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* gh-95778: Correctly pre-check for int-to-str conversion (GH-96537)Miss Islington (bot)2022-09-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Converting a large enough `int` to a decimal string raises `ValueError` as expected. However, the raise comes _after_ the quadratic-time base-conversion algorithm has run to completion. For effective DOS prevention, we need some kind of check before entering the quadratic-time loop. Oops! =) The quick fix: essentially we catch _most_ values that exceed the threshold up front. Those that slip through will still be on the small side (read: sufficiently fast), and will get caught by the existing check so that the limit remains exact. The justification for the current check. The C code check is: ```c max_str_digits / (3 * PyLong_SHIFT) <= (size_a - 11) / 10 ``` In GitHub markdown math-speak, writing $M$ for `max_str_digits`, $L$ for `PyLong_SHIFT` and $s$ for `size_a`, that check is: $$\left\lfloor\frac{M}{3L}\right\rfloor \le \left\lfloor\frac{s - 11}{10}\right\rfloor$$ From this it follows that $$\frac{M}{3L} < \frac{s-1}{10}$$ hence that $$\frac{L(s-1)}{M} > \frac{10}{3} > \log_2(10).$$ So $$2^{L(s-1)} > 10^M.$$ But our input integer $a$ satisfies $|a| \ge 2^{L(s-1)}$, so $|a|$ is larger than $10^M$. This shows that we don't accidentally capture anything _below_ the intended limit in the check. <!-- gh-issue-number: gh-95778 --> * Issue: gh-95778 <!-- /gh-issue-number --> Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org> (cherry picked from commit b126196838bbaf5f4d35120e0e6bcde435b0b480) Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
* [3.11] gh-95778: CVE-2020-10735: Prevent DoS by very large int() (#96500)Gregory P. Smith2022-09-021-0/+35
| | | | | | | | | | | | | | | | | | Integer to and from text conversions via CPython's bignum `int` type is not safe against denial of service attacks due to malicious input. Very large input strings with hundred thousands of digits can consume several CPU seconds. This PR comes fresh from a pile of work done in our private PSRT security response team repo. This backports https://github.com/python/cpython/pull/96499 aka 511ca9452033ef95bc7d7fc404b8161068226002 Signed-off-by: Christian Heimes [Red Hat] <christian@python.org> Tons-of-polishing-up-by: Gregory P. Smith [Google] <greg@krypto.org> Reviews via the private PSRT repo via many others (see the NEWS entry in the PR). <!-- gh-issue-number: gh-95778 --> * Issue: gh-95778 <!-- /gh-issue-number --> I wrote up [a one pager for the release managers](https://docs.google.com/document/d/1KjuF_aXlzPUxTK4BMgezGJ2Pn7uevfX7g0_mvgHlL7Y/edit#).
* bpo-47012: speed up iteration of bytes and bytearray (GH-31867)Kumar Aditya2022-03-231-2/+8
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* bpo-46417: Finalize structseq types at exit (GH-30645)Victor Stinner2022-01-211-0/+1
| | | | | | | | | | | | | | | | | | Add _PyStructSequence_FiniType() and _PyStaticType_Dealloc() functions to finalize a structseq static type in Py_Finalize(). Currrently, these functions do nothing if Python is built in release mode. Clear static types: * AsyncGenHooksType: sys.set_asyncgen_hooks() * FlagsType: sys.flags * FloatInfoType: sys.float_info * Hash_InfoType: sys.hash_info * Int_InfoType: sys.int_info * ThreadInfoType: sys.thread_info * UnraisableHookArgsType: sys.unraisablehook * VersionInfoType: sys.version * WindowsVersionType: sys.getwindowsversion()
* bpo-45953: Statically initialize the small ints. (gh-30092)Eric Snow2021-12-141-3/+8
| | | | | | | The array of small PyLong objects has been statically declared. Here I also statically initialize them. Consequently they are no longer initialized dynamically during runtime init. I've also moved them under a new sub-struct in _PyRuntimeState, in preparation for static allocation and initialization of other global objects. https://bugs.python.org/issue45953
* bpo-46008: Make runtime-global object/type lifecycle functions and state ↵Eric Snow2021-12-091-3/+13
| | | | | | | | | | | | consistent. (gh-29998) This change is strictly renames and moving code around. It helps in the following ways: * ensures type-related init functions focus strictly on one of the three aspects (state, objects, types) * passes in PyInterpreterState * to all those functions, simplifying work on moving types/objects/state to the interpreter * consistent naming conventions help make what's going on more clear * keeping API related to a type in the corresponding header file makes it more obvious where to look for it https://bugs.python.org/issue46008
* bpo-45510: Specialize BINARY_SUBTRACT (GH-29523)Dong-hee Na2021-11-181-0/+1
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* bpo-45691: Make array of small ints static to fix use-after-free error. ↵Mark Shannon2021-11-031-15/+2
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* Store actual ints, not pointers to them in the interpreter state. (GH-29274)Mark Shannon2021-10-281-1/+1
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* bpo-35134: Add Include/cpython/longobject.h (GH-29044)Victor Stinner2021-10-191-0/+26
| | | | | | | | | | Move Include/longobject.h non-limited API to a new Include/cpython/longobject.h header file. Move the following definitions to the internal C API: * _PyLong_DigitValue * _PyLong_FormatAdvancedWriter() * _PyLong_FormatWriter()
* bpo-45367: Specialize BINARY_MULTIPLY (GH-28727)Dennis Sweeney2021-10-141-0/+1
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* bpo-44945: Specialize BINARY_ADD (GH-27967)Mark Shannon2021-08-271-0/+2
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* bpo-43687: Py_Initialize() creates singletons earlier (GH-25147)Victor Stinner2021-04-021-2/+2
| | | | | Reorganize pycore_interp_init() to initialize singletons before the the first PyType_Ready() call. Fix an issue when Python is configured using --without-doc-strings.
* bpo-43268: Replace _PyThreadState_GET() with _PyInterpreterState_GET() ↵Victor Stinner2021-02-191-5/+2
| | | | | | | | | | | (GH-24576) Replace _PyThreadState_GET() with _PyInterpreterState_GET() in functions which only need the current interpreter, but don't need the current Python thread state. Replace also _PyThreadState_UncheckedGet() with _PyThreadState_GET() in faulthandler.c, since _PyThreadState_UncheckedGet() is just an alias to _PyThreadState_GET() in practice.
* bpo-42161: Add _PyLong_GetZero() and _PyLong_GetOne() (GH-22993)Victor Stinner2020-10-261-0/+43
Add _PyLong_GetZero() and _PyLong_GetOne() functions and a new internal pycore_long.h header file. Python cannot be built without small integer singletons anymore.