Port shim fix (#27)

Port shim fixes containerd/containerd#3264, containerd/containerd#3264

Update containerd to newest release/1.2 commit.

4 files changed, 533 insertions, 6 deletions

diff --git a/vendor/github.com/opencontainers/runc/README.md b/vendor/github.com/opencontainers/runc/README.md
index e755fb7bc..11fa4138b 100644
--- a/vendor/github.com/opencontainers/runc/README.md
+++ b/vendor/github.com/opencontainers/runc/README.md
@@ -16,10 +16,9 @@ This means that `runc` 1.0.0 should implement the 1.0 version of the specificati
 
 You can find official releases of `runc` on the [release](https://github.com/opencontainers/runc/releases) page.
 
-### Security
+## Security
 
-If you wish to report a security issue, please disclose the issue responsibly
-to security@opencontainers.org.
+Reporting process and disclosure communications are outlined in [/org/security](https://github.com/opencontainers/org/blob/master/security/)
 
 ## Building
 
diff --git a/vendor/github.com/opencontainers/runc/libcontainer/nsenter/cloned_binary.c b/vendor/github.com/opencontainers/runc/libcontainer/nsenter/cloned_binary.c
new file mode 100644
index 000000000..ad10f1406
--- /dev/null
+++ b/vendor/github.com/opencontainers/runc/libcontainer/nsenter/cloned_binary.c
@@ -0,0 +1,516 @@
+/*
+ * Copyright (C) 2019 Aleksa Sarai <cyphar@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/statfs.h>
+#include <sys/vfs.h>
+#include <sys/mman.h>
+#include <sys/mount.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
+/* 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)
+{
+#ifdef SYS_memfd_create
+	return syscall(SYS_memfd_create, name, flags);
+#else
+	errno = ENOSYS;
+	return -1;
+#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 CLONED_BINARY_ENV "_LIBCONTAINER_CLONED_BINARY"
+#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)
+
+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;
+	struct stat statbuf = {};
+	struct statfs fsbuf = {};
+
+	fd = open("/proc/self/exe", O_RDONLY|O_CLOEXEC);
+	if (fd < 0)
+		return -ENOTRECOVERABLE;
+
+	/*
+	 * Is the binary a fully-sealed memfd? We don't need CLONED_BINARY_ENV for
+	 * this, because you cannot write to a sealed memfd no matter what (so
+	 * sharing it isn't a bad thing -- and an admin could bind-mount a sealed
+	 * memfd to /usr/bin/runc to allow re-use).
+	 */
+	ret = fcntl(fd, F_GET_SEALS);
+	if (ret >= 0) {
+		is_cloned = (ret == RUNC_MEMFD_SEALS);
+		goto out;
+	}
+
+	/*
+	 * All other forms require CLONED_BINARY_ENV, since they are potentially
+	 * writeable (or we can't tell if they're fully safe) and thus we must
+	 * check the environment as an extra layer of defence.
+	 */
+	if (!getenv(CLONED_BINARY_ENV)) {
+		is_cloned = false;
+		goto out;
+	}
+
+	/*
+	 * Is the binary on a read-only filesystem? We can't detect bind-mounts in
+	 * particular (in-kernel they are identical to regular mounts) but we can
+	 * at least be sure that it's read-only. In addition, to make sure that
+	 * it's *our* bind-mount we check CLONED_BINARY_ENV.
+	 */
+	if (fstatfs(fd, &fsbuf) >= 0)
+		is_cloned |= (fsbuf.f_flags & MS_RDONLY);
+
+	/*
+	 * Okay, we're a tmpfile -- or we're currently running on RHEL <=7.6
+	 * which appears to have a borked backport of F_GET_SEALS. Either way,
+	 * having a file which has no hardlinks indicates that we aren't using
+	 * a host-side "runc" binary and this is something that a container
+	 * cannot fake (because unlinking requires being able to resolve the
+	 * path that you want to unlink).
+	 */
+	if (fstat(fd, &statbuf) >= 0)
+		is_cloned |= (statbuf.st_nlink == 0);
+
+out:
+	close(fd);
+	return is_cloned;
+}
+
+/* Read a given file into a new buffer, and providing the length. */
