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# TODO: Make progressive output work
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# Question: Will having a large buffer size stop progressive output from
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# working on smaller output
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CGI_BLOCK_SIZE = 65535
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PATH = "/usr/local/bin:/usr/bin:/bin"
41
def interpret_file(req, owner, jail_dir, filename, interpreter, gentle=True):
43
def interpret_file(req, owner, jail_dir, filename, interpreter, gentle=True,
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"""Serves a file by interpreting it using one of IVLE's builtin
43
46
interpreters. All interpreters are intended to run in the user's jail. The
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jail location is provided as an argument to the interpreter but it is up
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52
jail_dir: Absolute path to the user's jail.
50
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filename: Absolute filename within the user's jail.
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interpreter: A function object to call.
56
overrides: A dict mapping env var names to strings, to override arbitrary
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environment variables in the resulting CGI environent.
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# We can't test here whether or not the target file actually exists,
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# because the apache user may not have permission. Instead we have to
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self.headers = {} # Header names : values
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def execute_cgi(interpreter, owner, jail_dir, working_dir, script_path,
98
req, gentle, overrides=None):
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trampoline: Full path on the local system to the CGI wrapper program
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f.seek(0) # Rewind, for reading
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# Set up the environment
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# This automatically asks mod_python to load up the CGI variables into the
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# environment (which is a good first approximation)
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old_env = os.environ.copy()
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for k in os.environ.keys():
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for (k,v) in req.get_cgi_environ().items():
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fixup_environ(req, script_path, owner)
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environ = cgi_environ(req, script_path, owner, overrides=overrides)
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# usage: tramp uid jail_dir working_dir script_path
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cmd_line = [trampoline, str(owner.unixid),
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for s in cmd_line]
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pid = subprocess.Popen(cmd_line,
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stdin=f, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
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# Restore the environment
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for k in os.environ.keys():
157
for (k,v) in old_env.items():
154
cwd=tramp_dir, env=environ)
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# We don't want any output! Bail out after the process terminates.
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if len(split) == 1:
228
224
split = headers.split('\n', 1)
230
# Is this an internal IVLE error condition?
231
hs = cgiflags.headers
232
if 'X-IVLE-Error-Type' in hs:
233
t = hs['X-IVLE-Error-Type']
234
if t == IVLEError.__name__:
235
raise IVLEError(int(hs['X-IVLE-Error-Code']),
236
hs['X-IVLE-Error-Message'])
226
# If not executing in gentle mode (which presents CGI violations
227
# to users nicely), check if this an internal IVLE error
229
if not cgiflags.gentle:
230
hs = cgiflags.headers
231
if 'X-IVLE-Error-Type' in hs:
239
233
raise IVLEJailError(hs['X-IVLE-Error-Type'],
240
234
hs['X-IVLE-Error-Message'],
241
235
hs['X-IVLE-Error-Info'])
243
raise IVLEError(500, 'bad error headers written by CGI')
237
raise AssertionError("Bad error headers written by CGI.")
245
239
# Check to make sure the required headers were written
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240
if cgiflags.wrote_html_warning or not cgiflags.gentle:
300
294
process_cgi_output(req, line + '\n', cgiflags)
297
# Check if CGI field-name is valid
298
CGI_SEPERATORS = set(['(', ')', '<', '>', '@', ',', ';', ':', '\\', '"',
299
'/', '[', ']', '?', '=', '{', '}', ' ', '\t'])
300
if any((char in CGI_SEPERATORS for char in name)):
302
if not cgiflags.gentle:
303
message = """An unexpected server error has occured."""
306
# Header contained illegal characters
307
message = """You printed an invalid CGI header. CGI header
308
field-names can not contain any of the following characters:
309
<code>( ) < > @ , ; : \\ " / [ ] ? = { } <em>SPACE
311
write_html_warning(req, message, warning=warning)
312
cgiflags.wrote_html_warning = True
313
# Handle the rest of this line as normal data
314
process_cgi_output(req, line + '\n', cgiflags)
303
317
# Read CGI headers
304
318
value = value.strip()
305
319
if name == "Content-Type":
362
376
# python-server-page
365
def fixup_environ(req, script_path, user):
366
"""Assuming os.environ has been written with the CGI variables from
367
apache, make a few changes for security and correctness.
379
def cgi_environ(req, script_path, user, overrides=None):
380
"""Gets CGI variables from apache and makes a few changes for security and
369
383
Does not modify req, only reads it.
385
overrides: A dict mapping env var names to strings, to override arbitrary
386
environment variables in the resulting CGI environent.
372
389
# Comments here are on the heavy side, explained carefully for security
373
390
# reasons. Please read carefully before making changes.
392
# This automatically asks mod_python to load up the CGI variables into the
393
# environment (which is a good first approximation)
394
for (k,v) in req.get_cgi_environ().items():
375
397
# Remove DOCUMENT_ROOT and SCRIPT_FILENAME. Not part of CGI spec and
376
398
# exposes unnecessary details about server.
447
473
stdin=subprocess.PIPE, stdout=subprocess.PIPE,
448
474
stderr=subprocess.PIPE, cwd=tramp_dir, close_fds=True,
449
475
env={'HOME': os.path.join('/home', user.login),
450
'PATH': os.environ['PATH'],
451
477
'USER': user.login,
452
478
'LOGNAME': user.login})
458
484
raise ExecutionError('subprocess ended with code %d, stderr: "%s"' %
459
485
(exitcode, stderr))
460
486
return (stdout, stderr)
488
def jail_call(req, cgi_script, script_name, query_string=None,
489
request_method="GET", extra_overrides=None):
491
Makes a call to a CGI script inside the jail from outside the jail.
492
This can be used to allow Python scripts to access jail-only functions and
493
data without having to perform a full API request.
495
req: A Request object (will not be written to or attributes modified).
496
cgi_script: Path to cgi script outside of jail.
497
eg: os.path.join(req.config['paths']['share'],
498
'services/fileservice')
499
script_name: Name to set as SCRIPT_NAME for the CGI environment.
501
query_string: Query string to set as QUERY_STRING for the CGI environment.
502
eg: "action=svnrepostat&path=/users/studenta/"
503
request_method: Method to set as REQUEST_METHOD for the CGI environment.
504
eg: "POST". Defaults to "GET".
505
extra_overrides: A dict mapping env var names to strings, to override
506
arbitrary environment variables in the resulting CGI environent.
508
Returns a triple (status_code, content_type, contents).
510
interp_object = interpreter_objects["cgi-python"]
511
user_jail_dir = os.path.join(req.config['paths']['jails']['mounts'],
514
"SCRIPT_NAME": script_name,
515
"QUERY_STRING": query_string,
516
"REQUEST_URI": "%s%s%s" % (script_name, "?" if query_string else "",
518
"REQUEST_METHOD": request_method,
520
if extra_overrides is not None:
521
overrides.update(extra_overrides)
522
result = DummyReq(req)
523
interpret_file(result, req.user, user_jail_dir, cgi_script, interp_object,
524
gentle=False, overrides=overrides)
525
return result.status, result.content_type, result.getvalue()
527
class DummyReq(StringIO.StringIO):
528
"""A dummy request object, built from a real request object, which can be
529
used like a req but doesn't mutate the existing request.
530
(Used for reading CGI responses as strings rather than forwarding their
531
output to the current request.)
533
def __init__(self, req):
534
StringIO.StringIO.__init__(self)
536
def get_cgi_environ(self):
537
return self._real_req.get_cgi_environ()
538
def __getattr__(self, name):
539
return getattr(self._real_req, name)
added
removed
ivle/interpret.py
