[ovs-dev] [PATCH] stream-unix: only use path-based socket names

[Ben Pfaff]

On Fri, Sep 09, 2016 at 01:47:01PM -0700, Joe Stringer wrote:
> On 19 July 2016 at 20:08, Ben Pfaff <blp at ovn.org> wrote:
> > On Tue, Jul 19, 2016 at 05:05:51PM -0300, Thadeu Lima de Souza Cascardo wrote:
> >> FreeBSD returns a socklen of sockaddr_storage when doing an accept on an unix
> >> STREAM socket. The current code will assume it means a sun_path larger than 0.
> >>
> >> That breaks some tests like the one below which don't expect to find "unix::" on
> >> the logs.
> >>
> >> As a Linux abstract address would not have a more useful name either, it's
> >> better to check that sun_path starts with a non-zero byte and return 0 length in
> >> case it doesn't.
> >>
> >> 402: ovs-ofctl replace-flows with --bundle      FAILED (ovs-ofctl.at:2928)
> >> 2016-07-08T12:44:30.068Z|00020|vconn|DBG|unix:: sent (Success): OFPT_HELLO (OF1.6) (xid=0x1):
> >>
> >> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
> >
> > Applied, thanks!
> 
> For what it's worth, this introduces a warning on my Linux x86_64
> machine with valgrind:
> 
> ==18725== Conditional jump or move depends on uninitialised value(s)
> ==18725==    at 0x45BF65: get_unix_name_len (socket-util-unix.c:392)
> ==18725==    by 0x45C842: punix_accept (stream-unix.c:113)
> ==18725==    by 0x46897B: pfd_accept (stream-fd.c:263)
> ==18725==    by 0x44CF6F: pstream_accept (stream.c:557)
> ==18725==    by 0x44FE6C: unixctl_server_run (unixctl.c:385)
> ==18725==    by 0x4081AC: main_loop (ovsdb-server.c:182)
> ==18725==    by 0x406432: main (ovsdb-server.c:429)

Does this help?

diff --git a/lib/socket-util-unix.c b/lib/socket-util-unix.c
index 5d4b88c..a7a7e03 100644
--- a/lib/socket-util-unix.c
+++ b/lib/socket-util-unix.c
@@ -389,7 +389,7 @@ error:
 int
 get_unix_name_len(const struct sockaddr_un *sun, socklen_t sun_len)
 {
-    return (sun_len >= offsetof(struct sockaddr_un, sun_path) &&
+    return (sun_len > offsetof(struct sockaddr_un, sun_path) &&
             sun->sun_path[0] != 0
             ? sun_len - offsetof(struct sockaddr_un, sun_path)
             : 0);