(q_args), self.current_dir)
+        try:
+            retcode = self._test_app(q_args)
+        except OSError:
+            e = sys.exc_info()[1]
+            multilog(test_summary + "Error: Start of '%s' failed. " \
+                     "Reason: %s\n\n" % (os.path.basename(self.exec_bin[0]),
+                                         e[1]),
+                     sys.stderr, self.log, self.parent_log)
+            raise TestException
+
+        if retcode < 0:
+            multilog(test_summary + "FAIL: Test terminated by signal %s\n\n"
+                     % str_signal(-retcode), sys.stderr, self.log,
+                     self.parent_log)
+        elif self.log_all:
+            multilog(test_summary + "PASS: Application exited with the code" +
+                     " '%d'\n\n" % retcode, sys.stdout, self.log,
+                     self.parent_log)
+            self.result = True
+        else:
+            self.result = True
+
+    def finish(self):
+        """ Restore environment after a test execution. Remove folders of
+        passed tests
+        """
+        self.log.close()
+        self.parent_log.close()
+        os.chdir(self.init_path)
+        if self.result and self.cleanup:
+            rmtree(self.current_dir)
+
+if __name__ == '__main__':
+
+    def usage():
+        print """
+        Usage: runner.py [OPTION...] TEST_DIR IMG_GENERATOR
+
+        Set up test environment in TEST_DIR and run a test in it. A module for
+        test image generation should be specified via IMG_GENERATOR. Use
+        TEST_IMG alias to mark the position in the command where a test image
+        name should be placed.
+        Example:
+        python runner.py -b ./qemu-img -c 'info TEST_IMG' /tmp/test ../qcow2
+
+        Optional arguments:
+          -h, --help                    display this help and exit
+          -b, --binary=PATH             path to the application under test,
+                                        by default "qemu-img" in PATH or
+                                        QEMU_IMG environment variables
+          -c, --command=STRING          execute the tested application
+                                        with arguments specified,
+                                        by default STRING="check"
+          -s, --seed=STRING             seed for a test image generation,
+                                        by default will be generated randomly
+          --config=FILE                 take fuzzer a configuration from FILE
+          -k, --keep_passed             don't remove folders of passed tests
+          -v, --verbose                 log information about passed tests
+        """
+
+    def run_test(test_id, seed, work_dir, run_log, test_bin, cleanup, log_all,
+                 command, fuzz_config):
+        """Setup environment for one test and execute this test"""
+        try:
+            test = TestEnv(test_id, seed, work_dir, run_log, test_bin, cleanup,
+                           log_all, fuzz_config)
+        except TestException:
+            sys.exit(1)
+
+        # Python 2.4 doesn't support 'finally' and 'except' in the same 'try'
+        # block
+        try:
+            try:
+                test.execute(command)
+            # Silent exit on user break
+            except TestException:
+                sys.exit(1)
+        finally:
+            test.finish()
+
+    try:
+        opts, args = getopt.gnu_getopt(sys.argv[1:], 'c:hb:s:kv',
+                                       ['command=', 'help', 'binary=', 'seed=',
+                                        'config=', 'keep_passed', 'verbose'])
+    except getopt.error:
+        e = sys.exc_info()[1]
+        print "Error: %s\n\nTry 'runner.py --help' for more information" % e
+        sys.exit(1)
+
+    command = ['check']
+    cleanup = True
+    log_all = False
+    test_bin = None
+    seed = None
+    config_file = None
+    for opt, arg in opts:
+        if opt in ('-h', '--help'):
+            usage()
+            sys.exit()
+        elif opt in ('-c', '--command'):
+            command = arg.split(" ")
+        elif opt in ('-k', '--keep_passed'):
+            cleanup = False
+        elif opt in ('-v', '--verbose'):
+            log_all = True
+        elif opt in ('-b', '--binary'):
+            test_bin = os.path.realpath(arg)
+        elif opt in ('-s', '--seed'):
+            seed = arg
+        elif opt == '--config':
+            config_file = arg
+
+    if not len(args) == 2:
+        print "Missed parameter\nTry 'runner.py --help' " \
+            "for more information"
+        sys.exit(1)
+
+    work_dir = os.path.realpath(args[0])
+    # run_log is created in 'main', because multiple tests are expected to
+    # log in it
+    run_log = os.path.join(work_dir, 'run.log')
+
+    # Add the path to the image generator module to sys.path
+    sys.path.append(os.path.dirname(os.path.realpath(args[1])))
+    # Remove a script extension from image generator module if any
+    generator_name = os.path.splitext(os.path.basename(args[1]))[0]
+    try:
+        image_generator = __import__(generator_name)
+    except ImportError:
+        e = sys.exc_info()[1]
+        print "Error: The image generator '%s' cannot be imported.\n" \
+            "Reason: %s" % (generator_name, e)
+        sys.exit(1)
+
+    # Replace test image alias with its real name
+    for idx, item in enumerate(command):
+        if item == 'TEST_IMG':
+            command[idx] = 'test_image'
+    # Read fuzzer configuration
+    if config_file is None:
+        fuzz_config = None
+    else:
+        fuzz_config = []
+        config = ConfigParser.RawConfigParser()
+        config.read(config_file)
+        for s in config.sections():
+            opt_list = config.options(s)
+            if len(opt_list) == 0:
+                fuzz_config.append([s])
+            else:
+                for o in opt_list:
+                    fuzz_config.append([s, o])
+    # If a seed is specified, only one test will be executed.
+    # Otherwise runner will terminate after a keyboard interruption
+    for test_id in count(1):
+        try:
+            run_test(str(test_id), seed, work_dir, run_log, test_bin, cleanup,
+                     log_all, command, fuzz_config)
+        except (KeyboardInterrupt, SystemExit):
+            sys.exit(1)
+
+        if seed is not None:
+            break
-- 
1.9.3

