From: Stefan Hajnoczi <stefa...@redhat.com>
There is a small change in behavior: if fuse_write_in->size doesn't
match the input buffer size then the request is failed. Previously
write requests with 1 fuse_buf element would truncate to
fuse_write_in->size.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
contrib/virtiofsd/fuse_lowlevel.c | 62 +++++++++++++++++++------------
1 file changed, 38 insertions(+), 24 deletions(-)
diff --git a/contrib/virtiofsd/fuse_lowlevel.c
b/contrib/virtiofsd/fuse_lowlevel.c
index 2bd2ba00b9..7927348398 100644
--- a/contrib/virtiofsd/fuse_lowlevel.c
+++ b/contrib/virtiofsd/fuse_lowlevel.c
@@ -1006,7 +1006,8 @@ static void do_write(fuse_req_t req, fuse_ino_t nodeid,
const void *inarg)
fuse_reply_err(req, ENOSYS);
}
-static void do_write_buf(fuse_req_t req, fuse_ino_t nodeid, const void *inarg,
+static void do_write_buf(fuse_req_t req, fuse_ino_t nodeid,
+ struct fuse_mbuf_iter *iter,
struct fuse_bufvec *ibufv)
{
struct fuse_session *se = req->se;
@@ -1015,34 +1016,36 @@ static void do_write_buf(fuse_req_t req, fuse_ino_t
nodeid, const void *inarg,
.buf[0] = ibufv->buf[0],
.count = 1,
};
- struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
+ struct fuse_write_in *arg;
+ size_t arg_size = sizeof(*arg);
struct fuse_file_info fi;
memset(&fi, 0, sizeof(fi));
+
+ if (se->conn.proto_minor < 9) {
+ arg_size = FUSE_COMPAT_WRITE_IN_SIZE;
+ }
+
+ arg = fuse_mbuf_iter_advance(iter, arg_size);
+ if (!arg) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
+ /* Only access non-compat fields here! */
+ if (se->conn.proto_minor >= 9) {
+ fi.lock_owner = arg->lock_owner;
+ fi.flags = arg->flags;
+ }
+
fi.fh = arg->fh;
fi.writepage = arg->write_flags & FUSE_WRITE_CACHE;
if (ibufv->count == 1) {
- if (se->conn.proto_minor < 9) {
- tmpbufv.buf[0].mem = ((char *) arg) +
FUSE_COMPAT_WRITE_IN_SIZE;
- tmpbufv.buf[0].size -= sizeof(struct fuse_in_header) +
- FUSE_COMPAT_WRITE_IN_SIZE;
- assert(!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD));
- } else {
- fi.lock_owner = arg->lock_owner;
- fi.flags = arg->flags;
- if (!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD))
- tmpbufv.buf[0].mem = PARAM(arg);
-
- tmpbufv.buf[0].size -= sizeof(struct fuse_in_header) +
- sizeof(struct fuse_write_in);
- }
- if (tmpbufv.buf[0].size < arg->size) {
- fuse_log(FUSE_LOG_ERR, "fuse: do_write_buf: buffer size
too small\n");
- fuse_reply_err(req, EIO);
- return;
- }
- tmpbufv.buf[0].size = arg->size;
+ assert(!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD));
+ tmpbufv.buf[0].mem = ((char *) arg) + arg_size;
+ tmpbufv.buf[0].size -= sizeof(struct fuse_in_header) +
+ arg_size;
pbufv = &tmpbufv;
} else {
// Input bufv contains the headers in the first element
@@ -1050,6 +1053,12 @@ static void do_write_buf(fuse_req_t req, fuse_ino_t
nodeid, const void *inarg,
ibufv->buf[0].size = 0;
}
+ if (fuse_buf_size(pbufv) != arg->size) {
+ fuse_log(FUSE_LOG_ERR, "fuse: do_write_buf: buffer size doesn't
match arg->size\n");
+ fuse_reply_err(req, EIO);
+ return;
+ }
+
se->op.write_buf(req, nodeid, pbufv, arg->offset, &fi);
}
@@ -2002,12 +2011,17 @@ void fuse_session_process_buf_int(struct fuse_session
*se,
struct fuse_bufvec *bufv, struct fuse_chan
*ch)
{
const struct fuse_buf *buf = bufv->buf;
+ struct fuse_mbuf_iter iter = FUSE_MBUF_ITER_INIT(buf);
struct fuse_in_header *in;
const void *inarg;
struct fuse_req *req;
int err;
- in = buf->mem;
+ /* The first buffer must be a memory buffer */
+ assert(!(buf->flags & FUSE_BUF_IS_FD));
+
+ in = fuse_mbuf_iter_advance(&iter, sizeof(*in));
+ assert(in); /* caller guarantees the input buffer is large enough */
if (se->debug) {
fuse_log(FUSE_LOG_DEBUG,
@@ -2074,7 +2088,7 @@ void fuse_session_process_buf_int(struct fuse_session *se,
inarg = (void *) &in[1];
if (in->opcode == FUSE_WRITE && se->op.write_buf)
- do_write_buf(req, in->nodeid, inarg, bufv);
+ do_write_buf(req, in->nodeid, &iter, bufv);
else
fuse_ll_ops[in->opcode].func(req, in->nodeid, inarg);
--
2.23.0
