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, 35 insertions, 0 deletions

diff --git a/inet/bits/inet-fortified-decl.h b/inet/bits/inet-fortified-decl.h
new file mode 100644
index 0000000..23e3cf4
--- /dev/null
+++ b/inet/bits/inet-fortified-decl.h
@@ -0,0 +1,35 @@
+/* Declarations of checking macros for inet functions.
+   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/>.  */
+
+#ifndef _BITS_INET_FORTIFIED_DEC_H
+#define _BITS_INET_FORTIFIED_DEC_H 1
+
+#ifndef _ARPA_INET_H
+# error "Never include <bits/inet-fortified-decl.h> directly; use <arpa/inet.h> instead."
+#endif
+
+extern const char *__inet_ntop_chk (int, const void *, char *, socklen_t, size_t);
+
+extern const char *__REDIRECT_FORTIFY_NTH (__inet_ntop_alias,
+					   (int, const void *, char *, socklen_t), inet_ntop);
+extern const char *__REDIRECT_NTH (__inet_ntop_chk_warn,
+				   (int, const void *, char *, socklen_t, size_t), __inet_ntop_chk)
+     __warnattr ("inet_ntop called with bigger length than "
+		 "size of destination buffer");
+
+#endif /* bits/inet-fortified-decl.h.  */