[Qemu-devel] [PATCH V2 3/6] fuzz: Fuzzing functions for qcow2 images

[Maria Kustova]

Fuzz submodule of qcow2 image generator contains fuzzing functions for image
fields.
Each fuzzing function contains list of constraints and call of a helper
function that randomly selects a fuzzed value satisfied to one of constraints.
For now constraints are only known as invalid or potentially dangerous values.
But after investigation of code coverage by fuzz tests they will be expanded
by heuristic values based on inner checks and flows of a program under test.

Now fuzzing of header and header extensions is supported.

v1 -> v2:
Fixed incorrect string truncation in 'truncate_string()'

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/qcow2/fuzz.py | 328 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 328 insertions(+)
 create mode 100644 tests/image-fuzzer/qcow2/fuzz.py

diff --git a/tests/image-fuzzer/qcow2/fuzz.py b/tests/image-fuzzer/qcow2/fuzz.py
new file mode 100644
index 0000000..a8f8f79
--- /dev/null
+++ b/tests/image-fuzzer/qcow2/fuzz.py
@@ -0,0 +1,328 @@
+# Fuzzing functions for qcow2 fields
+#
+# Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import random
+
+
+UINT32 = 0xffffffff
+UINT64 = 0xffffffffffffffff
+# Most significant bit orders
+UINT32_M = 31
+UINT64_M = 63
+# Fuzz vectors
+UINT32_V = [0, 0x100, 0x1000, 0x10000, 0x100000, UINT32/4, UINT32/2 - 1,
+            UINT32/2, UINT32/2 + 1, UINT32 - 1, UINT32]
+UINT64_V = UINT32_V + [0x1000000, 0x10000000, 0x100000000, UINT64/4,
+                       UINT64/2 - 1, UINT64/2, UINT64/2 + 1, UINT64 - 1,
+                       UINT64]
+STRING_V = ['%s%p%x%d', '.1024d', '%.2049d', '%p%p%p%p', '%x%x%x%x',
+            '%d%d%d%d', '%s%s%s%s', '%99999999999s', '%08x', '%%20d', '%%20n',
+            '%%20x', '%%20s', '%s%s%s%s%s%s%s%s%s%s', '%p%p%p%p%p%p%p%p%p%p',
+            '%#0123456x%08x%x%s%p%d%n%o%u%c%h%l%q%j%z%Z%t%i%e%g%f%a%C%S%08x%%',
+            '%s x 129', '%x x 257']
+
+
+def random_from_intervals(intervals):
+    """Select a random integer number from the list of specified intervals
+
+    Each interval is a tuple of lower and upper limits of the interval. The
+    limits are included. Intervals in a list should not overlap.
+    """
+    total = reduce(lambda x, y: x + y[1] - y[0] + 1, intervals, 0)
+    r = random.randint(0, total-1) + intervals[0][0]
+    temp = zip(intervals, intervals[1:])
+    for x in temp:
+        r = r + (r > x[0][1])*(x[1][0] - x[0][1] - 1)
+    return r
+
+
+def random_bits(bit_ranges):
+    """Generate random binary mask with ones in the specified bit ranges
+
+    Each bit_ranges is a list of tuples of lower and upper limits of bit
+    positions will be fuzzed. The limits are included. Random amount of bits
+    in range limits will be set to ones. The mask is returned in decimal
+    integer format.
+    """
+    bit_numbers = []
+    # Select random amount of random positions in bit_ranges
+    for rng in bit_ranges:
+        bit_numbers += random.sample(range(rng[0], rng[1] + 1),
+                                     random.randint(0, rng[1] - rng[0] + 1))
+    val = 0
+    # Set bits on selected possitions to ones
+    for bit in bit_numbers:
+        val |= 1 << bit
+    return val
+
+
+def truncate_string(strings, length):
+    """Return strings truncated to the specified length"""
+    if type(strings) == list:
+        return [s[:length] for s in strings]
+    else:
+        return strings[:length]
+
+
+def int_validator(current, intervals):
+    """Return a random value from intervals not equal to the current.
+
+    This function is useful for selection from valid values except current one.
+    """
+    val = random_from_intervals(intervals)
+    if val == current:
+        return int_validator(current, intervals)
+    else:
+        return val
+
+
+def bit_validator(current, bit_ranges):
+    """Return a random bit mask not equal to the current.
+
+    This function is useful for selection from valid values except current one.
+    """
+
+    val = random_bits(bit_ranges)
+    if val == current:
+        return bit_validator(current, bit_ranges)
+    else:
+        return val
+
+
+def string_validator(current, strings):
+    """Return a random string value from the list not equal to the current.
+
+    This function is useful for selection from valid values except current one.
+    """
+    val = random.choice(strings)
+    if val == current:
+        return string_validator(current, strings)
+    else:
+        return val
+
+
+def selector(current, constraints, fmt=None):
+    """Select one value from all defined by constraints
+
+    Each constraint produces one random value satisfying to it. The function
+    randomly selects one value satisfying at least one constraint (depending on
+    constraints overlaps).
+    """
+    validate = {
+        'bitmask': bit_validator,
+        'string': string_validator
+    }.get(fmt, int_validator)
+
+    def iter_validate(c):
+        """Apply validate() only to constraints represented as lists
+
