Various errors with polybori including segmentation fault

[kliem]

Looks a bit like #17143.

sage: def foo(): 
....:      sr = mq.SR(2,1,1,4,gf2=True, polybori=True)    
....:      F, s = sr.polynomial_system()      
....:      I = F.ideal()       
....:      return I.groebner_basis()
....:
sage: set_random_seed(0)                                                                                                              
sage: foo()                                                                                                                           
Polynomial Sequence with 36 Polynomials in 36 Variables
sage: foo()                                                                                                                           
terminate called recursively
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-68-c19b6d9633cf> in <module>
----> 1 foo()

<ipython-input-65-541c6b0ff85c> in foo()
      3      F, s = sr.polynomial_system()
      4      I = F.ideal()
----> 5      return I.groebner_basis()
      6 

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/rings/polynomial/pbori/pbori.pyx in sage.rings.polynomial.pbori.pbori.BooleanPolynomialIdeal.groebner_basis (build/cythonized/sage/rings/polynomial/pbori/pbori.cpp:42385)()
   4999             if "redsb" not in kwds:
   5000                 kwds["redsb"]=True
-> 5001             sig_on()
   5002             gb = self._groebner_basis(**kwds)
   5003             sig_off()

RuntimeError: Aborted
sage: foo()                                                                                                                           
Polynomial Sequence with 36 Polynomials in 36 Variables
sage: foo()                                                                                                                           
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-70-c19b6d9633cf> in <module>
----> 1 foo()

<ipython-input-65-541c6b0ff85c> in foo()
      1 def foo():
      2      sr = mq.SR(Integer(2),Integer(1),Integer(1),Integer(4),gf2=True, polybori=True)
----> 3      F, s = sr.polynomial_system()
      4      I = F.ideal()
      5      return I.groebner_basis()

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/crypto/mq/sr.py in polynomial_system(self, P, K, C)
   2137 
   2138         if ciphertext is None:
-> 2139             ciphertext = self(plaintext, key)
   2140         elif ciphertext is False:
   2141             raise TypeError("type %s of C not understood"%(type(ciphertext)))

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/crypto/mq/sr.py in __call__(self, P, K)
   1386                 print("R[%02d].m_col   %s"%(self.n, self.hex_str_vector(P)))
   1387 
-> 1388         K = KeyExpansion(K, self._n)
   1389         if get_verbose() >= 2:
   1390             print("R[%02d].k_sch   %s"%(self.n, self.hex_str_vector(K)))

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/crypto/mq/sr.py in key_schedule(self, kj, i)
   1179 
   1180         if r == 1:
-> 1181             s0 = SubByte(kj[0, c-1])
   1182 
   1183             if c > 1:

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/crypto/mq/sr.py in sub_byte(self, b)
    726         if not b:
    727             if not self._allow_zero_inversions:
--> 728                 raise ZeroDivisionError("A zero inversion occurred during an encryption or key schedule.")
    729             else:
    730                 return self.sbox_constant()

ZeroDivisionError: A zero inversion occurred during an encryption or key schedule.

Depending on the session, the RuntimeError can also be a SignalError with segmentation fault.

Component: algebra

Issue created by migration from https://trac.sagemath.org/ticket/32083

[kliem]

comment:1

foo is a doctest from src/sage/rings/polynomial/pbori/pbori.pyx that I'm going to mark not tested in #29979).