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Added checks for integer overflows, contributed by Google. Some are

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only available if asserts are left in the code, in cases where they
can't be triggered from Python code.
This commit is contained in:
Martin v. Löwis 2008-02-14 11:26:18 +00:00
parent abcb59a1d8
commit 73c01d4101
25 changed files with 464 additions and 59 deletions
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60
Python/bltinmodule.c
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@ -2496,11 +2496,43 @@ filterstring(PyObject *func, PyObject *strobj)
PyString_AS_STRING(item)[0];
} else {
/* do we need more space? */
Py_ssize_t need = j + reslen + len-i-1;
Py_ssize_t need = j;
/* calculate space requirements while checking for overflow */
if (need > PY_SSIZE_T_MAX - reslen) {
Py_DECREF(item);
goto Fail_1;
}
need += reslen;
if (need > PY_SSIZE_T_MAX - len) {
Py_DECREF(item);
goto Fail_1;
}
need += len;
if (need <= i) {
Py_DECREF(item);
goto Fail_1;
}
need = need - i - 1;
assert(need >= 0);
assert(outlen >= 0);
if (need > outlen) {
/* overallocate, to avoid reallocations */
if (need<2*outlen)
if (outlen > PY_SSIZE_T_MAX / 2) {
Py_DECREF(item);
return NULL;
}
if (need<2*outlen) {
need = 2*outlen;
}
if (_PyString_Resize(&result, need)) {
Py_DECREF(item);
return NULL;
@ -2592,11 +2624,31 @@ filterunicode(PyObject *func, PyObject *strobj)
else {
/* do we need more space? */
Py_ssize_t need = j + reslen + len - i - 1;
/* check that didnt overflow */
if ((j > PY_SSIZE_T_MAX - reslen) ||
((j + reslen) > PY_SSIZE_T_MAX - len) ||
((j + reslen + len) < i) ||
((j + reslen + len - i) <= 0)) {
Py_DECREF(item);
return NULL;
}
assert(need >= 0);
assert(outlen >= 0);
if (need > outlen) {
/* overallocate,
to avoid reallocations */
if (need < 2 * outlen)
need = 2 * outlen;
if (need < 2 * outlen) {
if (outlen > PY_SSIZE_T_MAX / 2) {
Py_DECREF(item);
return NULL;
} else {
need = 2 * outlen;
}
}
if (PyUnicode_Resize(
&result, need) < 0) {
Py_DECREF(item);