Skip to content

bpo-34001: Change handling of SSL protocol bounds with LibreSSL #8055

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 5 commits into from
Closed

bpo-34001: Change handling of SSL protocol bounds with LibreSSL #8055

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
4254483
bpo-34001: add checks for protocol boundary ranges
Jul 2, 2018
8352fd3
bpo-34001: add checks for LibreSSL
Jul 2, 2018
77d24d8
bpo-34001: fix tests
Jul 2, 2018
2a09611
bpo-34001: add test for protocol boundary restrictions
Jul 3, 2018
f415a39
bpo-34001: add blurb
Jul 2, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 19 additions & 1 deletion Lib/test/test_ssl.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1097,13 +1097,31 @@ def test_min_max_version(self):
ctx.maximum_version,
{ssl.TLSVersion.TLSv1, ssl.TLSVersion.SSLv3}
)
ctx.maximum_version = ssl.TLSVersion.MAXIMUM_SUPPORTED

ctx.minimum_version = ssl.TLSVersion.MAXIMUM_SUPPORTED
self.assertIn(
ctx.minimum_version,
{ssl.TLSVersion.TLSv1_2, ssl.TLSVersion.TLSv1_3}
)

with self.assertRaises(ValueError):
ctx.maximum_version = ssl.TLSVersion.MINIMUM_SUPPORTED

self.assertEqual(
ctx.maximum_version, ssl.TLSVersion.MAXIMUM_SUPPORTED
)

ctx.minimum_version = ssl.TLSVersion.MINIMUM_SUPPORTED
ctx.maximum_version = ssl.TLSVersion.MINIMUM_SUPPORTED

with self.assertRaises(ValueError):
ctx.minimum_version = ssl.TLSVersion.MAXIMUM_SUPPORTED

self.assertEqual(
ctx.minimum_version, ssl.TLSVersion.MINIMUM_SUPPORTED
)

with self.assertRaises(ValueError):
ctx.minimum_version = 42

Expand Down Expand Up @@ -3572,8 +3590,8 @@ def test_min_max_version(self):
self.assertEqual(s.version(), 'TLSv1.1')

# client 1.0, server 1.2 (mismatch)
server_context.minimum_version = ssl.TLSVersion.TLSv1_2
server_context.maximum_version = ssl.TLSVersion.TLSv1_2
server_context.minimum_version = ssl.TLSVersion.TLSv1_2
client_context.minimum_version = ssl.TLSVersion.TLSv1
client_context.maximum_version = ssl.TLSVersion.TLSv1
with ThreadedEchoServer(context=server_context) as server:
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2018-07-02-18-22-19.bpo-34001.e5KBtP.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Add checks for protocol version bounds when the ssl module is built using
LibreSSL.
48 changes: 48 additions & 0 deletions Modules/_ssl.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3383,7 +3383,11 @@ set_verify_flags(PySSLContext *self, PyObject *arg, void *c)
static int
set_min_max_proto_version(PySSLContext *self, PyObject *arg, int what)
{
long min;
long max;
long v;
long prev;
long new;
int result;

if (!PyArg_Parse(arg, "l", &v))
Expand All @@ -3408,6 +3412,7 @@ set_min_max_proto_version(PySSLContext *self, PyObject *arg, int what)
}

if (what == 0) {
/* set_minimum_version */
switch(v) {
case PY_PROTO_MINIMUM_SUPPORTED:
v = 0;
Expand All @@ -3419,9 +3424,31 @@ set_min_max_proto_version(PySSLContext *self, PyObject *arg, int what)
default:
break;
}
max = SSL_CTX_get_max_proto_version(self->ctx);
if(v > PY_PROTO_MAXIMUM_AVAILABLE ||
(max != 0 && v > max)) {
PyErr_SetString(
PyExc_ValueError,
"SSLContext.minimum_version cannot be greater than "
"SSLContext.maximum_version."
);
return -1;
}
prev = SSL_CTX_get_min_proto_version(self->ctx);
result = SSL_CTX_set_min_proto_version(self->ctx, v);
new = SSL_CTX_get_min_proto_version(self->ctx);
#if defined(LIBRESSL_VERSION_NUMBER)
if((v != 0 && v != new) ||
(v == 0 && PY_PROTO_MINIMUM_AVAILABLE != new)) {
PyErr_Format(PyExc_ValueError,
"Unsupported protocol version 0x%x", v);
SSL_CTX_set_min_proto_version(self->ctx, prev);
return -1;
}
#endif
}
else {
/* set_maximum_version */
switch(v) {
case PY_PROTO_MAXIMUM_SUPPORTED:
v = 0;
Expand All @@ -3433,7 +3460,28 @@ set_min_max_proto_version(PySSLContext *self, PyObject *arg, int what)
default:
break;
}
min = SSL_CTX_get_min_proto_version(self->ctx);
if(v != 0 && (v < PY_PROTO_MINIMUM_AVAILABLE ||
(min != 0 && v < min))) {
PyErr_SetString(
PyExc_ValueError,
"SSLContext.minimum_version cannot be greater than "
"SSLContext.maximum_version."
);
return -1;
}
prev = SSL_CTX_get_max_proto_version(self->ctx);
result = SSL_CTX_set_max_proto_version(self->ctx, v);
new = SSL_CTX_get_max_proto_version(self->ctx);
#if defined(LIBRESSL_VERSION_NUMBER)
if((v != 0 && v != SSL_CTX_get_max_proto_version(self->ctx)) ||
(v == 0 && PY_PROTO_MAXIMUM_AVAILABLE != SSL_CTX_get_max_proto_version(self->ctx))) {
PyErr_Format(PyExc_ValueError,
"Unsupported protocol version 0x%x", v);
result = SSL_CTX_set_max_proto_version(self->ctx, prev);
return -1;
}
#endif
}
if (result == 0) {
PyErr_Format(PyExc_ValueError,
Expand Down