durin42 edited the summary of this revision. durin42 retitled this revision from "sha1dc: initial implementation of Python extension (NOT READY)" to "sha1dc: initial implementation of Python extension". durin42 updated this revision to Diff 19119.
REPOSITORY rHG Mercurial CHANGES SINCE LAST UPDATE https://phab.mercurial-scm.org/D7815?vs=19116&id=19119 BRANCH default CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7815/new/ REVISION DETAIL https://phab.mercurial-scm.org/D7815 AFFECTED FILES mercurial/thirdparty/sha1dc/cext.c setup.py CHANGE DETAILS diff --git a/setup.py b/setup.py --- a/setup.py +++ b/setup.py @@ -1481,6 +1481,14 @@ ], ), Extension( + 'mercurial.thirdparty.sha1dc', + [ + 'mercurial/thirdparty/sha1dc/cext.c', + 'mercurial/thirdparty/sha1dc/lib/sha1.c', + 'mercurial/thirdparty/sha1dc/lib/ubc_check.c', + ], + ), + Extension( 'hgext.fsmonitor.pywatchman.bser', ['hgext/fsmonitor/pywatchman/bser.c'] ), RustStandaloneExtension( diff --git a/mercurial/thirdparty/sha1dc/cext.c b/mercurial/thirdparty/sha1dc/cext.c new file mode 100644 --- /dev/null +++ b/mercurial/thirdparty/sha1dc/cext.c @@ -0,0 +1,195 @@ +#define PY_SSIZE_T_CLEAN +#include <Python.h> + +#include "lib/sha1.h" + +#if PY_MAJOR_VERSION >= 3 +#define IS_PY3K +#endif + +/* helper to switch things like string literal depending on Python version */ +#ifdef IS_PY3K +#define PY23(py2, py3) py3 +#else +#define PY23(py2, py3) py2 +#endif + +static char sha1dc_doc[] = "Efficient detection of SHA1 collision constructs."; + +/* clang-format off */ +typedef struct { + PyObject_HEAD + SHA1_CTX ctx; +} pysha1ctx; +/* clang-format on */ + +static int pysha1ctx_init(pysha1ctx *self, PyObject *args) +{ + const char *data = NULL; + Py_ssize_t len; + + SHA1DCInit(&(self->ctx)); + /* We don't want "safe" sha1s, wherein sha1dc can give you a + different hash for something that's trying to give you a + collision. We just want to detect collisions. + */ + SHA1DCSetSafeHash(&(self->ctx), 0); + if (!PyArg_ParseTuple(args, PY23("|s#", "|y#"), &data, &len)) { + return -1; + } + if (data) { + SHA1DCUpdate(&(self->ctx), data, len); + } + return 0; +} + +static void pysha1ctx_dealloc(pysha1ctx *self) +{ + PyObject_Del(self); +} + +static PyObject *pysha1ctx_update(pysha1ctx *self, PyObject *args) +{ + const char *data; + Py_ssize_t len; + if (!PyArg_ParseTuple(args, PY23("s#", "y#"), &data, &len)) { + return NULL; + } + SHA1DCUpdate(&(self->ctx), data, len); + Py_RETURN_NONE; +} + +/* it is intentional that this take a ctx by value, as that clones the + context so we can keep using .update() without poisoning the state + with padding. +*/ +static int finalize(SHA1_CTX ctx, unsigned char *hash_out) { + if (SHA1DCFinal(hash_out, &ctx)) { + PyErr_SetString(PyExc_OverflowError, + "sha1 collision attack detected"); + return 0; + } + return 1; +} + +static PyObject *pysha1ctx_digest(pysha1ctx *self) +{ + unsigned char hash[20]; + if (!finalize(self->ctx, hash)) { + return NULL; + } + return PyBytes_FromStringAndSize((char *)hash, 