[PATCH 0/4] Fix two sunrpc buffer overflows

[PATCH 0/4] Fix two sunrpc buffer overflows

[Florian Weimer]

The first one was reported by Martin Sebor in 2017, but we didn't fix
it.  Grepping for sun_path I found another similar one.

Tested on i686-linux-gnu, x86_64-linux-gnu.  Built with
build-many-glibcs.py.

Thanks,
Florian

Florian Weimer (3):
  socket: Add the __sockaddr_un_set function
  sunrpc: Fix buffer overflow in clnt_create for "unix" (bug 22542)
  sunrpc: Fix path buffer overflow in svcunix_create (bug 28768)

Martin Sebor (1):
  sunrpc: Test case for clnt_create "unix" buffer overflow (bug 22542)

 NEWS                         |  7 +++-
 include/sys/un.h             | 12 +++++++
 socket/Makefile              |  6 +++-
 socket/sockaddr_un_set.c     | 41 ++++++++++++++++++++++++
 socket/tst-sockaddr_un_set.c | 62 ++++++++++++++++++++++++++++++++++++
 sunrpc/Makefile              |  5 ++-
 sunrpc/clnt_gen.c            | 10 ++++--
 sunrpc/svc_unix.c            | 11 +++----
 sunrpc/tst-bug22542.c        | 44 +++++++++++++++++++++++++
 sunrpc/tst-bug28768.c        | 42 ++++++++++++++++++++++++
 10 files changed, 227 insertions(+), 13 deletions(-)
 create mode 100644 socket/sockaddr_un_set.c
 create mode 100644 socket/tst-sockaddr_un_set.c
 create mode 100644 sunrpc/tst-bug22542.c
 create mode 100644 sunrpc/tst-bug28768.c


base-commit: 0005e54f762b2ec65cee2c4ecf1e9d42612030f0
-- 
2.34.1

[PATCH 1/4] socket: Add the __sockaddr_un_set function

[Florian Weimer]

---
 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

diff --git a/include/sys/un.h b/include/sys/un.h
index bdbee99980..152afd9fc7 100644
--- a/include/sys/un.h
+++ b/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 */
diff --git a/socket/Makefile b/socket/Makefile
index 39333e10ca..156eec6c85 100644
--- a/socket/Makefile
+++ b/socket/Makefile
@@ -29,13 +29,17 @@ headers	:= sys/socket.h sys/un.h bits/sockaddr.h bits/socket.h \
 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 \
   tst-sockopt \
   # tests
 
+tests-internal := \
+  tst-sockaddr_un_set \
+  # tests-internal
+
 tests-time64 := \
   tst-sockopt-time64 \
   # tests
diff --git a/socket/sockaddr_un_set.c b/socket/sockaddr_un_set.c
new file mode 100644
index 0000000000..0bd40dc34e
--- /dev/null
+++ b/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;
+}
diff --git a/socket/tst-sockaddr_un_set.c b/socket/tst-sockaddr_un_set.c
new file mode 100644
index 0000000000..29c2a81afd
--- /dev/null
+++ b/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_COMPARE (sun.sun_family, AF_UNIX);
+  TEST_COMPARE (__sockaddr_un_set (&sun, ""), 0);
+
+  memset (&sun, 0xcc, sizeof (sun));
+  TEST_COMPARE (__sockaddr_un_set (&sun, "/example"), 0);
+  TEST_COMPARE_STRING (sun.sun_path, "/example");
+
+  {
+    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_COMPARE (__sockaddr_un_set (&sun, pathname), 0);
+    TEST_COMPARE (sun.sun_family, AF_UNIX);
+    TEST_COMPARE_STRING (sun.sun_path, pathname);
+  }
+
+  {
+    char pathname[109];
+    memset (pathname, 'x', sizeof (pathname));
+    pathname[sizeof (pathname) - 1] = '\0';
+    memset (&sun, 0xcc, sizeof (sun));
+    errno = 0;
+    TEST_COMPARE (__sockaddr_un_set (&sun, pathname), -1);
+    TEST_COMPARE (errno, EINVAL);
+  }
+
+  return 0;
+}
+
+#include <support/test-driver.c>
-- 
2.34.1

