Bug 44680

It looks like we're not allowing enough space in a variable somewhere for the full socket path name.

Looking at the code, we're mostly pretty careful about our paths and using flexible allocation etc., however I do notice this:


pa_socket_server* pa_socket_server_new_unix(pa_mainloop_api *m, const char *filename) {
    int fd = -1;
    struct sockaddr_un sa;
    pa_socket_server *s;

    pa_assert(m);
    pa_assert(filename);

    if ((fd = pa_socket_cloexec(PF_UNIX, SOCK_STREAM, 0)) < 0) {
        pa_log("socket(): %s", pa_cstrerror(errno));
        goto fail;
    }

    memset(&sa, 0, sizeof(sa));
    sa.sun_family = AF_UNIX;
    pa_strlcpy(sa.sun_path, filename, sizeof(sa.sun_path));



Here, it's a limitation of the sa.sun_path.


Looking further in /usr/include/sys/un.h:

struct sockaddr_un
  {
    __SOCKADDR_COMMON (sun_);
    char sun_path[108];         /* Path name.  */
  };


So there we have it. 108 characters.

Not quite sure how to address this. I guess we could pass the path through realpath() first to reduce the file size down, but it's certainly not a universal solution. We should probably fail more gracelessly(!) when the path overflows.

Created attachment 58413 [details] [review]
Attempt to make runtime paths smaller

This patch might solve the problem in your case.

Longer term, we'll be wanting to switch to a folder inside /run/user/$USER/ which we can guarantee no other user can write to (which is why we do the whole crazy symlinking stuff).

Ultimately the /run/user/$USER/ dir is supplied to us in XDG_RUNTIME_DIR variable under modern systems.

However, in the mean time, please can you try this patch and let me know?

OK, I've tested and committed a similar patch to the one posted here.

It should work around the issues for now, but a "full and proper" fix is to use XDG_RUNTIME_DIR which we will support in the fullness of time.

Cheers

Thanks.  I was unable to test the patch, but it seems very reasonable.
On Mar 28, 2012, at 7:17 AM, bugzilla-daemon@freedesktop.org wrote:

> https://bugs.freedesktop.org/show_bug.cgi?id=44680
> 
> Colin Guthrie <fdo@colin.guthr.ie> changed:
> 
>           What    |Removed                     |Added
> ----------------------------------------------------------------------------
>             Status|NEW                         |RESOLVED
>         Resolution|                            |FIXED
> 
> --- Comment #3 from Colin Guthrie <fdo@colin.guthr.ie> 2012-03-28 04:17:38 PDT ---
> OK, I've tested and committed a similar patch to the one posted here.
> 
> It should work around the issues for now, but a "full and proper" fix is to use
> XDG_RUNTIME_DIR which we will support in the fullness of time.
> 
> Cheers
> 
> -- 
> Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email
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Peter Schwenk  ||  Campus IT Associate 3
Mathematical Sciences  ||  University of Delaware
Newark, DE  19716-2553  ||  (302) 831-0437 (v)
schwenk @ math . udel . edu  ||  http://www.math.udel.edu/~schwenk