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v0.5.1
v0.5.1
https://github.com/python/cpython
Revision 30e769382dfb67a68fe8e6bfe8509addb4aa9514 authored by Miss Islington (bot) on 04 February 2020, 21:41:55 UTC, committed by GitHub on 04 February 2020, 21:41:55 UTC
When called on a closed object, readinto() segfaults on account of a write to a freed buffer: ==220553== Process terminating with default action of signal 11 (SIGSEGV): dumping core ==220553== Access not within mapped region at address 0x2A ==220553== at 0x48408A0: memmove (vg_replace_strmem.c:1272) ==220553== by 0x58DB0C: _buffered_readinto_generic (bufferedio.c:972) ==220553== by 0x58DCBA: _io__Buffered_readinto_impl (bufferedio.c:1053) ==220553== by 0x58DCBA: _io__Buffered_readinto (bufferedio.c.h:253) Reproducer: reader = open ("/dev/zero", "rb") _void = reader.read (42) reader.close () reader.readinto (bytearray (42)) GH-GH-GH- BANG! The problem exists since 2012 when commit dc469454ec added code to free the read buffer on close(). Signed-off-by: Philipp Gesang <philipp.gesang@intra2net.com> (cherry picked from commit cb1c0746f277052e45a60d6c436a765e34722821) Co-authored-by: Philipp Gesang <phg@phi-gamma.net>
1 parent 9a740b6
Tip revision: 30e769382dfb67a68fe8e6bfe8509addb4aa9514 authored by Miss Islington (bot) on 04 February 2020, 21:41:55 UTC
closes bpo-39510: Fix use-after-free in BufferedReader.readinto() (GH-18295)
closes bpo-39510: Fix use-after-free in BufferedReader.readinto() (GH-18295)
Tip revision: 30e7693
pystrhex.c
/* bytes to hex implementation */
#include "Python.h"
#include "pystrhex.h"
static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
const PyObject* sep, int bytes_per_sep_group,
const int return_bytes)
{
PyObject *retval;
Py_UCS1* retbuf;
Py_ssize_t i, j, resultlen = 0;
Py_UCS1 sep_char = 0;
unsigned int abs_bytes_per_sep;
if (sep) {
Py_ssize_t seplen = PyObject_Length((PyObject*)sep);
if (seplen < 0) {
return NULL;
}
if (seplen != 1) {
PyErr_SetString(PyExc_ValueError, "sep must be length 1.");
return NULL;
}
if (PyUnicode_Check(sep)) {
if (PyUnicode_READY(sep))
return NULL;
if (PyUnicode_KIND(sep) != PyUnicode_1BYTE_KIND) {
PyErr_SetString(PyExc_ValueError, "sep must be ASCII.");
return NULL;
}
sep_char = PyUnicode_READ_CHAR(sep, 0);
} else if (PyBytes_Check(sep)) {
sep_char = PyBytes_AS_STRING(sep)[0];
} else {
PyErr_SetString(PyExc_TypeError, "sep must be str or bytes.");
return NULL;
}
if (sep_char > 127 && !return_bytes) {
PyErr_SetString(PyExc_ValueError, "sep must be ASCII.");
return NULL;
}
} else {
bytes_per_sep_group = 0;
}
assert(arglen >= 0);
abs_bytes_per_sep = abs(bytes_per_sep_group);
if (bytes_per_sep_group && arglen > 0) {
/* How many sep characters we'll be inserting. */
resultlen = (arglen - 1) / abs_bytes_per_sep;
}
/* Bounds checking for our Py_ssize_t indices. */
if (arglen >= PY_SSIZE_T_MAX / 2 - resultlen) {
return PyErr_NoMemory();
}
resultlen += arglen * 2;
if ((size_t)abs_bytes_per_sep >= (size_t)arglen) {
bytes_per_sep_group = 0;
abs_bytes_per_sep = 0;
}
if (return_bytes) {
/* If _PyBytes_FromSize() were public we could avoid malloc+copy. */
retbuf = (Py_UCS1*) PyMem_Malloc(resultlen);
if (!retbuf)
return PyErr_NoMemory();
retval = NULL; /* silence a compiler warning, assigned later. */
} else {
retval = PyUnicode_New(resultlen, 127);
if (!retval)
return NULL;
retbuf = PyUnicode_1BYTE_DATA(retval);
}
/* Hexlify */
for (i=j=0; i < arglen; ++i) {
assert(j < resultlen);
unsigned char c;
c = (argbuf[i] >> 4) & 0xf;
retbuf[j++] = Py_hexdigits[c];
c = argbuf[i] & 0xf;
retbuf[j++] = Py_hexdigits[c];
if (bytes_per_sep_group && i < arglen - 1) {
Py_ssize_t anchor;
anchor = (bytes_per_sep_group > 0) ? (arglen - 1 - i) : (i + 1);
if (anchor % abs_bytes_per_sep == 0) {
retbuf[j++] = sep_char;
}
}
}
assert(j == resultlen);
if (return_bytes) {
retval = PyBytes_FromStringAndSize((const char *)retbuf, resultlen);
PyMem_Free(retbuf);
}
#ifdef Py_DEBUG
else {
assert(_PyUnicode_CheckConsistency(retval, 1));
}
#endif
return retval;
}
PyObject * _Py_strhex(const char* argbuf, const Py_ssize_t arglen)
{
return _Py_strhex_impl(argbuf, arglen, NULL, 0, 0);
}
/* Same as above but returns a bytes() instead of str() to avoid the
* need to decode the str() when bytes are needed. */
PyObject * _Py_strhex_bytes(const char* argbuf, const Py_ssize_t arglen)
{
return _Py_strhex_impl(argbuf, arglen, NULL, 0, 1);
}
/* These variants include support for a separator between every N bytes: */
PyObject * _Py_strhex_with_sep(const char* argbuf, const Py_ssize_t arglen, const PyObject* sep, const int bytes_per_group)
{
return _Py_strhex_impl(argbuf, arglen, sep, bytes_per_group, 0);
}
/* Same as above but returns a bytes() instead of str() to avoid the
* need to decode the str() when bytes are needed. */
PyObject * _Py_strhex_bytes_with_sep(const char* argbuf, const Py_ssize_t arglen, const PyObject* sep, const int bytes_per_group)
{
return _Py_strhex_impl(argbuf, arglen, sep, bytes_per_group, 1);
}
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