[Buildroot] [git commit branch/2019.02.x] package/runc: bump to version 1.0.0-rc7

Peter Korsgaard peter at korsgaard.com
Sun Apr 14 21:09:04 UTC 2019


commit: https://git.buildroot.net/buildroot/commit/?id=8c5de3f841ebb0123c97634aaa5751e5cc285d47
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2019.02.x

This includes an improved fix for CVE-2019-5736 without the ~10MB memory
overhead per container and with fallback code using mkostemp(3) when
O_TMPFILE isn't available.

For more details, see the announcement:
https://github.com/opencontainers/runc/releases/tag/v1.0.0-rc7

Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit 56f495a07838fe898d995f572c0efac21ed61902)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 ...ne-proc-self-exe-to-avoid-exposing-host-b.patch | 338 ---------------------
 package/runc/runc.hash                             |   2 +-
 package/runc/runc.mk                               |   2 +-
 3 files changed, 2 insertions(+), 340 deletions(-)

diff --git a/package/runc/0001-nsenter-clone-proc-self-exe-to-avoid-exposing-host-b.patch b/package/runc/0001-nsenter-clone-proc-self-exe-to-avoid-exposing-host-b.patch
deleted file mode 100644
index a0bc7ba300..0000000000
--- a/package/runc/0001-nsenter-clone-proc-self-exe-to-avoid-exposing-host-b.patch
+++ /dev/null
@@ -1,338 +0,0 @@
-From 0a8e4117e7f715d5fbeef398405813ce8e88558b Mon Sep 17 00:00:00 2001
-From: Aleksa Sarai <asarai at suse.de>
-Date: Wed, 9 Jan 2019 13:40:01 +1100
-Subject: [PATCH] nsenter: clone /proc/self/exe to avoid exposing host binary
- to container
-
-There are quite a few circumstances where /proc/self/exe pointing to a
-pretty important container binary is a _bad_ thing, so to avoid this we
-have to make a copy (preferably doing self-clean-up and not being
-writeable).
-
-We require memfd_create(2) -- though there is an O_TMPFILE fallback --
-but we can always extend this to use a scratch MNT_DETACH overlayfs or
-tmpfs. The main downside to this approach is no page-cache sharing for
-the runc binary (which overlayfs would give us) but this is far less
-complicated.
-
-This is only done during nsenter so that it happens transparently to the
-Go code, and any libcontainer users benefit from it. This also makes
-ExtraFiles and --preserve-fds handling trivial (because we don't need to
-worry about it).
-
-Fixes: CVE-2019-5736
-Co-developed-by: Christian Brauner <christian.brauner at ubuntu.com>
-Signed-off-by: Aleksa Sarai <asarai at suse.de>
-Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
----
- libcontainer/nsenter/cloned_binary.c | 268 +++++++++++++++++++++++++++++++++++
- libcontainer/nsenter/nsexec.c        |  11 ++
- 2 files changed, 279 insertions(+)
- create mode 100644 libcontainer/nsenter/cloned_binary.c
-
-diff --git a/libcontainer/nsenter/cloned_binary.c b/libcontainer/nsenter/cloned_binary.c
-new file mode 100644
-index 00000000..c8a42c23
---- /dev/null
-+++ b/libcontainer/nsenter/cloned_binary.c
-@@ -0,0 +1,268 @@
-+/*
-+ * Copyright (C) 2019 Aleksa Sarai <cyphar at cyphar.com>
-+ * Copyright (C) 2019 SUSE LLC
-+ *
-+ * Licensed under the Apache License, Version 2.0 (the "License");
-+ * you may not use this file except in compliance with the License.
-+ * You may obtain a copy of the License at
-+ *
-+ *     http://www.apache.org/licenses/LICENSE-2.0
-+ *
-+ * Unless required by applicable law or agreed to in writing, software
-+ * distributed under the License is distributed on an "AS IS" BASIS,
-+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-+ * See the License for the specific language governing permissions and
-+ * limitations under the License.
-+ */
-+
-+#define _GNU_SOURCE
-+#include <unistd.h>
-+#include <stdio.h>
-+#include <stdlib.h>
-+#include <stdbool.h>
-+#include <string.h>
-+#include <limits.h>
-+#include <fcntl.h>
-+#include <errno.h>
-+
-+#include <sys/types.h>
