[3.14] gh-143602: Fix duplicate buffer exports in io.BytesIO.write (#143629) (#143872)
gh-143602: Fix duplicate buffer exports in io.BytesIO.write (#143629)
Fix an inconsistency issue in io.BytesIO.write() where the buffer was exported
twice, which could lead to unexpected data overwrites and position drift when
the buffer changes between exports.
(cherry picked from commit c461aa99e2)
(cherry picked from commit 1241432150)
Co-authored-by: zhong <60600792+superboy-zjc@users.noreply.github.com>
PyObject_GetBuffer() can execute user code (e.g. via __buffer__), which may
close or otherwise mutate a BytesIO object while write() or writelines()
is in progress. This could invalidate the internal buffer and lead to a
use-after-free.
Ensure that PyObject_GetBuffer() is called before validation checks.
(cherry picked from commit 6d54b6ac7d)
Co-authored-by: zhong <60600792+superboy-zjc@users.noreply.github.com>
Fix error in assertion which causes failure if pos is equal to PY_SSIZE_T_MAX.
Fix undefined behavior in read() and readinto() if pos is larger that the size
of the underlying buffer.
(cherry picked from commit 7d54374f9c)
We already intern and immortalize most string constants. In the
free-threaded build, other constants can be a source of reference count
contention because they are shared by all threads running the same code
objects.
It no longer spends much time doing complex calculations and no
longer consumes much memory for creating large constants that will
be dropped later.
This fixes also bpo-21074.
This matches the usage of ZipFile and BufferedWriter. This still requires
return values to be bytes() objects.
Also document and test that the write() methods should only access their
argument before they return.
I have compared output between pre- and post-patch runs of these tests
to make sure there's nothing missing and nothing broken, on both
Windows and Linux. The only differences I found were actually tests
that were previously *not* run.
frombytes() and tobytes(), respectively, to avoid confusion. Furthermore,
array.frombytes(), array.extend() as well as the array.array()
constructor now accept bytearray objects. Patch by Thomas Jollans.
svn+ssh://pythondev@svn.python.org/python/trunk
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r77890 | antoine.pitrou | 2010-01-31 23:26:04 +0100 (dim., 31 janv. 2010) | 7 lines
- Issue #6939: Fix file I/O objects in the `io` module to keep the original
file position when calling `truncate()`. It would previously change the
file position to the given argument, which goes against the tradition of
ftruncate() and other truncation APIs. Patch by Pascal Chambon.
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