+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 (;;) {
+		ssize_t 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 from /proc/self/cmdline.
+ * 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 *cmdline = NULL;
+	size_t cmdline_size;
+
+	cmdline = read_file("/proc/self/cmdline", &cmdline_size);
+	if (!cmdline)
+		goto error;
+
+	if (parse_xargs(cmdline, cmdline_size, argv) <= 0)
+		goto error;
+
+	return 0;
+
+error:
+	free(cmdline);
+	return -EINVAL;
+}
+
+enum {
+	EFD_NONE = 0,
+	EFD_MEMFD,
+	EFD_FILE,
+};
+
+/*
+ * This comes from <linux/fcntl.h>. We can't hard-code __O_TMPFILE because it
+ * changes depending on the architecture. If we don't have O_TMPFILE we always
+ * have the mkostemp(3) fallback.
+ */
+#ifndef O_TMPFILE
+#  if defined(__O_TMPFILE) && defined(O_DIRECTORY)
+#    define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
+#  endif
+#endif
+
+static int make_execfd(int *fdtype)
+{
+	int fd = -1;
+	char template[PATH_MAX] = {0};
+	char *prefix = getenv("_LIBCONTAINER_STATEDIR");
+
+	if (!prefix || *prefix != '/')
+		prefix = "/tmp";
+	if (snprintf(template, sizeof(template), "%s/runc.XXXXXX", prefix) < 0)
+		return -1;
+
+	/*
+	 * Now try memfd, it's much nicer than actually creating a file in STATEDIR
+	 * since it's easily detected thanks to sealing and also doesn't require
+	 * assumptions about STATEDIR.
+	 */
+	*fdtype = EFD_MEMFD;
+	fd = memfd_create(RUNC_MEMFD_COMMENT, MFD_CLOEXEC | MFD_ALLOW_SEALING);
+	if (fd >= 0)
+		return fd;
+	if (errno != ENOSYS && errno != EINVAL)
+		goto error;
+
+#ifdef O_TMPFILE
+	/*
+	 * Try O_TMPFILE to avoid races where someone might snatch our file. Note
+	 * that O_EXCL isn't actually a security measure here (since you can just
+	 * fd re-open it and clear O_EXCL).
+	 */
+	*fdtype = EFD_FILE;
+	fd = open(prefix, O_TMPFILE | O_EXCL | O_RDWR | O_CLOEXEC, 0700);
+	if (fd >= 0) {
+		struct stat statbuf = {};
+		bool working_otmpfile = false;
+
+		/*
+		 * open(2) ignores unknown O_* flags -- yeah, I was surprised when I
+		 * found this out too. As a result we can't check for EINVAL. However,
+		 * if we get nlink != 0 (or EISDIR) then we know that this kernel
+		 * doesn't support O_TMPFILE.
+		 */
+		if (fstat(fd, &statbuf) >= 0)
+			working_otmpfile = (statbuf.st_nlink == 0);
+
+		if (working_otmpfile)
+			return fd;
+
+		/* Pretend that we got EISDIR since O_TMPFILE failed. */
+		close(fd);
+		errno = EISDIR;
+	}
+	if (errno != EISDIR)
+		goto error;
+#endif /* defined(O_TMPFILE) */
+
+	/*
+	 * Our final option is to create a temporary file the old-school way, and
+	 * then unlink it so that nothing else sees it by accident.
+	 */
+	*fdtype = EFD_FILE;
+	fd = mkostemp(template, O_CLOEXEC);
+	if (fd >= 0) {
+		if (unlink(template) >= 0)
+			return fd;
+		close(fd);
+	}
+
+error:
+	*fdtype = EFD_NONE;
+	return -1;
+}
+
+static int seal_execfd(int *fd, int fdtype)
+{
+	switch (fdtype) {
+	case EFD_MEMFD:
+		return fcntl(*fd, F_ADD_SEALS, RUNC_MEMFD_SEALS);
+	case EFD_FILE: {
+		/* Need to re-open our pseudo-memfd as an O_PATH to avoid execve(2) giving -ETXTBSY. */
+		int newfd;
+		char fdpath[PATH_MAX] = {0};
+
+		if (fchmod(*fd, 0100) < 0)
+			return -1;
+
+		if (snprintf(fdpath, sizeof(fdpath), "/proc/self/fd/%d", *fd) < 0)
+			return -1;
+
+		newfd = open(fdpath, O_PATH | O_CLOEXEC);
+		if (newfd < 0)
+			return -1;
+
+		close(*fd);
+		*fd = newfd;
+		return 0;
+	}
+	default:
+	   break;
+	}
+	return -1;
+}
+
+static int try_bindfd(void)
+{
+	int fd, ret = -1;
+	char template[PATH_MAX] = {0};
+	char *prefix = getenv("_LIBCONTAINER_STATEDIR");
+
+	if (!prefix || *prefix != '/')
+		prefix = "/tmp";
+	if (snprintf(template, sizeof(template), "%s/runc.XXXXXX", prefix) < 0)
