For passthrough, it passes corresponding ioctls to host directly. Currently only these ioctls that handling persistent inode flags, i.e., FS_IOC_[G|S]ETFLAGS and FS_IOC_FS[G|S]ETXATTR are supported for security concern, though it's implemented in a quite general way, so that we can expand the scope of allowed ioctls if it is really needed later.
Signed-off-by: Jeffle Xu <[email protected]> --- tools/virtiofsd/passthrough_ll.c | 59 +++++++++++++++++++++++++++ tools/virtiofsd/passthrough_seccomp.c | 1 + 2 files changed, 60 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index b76d878509..5969d67810 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -47,6 +47,7 @@ #include <dirent.h> #include <pthread.h> #include <sys/file.h> +#include <sys/ioctl.h> #include <sys/mount.h> #include <sys/prctl.h> #include <sys/resource.h> @@ -54,6 +55,7 @@ #include <sys/wait.h> #include <sys/xattr.h> #include <syslog.h> +#include <linux/fs.h> #include "qemu/cutils.h" #include "passthrough_helpers.h" @@ -2105,6 +2107,62 @@ out: fuse_reply_err(req, saverr); } + +static void lo_ioctl(fuse_req_t req, fuse_ino_t ino, unsigned int cmd, void *arg, + struct fuse_file_info *fi, unsigned flags, const void *in_buf, + size_t in_bufsz, size_t out_bufsz) +{ + int fd = lo_fi_fd(req, fi); + int res; + int saverr = ENOSYS; + int dir; + void *buf = NULL; + size_t size = 0; + + fuse_log(FUSE_LOG_DEBUG, "lo_ioctl(ino=%" PRIu64 ", cmd=0x%x, flags=0x%x, " + "in_bufsz = %lu, out_bufsz = %lu)\n", + ino, cmd, flags, in_bufsz, out_bufsz); + + if (cmd != FS_IOC_SETFLAGS || cmd != FS_IOC_GETFLAGS || + cmd != FS_IOC_FSSETXATTR || cmd != FS_IOC_FSGETXATTR) + goto out; + + /* unrestricted ioctl is not supported yet */ + if (flags & FUSE_IOCTL_UNRESTRICTED) + goto out; + + dir = _IOC_DIR(cmd); + + if (dir & _IOC_READ) { + size = out_bufsz; + buf = malloc(size); + if (!buf) + goto out_err; + + if (dir & _IOC_WRITE) + memcpy(buf, in_buf, size); + + res = ioctl(fd, cmd, buf); + } + else if (dir & _IOC_WRITE) { + res = ioctl(fd, cmd, in_buf); + } + else { + res = ioctl(fd, cmd, arg); + } + + if (res < 0) + goto out_err; + + fuse_reply_ioctl(req, 0, buf, size); + return; + +out_err: + saverr = errno; +out: + fuse_reply_err(req, saverr); +} + static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) { @@ -3278,6 +3336,7 @@ static struct fuse_lowlevel_ops lo_oper = { .fsyncdir = lo_fsyncdir, .create = lo_create, .getlk = lo_getlk, + .ioctl = lo_ioctl, .setlk = lo_setlk, .open = lo_open, .release = lo_release, diff --git a/tools/virtiofsd/passthrough_seccomp.c b/tools/virtiofsd/passthrough_seccomp.c index 62441cfcdb..2a5f7614fc 100644 --- a/tools/virtiofsd/passthrough_seccomp.c +++ b/tools/virtiofsd/passthrough_seccomp.c @@ -62,6 +62,7 @@ static const int syscall_allowlist[] = { SCMP_SYS(gettid), SCMP_SYS(gettimeofday), SCMP_SYS(getxattr), + SCMP_SYS(ioctl), SCMP_SYS(linkat), SCMP_SYS(listxattr), SCMP_SYS(lseek), -- 2.27.0 _______________________________________________ Virtio-fs mailing list [email protected] https://listman.redhat.com/mailman/listinfo/virtio-fs