+        This auxiliary function replaces short circuit conditions not supported
+        in Python 2.4
+        """
+        if type(c) == list:
+            return validate(current, c)
+        else:
+            return c
+    fuzz_values = [iter_validate(c) for c in constraints]
+    # Remove current for cases it's implicitly specified in constraints
+    # Duplicate validator functionality to prevent decreasing of probability
+    # to get one of allowable values
+    # TODO: remove validators after implementation of intelligent selection
+    # of fields will be fuzzed
+    try:
+        fuzz_values.remove(current)
+    except ValueError:
+        pass
+    return random.choice(fuzz_values)
+
+
+def magic(current):
+    """Fuzz magic header field
+
+    The function just returns the current magic value and provides uniformity
+    of calls for all fuzzing functions
+    """
+    return current
+
+
+def version(current):
+    """Fuzz version header field"""
+    constraints = UINT32_V + [
+        [(2, 3)],  # correct values
+        [(0, 1), (4, UINT32)]
+    ]
+    return selector(current, constraints)
+
+
+def backing_file_offset(current):
+    """Fuzz backing file offset header field"""
+    constraints = UINT64_V
+    return selector(current, constraints)
+
+
+def backing_file_size(current):
+    """Fuzz backing file size header field"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def cluster_bits(current):
+    """Fuzz cluster bits header field"""
+    constraints = UINT32_V + [
+        [(9, 20)],  # correct values
+        [(0, 9), (20, UINT32)]
+    ]
+    return selector(current, constraints)
+
+
+def size(current):
+    """Fuzz image size header field"""
+    constraints = UINT64_V
+    return selector(current, constraints)
+
+
+def crypt_method(current):
+    """Fuzz crypt method header field"""
+    constraints = UINT32_V + [
+        1,
+        [(2, UINT32)]
+    ]
+    return selector(current, constraints)
+
+
+def l1_size(current):
+    """Fuzz L1 table size header field"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def l1_table_offset(current):
+    """Fuzz L1 table offset header field"""
+    constraints = UINT64_V
+    return selector(current, constraints)
+
+
+def refcount_table_offset(current):
+    """Fuzz refcount table offset header field"""
+    constraints = UINT64_V
+    return selector(current, constraints)
+
+
+def refcount_table_clusters(current):
+    """Fuzz refcount table clusters header field"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def nb_snapshots(current):
+    """Fuzz number of snapshots header field"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def snapshots_offset(current):
+    """Fuzz snapshots offset header field"""
+    constraints = UINT64_V
+    return selector(current, constraints)
+
+
+def incompatible_features(current):
+    """Fuzz incompatible features header field"""
+    constraints = [
+        [(0, 1)],  # allowable values
+        [(0, UINT64_M)]
+    ]
+    return selector(current, constraints, 'bitmask')
+
+
+def compatible_features(current):
+    """Fuzz compatible features header field"""
+    constraints = [
+        [(0, UINT64_M)]
+    ]
+    return selector(current, constraints, 'bitmask')
+
+
+def autoclear_features(current):
+    """Fuzz autoclear features header field"""
+    constraints = [
+        [(0, UINT64_M)]
+    ]
+    return selector(current, constraints, 'bitmask')
+
+
+def refcount_order(current):
+    """Fuzz number of refcount order header field"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def header_length(current):
+    """Fuzz number of refcount order header field"""
+    constraints = UINT32_V + [
+        72,
+        104,
+        [(0, UINT32)]
+    ]
+    return selector(current, constraints)
+
+
+def ext_magic(current):
+    """Fuzz magic field of a header extension"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def ext_length(current):
+    """Fuzz length field of a header extension"""
+    constraints = UINT32_V
+    return selector(current, constraints)
+
+
+def bf_data(current):
+    """Fuzz backing file format in the corresponding header extension"""
+    constraints = [
+        truncate_string(STRING_V, len(current)),
+        truncate_string(STRING_V, (len(current) + 7) & ~7)  # Fuzz padding
+    ]
+    return selector(current, constraints, 'string')
+
+
+def feat_type(current):
+    """Fuzz feature type field of a feature name table header extension"""
+    constraints = [
+        [(0, 255)]
+    ]
+    return selector(current, constraints)
+
+
+def feat_bit_number(current):
+    """Fuzz bit number field of a feature name table header extension"""
+    constraints = [
+        [(0, 255)]
+    ]
+    return selector(current, constraints)
+
+
+def feat_name(current):
+    """Fuzz feature name field of a feature name table header extension"""
+    constraints = [
+        truncate_string(STRING_V, len(current)),
+        truncate_string(STRING_V, 48)  # Fuzz padding (field length = 48)
+    ]
+    return selector(current, constraints, 'string')
-- 
1.9.3

