From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Sat, 29 Oct 2022 10:27:10 +0000 (+0200)
Subject: fix(c): guard select() from high number file descriptors
X-Git-Tag: 3.1.5~7^2~6
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=291524c7f7d769fcb0f5cce2497e1d14e46465d9;p=thirdparty%2Fpsycopg.git

fix(c): guard select() from high number file descriptors

The Python `select.select()` wrapper raises ValueError. Without a guard,
the C `wait_select()` segfaults. The C way to say you have been naughty.

On Windows this seems not only not needed, but it actually stops from creating
any connection at all.
---

diff --git a/psycopg_c/psycopg_c/_psycopg/waiting.pyx b/psycopg_c/psycopg_c/_psycopg/waiting.pyx
index be8aaee56..3dc068b90 100644
--- a/psycopg_c/psycopg_c/_psycopg/waiting.pyx
+++ b/psycopg_c/psycopg_c/_psycopg/waiting.pyx
@@ -31,6 +31,15 @@ select_impl(int fileno, int wait, float timeout)
     struct timeval tv, *tvptr;
     int select_rv;
 
+#ifdef MS_WINDOWS
+    if (fileno >= 1024) {
+        PyErr_SetString(
+            PyExc_ValueError,  /* same exception of Python's 'select.select()' */
+            "connection file descriptor out of range for 'select()'");
+        return -1;
+    }
+#endif
+
     FD_ZERO(&ifds);
     FD_ZERO(&ofds);
     FD_ZERO(&efds);
diff --git a/tests/test_waiting.py b/tests/test_waiting.py
index acd1e95b1..72c258d78 100644
--- a/tests/test_waiting.py
+++ b/tests/test_waiting.py
@@ -76,6 +76,35 @@ def test_wait_bad(pgconn, waitfn):
         waitfn(gen, pgconn.socket)
 
 
+@pytest.mark.slow
+@pytest.mark.parametrize("waitfn", waitfns)
+def test_wait_large_fd(dsn, waitfn):
+    files = []
+    try:
+        try:
+            for i in range(1100):
+                files.append(open(__file__))
+        except OSError:
+            pytest.skip("can't open the number of files needed for the test")
+
+        pgconn = psycopg.pq.PGconn.connect(dsn.encode())
+        try:
+            assert pgconn.socket > 1024
+            pgconn.send_query(b"select 1")
+            gen = generators.execute(pgconn)
+            if waitfn is waiting.wait_select and sys.platform != "win32":
+                with pytest.raises(ValueError):
+                    waitfn(gen, pgconn.socket)
+            else:
+                (res,) = waitfn(gen, pgconn.socket)
+                assert res.status == ExecStatus.TUPLES_OK
+        finally:
+            pgconn.finish()
+    finally:
+        for f in files:
+            f.close()
+
+
 @pytest.mark.parametrize("timeout", timeouts)
 @pytest.mark.asyncio
 async def test_wait_conn_async(dsn, timeout):