-+#include <sys/stat.h>
-+#include <sys/vfs.h>
-+#include <sys/mman.h>
-+#include <sys/sendfile.h>
-+#include <sys/syscall.h>
-+
-+/* Use our own wrapper for memfd_create. */
-+#if !defined(SYS_memfd_create) && defined(__NR_memfd_create)
-+#  define SYS_memfd_create __NR_memfd_create
-+#endif
-+#ifdef SYS_memfd_create
-+#  define HAVE_MEMFD_CREATE
-+/* memfd_create(2) flags -- copied from <linux/memfd.h>. */
-+#  ifndef MFD_CLOEXEC
-+#    define MFD_CLOEXEC       0x0001U
-+#    define MFD_ALLOW_SEALING 0x0002U
-+#  endif
-+int memfd_create(const char *name, unsigned int flags)
-+{
-+	return syscall(SYS_memfd_create, name, flags);
-+}
-+#endif
-+
-+/* This comes directly from <linux/fcntl.h>. */
-+#ifndef F_LINUX_SPECIFIC_BASE
-+#  define F_LINUX_SPECIFIC_BASE 1024
-+#endif
-+#ifndef F_ADD_SEALS
-+#  define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
-+#  define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
-+#endif
-+#ifndef F_SEAL_SEAL
-+#  define F_SEAL_SEAL   0x0001	/* prevent further seals from being set */
-+#  define F_SEAL_SHRINK 0x0002	/* prevent file from shrinking */
-+#  define F_SEAL_GROW   0x0004	/* prevent file from growing */
-+#  define F_SEAL_WRITE  0x0008	/* prevent writes */
-+#endif
-+
-+#define RUNC_SENDFILE_MAX 0x7FFFF000 /* sendfile(2) is limited to 2GB. */
-+#ifdef HAVE_MEMFD_CREATE
-+#  define RUNC_MEMFD_COMMENT "runc_cloned:/proc/self/exe"
-+#  define RUNC_MEMFD_SEALS \
-+	(F_SEAL_SEAL | F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE)
-+#endif
-+
-+static void *must_realloc(void *ptr, size_t size)
-+{
-+	void *old = ptr;
-+	do {
-+		ptr = realloc(old, size);
-+	} while(!ptr);
-+	return ptr;
-+}
-+
-+/*
-+ * Verify whether we are currently in a self-cloned program (namely, is
-+ * /proc/self/exe a memfd). F_GET_SEALS will only succeed for memfds (or rather
-+ * for shmem files), and we want to be sure it's actually sealed.
-+ */
-+static int is_self_cloned(void)
-+{
-+	int fd, ret, is_cloned = 0;
-+
-+	fd = open("/proc/self/exe", O_RDONLY|O_CLOEXEC);
-+	if (fd < 0)
-+		return -ENOTRECOVERABLE;
-+
-+#ifdef HAVE_MEMFD_CREATE
-+	ret = fcntl(fd, F_GET_SEALS);
-+	is_cloned = (ret == RUNC_MEMFD_SEALS);
-+#else
-+	struct stat statbuf = {0};
-+	ret = fstat(fd, &statbuf);
-+	if (ret >= 0)
-+		is_cloned = (statbuf.st_nlink == 0);
-+#endif
-+	close(fd);
-+	return is_cloned;
-+}
-+
-+/*
-+ * Basic wrapper around mmap(2) that gives you the file length so you can
-+ * safely treat it as an ordinary buffer. Only gives you read access.
-+ */
-+static char *read_file(char *path, size_t *length)
-+{
-+	int fd;
-+	char buf[4096], *copy = NULL;
-+
-+	if (!length)
-+		return NULL;
-+
-+	fd = open(path, O_RDONLY | O_CLOEXEC);
-+	if (fd < 0)
-+		return NULL;
-+
-+	*length = 0;
-+	for (;;) {
-+		int n;
-+
-+		n = read(fd, buf, sizeof(buf));
-+		if (n < 0)
-+			goto error;
-+		if (!n)
-+			break;
-+
-+		copy = must_realloc(copy, (*length + n) * sizeof(*copy));
-+		memcpy(copy + *length, buf, n);
-+		*length += n;
-+	}
-+	close(fd);
-+	return copy;
-+
-+error:
-+	close(fd);
-+	free(copy);
-+	return NULL;
-+}
-+
-+/*
-+ * A poor-man's version of "xargs -0". Basically parses a given block of
-+ * NUL-delimited data, within the given length and adds a pointer to each entry
-+ * to the array of pointers.
-+ */
-+static int parse_xargs(char *data, int data_length, char ***output)
-+{
-+	int num = 0;
-+	char *cur = data;
-+
-+	if (!data || *output != NULL)
-+		return -1;
-+
-+	while (cur < data + data_length) {
-+		num++;
-+		*output = must_realloc(*output, (num + 1) * sizeof(**output));
-+		(*output)[num - 1] = cur;
-+		cur += strlen(cur) + 1;
-+	}
-+	(*output)[num] = NULL;
-+	return num;
-+}
-+
-+/*
-+ * "Parse" out argv and envp from /proc/self/cmdline and /proc/self/environ.
-+ * This is necessary because we are running in a context where we don't have a
