diff options
| -rw-r--r-- | Doc/library/re.rst | 3 | ||||
| -rw-r--r-- | Lib/test/test_re.py | 5 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2022-10-27-12-56-38.gh-issue-98740.ZoqqGM.rst | 3 | ||||
| -rw-r--r-- | Modules/_sre/sre.c | 56 |
4 files changed, 40 insertions, 27 deletions
diff --git a/Doc/library/re.rst b/Doc/library/re.rst index 5b304f7..0e7dda0 100644 --- a/Doc/library/re.rst +++ b/Doc/library/re.rst @@ -483,6 +483,9 @@ The special characters are: some fixed length. Patterns which start with negative lookbehind assertions may match at the beginning of the string being searched. +.. _re-conditional-expression: +.. index:: single: (?(; in regular expressions + ``(?(id/name)yes-pattern|no-pattern)`` Will try to match with ``yes-pattern`` if the group with given *id* or *name* exists, and with ``no-pattern`` if it doesn't. ``no-pattern`` is diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py index 3f0f84e..11628a2 100644 --- a/Lib/test/test_re.py +++ b/Lib/test/test_re.py @@ -630,6 +630,11 @@ class ReTests(unittest.TestCase): self.checkPatternError(r'()(?(2)a)', "invalid group reference 2", 5) + def test_re_groupref_exists_validation_bug(self): + for i in range(256): + with self.subTest(code=i): + re.compile(r'()(?(1)\x%02x?)' % i) + def test_re_groupref_overflow(self): from re._constants import MAXGROUPS self.checkTemplateError('()', r'\g<%s>' % MAXGROUPS, 'xx', diff --git a/Misc/NEWS.d/next/Library/2022-10-27-12-56-38.gh-issue-98740.ZoqqGM.rst b/Misc/NEWS.d/next/Library/2022-10-27-12-56-38.gh-issue-98740.ZoqqGM.rst new file mode 100644 index 0000000..887d506 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-10-27-12-56-38.gh-issue-98740.ZoqqGM.rst @@ -0,0 +1,3 @@ +Fix internal error in the :mod:`re` module which in very rare circumstances +prevented compilation of a regular expression containing a :ref:`conditional +expression <re-conditional-expression>` without the "else" branch. diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c index aae0265..44039ce 100644 --- a/Modules/_sre/sre.c +++ b/Modules/_sre/sre.c @@ -1623,7 +1623,7 @@ bad_template: #endif /* Report failure */ -#define FAIL do { VTRACE(("FAIL: %d\n", __LINE__)); return 0; } while (0) +#define FAIL do { VTRACE(("FAIL: %d\n", __LINE__)); return -1; } while (0) /* Extract opcode, argument, or skip count from code array */ #define GET_OP \ @@ -1647,7 +1647,7 @@ bad_template: skip = *code; \ VTRACE(("%lu (skip to %p)\n", \ (unsigned long)skip, code+skip)); \ - if (skip-adj > (uintptr_t)(end - code)) \ + if (skip-adj > (uintptr_t)(end - code)) \ FAIL; \ code++; \ } while (0) @@ -1736,9 +1736,10 @@ _validate_charset(SRE_CODE *code, SRE_CODE *end) } } - return 1; + return 0; } +/* Returns 0 on success, -1 on failure, and 1 if the last op is JUMP. */ static int _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) { @@ -1816,7 +1817,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) case SRE_OP_IN_LOC_IGNORE: GET_SKIP; /* Stop 1 before the end; we check the FAILURE below */ - if (!_validate_charset(code, code+skip-2)) + if (_validate_charset(code, code+skip-2)) FAIL; if (code[skip-2] != SRE_OP_FAILURE) FAIL; @@ -1870,7 +1871,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) } /* Validate the charset */ if (flags & SRE_INFO_CHARSET) { - if (!_validate_charset(code, newcode-1)) + if (_validate_charset(code, newcode-1)) FAIL; if (newcode[-1] != SRE_OP_FAILURE) FAIL; @@ -1891,7 +1892,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) if (skip == 0) break; /* Stop 2 before the end; we check the JUMP below */ - if (!_validate_inner(code, code+skip-3, groups)) + if (_validate_inner(code, code+skip-3, groups)) FAIL; code += skip-3; /* Check that it ends with a JUMP, and that each JUMP @@ -1905,6 +1906,8 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) else if (code+skip-1 != target) FAIL; } + if (code != target) + FAIL; } break; @@ -1920,7 +1923,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) FAIL; if (max > SRE_MAXREPEAT) FAIL; - if (!_validate_inner(code, code+skip-4, groups)) + if (_validate_inner(code, code+skip-4, groups)) FAIL; code += skip-4; GET_OP; @@ -1940,7 +1943,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) FAIL; if (max > SRE_MAXREPEAT) FAIL; - if (!_validate_inner(code, code+skip-3, groups)) + if (_validate_inner(code, code+skip-3, groups)) FAIL; code += skip-3; GET_OP; @@ -1958,7 +1961,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) case SRE_OP_ATOMIC_GROUP: { GET_SKIP; - if (!_validate_inner(code, code+skip-2, groups)) + if (_validate_inner(code, code+skip-2, groups)) FAIL; code += skip-2; GET_OP; @@ -2010,24 +2013,17 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) to allow arbitrary jumps anywhere in the code; so we just look for a JUMP opcode preceding our skip target. */ - if (skip >= 3 && skip-3 < (uintptr_t)(end - code) && - code[skip-3] == SRE_OP_JUMP) - { - VTRACE(("both then and else parts present\n")); - if (!_validate_inner(code+1, code+skip-3, groups)) - FAIL; + VTRACE(("then part:\n")); + int rc = _validate_inner(code+1, code+skip-1, groups); + if (rc == 1) { + VTRACE(("else part:\n")); code += skip-2; /* Position after JUMP, at <skipno> */ GET_SKIP; - if (!_validate_inner(code, code+skip-1, groups)) - FAIL; - code += skip-1; - } - else { - VTRACE(("only a then part present\n")); - if (!_validate_inner(code+1, code+skip-1, groups)) - FAIL; - code += skip-1; + rc = _validate_inner(code, code+skip-1, groups); } + if (rc) + FAIL; + code += skip-1; break; case SRE_OP_ASSERT: @@ -2038,7 +2034,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) if (arg & 0x80000000) FAIL; /* Width too large */ /* Stop 1 before the end; we check the SUCCESS below */ - if (!_validate_inner(code+1, code+skip-2, groups)) + if (_validate_inner(code+1, code+skip-2, groups)) FAIL; code += skip-2; GET_OP; @@ -2046,6 +2042,12 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) FAIL; break; + case SRE_OP_JUMP: + if (code + 1 != end) + FAIL; + VTRACE(("JUMP: %d\n", __LINE__)); + return 1; + default: FAIL; @@ -2053,7 +2055,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) } VTRACE(("okay\n")); - return 1; + return 0; } static int @@ -2068,7 +2070,7 @@ _validate_outer(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups) static int _validate(PatternObject *self) { - if (!_validate_outer(self->code, self->code+self->codesize, self->groups)) + if (_validate_outer(self->code, self->code+self->codesize, self->groups)) { PyErr_SetString(PyExc_RuntimeError, "invalid SRE code"); return 0; |