266 lines
7.4 KiB
Diff
266 lines
7.4 KiB
Diff
From: Stefan Hajnoczi <stefanha@redhat.com>
|
|
Date: Mon, 27 Jan 2020 19:01:30 +0000
|
|
Subject: [PATCH] virtiofsd: add seccomp whitelist
|
|
|
|
Only allow system calls that are needed by virtiofsd. All other system
|
|
calls cause SIGSYS to be directed at the thread and the process will
|
|
coredump.
|
|
|
|
Restricting system calls reduces the kernel attack surface and limits
|
|
what the process can do when compromised.
|
|
|
|
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
with additional entries by:
|
|
Signed-off-by: Ganesh Maharaj Mahalingam <ganesh.mahalingam@intel.com>
|
|
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
|
|
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
|
|
Signed-off-by: piaojun <piaojun@huawei.com>
|
|
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
|
|
Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
|
|
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
|
|
(cherry picked from commit 4f8bde99c175ffd86b5125098a4707d43f5e80c6)
|
|
---
|
|
Makefile | 5 +-
|
|
tools/virtiofsd/Makefile.objs | 5 +-
|
|
tools/virtiofsd/passthrough_ll.c | 2 +
|
|
tools/virtiofsd/seccomp.c | 151 +++++++++++++++++++++++++++++++
|
|
tools/virtiofsd/seccomp.h | 14 +++
|
|
5 files changed, 174 insertions(+), 3 deletions(-)
|
|
create mode 100644 tools/virtiofsd/seccomp.c
|
|
create mode 100644 tools/virtiofsd/seccomp.h
|
|
|
|
diff --git a/Makefile b/Makefile
|
|
index aebb57aed8..9a17e34603 100644
|
|
--- a/Makefile
|
|
+++ b/Makefile
|
|
@@ -330,7 +330,7 @@ endif
|
|
endif
|
|
endif
|
|
|
|
-ifdef CONFIG_LINUX
|
|
+ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP),yy)
|
|
HELPERS-y += virtiofsd$(EXESUF)
|
|
vhost-user-json-y += tools/virtiofsd/50-qemu-virtiofsd.json
|
|
endif
|
|
@@ -680,7 +680,8 @@ rdmacm-mux$(EXESUF): LIBS += "-libumad"
|
|
rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS)
|
|
$(call LINK, $^)
|
|
|
|
-ifdef CONFIG_LINUX # relies on Linux-specific syscalls
|
|
+# relies on Linux-specific syscalls
|
|
+ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP),yy)
|
|
virtiofsd$(EXESUF): $(virtiofsd-obj-y) libvhost-user.a $(COMMON_LDADDS)
|
|
$(call LINK, $^)
|
|
endif
|
|
diff --git a/tools/virtiofsd/Makefile.objs b/tools/virtiofsd/Makefile.objs
|
|
index 45a807500d..076f667e46 100644
|
|
--- a/tools/virtiofsd/Makefile.objs
|
|
+++ b/tools/virtiofsd/Makefile.objs
|
|
@@ -5,5 +5,8 @@ virtiofsd-obj-y = buffer.o \
|
|
fuse_signals.o \
|
|
fuse_virtio.o \
|
|
helper.o \
|
|
- passthrough_ll.o
|
|
+ passthrough_ll.o \
|
|
+ seccomp.o
|
|
|
|
+seccomp.o-cflags := $(SECCOMP_CFLAGS)
|
|
+seccomp.o-libs := $(SECCOMP_LIBS)
|
|
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
|
|
index 0947d14e5b..bd8925bd83 100644
|
|
--- a/tools/virtiofsd/passthrough_ll.c
|
|
+++ b/tools/virtiofsd/passthrough_ll.c
|
|
@@ -59,6 +59,7 @@
|
|
#include <unistd.h>
|
|
|
|
#include "passthrough_helpers.h"
|
|
+#include "seccomp.h"
|
|
|
|
struct lo_map_elem {
|
|
union {
|
|
@@ -2091,6 +2092,7 @@ static void setup_sandbox(struct lo_data *lo, struct fuse_session *se)
|
|
{
|
|
setup_namespaces(lo, se);
|
|
setup_mounts(lo->source);
|
|
+ setup_seccomp();
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c
|
|
new file mode 100644
|
|
index 0000000000..691fb63dea
|
|
--- /dev/null
|
|
+++ b/tools/virtiofsd/seccomp.c
|
|
@@ -0,0 +1,151 @@
|
|
+/*
|
|
+ * Seccomp sandboxing for virtiofsd
|
|
+ *
|
|
+ * Copyright (C) 2019 Red Hat, Inc.