20); +} + +static PyObject *pysha1ctx_hexdigest(pysha1ctx *self) +{ + unsigned char hash[20]; + if (!finalize(self->ctx, hash)) { + return NULL; + } + char hexhash[40]; + static const char hexdigit[] = "0123456789abcdef"; + for (int i = 0; i < 20; ++i) { + hexhash[i * 2] = hexdigit[hash[i] >> 4]; + hexhash[i * 2 + 1] = hexdigit[hash[i] & 15]; + } + return PyBytes_FromStringAndSize(hexhash, 40); +} + +static PyTypeObject sha1ctxType; + +static PyObject *pysha1ctx_copy(pysha1ctx *self) +{ + pysha1ctx *clone = (pysha1ctx *)PyObject_New(pysha1ctx, &sha1ctxType); + if (!clone) { + return NULL; + } + clone->ctx = self->ctx; + return (PyObject *)clone; +} + +static PyMethodDef pysha1ctx_methods[] = { + {"update", (PyCFunction)pysha1ctx_update, METH_VARARGS, + "Update this hash object's state with the provided bytes."}, + {"digest", (PyCFunction)pysha1ctx_digest, METH_NOARGS, + "Return the digest value as a string of binary data."}, + {"hexdigest", (PyCFunction)pysha1ctx_hexdigest, METH_NOARGS, + "Return the digest value as a string of hexadecimal digits."}, + {"copy", (PyCFunction)pysha1ctx_copy, METH_NOARGS, + "Return a copy of the hash object."}, + {NULL}, +}; + +/* clang-format off */ +static PyTypeObject sha1ctxType = { + PyVarObject_HEAD_INIT(NULL, 0) /* header */ + "sha1dc.sha1", /* tp_name */ + sizeof(pysha1ctx), /* tp_basicsize */ + 0, /* tp_itemsize */ + (destructor)pysha1ctx_dealloc, /* tp_dealloc */ + 0, /* tp_print */ + 0, /* tp_getattr */ + 0, /* tp_setattr */ + 0, /* tp_compare */ + 0, /* tp_repr */ + 0, /* tp_as_number */ + 0, /* tp_as_sequence */ + 0, /* tp_as_mapping */ + 0, /* tp_hash */ + 0, /* tp_call */ + 0, /* tp_str */ + 0, /* tp_getattro */ + 0, /* tp_setattro */ + 0, /* tp_as_buffer */ + Py_TPFLAGS_DEFAULT, /* tp_flags */ + "sha1 implementation that looks for collisions", /* tp_doc */ + 0, /* tp_traverse */ + 0, /* tp_clear */ + 0, /* tp_richcompare */ + 0, /* tp_weaklistoffset */ + 0, /* tp_iter */ + 0, /* tp_iternext */ + pysha1ctx_methods, /* tp_methods */ + 0, /* tp_members */ + 0, /* tp_getset */ + 0, /* tp_base */ + 0, /* tp_dict */ + 0, /* tp_descr_get */ + 0, /* tp_descr_set */ + 0, /* tp_dictoffset */ + (initproc)pysha1ctx_init, /* tp_init */ + 0, /* tp_alloc */ +}; +/* clang-format on */ + +static PyMethodDef methods[] = { + {NULL, NULL}, +}; + +static void module_init(PyObject *mod) +{ + sha1ctxType.tp_new = PyType_GenericNew; + if (PyType_Ready(&sha1ctxType) < 0) + return; + Py_INCREF(&sha1ctxType); + + PyModule_AddObject(mod, "sha1", (PyObject *)&sha1ctxType); +} + +#ifdef IS_PY3K +static struct PyModuleDef sha1dc_module = {PyModuleDef_HEAD_INIT, "sha1dc", + sha1dc_doc, -1, methods}; + +PyMODINIT_FUNC PyInit_sha1dc(void) +{ + PyObject *mod = PyModule_Create(&sha1dc_module); + module_init(mod); + return mod; +} +#else +PyMODINIT_FUNC initsha1dc(void) +{ + PyObject *mod = Py_InitModule3("sha1dc", methods, sha1dc_doc); + module_init(mod); +} +#endif To: durin42, #hg-reviewers Cc: spectral, mjpieters, mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
