gh-143756: Fix potential data race in SSLContext.load_cert_chain #143818
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1 @@ | ||
| Fix potential thread safety issues in :mod:`ssl` module. |
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| Original file line number | Diff line number | Diff line change | ||||||
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@@ -43,14 +43,17 @@ | |||||||
| /* Redefined below for Windows debug builds after important #includes */ | ||||||||
| #define _PySSL_FIX_ERRNO | ||||||||
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| #define PySSL_BEGIN_ALLOW_THREADS_S(save) \ | ||||||||
| do { (save) = PyEval_SaveThread(); } while(0) | ||||||||
| #define PySSL_END_ALLOW_THREADS_S(save) \ | ||||||||
| do { PyEval_RestoreThread(save); _PySSL_FIX_ERRNO; } while(0) | ||||||||
| #define PySSL_BEGIN_ALLOW_THREADS(self) { \ | ||||||||
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Member
There was a problem hiding this comment. While you are it, can you use a do-while construct? (here we would just have the do {) In addition can you make it multiline with line continuations aligned on a tab multiple? (like PEP-7) TiA. |
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| PyThreadState *_save = NULL; \ | ||||||||
| PySSL_BEGIN_ALLOW_THREADS_S(_save); \ | ||||||||
| PyMutex_Lock(&(self)->tstate_mutex); | ||||||||
| #define PySSL_END_ALLOW_THREADS(self) \ | ||||||||
| PyMutex_Unlock(&(self)->tstate_mutex); \ | ||||||||
| PySSL_END_ALLOW_THREADS_S(_save); } | ||||||||
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||||||||
| #if defined(HAVE_POLL_H) | ||||||||
| #include <poll.h> | ||||||||
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@@ -4543,60 +4546,25 @@ _password_callback(char *buf, int size, int rwflag, void *userdata) | |||||||
| return -1; | ||||||||
| } | ||||||||
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| static PyObject * | ||||||||
| load_cert_chain_lock_held(PySSLContext *self, _PySSLPasswordInfo *pw_info, | ||||||||
| PyObject *certfile_bytes, PyObject *keyfile_bytes) | ||||||||
| { | ||||||||
| int r; | ||||||||
| PyObject *ret = NULL; | ||||||||
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| pem_password_cb *orig_passwd_cb = SSL_CTX_get_default_passwd_cb(self->ctx); | ||||||||
| void *orig_passwd_userdata = SSL_CTX_get_default_passwd_cb_userdata(self->ctx); | ||||||||
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| SSL_CTX_set_default_passwd_cb(self->ctx, _password_callback); | ||||||||
| SSL_CTX_set_default_passwd_cb_userdata(self->ctx, pw_info); | ||||||||
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| PySSL_BEGIN_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| r = SSL_CTX_use_certificate_chain_file(self->ctx, | ||||||||
| PyBytes_AS_STRING(certfile_bytes)); | ||||||||
| PySSL_END_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| if (r != 1) { | ||||||||
| if (pw_info->error) { | ||||||||
| ERR_clear_error(); | ||||||||
| /* the password callback has already set the error information */ | ||||||||
| } | ||||||||
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@@ -4609,15 +4577,14 @@ _ssl__SSLContext_load_cert_chain_impl(PySSLContext *self, PyObject *certfile, | |||||||
| } | ||||||||
| goto error; | ||||||||
| } | ||||||||
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| PySSL_BEGIN_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| r = SSL_CTX_use_PrivateKey_file(self->ctx, | ||||||||
| PyBytes_AS_STRING(keyfile_bytes ? keyfile_bytes : certfile_bytes), | ||||||||
| SSL_FILETYPE_PEM); | ||||||||
| PySSL_END_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| if (r != 1) { | ||||||||
| if (pw_info->error) { | ||||||||
| ERR_clear_error(); | ||||||||
| /* the password callback has already set the error information */ | ||||||||
| } | ||||||||
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@@ -4630,25 +4597,74 @@ _ssl__SSLContext_load_cert_chain_impl(PySSLContext *self, PyObject *certfile, | |||||||
| } | ||||||||
| goto error; | ||||||||
| } | ||||||||
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| PySSL_BEGIN_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| r = SSL_CTX_check_private_key(self->ctx); | ||||||||
| PySSL_END_ALLOW_THREADS_S(pw_info->thread_state); | ||||||||
| if (r != 1) { | ||||||||
| _setSSLError(get_state_ctx(self), NULL, 0, __FILE__, __LINE__); | ||||||||