[Qemu-devel] [PATCH V2 4/6] layout: Generator of fuzzed qcow2 images

[Maria Kustova]

Layout submodule of qcow2 package creates a random valid image, randomly
selects some amount of its fields, fuzzes them and write the fuzzed image to
the file.
Now only header and header extensions are generated, a remaining file is filled
by zeroes.

v1 -> v2:
 * Added support of fuzzer configurations.
 * Created general Image class:
 ** fixed mixed defs/classes module style
 ** internalized all functions related to image generation
 ** simplified internal image representation

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/qcow2/layout.py | 319 +++++++++++++++++++++++++++++++++++++
 1 file changed, 319 insertions(+)
 create mode 100644 tests/image-fuzzer/qcow2/layout.py

diff --git a/tests/image-fuzzer/qcow2/layout.py b/tests/image-fuzzer/qcow2/layout.py
new file mode 100644
index 0000000..d6fc1ab
--- /dev/null
+++ b/tests/image-fuzzer/qcow2/layout.py
@@ -0,0 +1,319 @@
+# Generator of fuzzed qcow2 images
+#
+# Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import random
+import struct
+import qcow2.fuzz
+
+MAX_IMAGE_SIZE = 10*2**20
+# Standard sizes
+UINT32_S = 4
+UINT64_S = 8
+
+# Percentage of fields will be fuzzed
+BIAS = random.uniform(0.2, 0.5)
+
+
+class Field(object):
+    """Atomic image element (field)
+
+    The class represents an image field as quadruple of a data format
+    of value necessary for its packing to binary form, an offset from
+    the beginning of the image, a value and a name.
+
+    The field can be iterated as a list [format, offset, value]
+    """
+    __slots__ = ('fmt', 'offset', 'value', 'name')
+
+    def __init__(self, fmt, offset, val, name):
+        self.fmt = fmt
+        self.offset = offset
+        self.value = val
+        self.name = name
+
+    def __iter__(self):
+        return (x for x in [self.fmt, self.offset, self.value])
+
+    def __repr__(self):
+        return "Field(fmt='%s', offset=%d, value=%s, name=%s)" % \
+            (self.fmt, self.offset, str(self.value), self.name)
+
+
+class FieldsList(object):
+    """List of fields
+
+    The class allows access to a field in the list by its name and joins
+    several list in one via in-place addition
+    """
+    def __init__(self, meta_data=None):
+        if meta_data is None:
+            self.data = []
+        else:
+            self.data = [Field(f[0], f[1], f[2], f[3])
+                         for f in meta_data]
+
+    def __getitem__(self, name):
+        return [x for x in self.data if x.name == name]
+
+    def __iter__(self):
+        return (x for x in self.data)
+
+    def __iadd__(self, other):
+        self.data += other.data
+        return self
+
+    def __len__(self):
+        return len(self.data)
+
+
+class Image(object):
+    """ Qcow2 image object
+
+    This class allows to create valid qcow2 images with random structure,
+    fuzz them via external qcow2.fuzz module and write to files.
+    """
+    @staticmethod
+    def _size_params():
+        """Generate a random file size aligned to a random correct cluster size
+        """
+        cluster_bits = random.randrange(9, 21)
+        cluster_size = 1 << cluster_bits
+        # Minimal image size is equal to 5 clusters as for qcow2 empty image
+        # created by qemu-img
+        file_size = random.randrange(5*cluster_size, MAX_IMAGE_SIZE + 1,
+                                     cluster_size)
+        return [cluster_bits, file_size]
+
+    @staticmethod
+    def _header(cluster_bits, img_size):
+        """Generate a random valid header"""
+        meta_header = [
+            ['>4s', 0, "QFI\xfb", 'magic'],
+            ['>I', 4, random.randint(2, 3), 'version'],
+            ['>Q', 8, 0, 'backing_file_offset'],
+            ['>I', 16, 0, 'backing_file_size'],
+            ['>I', 20, cluster_bits, 'cluster_bits'],
+            ['>Q', 24, img_size, 'size'],
+            ['>I', 32, 0, 'crypt_method'],
+            ['>I', 36, 0, 'l1_size'],
+            ['>Q', 40, 0, 'l1_table_offset'],
+            ['>Q', 48, 0, 'refcount_table_offset'],
+            ['>I', 56, 0, 'refcount_table_clusters'],
+            ['>I', 60, 0, 'nb_snapshots'],
+            ['>Q', 64, 0, 'snapshots_offset'],