|
|
+ *
|
|
+ * SPDX-License-Identifier: GPL-2.0-or-later
|
|
+ */
|
|
+
|
|
+#include "qemu/osdep.h"
|
|
+#include "seccomp.h"
|
|
+#include "fuse_i.h"
|
|
+#include "fuse_log.h"
|
|
+#include <errno.h>
|
|
+#include <glib.h>
|
|
+#include <seccomp.h>
|
|
+#include <stdlib.h>
|
|
+
|
|
+/* Bodge for libseccomp 2.4.2 which broke ppoll */
|
|
+#if !defined(__SNR_ppoll) && defined(__SNR_brk)
|
|
+#ifdef __NR_ppoll
|
|
+#define __SNR_ppoll __NR_ppoll
|
|
+#else
|
|
+#define __SNR_ppoll __PNR_ppoll
|
|
+#endif
|
|
+#endif
|
|
+
|
|
+static const int syscall_whitelist[] = {
|
|
+ /* TODO ireg sem*() syscalls */
|
|
+ SCMP_SYS(brk),
|
|
+ SCMP_SYS(capget), /* For CAP_FSETID */
|
|
+ SCMP_SYS(capset),
|
|
+ SCMP_SYS(clock_gettime),
|
|
+ SCMP_SYS(clone),
|
|
+#ifdef __NR_clone3
|
|
+ SCMP_SYS(clone3),
|
|
+#endif
|
|
+ SCMP_SYS(close),
|
|
+ SCMP_SYS(copy_file_range),
|
|
+ SCMP_SYS(dup),
|
|
+ SCMP_SYS(eventfd2),
|
|
+ SCMP_SYS(exit),
|
|
+ SCMP_SYS(exit_group),
|
|
+ SCMP_SYS(fallocate),
|
|
+ SCMP_SYS(fchmodat),
|
|
+ SCMP_SYS(fchownat),
|
|
+ SCMP_SYS(fcntl),
|
|
+ SCMP_SYS(fdatasync),
|
|
+ SCMP_SYS(fgetxattr),
|
|
+ SCMP_SYS(flistxattr),
|
|
+ SCMP_SYS(flock),
|
|
+ SCMP_SYS(fremovexattr),
|
|
+ SCMP_SYS(fsetxattr),
|
|
+ SCMP_SYS(fstat),
|
|
+ SCMP_SYS(fstatfs),
|
|
+ SCMP_SYS(fsync),
|
|
+ SCMP_SYS(ftruncate),
|
|
+ SCMP_SYS(futex),
|
|
+ SCMP_SYS(getdents),
|
|
+ SCMP_SYS(getdents64),
|
|
+ SCMP_SYS(getegid),
|
|
+ SCMP_SYS(geteuid),
|
|
+ SCMP_SYS(getpid),
|
|
+ SCMP_SYS(gettid),
|
|
+ SCMP_SYS(gettimeofday),
|
|
+ SCMP_SYS(linkat),
|
|
+ SCMP_SYS(lseek),
|
|
+ SCMP_SYS(madvise),
|
|
+ SCMP_SYS(mkdirat),
|
|
+ SCMP_SYS(mknodat),
|
|
+ SCMP_SYS(mmap),
|
|
+ SCMP_SYS(mprotect),
|
|
+ SCMP_SYS(mremap),
|
|
+ SCMP_SYS(munmap),
|
|
+ SCMP_SYS(newfstatat),
|
|
+ SCMP_SYS(open),
|
|
+ SCMP_SYS(openat),
|
|
+ SCMP_SYS(ppoll),
|
|
+ SCMP_SYS(prctl), /* TODO restrict to just PR_SET_NAME? */
|
|
+ SCMP_SYS(preadv),
|
|
+ SCMP_SYS(pread64),
|
|
+ SCMP_SYS(pwritev),
|
|
+ SCMP_SYS(pwrite64),
|
|
+ SCMP_SYS(read),
|
|
+ SCMP_SYS(readlinkat),
|
|
+ SCMP_SYS(recvmsg),
|
|
+ SCMP_SYS(renameat),
|
|
+ SCMP_SYS(renameat2),
|
|
+ SCMP_SYS(rt_sigaction),
|
|
+ SCMP_SYS(rt_sigprocmask),
|
|
+ SCMP_SYS(rt_sigreturn),