| goto error; | ||||||||
| } | ||||||||
| ret = Py_None; | ||||||||
| error: | ||||||||
| SSL_CTX_set_default_passwd_cb(self->ctx, orig_passwd_cb); | ||||||||
| SSL_CTX_set_default_passwd_cb_userdata(self->ctx, orig_passwd_userdata); | ||||||||
| return ret; | ||||||||
| } | ||||||||
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||||||||
| /*[clinic input] | ||||||||
| _ssl._SSLContext.load_cert_chain | ||||||||
| certfile: object | ||||||||
| keyfile: object = None | ||||||||
| password: object = None | ||||||||
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||||||||
| [clinic start generated code]*/ | ||||||||
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| static PyObject * | ||||||||
| _ssl__SSLContext_load_cert_chain_impl(PySSLContext *self, PyObject *certfile, | ||||||||
| PyObject *keyfile, PyObject *password) | ||||||||
| /*[clinic end generated code: output=9480bc1c380e2095 input=30bc7e967ea01a58]*/ | ||||||||
| { | ||||||||
| PyObject *certfile_bytes = NULL, *keyfile_bytes = NULL; | ||||||||
| _PySSLPasswordInfo pw_info = { NULL, NULL, NULL, 0, 0 }; | ||||||||
| PyObject *ret = NULL; | ||||||||
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| errno = 0; | ||||||||
| ERR_clear_error(); | ||||||||
| if (keyfile == Py_None) | ||||||||
| keyfile = NULL; | ||||||||
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Comment on lines
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Member
There was a problem hiding this comment. I think this can be added in the if (keyfile) check instead.
Contributor
Author
There was a problem hiding this comment. ditto; this is existing code |
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| if (!PyUnicode_FSConverter(certfile, &certfile_bytes)) { | ||||||||
| if (PyErr_ExceptionMatches(PyExc_TypeError)) { | ||||||||
| PyErr_SetString(PyExc_TypeError, | ||||||||
| "certfile should be a valid filesystem path"); | ||||||||
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Member
There was a problem hiding this comment. For a follow-up: This is a bit misleading. For me such message usually implies a ValueError instead of TypeError. Do we use this formulation for other occurrences of FSConverter? Maybe: "expecting a path-like object for 'certfile', got ..." |
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| } | ||||||||
| return NULL; | ||||||||
| } | ||||||||
| if (keyfile && !PyUnicode_FSConverter(keyfile, &keyfile_bytes)) { | ||||||||
| if (PyErr_ExceptionMatches(PyExc_TypeError)) { | ||||||||
| PyErr_SetString(PyExc_TypeError, | ||||||||
| "keyfile should be a valid filesystem path"); | ||||||||
| } | ||||||||
| goto done; | ||||||||
| } | ||||||||
| if (password != Py_None) { | ||||||||
| if (PyCallable_Check(password)) { | ||||||||
| pw_info.callable = password; | ||||||||
| } else if (!_pwinfo_set(&pw_info, password, | ||||||||
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Member
There was a problem hiding this comment.
Suggested change
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| "password should be a string or callable")) { | ||||||||
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Member
There was a problem hiding this comment. And realign this adter putting the elseif on its own line |
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| goto done; | ||||||||
| } | ||||||||
| } | ||||||||
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| PyMutex_Lock(&self->tstate_mutex); | ||||||||
| ret = load_cert_chain_lock_held(self, &pw_info, certfile_bytes, keyfile_bytes); | ||||||||
| PyMutex_Unlock(&self->tstate_mutex); | ||||||||
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||||||||
| done: | ||||||||
| PyMem_Free(pw_info.password); | ||||||||
| Py_XDECREF(keyfile_bytes); | ||||||||
| Py_XDECREF(certfile_bytes); | ||||||||
| return ret; | ||||||||
| } | ||||||||
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| /* internal helper function, returns -1 on error | ||||||||
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Can you use uppercase letters for the macro parameters please?
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Let's not do a bunch of extra refactoring in a bugfix PR
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Oh right you want to backport this. I think there will be anyway conflicts so yeah let's not make it more complicate