-+ * main() that we can just get the arguments from.
-+ */
-+static int fetchve(char ***argv, char ***envp)
-+{
-+	char *cmdline = NULL, *environ = NULL;
-+	size_t cmdline_size, environ_size;
-+
-+	cmdline = read_file("/proc/self/cmdline", &cmdline_size);
-+	if (!cmdline)
-+		goto error;
-+	environ = read_file("/proc/self/environ", &environ_size);
-+	if (!environ)
-+		goto error;
-+
-+	if (parse_xargs(cmdline, cmdline_size, argv) <= 0)
-+		goto error;
-+	if (parse_xargs(environ, environ_size, envp) <= 0)
-+		goto error;
-+
-+	return 0;
-+
-+error:
-+	free(environ);
-+	free(cmdline);
-+	return -EINVAL;
-+}
-+
-+static int clone_binary(void)
-+{
-+	int binfd, memfd;
-+	ssize_t sent = 0;
-+
-+#ifdef HAVE_MEMFD_CREATE
-+	memfd = memfd_create(RUNC_MEMFD_COMMENT, MFD_CLOEXEC | MFD_ALLOW_SEALING);
-+#else
-+	memfd = open("/tmp", O_TMPFILE | O_EXCL | O_RDWR | O_CLOEXEC, 0711);
-+#endif
-+	if (memfd < 0)
-+		return -ENOTRECOVERABLE;
-+
-+	binfd = open("/proc/self/exe", O_RDONLY | O_CLOEXEC);
-+	if (binfd < 0)
-+		goto error;
-+
-+	sent = sendfile(memfd, binfd, NULL, RUNC_SENDFILE_MAX);
-+	close(binfd);
-+	if (sent < 0)
-+		goto error;
-+
-+#ifdef HAVE_MEMFD_CREATE
-+	int err = fcntl(memfd, F_ADD_SEALS, RUNC_MEMFD_SEALS);
-+	if (err < 0)
-+		goto error;
-+#else
-+	/* Need to re-open "memfd" as read-only to avoid execve(2) giving -EXTBUSY. */
-+	int newfd;
-+	char *fdpath = NULL;
-+
-+	if (asprintf(&fdpath, "/proc/self/fd/%d", memfd) < 0)
-+		goto error;
-+	newfd = open(fdpath, O_RDONLY | O_CLOEXEC);
-+	free(fdpath);
-+	if (newfd < 0)
-+		goto error;
-+
-+	close(memfd);
-+	memfd = newfd;
-+#endif
-+	return memfd;
-+
-+error:
-+	close(memfd);
-+	return -EIO;
-+}
-+
-+int ensure_cloned_binary(void)
-+{
-+	int execfd;
-+	char **argv = NULL, **envp = NULL;
-+
-+	/* Check that we're not self-cloned, and if we are then bail. */
-+	int cloned = is_self_cloned();
-+	if (cloned > 0 || cloned == -ENOTRECOVERABLE)
-+		return cloned;
-+
-+	if (fetchve(&argv, &envp) < 0)
-+		return -EINVAL;
-+
-+	execfd = clone_binary();
-+	if (execfd < 0)
-+		return -EIO;
-+
-+	fexecve(execfd, argv, envp);
-+	return -ENOEXEC;
-+}
-diff --git a/libcontainer/nsenter/nsexec.c b/libcontainer/nsenter/nsexec.c
-index 28269dfc..7750af35 100644
---- a/libcontainer/nsenter/nsexec.c
-+++ b/libcontainer/nsenter/nsexec.c
-@@ -534,6 +534,9 @@ void join_namespaces(char *nslist)
- 	free(namespaces);
- }
- 
-+/* Defined in cloned_binary.c. */
-+extern int ensure_cloned_binary(void);
-+
- void nsexec(void)
- {
- 	int pipenum;
-@@ -549,6 +552,14 @@ void nsexec(void)
- 	if (pipenum == -1)
- 		return;
- 
-+	/*
-+	 * We need to re-exec if we are not in a cloned binary. This is necessary
-+	 * to ensure that containers won't be able to access the host binary
-+	 * through /proc/self/exe. See CVE-2019-5736.
-+	 */
-+	if (ensure_cloned_binary() < 0)
-+		bail("could not ensure we are a cloned binary");
-+
- 	/* Parse all of the netlink configuration. */
- 	nl_parse(pipenum, &config);
- 
--- 
-2.11.0
-
diff --git a/package/runc/runc.hash b/package/runc/runc.hash
index 1636e5b8e9..24c30f5726 100644
--- a/package/runc/runc.hash
+++ b/package/runc/runc.hash
@@ -1,3 +1,3 @@
 # Locally computed
-sha256	a221f8380e7b5806031f54d423af6dde24c305dad49868056cf70e5f5f4ef771  runc-v1.0.0-rc6.tar.gz
+sha256	e8388b812d93a8a131a2a2fdd851847295c8e341721002940dadd2999fb81b51  runc-v1.0.0-rc7.tar.gz
 sha256  552a739c3b25792263f731542238b92f6f8d07e9a488eae27e6c4690038a8243  LICENSE
diff --git a/package/runc/runc.mk b/package/runc/runc.mk
index 0539661266..56463b468e 100644
--- a/package/runc/runc.mk
+++ b/package/runc/runc.mk
@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-RUNC_VERSION = v1.0.0-rc6
+RUNC_VERSION = v1.0.0-rc7
 RUNC_SITE = $(call github,opencontainers,runc,$(RUNC_VERSION))
 RUNC_LICENSE = Apache-2.0
 RUNC_LICENSE_FILES = LICENSE


More information about the buildroot mailing list