Add .ioctl() support for passthrough, in prep for the following support
for following per-file DAX feature.
Once advertising support for per-file DAX feature, virtiofsd should
support storing FS_DAX_FL flag persistently passed by
FS_IOC_SETFLAGS/FS_IOC_FSSETXATTR ioctl, and set FUSE_ATTR_DAX in
FUSE_LOOKUP accordingly if the file is capable of per-file DAX.
When it comes to passthrough, it passes corresponding ioctls to host
directly. Currently only these ioctls that are needed for per-file DAX
feature, i.e., FS_IOC_GETFLAGS/FS_IOC_SETFLAGS and
FS_IOC_FSGETXATTR/FS_IOC_FSSETXATTR are supported. Later we can restrict
the flags/attributes allowed to be set to reinforce the security, or
extend the scope of allowed ioctls if it is really needed later.
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
tools/virtiofsd/passthrough_ll.c | 53 +++++++++++++++++++++++++++
tools/virtiofsd/passthrough_seccomp.c | 1 +
2 files changed, 54 insertions(+)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index b76d878509..e170b17adb 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -54,6 +54,7 @@
#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 +2106,57 @@ 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;
+
+ 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);
+
+ /* unrestricted ioctl is not supported yet */
+ if (flags & FUSE_IOCTL_UNRESTRICTED)
+ goto out;
+
+ /*
+ * Currently only those ioctls needed to support per-file DAX feature,
+ * i.e., FS_IOC_GETFLAGS/FS_IOC_SETFLAGS and
+ * FS_IOC_FSGETXATTR/FS_IOC_FSSETXATTR are supported.
+ */
+ if (cmd == FS_IOC_SETFLAGS || cmd == FS_IOC_FSSETXATTR) {
+ res = ioctl(fd, cmd, in_buf);
+ if (res < 0)
+ goto out_err;
+
+ fuse_reply_ioctl(req, 0, NULL, 0);
+ }
+ else if (cmd == FS_IOC_GETFLAGS || cmd == FS_IOC_FSGETXATTR) {
+ /* reused for 'unsigned int' for FS_IOC_GETFLAGS */
+ struct fsxattr attr;
+
+ res = ioctl(fd, cmd, &attr);
+ if (res < 0)
+ goto out_err;
+
+ fuse_reply_ioctl(req, 0, &attr, out_bufsz);
+ }
+ else {
+ fuse_log(FUSE_LOG_DEBUG, "Unsupported ioctl 0x%x\n", cmd);
+ goto out;
+ }
+
+ 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)
{
@@ -3279,6 +3331,7 @@ static struct fuse_lowlevel_ops lo_oper = {
.create = lo_create,
.getlk = lo_getlk,
.setlk = lo_setlk,
+ .ioctl = lo_ioctl,
.open = lo_open,
.release = lo_release,
.flush = lo_flush,
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
