Package: release.debian.org Severity: normal Tags: stretch User: release.debian.org@packages.debian.org Usertags: pu This includes patch for CVE-2019-5736. As discussed with security-team, there's no urgency to go through scurity-upload. So let's fix it through stable-proposed-updates. -- Shengjing Zhu
diff -Nru runc-0.1.1+dfsg1/debian/changelog runc-0.1.1+dfsg1/debian/changelog
--- runc-0.1.1+dfsg1/debian/changelog 2017-02-01 23:17:54.000000000 +0800
+++ runc-0.1.1+dfsg1/debian/changelog 2019-03-19 00:50:07.000000000 +0800
@@ -1,3 +1,10 @@
+runc (0.1.1+dfsg1-2+deb9u1) stretch; urgency=medium
+
+ * Team upload.
+ * Add patch to address CVE-2019-5736 (Closes: #922050)
+
+ -- Shengjing Zhu <zhsj@debian.org> Tue, 19 Mar 2019 00:50:07 +0800
+
runc (0.1.1+dfsg1-2) unstable; urgency=medium
* Team upload.
diff -Nru runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch
--- runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch 1970-01-01 08:00:00.000000000 +0800
+++ runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch 2019-03-19 00:50:07.000000000 +0800
@@ -0,0 +1,572 @@
+From: Shengjing Zhu <zhsj@debian.org>
+Date: Sun, 10 Mar 2019 17:47:46 +0800
+Subject: CVE-2019-5736
+
+Backport upstream patches for CVE-2019-5736
+
+Fix in nsexec.c is adjusted to current version
+
+Include commits:
+2d4a37b427167907ef2402586a8e8e2931a22490 nsenter: cloned_binary: userspace copy fallback if sendfile fails
+16612d74de5f84977e50a9c8ead7f0e9e13b8628 nsenter: cloned_binary: try to ro-bind /proc/self/exe before copying
+af9da0a45082783f6005b252488943b5ee2e2138 nsenter: cloned_binary: use the runc statedir for O_TMPFILE
+2429d59352b81f6b9cc79b5ed26780c5fe6ba4ec nsenter: cloned_binary: expand and add pre-3.11 fallbacks
+5b775bf297c47a6bc50e36da89d1ec74a6fa01dc nsenter: cloned_binary: detect and handle short copies
+bb7d8b1f41f7bf0399204d54009d6da57c3cc775 nsexec (CVE-2019-5736): avoid parsing environ
+0a8e4117e7f715d5fbeef398405813ce8e88558b nsenter: clone /proc/self/exe to avoid exposing host binary to container
+
+Bug-Debian: https://bugs.debian.org/922050
+---
+ libcontainer/nsenter/cloned_binary.c | 516 +++++++++++++++++++++++++++++++++++
+ libcontainer/nsenter/nsexec.c | 8 +
+ 2 files changed, 524 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 0000000..b410e29
+--- /dev/null
++++ b/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 = secure_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 = secure_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/libcontainer/nsenter/nsexec.c b/libcontainer/nsenter/nsexec.c
+index 3c74c63..a6ec725 100644
+--- a/libcontainer/nsenter/nsexec.c
++++ b/libcontainer/nsenter/nsexec.c
+@@ -353,6 +353,9 @@ static struct nsenter_config process_nl_attributes(int pipenum, char *data, int
+ return config;
+ }
+
++/* Defined in cloned_binary.c. */
++extern int ensure_cloned_binary(void);
++
+ void nsexec(void)
+ {
+ int pipenum;
+@@ -364,6 +367,11 @@ void nsexec(void)
+ return;
+ }
+
++ if (ensure_cloned_binary() < 0) {
++ pr_perror("could not ensure we are a cloned binary");
++ exit(1);
++ }
++
+ /* make the process non-dumpable */
+ if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) != 0) {
+ pr_perror("Failed to set process as non-dumpable");
diff -Nru runc-0.1.1+dfsg1/debian/patches/series runc-0.1.1+dfsg1/debian/patches/series
--- runc-0.1.1+dfsg1/debian/patches/series 2017-02-01 12:48:05.000000000 +0800
+++ runc-0.1.1+dfsg1/debian/patches/series 2019-03-19 00:50:07.000000000 +0800
@@ -1,2 +1,3 @@
disable-failing-tests.patch
cve-2016-9962.patch
+CVE-2019-5736.patch
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