+		return ret;
+
+	/*
+	 * We need somewhere to mount it, mounting anything over /proc/self is a
+	 * BAD idea on the host -- even if we do it temporarily.
+	 */
+	fd = mkstemp(template);
+	if (fd < 0)
+		return ret;
+	close(fd);
+
+	/*
+	 * For obvious reasons this won't work in rootless mode because we haven't
+	 * created a userns+mntns -- but getting that to work will be a bit
+	 * complicated and it's only worth doing if someone actually needs it.
+	 */
+	ret = -EPERM;
+	if (mount("/proc/self/exe", template, "", MS_BIND, "") < 0)
+		goto out;
+	if (mount("", template, "", MS_REMOUNT | MS_BIND | MS_RDONLY, "") < 0)
+		goto out_umount;
+
+
+	/* Get read-only handle that we're sure can't be made read-write. */
+	ret = open(template, O_PATH | O_CLOEXEC);
+
+out_umount:
+	/*
+	 * Make sure the MNT_DETACH works, otherwise we could get remounted
+	 * read-write and that would be quite bad (the fd would be made read-write
+	 * too, invalidating the protection).
+	 */
+	if (umount2(template, MNT_DETACH) < 0) {
+		if (ret >= 0)
+			close(ret);
+		ret = -ENOTRECOVERABLE;
+	}
+
+out:
+	/*
+	 * We don't care about unlink errors, the worst that happens is that
+	 * there's an empty file left around in STATEDIR.
+	 */
+	unlink(template);
+	return ret;
+}
+
+static ssize_t fd_to_fd(int outfd, int infd)
+{
+	ssize_t total = 0;
+	char buffer[4096];
+
+	for (;;) {
+		ssize_t nread, nwritten = 0;
+
+		nread = read(infd, buffer, sizeof(buffer));
+		if (nread < 0)
+			return -1;
+		if (!nread)
+			break;
+
+		do {
+			ssize_t n = write(outfd, buffer + nwritten, nread - nwritten);
+			if (n < 0)
+				return -1;
+			nwritten += n;
+		} while(nwritten < nread);
+
+		total += nwritten;
+	}
+
+	return total;
+}
+
+static int clone_binary(void)
+{
+	int binfd, execfd;
+	struct stat statbuf = {};
+	size_t sent = 0;
+	int fdtype = EFD_NONE;
+
+	/*
+	 * Before we resort to copying, let's try creating an ro-binfd in one shot
+	 * by getting a handle for a read-only bind-mount of the execfd.
+	 */
+	execfd = try_bindfd();
+	if (execfd >= 0)
+		return execfd;
+
+	/*
+	 * Dammit, that didn't work -- time to copy the binary to a safe place we
+	 * can seal the contents.
+	 */
+	execfd = make_execfd(&fdtype);
+	if (execfd < 0 || fdtype == EFD_NONE)
+		return -ENOTRECOVERABLE;
+
+	binfd = open("/proc/self/exe", O_RDONLY | O_CLOEXEC);
+	if (binfd < 0)
+		goto error;
+
+	if (fstat(binfd, &statbuf) < 0)
+		goto error_binfd;
+
+	while (sent < statbuf.st_size) {
+		int n = sendfile(execfd, binfd, NULL, statbuf.st_size - sent);
+		if (n < 0) {
+			/* sendfile can fail so we fallback to a dumb user-space copy. */
+			n = fd_to_fd(execfd, binfd);
+			if (n < 0)
+				goto error_binfd;
+		}
+		sent += n;
+	}
+	close(binfd);
+	if (sent != statbuf.st_size)
+		goto error;
+
+	if (seal_execfd(&execfd, fdtype) < 0)
+		goto error;
+
+	return execfd;
+
+error_binfd:
+	close(binfd);
+error:
+	close(execfd);
+	return -EIO;
+}
+
+/* Get cheap access to the environment. */
+extern char **environ;
+
+int ensure_cloned_binary(void)
+{
+	int execfd;
+	char **argv = 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) < 0)
+		return -EINVAL;
+
+	execfd = clone_binary();
+	if (execfd < 0)
+		return -EIO;
+
+	if (putenv(CLONED_BINARY_ENV "=1"))
+		goto error;
+
+	fexecve(execfd, argv, environ);
+error:
+	close(execfd);
+	return -ENOEXEC;
+}
diff --git a/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c b/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c
index 28269dfc0..7750af35e 100644
--- a/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c
+++ b/vendor/github.com/opencontainers/runc/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);
 