+            ['>Q', 72, 0, 'incompatible_features'],
+            ['>Q', 80, 0, 'compatible_features'],
+            ['>Q', 88, 0, 'autoclear_features'],
+            # From the e-mail thread for [PATCH] docs: Define refcount_bits
+            # value: Only refcount_order = 4 is supported by QEMU at the moment
+            ['>I', 96, 4, 'refcount_order'],
+            ['>I', 100, 0, 'header_length']
+        ]
+        v_header = FieldsList(meta_header)
+
+        if v_header['version'][0].value == 2:
+            v_header['header_length'][0].value = 72
+        else:
+            v_header['incompatible_features'][0].value = random.getrandbits(2)
+            v_header['compatible_features'][0].value = random.getrandbits(1)
+            v_header['header_length'][0].value = 104
+
+        return v_header
+
+    @staticmethod
+    def _backing_file_format_ext(header):
+        """Generate a random header extension for name of backing file
+        format
+
+        If the header doesn't contain information about the backing file,
+        this extension is left empty
+        """
+        offset = struct.calcsize(header['header_length'][0].fmt) + \
+                 header['header_length'][0].offset
+
+        if not header['backing_file_offset'][0].value == 0:
+            # Till real backup image is not supported, a random valid fmt
+            # is set
+            ext_data = random.choice(['raw', 'qcow', 'qcow2', 'qed',
+                                      'cow', 'vdi', 'vmdk', 'vpc',
+                                      'vhdx', 'bochs', 'cloop',
+                                      'dmg', 'parallels'])
+            ext_data_len = len(ext_data)
+            ext_data_padded = '>' + str(ext_data_len) + 's' + \
+                              str(7 - (ext_data_len - 1) % 8) + 'x'
+            ext = FieldsList([
+                ['>I', offset, 0xE2792ACA, 'ext_magic'],
+                ['>I', offset + UINT32_S, ext_data_len, 'ext_length'],
+                [ext_data_padded, offset + UINT32_S*2, ext_data,
+                 'bf_data']
+            ])
+            offset = ext['bf_data'][0].offset + \
+                     struct.calcsize(ext['bf_data'][0].fmt)
+        else:
+            ext = FieldsList()
+        return (ext, offset)
+
+    @staticmethod
+    def _feature_name_table_ext(header, offset):
+        """Generate a random header extension for names of features used in
+        the image
+
+        If all features bit masks in the header are set to zeroes,
+        this extension is left empty
+        """
+        feature_tables = []
+        # Current offset + magic and length fields of the feature table
+        # extension
+        inner_offset = offset + 2*UINT32_S
+
+        # Each tuple includes bit value in the corresponding header field,
+        # feature type, number of the bit in the header field and feature name
+        feature_list = [
+            (header['incompatible_features'][0].value & 1, 0,
+             1, 'dirty bit'),
+            (header['incompatible_features'][0].value & 2, 0,
+             2, 'corrupt bit'),
+            (header['compatible_features'][0].value & 1, 1,
+             1, 'lazy refcounts bit')
+        ]
+        for item in feature_list:
+            if not item[0] == 0:
+                name_len = len(item[3])
+                name_padded_fmt = '>' + str(name_len) + 's' + \
+                                  str(46 - name_len) + 'x'
+                feature_tables += [['B', inner_offset, item[1], 'feat_type'],
+                                   ['B', inner_offset + 1,
+                                    item[2], 'feat_bit_number'],
+                                   [name_padded_fmt, inner_offset + 2,
+                                    item[3], 'feat_name']
+                ]
+                inner_offset = inner_offset + 2 + \
+                               struct.calcsize(name_padded_fmt)
+
+        if not len(feature_tables) == 0:
+            # No padding for the extension is necessary, because
+            # the extension length = 8 + 48*N is multiple of 8
+            ext = FieldsList([
+                ['>I', offset, 0x6803f857, 'ext_magic'],
