File clnt-create-unix-overflow.patch of Package glibc.22972
From 226b46770c82899b555986583294b049c6ec9b40 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 17 Jan 2022 10:21:34 +0100
Subject: [PATCH] CVE-2022-23219: Buffer overflow in sunrpc clnt_create for
"unix" (bug 22542)
Processing an overlong pathname in the sunrpc clnt_create function
results in a stack-based buffer overflow.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
include/sys/un.h | 12 +++++++
socket/Makefile | 6 +++-
socket/sockaddr_un_set.c | 41 ++++++++++++++++++++++++
socket/tst-sockaddr_un_set.c | 62 ++++++++++++++++++++++++++++++++++++
4 files changed, 120 insertions(+), 1 deletion(-)
create mode 100644 socket/sockaddr_un_set.c
create mode 100644 socket/tst-sockaddr_un_set.c
Index: glibc-2.26/include/sys/un.h
===================================================================
--- glibc-2.26.orig/include/sys/un.h
+++ glibc-2.26/include/sys/un.h
@@ -1 +1,13 @@
#include <socket/sys/un.h>
+
+#ifndef _ISOMAC
+
+/* Set ADDR->sun_family to AF_UNIX and ADDR->sun_path to PATHNAME.
+ Return 0 on success or -1 on failure (due to overlong PATHNAME).
+ The caller should always use sizeof (struct sockaddr_un) as the
+ socket address length, disregaring the length of PATHNAME.
+ Only concrete (non-abstract) pathnames are supported. */
+int __sockaddr_un_set (struct sockaddr_un *addr, const char *pathname)
+ attribute_hidden;
+
+#endif /* _ISOMAC */
Index: glibc-2.26/socket/Makefile
===================================================================
--- glibc-2.26.orig/socket/Makefile
+++ glibc-2.26/socket/Makefile
@@ -29,10 +29,14 @@ headers := sys/socket.h sys/un.h bits/so
routines := accept bind connect getpeername getsockname getsockopt \
listen recv recvfrom recvmsg send sendmsg sendto \
setsockopt shutdown socket socketpair isfdtype opensock \
- sockatmark accept4 recvmmsg sendmmsg
+ sockatmark accept4 recvmmsg sendmmsg sockaddr_un_set
tests := tst-accept4
+tests-internal := \
+ tst-sockaddr_un_set \
+ # tests-internal
+
aux := sa_len
include ../Rules
Index: glibc-2.26/socket/sockaddr_un_set.c
===================================================================
--- /dev/null
+++ glibc-2.26/socket/sockaddr_un_set.c
@@ -0,0 +1,41 @@
+/* Set the sun_path member of struct sockaddr_un.
+ Copyright (C) 2022 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 <errno.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+int
+__sockaddr_un_set (struct sockaddr_un *addr, const char *pathname)
+{
+ size_t name_length = strlen (pathname);
+
+ /* The kernel supports names of exactly sizeof (addr->sun_path)
+ bytes, without a null terminator, but userspace does not; see the
+ SUN_LEN macro. */
+ if (name_length >= sizeof (addr->sun_path))
+ {
+ __set_errno (EINVAL); /* Error code used by the kernel. */
+ return -1;
+ }
+
+ addr->sun_family = AF_UNIX;
+ memcpy (addr->sun_path, pathname, name_length + 1);
+ return 0;
+}
Index: glibc-2.26/socket/tst-sockaddr_un_set.c
===================================================================
--- /dev/null
+++ glibc-2.26/socket/tst-sockaddr_un_set.c
@@ -0,0 +1,62 @@
+/* Test the __sockaddr_un_set function.
+ Copyright (C) 2022 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/>. */
+
+/* Re-compile the function because the version in libc is not
+ exported. */
+#include "sockaddr_un_set.c"
+
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+ struct sockaddr_un sun;
+
+ memset (&sun, 0xcc, sizeof (sun));
+ __sockaddr_un_set (&sun, "");
+ TEST_VERIFY (sun.sun_family == AF_UNIX);
+ TEST_VERIFY (__sockaddr_un_set (&sun, "") == 0);
+
+ memset (&sun, 0xcc, sizeof (sun));
+ TEST_VERIFY (__sockaddr_un_set (&sun, "/example") == 0);
+ TEST_VERIFY (strcmp (sun.sun_path, "/example") == 0);
+
+ {
+ char pathname[108]; /* Length of sun_path (ABI constant). */
+ memset (pathname, 'x', sizeof (pathname));
+ pathname[sizeof (pathname) - 1] = '\0';
+ memset (&sun, 0xcc, sizeof (sun));
+ TEST_VERIFY (__sockaddr_un_set (&sun, pathname) == 0);
+ TEST_VERIFY (sun.sun_family == AF_UNIX);
+ TEST_VERIFY (strcmp (sun.sun_path, pathname) == 0);
+ }
+
+ {
+ char pathname[109];
+ memset (pathname, 'x', sizeof (pathname));
+ pathname[sizeof (pathname) - 1] = '\0';
+ memset (&sun, 0xcc, sizeof (sun));
+ errno = 0;
+ TEST_VERIFY (__sockaddr_un_set (&sun, pathname) == -1);
+ TEST_VERIFY (errno == EINVAL);
+ }
+
+ return 0;
+}
+
+#include <support/test-driver.c>
Index: glibc-2.26/sunrpc/clnt_gen.c
===================================================================
--- glibc-2.26.orig/sunrpc/clnt_gen.c
+++ glibc-2.26/sunrpc/clnt_gen.c
@@ -57,9 +57,13 @@ clnt_create (const char *hostname, u_lon
if (strcmp (proto, "unix") == 0)
{
- memset ((char *)&sun, 0, sizeof (sun));
- sun.sun_family = AF_UNIX;
- strcpy (sun.sun_path, hostname);
+ if (__sockaddr_un_set (&sun, hostname) < 0)
+ {
+ struct rpc_createerr *ce = &get_rpc_createerr ();
+ ce->cf_stat = RPC_SYSTEMERROR;
+ ce->cf_error.re_errno = errno;
+ return NULL;
+ }
sock = RPC_ANYSOCK;
client = clntunix_create (&sun, prog, vers, &sock, 0, 0);
if (client == NULL)
