152 lines
4.9 KiB
Diff
152 lines
4.9 KiB
Diff
From 045e368799cd253ddbf8bdec42ed92e8ebb3ce67 Mon Sep 17 00:00:00 2001
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From: Florian Weimer <fweimer@redhat.com>
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Date: Tue, 28 Feb 2017 17:05:46 +0100
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Subject: sunrpc: Avoid use-after-free read access in clntudp_call [BZ #21115]
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After commit bc779a1a5b3035133024b21e2f339fe4219fb11c
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(CVE-2016-4429: sunrpc: Do not use alloca in clntudp_call
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[BZ #20112]), ancillary data is stored on the heap,
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but it is accessed after it has been freed.
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The test case must be run under a heap debugger such as valgrind
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to observe the invalid access. A malloc implementation which
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immediately calls munmap on free would catch this bug as well.
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(cherry picked from commit d42eed4a044e5e10dfb885cf9891c2518a72a491)
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diff --git a/ChangeLog b/ChangeLog
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index c88238e0fa..3d781a354a 100644
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--- a/ChangeLog
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+++ b/ChangeLog
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@@ -1,3 +1,11 @@
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+2017-02-27 Florian Weimer <fweimer@redhat.com>
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+
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+ [BZ #21115]
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+ * sunrpc/clnt_udp.c (clntudp_call): Free ancillary data later.
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+ * sunrpc/Makefile (tests): Add tst-udp-error.
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+ (tst-udp-error): Link against libc.so explicitly.
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+ * sunrpc/tst-udp-error: New file.
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+
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2017-02-08 Siddhesh Poyarekar <siddhesh@sourceware.org>
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[BZ #21109]
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diff --git a/NEWS b/NEWS
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index 325cac78e4..5ecc565371 100644
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--- a/NEWS
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+++ b/NEWS
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@@ -10,6 +10,7 @@ Version 2.25.1
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The following bugs are resolved with this release:
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[21109] Tunables broken on big-endian
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+ [21115] sunrpc: Use-after-free in error path in clntudp_call
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Version 2.25
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diff --git a/sunrpc/Makefile b/sunrpc/Makefile
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index 0c1e6124ff..daf8a28f1a 100644
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--- a/sunrpc/Makefile
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+++ b/sunrpc/Makefile
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@@ -93,7 +93,7 @@ rpcgen-objs = rpc_main.o rpc_hout.o rpc_cout.o rpc_parse.o \
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extra-objs = $(rpcgen-objs) $(addprefix cross-,$(rpcgen-objs))
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others += rpcgen
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-tests = tst-xdrmem tst-xdrmem2 test-rpcent
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+tests = tst-xdrmem tst-xdrmem2 test-rpcent tst-udp-error
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xtests := tst-getmyaddr
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ifeq ($(have-thread-library),yes)
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@@ -155,6 +155,7 @@ BUILD_CPPFLAGS += $(sunrpc-CPPFLAGS)
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$(objpfx)tst-getmyaddr: $(common-objpfx)linkobj/libc.so
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$(objpfx)tst-xdrmem: $(common-objpfx)linkobj/libc.so
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$(objpfx)tst-xdrmem2: $(common-objpfx)linkobj/libc.so
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+$(objpfx)tst-udp-error: $(common-objpfx)linkobj/libc.so
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$(objpfx)rpcgen: $(addprefix $(objpfx),$(rpcgen-objs))
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diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c
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index 4d9acb1e6a..1de25cb771 100644
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--- a/sunrpc/clnt_udp.c
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+++ b/sunrpc/clnt_udp.c
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@@ -421,9 +421,9 @@ send_again:
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cmsg = CMSG_NXTHDR (&msg, cmsg))
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if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
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{
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- free (cbuf);
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e = (struct sock_extended_err *) CMSG_DATA(cmsg);
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cu->cu_error.re_errno = e->ee_errno;
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+ free (cbuf);
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return (cu->cu_error.re_status = RPC_CANTRECV);
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}
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free (cbuf);
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diff --git a/sunrpc/tst-udp-error.c b/sunrpc/tst-udp-error.c
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new file mode 100644
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index 0000000000..1efc02f5c6
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--- /dev/null
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+++ b/sunrpc/tst-udp-error.c
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@@ -0,0 +1,62 @@
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+/* Check for use-after-free in clntudp_call (bug 21115).
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+ Copyright (C) 2017 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <http://www.gnu.org/licenses/>. */
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+
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+#include <netinet/in.h>
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+#include <rpc/clnt.h>
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+#include <rpc/svc.h>
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+#include <support/check.h>
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+#include <support/namespace.h>
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+#include <support/xsocket.h>
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+#include <unistd.h>
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+
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+static int
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+do_test (void)
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+{
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+ support_become_root ();
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+ support_enter_network_namespace ();
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+
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+ /* Obtain a likely-unused port number. */
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+ struct sockaddr_in sin =
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+ {
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+ .sin_family = AF_INET,
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+ .sin_addr.s_addr = htonl (INADDR_LOOPBACK),
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+ };
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+ {
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+ int fd = xsocket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
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+ xbind (fd, (struct sockaddr *) &sin, sizeof (sin));
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+ socklen_t sinlen = sizeof (sin);
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+ xgetsockname (fd, (struct sockaddr *) &sin, &sinlen);
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+ /* Close the socket, so that we will receive an error below. */
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+ close (fd);
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+ }
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+
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+ int sock = RPC_ANYSOCK;
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+ CLIENT *clnt = clntudp_create
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+ (&sin, 1, 2, (struct timeval) { 1, 0 }, &sock);
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+ TEST_VERIFY_EXIT (clnt != NULL);
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+ TEST_VERIFY (clnt_call (clnt, 3,
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+ (xdrproc_t) xdr_void, NULL,
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+ (xdrproc_t) xdr_void, NULL,
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+ ((struct timeval) { 3, 0 }))
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+ == RPC_CANTRECV);
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+ clnt_destroy (clnt);
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+
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+ return 0;
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+}
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+
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+#include <support/test-driver.c>
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--
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2.13.1
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