bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

[Andrew Eggenberger]

The emacsclient binary produced by the native-comp branch cannot connect
to the server. When a connection is attempted, the error message
"emacsclient: Invalid socket owner" is displayed. I have 27.1 without
native-comp installed, and that emacsclient can connect to the
native-comp server without issue.

The error is the result of a failed uid comparison in
lib-src/emacsclient.c. It appears that the uid produced by geteuid()
isn't matching the uid for the server socket.

I first noticed the issue while trying to do a magit commit. But the
same error happens when trying to run emacsclient from the command line.


In GNU Emacs 28.0.50 (build 1, i686-unknown-gnu0.9, GTK+ Version 3.24.20, cairo version 1.16.0)
 of 2020-10-21 built on debian
Repository revision: 3be93390fb6680d1e0c3256af72c86635a9eb327
Repository branch: feature/native-comp
System Description: Debian GNU/Hurd bullseye/sid

Configured using:
 'configure --with-nativecomp --prefix=/home/demo/.local/'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO DBUS GSETTINGS GLIB NOTIFY GFILENOTIFY
ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES NATIVE_COMP THREADS
LIBSYSTEMD PDUMPER LCMS2

Important settings:
  locale-coding-system: nil

Major mode: Magit Process

Minor modes in effect:
  global-undo-tree-mode: t
  undo-tree-mode: t
  global-magit-file-mode: t
  magit-auto-revert-mode: t
  global-git-commit-mode: t
  which-key-mode: t
  projectile-mode: t
  global-flycheck-mode: t
  global-company-mode: t
  company-mode: t
  helm-mode: t
  helm-ff-cache-mode: t
  shell-dirtrack-mode: t
  helm--remap-mouse-mode: t
  async-bytecomp-package-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail helm-command helm-elisp
helm-eval edebug backtrace helm-info magit-extras mule-util face-remap
vc-git cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs winner image-file image-converter
helm-external helm-net xml url url-proxy url-privacy url-expand
url-methods url-history url-cookie url-domsuf url-util mailcap ffap
term/xterm xterm jka-compr undo-tree magit-submodule magit-obsolete
magit-blame magit-stash magit-reflog magit-bisect magit-push magit-pull
magit-fetch magit-clone magit-remote magit-commit magit-sequence
magit-notes magit-worktree magit-tag magit-merge magit-branch
magit-reset magit-files magit-refs magit-status magit magit-repos
magit-apply magit-wip magit-log which-func imenu magit-diff smerge-mode
diff diff-mode magit-core magit-autorevert autorevert filenotify
magit-margin magit-transient magit-process magit-mode git-commit
transient magit-git magit-section magit-utils crm log-edit message rmc
puny dired dired-loaddefs rfc822 mml mml-sec epa derived epg epg-config
gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse
rfc2231 rfc2047 rfc2045 mm-util ietf-drums mail-prsvr mailabbrev
mail-utils gmm-utils mailheader pcvs-util add-log with-editor server
which-key comp warnings projectile grep compile text-property-search
ibuf-ext ibuffer ibuffer-loaddefs thingatpt flycheck find-func rx dash
company-oddmuse company-keywords company-etags etags fileloop generator
xref project company-gtags company-dabbrev-code company-dabbrev
company-files company-clang company-capf company-cmake company-semantic
company-template company-bbdb company paredit helm-mode helm-files tramp
tramp-loaddefs trampver tramp-integration files-x tramp-compat shell
pcomplete comint ansi-color ring parse-time iso8601 time-date ls-lisp
helm-buffers helm-occur helm-tags helm-locate helm-grep helm-regexp
format-spec helm-utils helm-help helm-types helm-config helm easy-mmode
async-bytecomp advice helm-global-bindings helm-easymenu edmacro kmacro
helm-source eieio-compat helm-multi-match helm-lib async cl-extra
help-mode use-package-ensure use-package-core finder-inf disp-table info
package easymenu browse-url url-handlers url-parse auth-source cl-seq
eieio eieio-core cl-macs eieio-loaddefs password-cache json subr-x map
url-vars seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
font-core term/tty-colors frame minibuffer cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice button loaddefs faces cus-face pcase macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget hashtable-print-readable backquote threads dbusbind
gfilenotify lcms2 dynamic-setting system-font-setting
font-render-setting cairo move-toolbar gtk x-toolkit x multi-tty
make-network-process nativecomp emacs)

Memory information:
((conses 8 312548 30532)
 (symbols 24 26544 10)
 (strings 16 87420 8718)
 (string-bytes 1 3294833)
 (vectors 8 44603)
 (vector-slots 4 791812 51818)
 (floats 8 144 434)
 (intervals 28 736 356)
 (buffers 564 20))

bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

[Lars Ingebrigtsen]

Andrew Eggenberger <andrew.eggenberger@gmail.com> writes:

> The emacsclient binary produced by the native-comp branch cannot connect
> to the server. When a connection is attempted, the error message
> "emacsclient: Invalid socket owner" is displayed. I have 27.1 without
> native-comp installed, and that emacsclient can connect to the
> native-comp server without issue.

