On Thu, 16 Jan 2020 17:51:10 +0100 Christian Schoenebeck <qemu_...@crudebyte.com> wrote:
> On Donnerstag, 16. Januar 2020 14:33:42 CET Greg Kurz wrote: > > On Mon, 13 Jan 2020 23:22:08 +0100 > > > > Christian Schoenebeck <qemu_...@crudebyte.com> wrote: > > > A good 9p client sends T_readdir with "count" parameter that's > > > sufficiently smaller than client's initially negotiated msize > > > (maximum message size). We perform a check for that though to > > > avoid the server to be interrupted with a "Failed to encode > > > VirtFS reply type 41" error message by bad clients. > > > > > > Signed-off-by: Christian Schoenebeck <qemu_...@crudebyte.com> > > > --- > > > > > > hw/9pfs/9p.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c > > > index a5fbe821d4..30da2fedf3 100644 > > > --- a/hw/9pfs/9p.c > > > +++ b/hw/9pfs/9p.c > > > @@ -2426,6 +2426,7 @@ static void coroutine_fn v9fs_readdir(void *opaque) > > > > > > int32_t count; > > > uint32_t max_count; > > > V9fsPDU *pdu = opaque; > > > > > > + V9fsState *s = pdu->s; > > > > > > retval = pdu_unmarshal(pdu, offset, "dqd", &fid, > > > > > > &initial_offset, &max_count); > > > > > > @@ -2434,6 +2435,13 @@ static void coroutine_fn v9fs_readdir(void *opaque) > > > > > > } > > > trace_v9fs_readdir(pdu->tag, pdu->id, fid, initial_offset, > > > max_count); > > > > > > + if (max_count > s->msize - P9_IOHDRSZ) { > > > > P9_IOHDRSZ relates to Twrite. The Rreaddir message has a smaller header > > of size 11: > > > > size[4] Rreaddir tag[2] count[4] > > Right, looks like I have falsely picked P9_IOHDRSZ after looking at: > > static size_t v9fs_readdir_data_size(V9fsString *name) > { > /* > * Size of each dirent on the wire: size of qid (13) + size of offset (8) > * size of type (1) + size of name.size (2) + strlen(name.data) > */ > return 24 + v9fs_string_size(name); > } > > I'll have to correct that in the test cases as well. So no need to comment on > them for now. > > But if you have an idea about the issue mentioned in cover letter (patch 7), > let me know. I have a feeling that there is some problem with the test > environment, because I also get strange error messages when I just add some > more e.g. noop 9pfs test cases (empty test cases doing nothing) or by copy > pasting existing tests and then running > > tests/qos-test -l > > which obviously should just list the test cases, but not executing any of > them. I'd end up with "cannot push stack" error messages for some reason. > No idea. I'll have to look more. > > > + max_count = s->msize - P9_IOHDRSZ; > > > + warn_report_once( > > > + "9p: bad client: T_readdir with count > msize - P9_IOHDRSZ" > > > + ); > > > + } > > > + > > > > > > fidp = get_fid(pdu, fid); > > > if (fidp == NULL) { > > > > > > retval = -EINVAL; > > Best regards, > Christian Schoenebeck > >