+                ['>I', offset + UINT32_S, len(feature_tables)*48,'ext_length']
+            ] + feature_tables)
+            offset = inner_offset
+        else:
+            ext = FieldsList()
+
+        return (ext, offset)
+
+    @staticmethod
+    def _end_ext(offset):
+        """Generate a mandatory header extension marking end of header
+        extensions
+        """
+        ext = FieldsList([
+            ['>I', offset, 0, 'ext_magic'],
+            ['>I', offset + UINT32_S, 0, 'ext_length']
+        ])
+        return (ext, offset)
+
+    def __init__(self):
+        """Create a random valid qcow2 image with the correct inner structure
+        and allowable values
+        """
+        # Image size is necessary for writing, but the field with it can be
+        # fuzzed so it's saved separately.
+        cluster_bits, self.image_size = self._size_params()
+        self.header = self._header(cluster_bits, self.image_size)
+        self.backing_file_format_ext, \
+            offset = self._backing_file_format_ext(self.header)
+        self.feature_name_table_ext, \
+            offset = self._feature_name_table_ext(self.header, offset)
+        self.end_ext, offset = self._end_ext(offset)
+        # Container for entire image
+        self.data = FieldsList()
+
+    def __iter__(self):
+        return (x for x in [self.header, self.backing_file_format_ext,
+                            self.feature_name_table_ext, self.end_ext])
+
+    def _join(self):
+        """Join all image structure elements as header, tables, etc in one
+        list of fields
+        """
+        if len(self.data) == 0:
+            for v in self:
+                self.data += v
+
+    def fuzz(self, fields_to_fuzz=None):
+        """Fuzz an image by corrupting values of a random subset of its fields
+
+        Without parameters the method fuzzes an entire image.
+        If 'fields_to_fuzz' is specified then only fields in this list will be
+        fuzzed. 'fields_to_fuzz' can contain both individual fields and more
+        general image elements as header or tables.
+        In the first case the single field will be fuzzed always.
+        In the second a random subset of fields will be selected and fuzzed.
+        """
+        def coin():
+            """Return boolean value proportional to a portion of fields to be
+            fuzzed
+            """
+            return random.random() < BIAS
+
+        if fields_to_fuzz is None:
+            self._join()
+            for field in self.data:
+                if coin():
+                    field.value = getattr(qcow2.fuzz, field.name)(field.value)
+        else:
+            for item in fields_to_fuzz:
+                if len(item) == 1:
+                    for field in self.__dict__[item[0]]:
+                        if coin():
+                            field.value = getattr(qcow2.fuzz,
+                                                  field.name)(field.value)
+                else:
+                    for field in self.__dict__[item[0]][item[1]]:
+                        try:
+                            field.value = getattr(qcow2.fuzz, field.name)(
+                                field.value)
+                        except AttributeError:
+                            # Some fields can be skipped depending on
+                            # references, e.g. FNT header extension is not
+                            # generated for a feature mask header field
+                            # equal to zero
+                            pass
+
+    def write(self, filename):
+        """Writes an entire image to the file"""
+        image_file = open(filename, 'w')
+        # Create an empty image
+        # (sparse if FS supports it or preallocated otherwise)
+        image_file.seek(self.image_size - 1)
+        image_file.write("\0")
+        self._join()
+        for field in self.data:
+            image_file.seek(field.offset)
+            image_file.write(struct.pack(field.fmt, field.value))
+
+        image_file.close()
+
+
+def create_image(test_img_path, fields_to_fuzz=None):
+    """Create a fuzzed image and write it to the specified file"""
+    image = Image()
+    image.fuzz(fields_to_fuzz)
+    image.write(test_img_path)
-- 
1.9.3