|
|
+ SCMP_SYS(sendmsg),
|
|
+ SCMP_SYS(setresgid),
|
|
+ SCMP_SYS(setresuid),
|
|
+#ifdef __NR_setresgid32
|
|
+ SCMP_SYS(setresgid32),
|
|
+#endif
|
|
+#ifdef __NR_setresuid32
|
|
+ SCMP_SYS(setresuid32),
|
|
+#endif
|
|
+ SCMP_SYS(set_robust_list),
|
|
+ SCMP_SYS(symlinkat),
|
|
+ SCMP_SYS(time), /* Rarely needed, except on static builds */
|
|
+ SCMP_SYS(tgkill),
|
|
+ SCMP_SYS(unlinkat),
|
|
+ SCMP_SYS(utimensat),
|
|
+ SCMP_SYS(write),
|
|
+ SCMP_SYS(writev),
|
|
+};
|
|
+
|
|
+void setup_seccomp(void)
|
|
+{
|
|
+ scmp_filter_ctx ctx;
|
|
+ size_t i;
|
|
+
|
|
+#ifdef SCMP_ACT_KILL_PROCESS
|
|
+ ctx = seccomp_init(SCMP_ACT_KILL_PROCESS);
|
|
+ /* Handle a newer libseccomp but an older kernel */
|
|
+ if (!ctx && errno == EOPNOTSUPP) {
|
|
+ ctx = seccomp_init(SCMP_ACT_TRAP);
|
|
+ }
|
|
+#else
|
|
+ ctx = seccomp_init(SCMP_ACT_TRAP);
|
|
+#endif
|
|
+ if (!ctx) {
|
|
+ fuse_log(FUSE_LOG_ERR, "seccomp_init() failed\n");
|
|
+ exit(1);
|
|
+ }
|
|
+
|
|
+ for (i = 0; i < G_N_ELEMENTS(syscall_whitelist); i++) {
|
|
+ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW,
|
|
+ syscall_whitelist[i], 0) != 0) {
|
|
+ fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d",
|
|
+ syscall_whitelist[i]);
|
|
+ exit(1);
|
|
+ }
|
|
+ }
|
|
+
|
|
+ /* libvhost-user calls this for post-copy migration, we don't need it */
|
|
+ if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOSYS),
|
|
+ SCMP_SYS(userfaultfd), 0) != 0) {
|
|
+ fuse_log(FUSE_LOG_ERR, "seccomp_rule_add userfaultfd failed\n");
|
|
+ exit(1);
|
|
+ }
|
|
+
|
|
+ if (seccomp_load(ctx) < 0) {
|
|
+ fuse_log(FUSE_LOG_ERR, "seccomp_load() failed\n");
|
|
+ exit(1);
|
|
+ }
|
|
+
|
|
+ seccomp_release(ctx);
|
|
+}
|
|
diff --git a/tools/virtiofsd/seccomp.h b/tools/virtiofsd/seccomp.h
|
|
new file mode 100644
|
|
index 0000000000..86bce72652
|
|
--- /dev/null
|
|
+++ b/tools/virtiofsd/seccomp.h
|
|
@@ -0,0 +1,14 @@
|
|
+/*
|
|
+ * Seccomp sandboxing for virtiofsd
|
|
+ *
|
|
+ * Copyright (C) 2019 Red Hat, Inc.
|
|
+ *
|
|
+ * SPDX-License-Identifier: GPL-2.0-or-later
|
|
+ */
|
|
+
|
|
+#ifndef VIRTIOFSD_SECCOMP_H
|
|
+#define VIRTIOFSD_SECCOMP_H
|
|
+
|
|
+void setup_seccomp(void);
|
|
+
|
|
+#endif /* VIRTIOFSD_SECCOMP_H */
|