diff --git a/vendor/github.com/opencontainers/runc/vendor.conf b/vendor/github.com/opencontainers/runc/vendor.conf
index fadbe0707..22cba0f1b 100644
--- a/vendor/github.com/opencontainers/runc/vendor.conf
+++ b/vendor/github.com/opencontainers/runc/vendor.conf
@@ -1,10 +1,11 @@
 # OCI runtime-spec. When updating this, make sure you use a version tag rather
 # than a commit ID so it's much more obvious what version of the spec we are
 # using.
-github.com/opencontainers/runtime-spec 5684b8af48c1ac3b1451fa499724e30e3c20a294
+github.com/opencontainers/runtime-spec 29686dbc5559d93fb1ef402eeda3e35c38d75af4
 # Core libcontainer functionality.
+github.com/checkpoint-restore/go-criu v3.11
 github.com/mrunalp/fileutils ed869b029674c0e9ce4c0dfa781405c2d9946d08
-github.com/opencontainers/selinux v1.0.0-rc1
+github.com/opencontainers/selinux v1.2.2
 github.com/seccomp/libseccomp-golang 84e90a91acea0f4e51e62bc1a75de18b1fc0790f
 github.com/sirupsen/logrus a3f95b5c423586578a4e099b11a46c2479628cac
 github.com/syndtr/gocapability db04d3cc01c8b54962a58ec7e491717d06cfcc16
@@ -18,7 +19,7 @@ github.com/golang/protobuf 18c9bb3261723cd5401db4d0c9fbc5c3b6c70fe8
 github.com/cyphar/filepath-securejoin v0.2.1
 github.com/docker/go-units v0.2.0
 github.com/urfave/cli d53eb991652b1d438abdd34ce4bfa3ef1539108e
-golang.org/x/sys 7ddbeae9ae08c6a06a59597f0c9edbc5ff2444ce https://github.com/golang/sys
+golang.org/x/sys 41f3e6584952bb034a481797859f6ab34b6803bd https://github.com/golang/sys
 
 # console dependencies
 github.com/containerd/console 2748ece16665b45a47f884001d5831ec79703880