bpo-41894: Fix UnicodeDecodeError while loading native module (GH-22466)

When running in a non-UTF-8 locale, if an error occurs while importing a
native Python module (say because a dependent share library is missing),
the error message string returned may contain non-ASCII code points
causing a UnicodeDecodeError.

PyUnicode_DecodeFSDefault is used for buffers which may contain
filesystem  paths. For consistency with os.strerror(),
PyUnicode_DecodeLocale is used for buffers which contain system error
messages. While the shortname parameter is always encoded in ASCII
according to PEP 489, it is left decoded using PyUnicode_FromString to
minimize the changes and since it should not affect the decoding (albeit
_potentially_ slower).

In dynload_hpux, since the error buffer contains a message generated
from a static ASCII string and the module filesystem path,
PyUnicode_DecodeFSDefault is used instead of PyUnicode_DecodeLocale as
is used elsewhere.

* bpo-41894: Fix bugs in dynload error msg handling

For both dynload_aix and dynload_hpux, properly handle the possibility
that decoding strings may return NULL and when such an error happens,
properly decrement any previously decoded strings and return early.

In addition, in dynload_aix, ensure that we pass the decoded string
*object* pathname_ob to PyErr_SetImportError instead of the original
pathname buffer.

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This commit is contained in:
Kevin Adler 2020-10-14 20:53:27 -05:00 committed by GitHub
parent c13b847a6f
commit 2d2af320d9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 28 additions and 8 deletions

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@ -0,0 +1,3 @@
When loading a native module and a load failure occurs, prevent a possible
UnicodeDecodeError when not running in a UTF-8 locale by decoding the load
error message using the current locale's encoding.

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@ -144,10 +144,16 @@ aix_loaderror(const char *pathname)
ERRBUF_APPEND(message[i]);
ERRBUF_APPEND("\n");
}
errbuf[strlen(errbuf)-1] = '\0'; /* trim off last newline */
pathname_ob = PyUnicode_FromString(pathname);
errbuf_ob = PyUnicode_FromString(errbuf);
PyErr_SetImportError(errbuf_ob, NULL, pathname);
/* Subtract 1 from the length to trim off trailing newline */
errbuf_ob = PyUnicode_DecodeLocaleAndSize(errbuf, strlen(errbuf)-1, "surrogateescape");
if (errbuf_ob == NULL)
return;
pathname_ob = PyUnicode_DecodeFSDefault(pathname);
if (pathname_ob == NULL) {
Py_DECREF(errbuf_ob);
return;
}
PyErr_SetImportError(errbuf_ob, NULL, pathname_ob);
Py_DECREF(pathname_ob);
Py_DECREF(errbuf_ob);
return;

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@ -36,9 +36,20 @@ dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
char buf[256];
PyOS_snprintf(buf, sizeof(buf), "Failed to load %.200s",
pathname);
PyObject *buf_ob = PyUnicode_FromString(buf);
PyObject *buf_ob = PyUnicode_DecodeFSDefault(buf);
if (buf_ob == NULL)
return NULL;
PyObject *shortname_ob = PyUnicode_FromString(shortname);
PyObject *pathname_ob = PyUnicode_FromString(pathname);
if (shortname_ob == NULL) {
Py_DECREF(buf_ob);
return NULL;
}
PyObject *pathname_ob = PyUnicode_DecodeFSDefault(pathname);
if (pathname_ob == NULL) {
Py_DECREF(buf_ob);
Py_DECREF(shortname_ob);
return NULL;
}
PyErr_SetImportError(buf_ob, shortname_ob, pathname_ob);
Py_DECREF(buf_ob);
Py_DECREF(shortname_ob);

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@ -106,7 +106,7 @@ _PyImport_FindSharedFuncptr(const char *prefix,
const char *error = dlerror();
if (error == NULL)
error = "unknown dlopen() error";
error_ob = PyUnicode_FromString(error);
error_ob = PyUnicode_DecodeLocale(error, "surrogateescape");
if (error_ob == NULL)
return NULL;
mod_name = PyUnicode_FromString(shortname);
@ -114,7 +114,7 @@ _PyImport_FindSharedFuncptr(const char *prefix,
Py_DECREF(error_ob);
return NULL;
}
path = PyUnicode_FromString(pathname);
path = PyUnicode_DecodeFSDefault(pathname);
if (path == NULL) {
Py_DECREF(error_ob);
Py_DECREF(mod_name);