https://github.com/python/cpython/commit/a86de0bc236fbb9452f98998fc8437e9fca35700 commit: a86de0bc236fbb9452f98998fc8437e9fca35700 branch: 3.15 author: Miss Islington (bot) <[email protected]> committer: zooba <[email protected]> date: 2026-06-17T16:42:35+01:00 summary:
[3.15] gh-151544: Fixes CVE-2026-12003 by removing the fallback to %VPATH%/Modules/Setup.local for discovering sources in getpath.py (GH-151545) (cherry picked from commit 9e863fab283eddca9c2a8f9d1ee30f4dc243e314) Co-authored-by: Steve Dower <[email protected]> files: A Misc/NEWS.d/next/Security/2026-06-16-14-58-02.gh-issue-151544._bexVy.rst M Makefile.pre.in M Modules/getpath.py diff --git a/Makefile.pre.in b/Makefile.pre.in index 9c358bc6fbc6818..e411160d3ba8420 100644 --- a/Makefile.pre.in +++ b/Makefile.pre.in @@ -1709,6 +1709,8 @@ Programs/_bootstrap_python.o: Programs/_bootstrap_python.c $(BOOTSTRAP_HEADERS) _bootstrap_python: $(LIBRARY_OBJS_OMIT_FROZEN) Programs/_bootstrap_python.o Modules/getpath.o Modules/Setup.local $(LINKCC) $(PY_LDFLAGS_NOLTO) -o $@ $(LIBRARY_OBJS_OMIT_FROZEN) \ Programs/_bootstrap_python.o Modules/getpath.o $(LIBS) $(MODLIBS) $(SYSLIBS) + # Dummy pybuilddir.txt is needed for _bootstrap_python to be runnable + @echo "none" > ./pybuilddir.txt ############################################################################ diff --git a/Misc/NEWS.d/next/Security/2026-06-16-14-58-02.gh-issue-151544._bexVy.rst b/Misc/NEWS.d/next/Security/2026-06-16-14-58-02.gh-issue-151544._bexVy.rst new file mode 100644 index 000000000000000..418e3b4b9677943 --- /dev/null +++ b/Misc/NEWS.d/next/Security/2026-06-16-14-58-02.gh-issue-151544._bexVy.rst @@ -0,0 +1,4 @@ +:file:`Modules/Setup.local` is no longer used as a landmark to discover +whether Python is running in a source tree, as it could potentially affect +actual installs. The :file:`pybuilddir.txt` file is now the sole indicator +of running in a source tree. diff --git a/Modules/getpath.py b/Modules/getpath.py index 4dceb5cdc8dfcf0..6199567bd777aa0 100644 --- a/Modules/getpath.py +++ b/Modules/getpath.py @@ -129,8 +129,7 @@ # checked by looking for the BUILDDIR_TXT file, which contains the # relative path to the platlib dir. The executable_dir value is # derived from joining the VPATH preprocessor variable to the -# directory containing pybuilddir.txt. If it is not found, the -# BUILD_LANDMARK file is found, which is part of the source tree. +# directory containing pybuilddir.txt. # prefix is then found by searching up for a file that should only # exist in the source tree, and the stdlib dir is set to prefix/Lib. @@ -177,7 +176,6 @@ if os_name == 'posix' or os_name == 'darwin': BUILDDIR_TXT = 'pybuilddir.txt' - BUILD_LANDMARK = 'Modules/Setup.local' DEFAULT_PROGRAM_NAME = f'python{VERSION_MAJOR}' STDLIB_SUBDIR = f'{platlibdir}/python{VERSION_MAJOR}.{VERSION_MINOR}{ABI_THREAD}' STDLIB_LANDMARKS = [f'{STDLIB_SUBDIR}/os.py', f'{STDLIB_SUBDIR}/os.pyc'] @@ -190,7 +188,6 @@ elif os_name == 'nt': BUILDDIR_TXT = 'pybuilddir.txt' - BUILD_LANDMARK = f'{VPATH}\\Modules\\Setup.local' DEFAULT_PROGRAM_NAME = f'python' STDLIB_SUBDIR = 'Lib' STDLIB_LANDMARKS = [f'{STDLIB_SUBDIR}\\os.py', f'{STDLIB_SUBDIR}\\os.pyc'] @@ -513,13 +510,9 @@ def search_up(prefix, *landmarks, test=isfile): platstdlib_dir = real_executable_dir build_prefix = joinpath(real_executable_dir, VPATH) except (FileNotFoundError, PermissionError): - if isfile(joinpath(real_executable_dir, BUILD_LANDMARK)): - build_prefix = joinpath(real_executable_dir, VPATH) - if os_name == 'nt': - # QUIRK: Windows builds need platstdlib_dir to be the executable - # dir. Normally the builddir marker handles this, but in this - # case we need to correct manually. - platstdlib_dir = real_executable_dir + # We used to check for an alternate landmark here, but now we require + # BUILDDIR_TXT to exist. (gh-151544; CVE-2026-12003) + pass if build_prefix: if os_name == 'nt': _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
