1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
#!/usr/bin/env python3
# Wireshark - Network traffic analyzer
# By Gerald Combs <gerald@wireshark.org>
# Copyright 1998 Gerald Combs
#
# SPDX-License-Identifier: GPL-2.0-or-later
# Scan dissectors for calls to val_to_str() and friends,
# checking for appropriate format specifier strings in
# 'unknown' arg.
# TODO:
# - more detailed format specifier checking (check letter, that there is only 1)
# - scan conformance (.cnf) files for ASN1 dissectors?
import os
import re
import subprocess
import argparse
import signal
# Try to exit soon after Ctrl-C is pressed.
should_exit = False
def signal_handler(sig, frame):
global should_exit
should_exit = True
print('You pressed Ctrl+C - exiting')
signal.signal(signal.SIGINT, signal_handler)
# Test for whether the given file was automatically generated.
def isGeneratedFile(filename):
# Check file exists - e.g. may have been deleted in a recent commit.
if not os.path.exists(filename):
return False
# Open file
f_read = open(os.path.join(filename), 'r', encoding="utf8")
lines_tested = 0
for line in f_read:
# The comment to say that its generated is near the top, so give up once
# get a few lines down.
if lines_tested > 10:
f_read.close()
return False
if (line.find('Generated automatically') != -1 or
line.find('Generated Automatically') != -1 or
line.find('Autogenerated from') != -1 or
line.find('is autogenerated') != -1 or
line.find('automatically generated by Pidl') != -1 or
line.find('Created by: The Qt Meta Object Compiler') != -1 or
line.find('This file was generated') != -1 or
line.find('This filter was automatically generated') != -1 or
line.find('This file is auto generated, do not edit!') != -1 or
line.find('This file is auto generated') != -1):
f_read.close()
return True
lines_tested = lines_tested + 1
# OK, looks like a hand-written file!
f_read.close()
return False
def removeComments(code_string):
code_string = re.sub(re.compile(r"/\*.*?\*/",re.DOTALL ) ,"" ,code_string) # C-style comment
code_string = re.sub(re.compile(r"//.*?\n" ) ,"" ,code_string) # C++-style comment
return code_string
def is_dissector_file(filename):
p = re.compile(r'.*packet-.*\.c')
return p.match(filename)
def findDissectorFilesInFolder(folder, recursive=False):
dissector_files = []
if recursive:
for root, subfolders, files in os.walk(folder):
for f in files:
if should_exit:
return
f = os.path.join(root, f)
dissector_files.append(f)
else:
for f in sorted(os.listdir(folder)):
if should_exit:
return
filename = os.path.join(folder, f)
dissector_files.append(filename)
return [x for x in filter(is_dissector_file, dissector_files)]
warnings_found = 0
errors_found = 0
# Check the given dissector file.
def checkFile(filename):
global warnings_found
global errors_found
# Check file exists - e.g. may have been deleted in a recent commit.
if not os.path.exists(filename):
print(filename, 'does not exist!')
return
with open(filename, 'r', encoding="utf8") as f:
contents = f.read()
# Remove comments so as not to trip up RE.
contents = removeComments(contents)
matches = re.finditer(r'(?<!try_)(?<!char_)(?<!bytes)(r?val_to_str(?:_ext|)(?:_const|))\(.*?,.*?,\s*(".*?\")\s*\)', contents)
for m in matches:
function = m.group(1)
format_string = m.group(2)
# Ignore what appears to be a macro.
if format_string.find('#') != -1:
continue
if function.endswith('_const'):
# These ones shouldn't have a specifier - its an error if they do.
# TODO: I suppose it could be escaped, but haven't seen this...
if format_string.find('%') != -1:
# This is an error as format specifier would show in app
print('Error:', filename, " ", m.group(0), ' - should not have specifiers in unknown string')
errors_found += 1
else:
# These ones need to have a specifier, and it should be suitable for an int
specifier_id = format_string.find('%')
if specifier_id == -1:
print('Warning:', filename, " ", m.group(0), ' - should have suitable format specifier in unknown string (or use _const()?)')
warnings_found += 1
# TODO: check allowed specifiers (d, u, x, ?) and modifiers (0-9*) in re ?
if format_string.find('%s') != -1:
# This is an error as this likely causes a crash
print('Error:', filename, " ", m.group(0), ' - inappropriate format specifier in unknown string')
errors_found += 1
#################################################################
# Main logic.
# command-line args. Controls which dissector files should be checked.
# If no args given, will scan all dissectors.
parser = argparse.ArgumentParser(description='Check calls in dissectors')
parser.add_argument('--file', action='append',
help='specify individual dissector file to test')
parser.add_argument('--commits', action='store',
help='last N commits to check')
parser.add_argument('--open', action='store_true',
help='check open files')
args = parser.parse_args()
# Get files from wherever command-line args indicate.
files = []
if args.file:
# Add specified file(s)
for f in args.file:
if not f.startswith('epan'):
f = os.path.join('epan', 'dissectors', f)
if not os.path.isfile(f):
print('Chosen file', f, 'does not exist.')
exit(1)
else:
files.append(f)
elif args.commits:
# Get files affected by specified number of commits.
command = ['git', 'diff', '--name-only', 'HEAD~' + args.commits]
files = [f.decode('utf-8')
for f in subprocess.check_output(command).splitlines()]
# Will examine dissector files only
files = list(filter(lambda f : is_dissector_file(f), files))
elif args.open:
# Unstaged changes.
command = ['git', 'diff', '--name-only']
files = [f.decode('utf-8')
for f in subprocess.check_output(command).splitlines()]
# Only interested in dissector files.
files = list(filter(lambda f : is_dissector_file(f), files))
# Staged changes.
command = ['git', 'diff', '--staged', '--name-only']
files_staged = [f.decode('utf-8')
for f in subprocess.check_output(command).splitlines()]
# Only interested in dissector files.
files_staged = list(filter(lambda f : is_dissector_file(f), files_staged))
for f in files_staged:
if not f in files:
files.append(f)
else:
# Find all dissector files from folder.
files = findDissectorFilesInFolder(os.path.join('epan', 'dissectors'))
files += findDissectorFilesInFolder(os.path.join('plugins', 'epan'), recursive=True)
files += findDissectorFilesInFolder(os.path.join('epan', 'dissectors', 'asn1'), recursive=True)
# If scanning a subset of files, list them here.
print('Examining:')
if args.file or args.commits or args.open:
if files:
print(' '.join(files), '\n')
else:
print('No files to check.\n')
else:
print('All dissectors\n')
# Now check the chosen files
for f in files:
if should_exit:
exit(1)
if not isGeneratedFile(f):
checkFile(f)
# Show summary.
print(warnings_found, 'warnings found')
if errors_found:
print(errors_found, 'errors found')
exit(1)
|