[Qemu-devel] [PATCH V2 5/6] package: Public API for image-fuzzer/runner/runner.py

[Maria Kustova]

__init__.py provides the public API required by the test runner

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/qcow2/__init__.py | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 tests/image-fuzzer/qcow2/__init__.py

diff --git a/tests/image-fuzzer/qcow2/__init__.py b/tests/image-fuzzer/qcow2/__init__.py
new file mode 100644
index 0000000..e2ebe19
--- /dev/null
+++ b/tests/image-fuzzer/qcow2/__init__.py
@@ -0,0 +1 @@
+from layout import create_image
-- 
1.9.3

[Qemu-devel] [PATCH V2 6/6] image-fuzzer: GPLv2 license file

[Maria Kustova]

Signed-off-by: Maria Kustova <maria.k@catit.be>
---
 tests/image-fuzzer/LICENSE | 339 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 339 insertions(+)
 create mode 100644 tests/image-fuzzer/LICENSE

diff --git a/tests/image-fuzzer/LICENSE b/tests/image-fuzzer/LICENSE
new file mode 100644
index 0000000..ecbc059
--- /dev/null
+++ b/tests/image-fuzzer/LICENSE
@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
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+    Copyright (C) <year>  <name of author>
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+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
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+    with this program; if not, write to the Free Software Foundation, Inc.,
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+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
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+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
\ No newline at end of file
-- 
1.9.3

Re: [Qemu-devel] [PATCH V2 2/6] runner: Tool for fuzz tests execution

[Fam Zheng]

On Fri, 07/04 15:39, Maria Kustova wrote:
> v1 -> v2:
> Added parameter for a fuzzer configuration file

In the future revisions, please put such revision change notes below a '---'
line, like:

    <commit log>

    Signed-off-by: Your Name <your@email.com>
    ---

    v1 -> v2: change

This way, it doesn't get into git log when maintainers apply your patch email
with "git am".

The reason is that revision notes only matter when reviewing patches, but has
no value once applied to master.

Thanks,
Fam

Re: [Qemu-devel] [PATCH V2 6/6] image-fuzzer: GPLv2 license file

[Fam Zheng]

On Fri, 07/04 15:39, Maria Kustova wrote:
> Signed-off-by: Maria Kustova <maria.k@catit.be>

You have the copyright headers in each file, so it's not really necessary to
put the license here.

No need to respin for this, if it's unwanted in the end, maintainer could
probably skip when merging the series.

Fam

Re: [Qemu-devel] [PATCH V2 4/6] layout: Generator of fuzzed qcow2 images

[Fam Zheng]

