bug#64089: 30.0.50; `ldap-search' errors out with `wrong-type-argument listp' when called WITHDN == t)

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 16 Jun 2023 00:11:15 +0200
> From:  Jens Schmidt via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> With the following patch things work as expected:
> 
> (ldap-search "(uid=<uid>)"
>                "ldap://<host>"
>                '("mail")
>                nil
>                t)
> => ((("dn" "cn=<NAME>,L=<REGION>,DC=<DOMAIN>,DC=COM") ("mail" 
> "<name>@<domain>.com")))
> 
> I tried to make the patch as conservative as possible and intentionally 
> do not check syntax of the dn line if its parsing is not required.

Stefan, any comments?  I think this is okay for emacs-29; do you
agree?

> From a646f5aa23f051f19910286c1bf9f4580a858f0f Mon Sep 17 00:00:00 2001
> From: Jens Schmidt <jschmidt4gnu@vodafonemail.de>
> Date: Fri, 16 Jun 2023 00:04:04 +0200
> Subject: [PATCH] Fix parsing of dn line if WITHDN is non-nil
> 
> Function `ldap-search' errors out with `wrong-type-argument listp'
> when called with WITHDN non-nil.
> * lisp/net/ldap.el (ldap-search-internal): Parse the dn line
> correctly so that `ldap-search' can grok it.  (Bug#64089)
> ---
>  lisp/net/ldap.el | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/lisp/net/ldap.el b/lisp/net/ldap.el
> index 78405414a28..4275b45e6f5 100644
> --- a/lisp/net/ldap.el
> +++ b/lisp/net/ldap.el
> @@ -703,7 +703,17 @@ ldap-search-internal
>  	(while (progn
>  		 (skip-chars-forward " \t\n")
>  		 (not (eobp)))
> -          (setq dn (buffer-substring (point) (line-end-position)))
> +          ;; Ignore first (dn) line if WITHDN equals nil.  If WITHDN
> +          ;; is non-nil, check syntax of the line and split it into a
> +          ;; pair as expected by `ldap-decode-attribute' (Bug#64089).
> +          ;; If the syntax is wrong, better throw an error here, since
> +          ;; otherwise `ldap-decode-attribute' would throw a much less
> +          ;; comprehensible error later.
> +          (cond ((not withdn))
> +                ((looking-at "^dn[=:\t ]+\\(.*\\)$")
> +                 (setq dn (list "dn" (match-string 1))))
> +                (t (error "Incorrect dn line \"%s\" in ldapsearch result"
> +                          (buffer-substring (point) (line-end-position)))))
>  	  (forward-line 1)
>            (while (looking-at "^\\([A-Za-z][-A-Za-z0-9]*\
>  \\|[0-9]+\\(?:\\.[0-9]+\\)*\\)\\(;[-A-Za-z0-9]+\\)*[=:\t ]+\
> -- 
> 2.30.2
>