[Python-checkins] gh-82052: Don't send partial UTF-8 sequences to the Windows API (GH-101103)
miss-islington
webhook-mailer at python.org
Tue Jan 17 14:53:51 EST 2023
https://github.com/python/cpython/commit/940763140f7519a125229782ca7a095af01edda4
commit: 940763140f7519a125229782ca7a095af01edda4
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2023-01-17T11:53:45-08:00
summary:
gh-82052: Don't send partial UTF-8 sequences to the Windows API (GH-101103)
Don't send partial UTF-8 sequences to the Windows API
(cherry picked from commit f34176b77f222726d901595968a4b44456186da4)
Co-authored-by: Paul Moore <p.f.moore at gmail.com>
files:
A Misc/NEWS.d/next/Windows/2023-01-17-18-17-58.gh-issue-82052.mWyysT.rst
M Modules/_io/winconsoleio.c
diff --git a/Misc/NEWS.d/next/Windows/2023-01-17-18-17-58.gh-issue-82052.mWyysT.rst b/Misc/NEWS.d/next/Windows/2023-01-17-18-17-58.gh-issue-82052.mWyysT.rst
new file mode 100644
index 000000000000..4f7ab200b85c
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2023-01-17-18-17-58.gh-issue-82052.mWyysT.rst
@@ -0,0 +1 @@
+Fixed an issue where writing more than 32K of Unicode output to the console screen in one go can result in mojibake.
diff --git a/Modules/_io/winconsoleio.c b/Modules/_io/winconsoleio.c
index 460f2d3fa071..7d605d9f9034 100644
--- a/Modules/_io/winconsoleio.c
+++ b/Modules/_io/winconsoleio.c
@@ -956,7 +956,7 @@ _io__WindowsConsoleIO_write_impl(winconsoleio *self, Py_buffer *b)
{
BOOL res = TRUE;
wchar_t *wbuf;
- DWORD len, wlen, n = 0;
+ DWORD len, wlen, orig_len, n = 0;
HANDLE handle;
if (self->fd == -1)
@@ -986,6 +986,21 @@ _io__WindowsConsoleIO_write_impl(winconsoleio *self, Py_buffer *b)
have to reduce and recalculate. */
while (wlen > 32766 / sizeof(wchar_t)) {
len /= 2;
+ orig_len = len;
+ /* Reduce the length until we hit the final byte of a UTF-8 sequence
+ * (top bit is unset). Fix for github issue 82052.
+ */
+ while (len > 0 && (((char *)b->buf)[len-1] & 0x80) != 0)
+ --len;
+ /* If we hit a length of 0, something has gone wrong. This shouldn't
+ * be possible, as valid UTF-8 can have at most 3 non-final bytes
+ * before a final one, and our buffer is way longer than that.
+ * But to be on the safe side, if we hit this issue we just restore
+ * the original length and let the console API sort it out.
+ */
+ if (len == 0) {
+ len = orig_len;
+ }
wlen = MultiByteToWideChar(CP_UTF8, 0, b->buf, len, NULL, 0);
}
Py_END_ALLOW_THREADS
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