I tried this with the current native-comp branch:

$ ./src/emacs -Q
M-x server-start
$ ./lib-src/emacsclient -t

and everything worked as it should, so I'm unable to reproduce this bug.

Do you have a recipe for reproducing this?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

[Andrea Corallo via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Andrew Eggenberger <andrew.eggenberger@gmail.com> writes:

> The emacsclient binary produced by the native-comp branch cannot connect
> to the server. When a connection is attempted, the error message
> "emacsclient: Invalid socket owner" is displayed. I have 27.1 without
> native-comp installed, and that emacsclient can connect to the
> native-comp server without issue.
>
> The error is the result of a failed uid comparison in
> lib-src/emacsclient.c. It appears that the uid produced by geteuid()
> isn't matching the uid for the server socket.
>
> I first noticed the issue while trying to do a magit commit. But the
> same error happens when trying to run emacsclient from the command line.

Hi Andrew,

thanks for reporting.  I believe this should not be related to the
native compilaiton (BTW for me it works, I always use emacsclient).

Could you try if you get the same error building master?

Thanks!

  Andrea

bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

[Andrew Eggenberger]

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Thanks all. It looks like the socket verification logic changes in Commit
3e5d7755454bea9b6ffd232b1d115c629cdb193d. I realized my other version where
it works was 26.3, before that change. I think my problem might be
hurd-specific, but I'll have to do some more digging.

Andrew

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bug#44131: 28.0.50; emacsclient Invalid socket owner error in gccemacs

[Andrew Eggenberger]

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Sorry, and to answer your question: the problem was still there when I
compiled 28 master.

>

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bug#44131: 28.0.50; emacsclient Invalid socket owner error

[Andrea Corallo via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Andrew Eggenberger <andrew.eggenberger@gmail.com> writes:

> Sorry, and to answer your question: the problem was still there when I compiled 28 master.

Hi Andrew,

thanks for checking, I've re-titled to bug.  Let us know if you discover
it's hurd specific we can narrow it down further.

Thanks

  Andrea

bug#44131: 28.0.50; emacsclient Invalid socket owner error

[Andrew Eggenberger]

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Hi,

The problem seems to stem from the way the hurd treats fstat calls on local
socket
file descriptors. They all have the uid of 0 (root), while emacsclient can
be run by
other users. After trying to teach the hurd's local socket server to use
the uid of
the user who requested the socket and failing, I created the naive patch
below that
fixes the problem.

Please let me know if there's a better solution. I git blamed the changes
that led to this
issue and I don't understand the race condition the uid comparison is
supposed prevent.

Andrew Eggenberger

diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
index 871fa7a8d3..6059993ff6 100644
--- a/lib-src/emacsclient.c
+++ b/lib-src/emacsclient.c
@@ -1480,8 +1480,13 @@ set_local_socket (char const *server_name)
        sock_status = errno;
       else if (connect_stat.st_uid == uid)
        return s;
+#ifdef __GNU__
+      else
+       return s;
+#else
       else
        sock_status = -1;
+#endif

       CLOSE_SOCKET (s);
     }

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bug#44131: 28.0.50; emacsclient Invalid socket owner error

[Eli Zaretskii]

> From: Andrew Eggenberger <andrew.eggenberger@gmail.com>
> Date: Sun, 1 Nov 2020 19:24:42 -0600
> Cc: 44131@debbugs.gnu.org
> 
> The problem seems to stem from the way the hurd treats fstat calls on local socket
> file descriptors. They all have the uid of 0 (root), while emacsclient can be run by 
> other users. After trying to teach the hurd's local socket server to use the uid of 
> the user who requested the socket and failing, I created the naive patch below that
> fixes the problem.
> 
> Please let me know if there's a better solution. I git blamed the changes that led to this
> issue and I don't understand the race condition the uid comparison is supposed prevent.
> 
> Andrew Eggenberger
> 
> diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
> index 871fa7a8d3..6059993ff6 100644
> --- a/lib-src/emacsclient.c
> +++ b/lib-src/emacsclient.c
> @@ -1480,8 +1480,13 @@ set_local_socket (char const *server_name)
>         sock_status = errno;
>        else if (connect_stat.st_uid == uid)
>         return s;
> +#ifdef __GNU__
> +      else
> +       return s;
> +#else
>        else
>         sock_status = -1;
> +#endif
> 
>        CLOSE_SOCKET (s);
>      }

Paul, any better ideas?  Or should I push this fix?

Thanks.

bug#44131: 28.0.50; emacsclient Invalid socket owner error

[Andrew Eggenberger]

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Hi Eli,

I've just submitted a patch to the hurd mailing list that resolves the
issue without any
changes to emacsclient. I think we can close this issue.

Thanks
Andrew

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bug#44131: 28.0.50; emacsclient Invalid socket owner error

[Lars Ingebrigtsen]

Andrew Eggenberger <andrew.eggenberger@gmail.com> writes:

> I've just submitted a patch to the hurd mailing list that resolves the
> issue without any changes to emacsclient. I think we can close this
> issue.

OK; done.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no