Tags: xeger
Rating:
## Regexpire (Misc/PPC, 100p)
###ENG
[PL](#pl-version)
Task almost identical to https://github.com/p4-team/ctf/tree/master/2016-06-04-backdoor-ctf/ppc_isolve so we solved it pretty much the same way - with simplified xeger:
```python
import socket
from rstr import xeger
def recvuntil(s, tails):
data = ""
while True:
for tail in tails:
if tail in data:
return data
data += s.recv(1)
def main():
url = "misc.chal.csaw.io"
port = 8001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((url, port))
task1 = recvuntil(s, "\n")
print(task1)
while True:
task2 = recvuntil(s, "\n")
print(task2)
to_solve = task2[:-1]
if len(to_solve) != 0:
print("to solve = '%s'" % to_solve)
solution = xeger(to_solve)
print("solution = %s" % solution)
s.sendall(solution + "\n")
main()
```
With modifications to:
```python
ALPHABETS = {'printable': ['a'],
'letters': ['a'],
'uppercase': ['A'],
'lowercase': ['a'],
'digits': ['1'],
'punctuation': [','],
'nondigits': ['a'],
'nonletters': ['1'],
'whitespace': [' '],
'nonwhitespace': ['a'],
'normal': ['a'],
'word': ['a'],
'nonword': ['#'],
'postalsafe': string.ascii_letters + string.digits + ' .-#/',
'urlsafe': string.ascii_letters + string.digits + '-._~',
'domainsafe': string.ascii_letters + string.digits + '-'
}
```
because the server did not handle everything.
`flag{^regularly_express_yourself$}`
###PL version
Zadanie prawie identyczne jak https://github.com/p4-team/ctf/tree/master/2016-06-04-backdoor-ctf/ppc_isolve więc rozwiązaliśmy je tak samo, zmodyfikowanym xegerem:
```python
import socket
from rstr import xeger
def recvuntil(s, tails):
data = ""
while True:
for tail in tails:
if tail in data:
return data
data += s.recv(1)
def main():
url = "misc.chal.csaw.io"
port = 8001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((url, port))
task1 = recvuntil(s, "\n")
print(task1)
while True:
task2 = recvuntil(s, "\n")
print(task2)
to_solve = task2[:-1]
if len(to_solve) != 0:
print("to solve = '%s'" % to_solve)
solution = xeger(to_solve)
print("solution = %s" % solution)
s.sendall(solution + "\n")
main()
```
Z modyfikacją dla:
```python
ALPHABETS = {'printable': ['a'],
'letters': ['a'],
'uppercase': ['A'],
'lowercase': ['a'],
'digits': ['1'],
'punctuation': [','],
'nondigits': ['a'],
'nonletters': ['1'],
'whitespace': [' '],
'nonwhitespace': ['a'],
'normal': ['a'],
'word': ['a'],
'nonword': ['#'],
'postalsafe': string.ascii_letters + string.digits + ' .-#/',
'urlsafe': string.ascii_letters + string.digits + '-._~',
'domainsafe': string.ascii_letters + string.digits + '-'
}
```
Bo serwer nie wszystko dobrze parsował.
`flag{^regularly_express_yourself$}`