[PATCH 2/4] sunrpc: Fix buffer overflow in clnt_create for "unix" (bug 22542)

[Florian Weimer]

---
 NEWS              |  4 +++-
 sunrpc/clnt_gen.c | 10 +++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index a957b19fdc..c1df8e1a0f 100644
--- a/NEWS
+++ b/NEWS
@@ -150,7 +150,9 @@ Changes to build and runtime requirements:
 
 Security related changes:
 
-  [Add security related changes here]
+  Passing an overlong file name to the clnt_create legacy function could
+  result in a stack-based buffer overflow when using the "unix"
+  protocol.  Reported by Martin Sebor.
 
 The following bugs are resolved with this release:
 
diff --git a/sunrpc/clnt_gen.c b/sunrpc/clnt_gen.c
index 13ced8994e..b44357cd88 100644
--- a/sunrpc/clnt_gen.c
+++ b/sunrpc/clnt_gen.c
@@ -57,9 +57,13 @@ clnt_create (const char *hostname, u_long prog, u_long vers,
 
   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)
-- 
2.34.1

[PATCH 3/4] sunrpc: Test case for clnt_create "unix" buffer overflow (bug 22542)

[Florian Weimer]

From: Martin Sebor <msebor@redhat.com>

---
 sunrpc/Makefile       |  5 ++++-
 sunrpc/tst-bug22542.c | 44 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 sunrpc/tst-bug22542.c

diff --git a/sunrpc/Makefile b/sunrpc/Makefile
index 9a31fe48b9..183ef3dc55 100644
--- a/sunrpc/Makefile
+++ b/sunrpc/Makefile
@@ -65,7 +65,8 @@ shared-only-routines = $(routines)
 endif
 
 tests = tst-xdrmem tst-xdrmem2 test-rpcent tst-udp-error tst-udp-timeout \
-  tst-udp-nonblocking
+  tst-udp-nonblocking tst-bug22542
+
 xtests := tst-getmyaddr
 
 ifeq ($(have-thread-library),yes)
@@ -110,6 +111,8 @@ $(objpfx)tst-udp-nonblocking: $(common-objpfx)linkobj/libc.so
 $(objpfx)tst-udp-garbage: \
   $(common-objpfx)linkobj/libc.so $(shared-thread-library)
 
+$(objpfx)tst-bug22542: $(common-objpfx)linkobj/libc.so
+
 else # !have-GLIBC_2.31
 
 routines = $(routines-for-nss)
diff --git a/sunrpc/tst-bug22542.c b/sunrpc/tst-bug22542.c
new file mode 100644
index 0000000000..d6cd79787b
--- /dev/null
+++ b/sunrpc/tst-bug22542.c
@@ -0,0 +1,44 @@
+/* Test to verify that overlong hostname is rejected by clnt_create
+   and doesn't cause a buffer overflow (bug  22542).
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <rpc/clnt.h>
+#include <string.h>
+#include <support/check.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+static int
+do_test (void)
+{
+  /* Create an arbitrary hostname that's longer than fits in sun_path.  */
+  char name [sizeof ((struct sockaddr_un*)0)->sun_path * 2];
+  memset (name, 'x', sizeof name - 1);
+  name [sizeof name - 1] = '\0';
+
+  errno = 0;
+  CLIENT *clnt = clnt_create (name, 0, 0, "unix");
+
+  TEST_VERIFY (clnt == NULL);
+  TEST_COMPARE (errno, EINVAL);
+  return 0;
+}
+
+#include <support/test-driver.c>
-- 
2.34.1

