Add _FORTIFY_SOURCE support for inet_ntop

- Create the __inet_ntop_chk routine that verifies that the builtin size
of the destination buffer is at least as big as the size given by the
user.
- Redirect calls from inet_ntop to __inet_ntop_chk or __inet_ntop_warn
- Update the abilist for this new routine
- Update the manual to mention the new fortification

Reviewed-by: Florian Weimer <fweimer@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/debug/inet_ntop_chk.c b/debug/inet_ntop_chk.c
new file mode 100644
index 0000000000..e1ec600fbb
--- /dev/null
+++ b/debug/inet_ntop_chk.c
@@ -0,0 +1,30 @@
+/* Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <arpa/inet.h>
+#include <stdio.h>
+
+const char *
+__inet_ntop_chk (int af, const void *src, char *dst,
+		 socklen_t size, size_t dst_size)
+{
+  if (size > dst_size)
+    __chk_fail ();
+
+  return __inet_ntop (af, src, dst, size);
+}
+libc_hidden_def (__inet_ntop_chk)