On Fri, 07/04 15:39, Maria Kustova wrote:
> Layout submodule of qcow2 package creates a random valid image, randomly
> selects some amount of its fields, fuzzes them and write the fuzzed image to
> the file.
> Now only header and header extensions are generated, a remaining file is filled
> by zeroes.
> 
> v1 -> v2:
>  * Added support of fuzzer configurations.
>  * Created general Image class:
>  ** fixed mixed defs/classes module style
>  ** internalized all functions related to image generation
>  ** simplified internal image representation
> 
> Signed-off-by: Maria Kustova <maria.k@catit.be>
> ---
>  tests/image-fuzzer/qcow2/layout.py | 319 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 319 insertions(+)
>  create mode 100644 tests/image-fuzzer/qcow2/layout.py
> 
> diff --git a/tests/image-fuzzer/qcow2/layout.py b/tests/image-fuzzer/qcow2/layout.py
> new file mode 100644
> index 0000000..d6fc1ab
> --- /dev/null
> +++ b/tests/image-fuzzer/qcow2/layout.py
> @@ -0,0 +1,319 @@
> +# Generator of fuzzed qcow2 images
> +#
> +# Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
> +#
> +# This program is free software: you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation, either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +#
> +
> +import random
> +import struct
> +import qcow2.fuzz
> +
> +MAX_IMAGE_SIZE = 10*2**20
> +# Standard sizes
> +UINT32_S = 4
> +UINT64_S = 8
> +
> +# Percentage of fields will be fuzzed
> +BIAS = random.uniform(0.2, 0.5)
> +
> +
> +class Field(object):
> +    """Atomic image element (field)
> +
> +    The class represents an image field as quadruple of a data format
> +    of value necessary for its packing to binary form, an offset from
> +    the beginning of the image, a value and a name.
> +
> +    The field can be iterated as a list [format, offset, value]
> +    """
> +    __slots__ = ('fmt', 'offset', 'value', 'name')
> +
> +    def __init__(self, fmt, offset, val, name):
> +        self.fmt = fmt
> +        self.offset = offset
> +        self.value = val
> +        self.name = name
> +
> +    def __iter__(self):
> +        return (x for x in [self.fmt, self.offset, self.value])
> +
> +    def __repr__(self):
> +        return "Field(fmt='%s', offset=%d, value=%s, name=%s)" % \
> +            (self.fmt, self.offset, str(self.value), self.name)
> +
> +
> +class FieldsList(object):
> +    """List of fields
> +
> +    The class allows access to a field in the list by its name and joins
> +    several list in one via in-place addition
> +    """
> +    def __init__(self, meta_data=None):
> +        if meta_data is None:
> +            self.data = []
> +        else:
> +            self.data = [Field(f[0], f[1], f[2], f[3])
> +                         for f in meta_data]
> +
> +    def __getitem__(self, name):
> +        return [x for x in self.data if x.name == name]
> +
> +    def __iter__(self):
> +        return (x for x in self.data)
> +
> +    def __iadd__(self, other):
> +        self.data += other.data
> +        return self
> +
> +    def __len__(self):
> +        return len(self.data)
> +
> +
> +class Image(object):
> +    """ Qcow2 image object
> +
> +    This class allows to create valid qcow2 images with random structure,
> +    fuzz them via external qcow2.fuzz module and write to files.
> +    """
> +    @staticmethod
> +    def _size_params():
> +        """Generate a random file size aligned to a random correct cluster size
> +        """
> +        cluster_bits = random.randrange(9, 21)
> +        cluster_size = 1 << cluster_bits
> +        # Minimal image size is equal to 5 clusters as for qcow2 empty image
> +        # created by qemu-img
> +        file_size = random.randrange(5*cluster_size, MAX_IMAGE_SIZE + 1,
> +                                     cluster_size)
> +        return [cluster_bits, file_size]
> +
> +    @staticmethod
> +    def _header(cluster_bits, img_size):
> +        """Generate a random valid header"""
> +        meta_header = [
> +            ['>4s', 0, "QFI\xfb", 'magic'],
> +            ['>I', 4, random.randint(2, 3), 'version'],
> +            ['>Q', 8, 0, 'backing_file_offset'],
> +            ['>I', 16, 0, 'backing_file_size'],
> +            ['>I', 20, cluster_bits, 'cluster_bits'],
> +            ['>Q', 24, img_size, 'size'],
> +            ['>I', 32, 0, 'crypt_method'],
> +            ['>I', 36, 0, 'l1_size'],
> +            ['>Q', 40, 0, 'l1_table_offset'],
> +            ['>Q', 48, 0, 'refcount_table_offset'],
> +            ['>I', 56, 0, 'refcount_table_clusters'],
> +            ['>I', 60, 0, 'nb_snapshots'],
> +            ['>Q', 64, 0, 'snapshots_offset'],
> +            ['>Q', 72, 0, 'incompatible_features'],
> +            ['>Q', 80, 0, 'compatible_features'],
> +            ['>Q', 88, 0, 'autoclear_features'],
> +            # From the e-mail thread for [PATCH] docs: Define refcount_bits
> +            # value: Only refcount_order = 4 is supported by QEMU at the moment

Better to refer docs/specs/qcow2.txt instead of an email thread, since it's
already merged.

Fam

> +            ['>I', 96, 4, 'refcount_order'],
> +            ['>I', 100, 0, 'header_length']
> +        ]