[PATCH 4/4] sunrpc: Fix path buffer overflow in svcunix_create (bug 28768)

[Florian Weimer]

---
 NEWS                  |  3 +++
 sunrpc/Makefile       |  2 +-
 sunrpc/svc_unix.c     | 11 ++++-------
 sunrpc/tst-bug28768.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 8 deletions(-)
 create mode 100644 sunrpc/tst-bug28768.c

diff --git a/NEWS b/NEWS
index c1df8e1a0f..6a11bf8131 100644
--- a/NEWS
+++ b/NEWS
@@ -154,6 +154,9 @@ Security related changes:
   result in a stack-based buffer overflow when using the "unix"
   protocol.  Reported by Martin Sebor.
 
+  Passing an overlong file name to the svcunix_create legacy function
+  could result in a stack-based buffer overflow.
+
 The following bugs are resolved with this release:
 
   [The release manager will add the list generated by
diff --git a/sunrpc/Makefile b/sunrpc/Makefile
index 183ef3dc55..a79a7195fc 100644
--- a/sunrpc/Makefile
+++ b/sunrpc/Makefile
@@ -65,7 +65,7 @@ shared-only-routines = $(routines)
 endif
 
 tests = tst-xdrmem tst-xdrmem2 test-rpcent tst-udp-error tst-udp-timeout \
-  tst-udp-nonblocking tst-bug22542
+  tst-udp-nonblocking tst-bug22542 tst-bug28768
 
 xtests := tst-getmyaddr
 
diff --git a/sunrpc/svc_unix.c b/sunrpc/svc_unix.c
index f2280b4c49..67177a2e78 100644
--- a/sunrpc/svc_unix.c
+++ b/sunrpc/svc_unix.c
@@ -154,7 +154,10 @@ svcunix_create (int sock, u_int sendsize, u_int recvsize, char *path)
   SVCXPRT *xprt;
   struct unix_rendezvous *r;
   struct sockaddr_un addr;
-  socklen_t len = sizeof (struct sockaddr_in);
+  socklen_t len = sizeof (addr);
+
+  if (__sockaddr_un_set (&addr, path) < 0)
+    return NULL;
 
   if (sock == RPC_ANYSOCK)
     {
@@ -165,12 +168,6 @@ svcunix_create (int sock, u_int sendsize, u_int recvsize, char *path)
 	}
       madesock = TRUE;
     }
-  memset (&addr, '\0', sizeof (addr));
-  addr.sun_family = AF_UNIX;
-  len = strlen (path) + 1;
-  memcpy (addr.sun_path, path, len);
-  len += sizeof (addr.sun_family);
-
   __bind (sock, (struct sockaddr *) &addr, len);
 
   if (__getsockname (sock, (struct sockaddr *) &addr, &len) != 0
diff --git a/sunrpc/tst-bug28768.c b/sunrpc/tst-bug28768.c
new file mode 100644
index 0000000000..35a4b7b0b3
--- /dev/null
+++ b/sunrpc/tst-bug28768.c
@@ -0,0 +1,42 @@
+/* Test to verify that long path is rejected by svcunix_create (bug 28768).
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <rpc/svc.h>
+#include <shlib-compat.h>
+#include <string.h>
+#include <support/check.h>
+
+/* svcunix_create does not have a default version in linkobj/libc.so.  */
+compat_symbol_reference (libc, svcunix_create, svcunix_create, GLIBC_2_1);
+
+static int
+do_test (void)
+{
+  char pathname[109];
+  memset (pathname, 'x', sizeof (pathname));
+  pathname[sizeof (pathname) - 1] = '\0';
+
+  errno = 0;
+  TEST_VERIFY (svcunix_create (RPC_ANYSOCK, 4096, 4096, pathname) == NULL);
+  TEST_COMPARE (errno, EINVAL);
+
+  return 0;
+}
+
+#include <support/test-driver.c>
-- 
2.34.1