commit: a1e4f4e2eaaba19d9bf5b30fe799df91b8613a6b Author: Manuel Rüger <mrueg <AT> gentoo <DOT> org> AuthorDate: Mon Feb 11 17:43:06 2019 +0000 Commit: Manuel Rüger <mrueg <AT> gentoo <DOT> org> CommitDate: Mon Feb 11 17:44:14 2019 +0000 URL: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=a1e4f4e2
app-emulation/runc: Fix security vuln Package-Manager: Portage-2.3.59, Repoman-2.3.12 Signed-off-by: Manuel Rüger <mrueg <AT> gentoo.org> app-emulation/runc/files/runc-fix-cve.patch | 334 +++++++++++++++++++++ .../runc/runc-1.0.0_rc6_p20181203-r1.ebuild | 65 ++++ 2 files changed, 399 insertions(+) diff --git a/app-emulation/runc/files/runc-fix-cve.patch b/app-emulation/runc/files/runc-fix-cve.patch new file mode 100644 index 00000000000..fa85cb0444f --- /dev/null +++ b/app-emulation/runc/files/runc-fix-cve.patch @@ -0,0 +1,334 @@ +From 0a8e4117e7f715d5fbeef398405813ce8e88558b Mon Sep 17 00:00:00 2001 +From: Aleksa Sarai <asa...@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.brau...@ubuntu.com> +Signed-off-by: Aleksa Sarai <asa...@suse.de> +--- + 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 000000000..c8a42c23f +--- /dev/null ++++ b/libcontainer/nsenter/cloned_binary.c +@@ -0,0 +1,268 @@ ++/* ++ * Copyright (C) 2019 Aleksa Sarai <cyp...@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 28269dfc0..7750af35e 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); + diff --git a/app-emulation/runc/runc-1.0.0_rc6_p20181203-r1.ebuild b/app-emulation/runc/runc-1.0.0_rc6_p20181203-r1.ebuild new file mode 100644 index 00000000000..44d7e6ca8b4 --- /dev/null +++ b/app-emulation/runc/runc-1.0.0_rc6_p20181203-r1.ebuild @@ -0,0 +1,65 @@ +# Copyright 1999-2019 Gentoo Authors +# Distributed under the terms of the GNU General Public License v2 + +EAPI=6 +EGO_PN="github.com/opencontainers/${PN}" + +if [[ ${PV} == *9999 ]]; then + inherit golang-build golang-vcs +else + MY_PV="${PV/_/-}" + RUNC_COMMIT="96ec2177ae841256168fcf76954f7177af9446eb" # Change this when you update the ebuild + SRC_URI="https://${EGO_PN}/archive/${RUNC_COMMIT}.tar.gz -> ${P}.tar.gz" + KEYWORDS="~amd64 ~arm ~arm64 ~ppc64" + inherit golang-build golang-vcs-snapshot +fi + +DESCRIPTION="runc container cli tools" +HOMEPAGE="http://runc.io"; + +LICENSE="Apache-2.0" +SLOT="0" +IUSE="+ambient apparmor hardened +kmem +seccomp" + +RDEPEND=" + apparmor? ( sys-libs/libapparmor ) + seccomp? ( sys-libs/libseccomp ) + !app-emulation/docker-runc +" + +PATCHES=( "${FILESDIR}/${PN}-fix-cve.patch" ) + +src_prepare() { + pushd src/${EGO_PN} + default + sed -i -e "/^GIT_BRANCH/d"\ + -e "/^GIT_BRANCH_CLEAN/d"\ + -e "/^COMMIT_NO/d"\ + -e "s/COMMIT :=.*/COMMIT := ${RUNC_COMMIT}/"\ + Makefile || die + popd || die +} + +src_compile() { + # Taken from app-emulation/docker-1.7.0-r1 + export CGO_CFLAGS="-I${ROOT}/usr/include" + export CGO_LDFLAGS="$(usex hardened '-fno-PIC ' '') + -L${ROOT}/usr/$(get_libdir)" + + # build up optional flags + local options=( + $(usex ambient 'ambient' '') + $(usex apparmor 'apparmor' '') + $(usex seccomp 'seccomp' '') + $(usex kmem '' 'nokmem') + ) + + GOPATH="${S}" emake BUILDTAGS="${options[*]}" -C src/${EGO_PN} +} + +src_install() { + pushd src/${EGO_PN} || die + dobin runc + dodoc README.md PRINCIPLES.md + popd || die +}
