bug#47718: Fix epa-file-insert-file-contents substring error

bug#47718: Fix epa-file-insert-file-contents substring error

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

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Hi

I think substring occurs error when TO is longer than its content.
This patch will fix the substring bug in epa-file-insert-file-contents.

The last commit this line was 2008, so no one seems not using it, though ;)

Thanks,

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From da85a87962cad14fb6dee231fe019fadafa1107e Mon Sep 17 00:00:00 2001
From: Junya Takahashi <jutakat@gmail.com>
Date: Mon, 12 Apr 2021 13:09:35 +0900
Subject: [PATCH] Fix args-out-of-range error in epa-file-insert-file-contents

Fix error below:

$ echo -n test > test
$ gpg -c test
elisp> (epa-file-insert-file-contents "test.gpg" nil 0 5)
       ;; => Args out of range: "test", 0, 5
---
 lisp/epa-file.el | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lisp/epa-file.el b/lisp/epa-file.el
index e46e3684c8..33bf5adabe 100644
--- a/lisp/epa-file.el
+++ b/lisp/epa-file.el
@@ -198,7 +198,9 @@ epa-file-insert-file-contents
                       (mapcar #'car (epg-context-result-for
                                      context 'encrypted-to)))
 	  (if (or beg end)
-	      (setq string (substring string (or beg 0) end)))
+              (setq string (substring string
+                                      (or beg 0)
+                                      (and end (min end (length string))))))
 	  (save-excursion
 	    ;; If visiting, bind off buffer-file-name so that
 	    ;; file-locking will not ask whether we should
-- 
2.31.1

bug#47718: Fix epa-file-insert-file-contents substring error

[Lars Ingebrigtsen]

juntaka <juntaka@protonmail.com> writes:

> I think substring occurs error when TO is longer than its content.
> This patch will fix the substring bug in epa-file-insert-file-contents.

Thanks; applied to Emacs 28.

This change was small enough to apply without assigning copyright to the
FSF, but for future patches you want to submit, it might make sense to
get the paperwork started now, so that subsequent patches can be applied
speedily. Would you be willing to sign such paperwork?

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

bug#47718: Fix epa-file-insert-file-contents substring error

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Mon, 12 Apr 2021 10:14:34 +0200
> Cc: 47718@debbugs.gnu.org
> 
> juntaka <juntaka@protonmail.com> writes:
> 
> > I think substring occurs error when TO is longer than its content.
> > This patch will fix the substring bug in epa-file-insert-file-contents.
> 
> Thanks; applied to Emacs 28.

Actually, I wonder whether this is TRT: why should we silently accept
invalid inputs when substring itself doesn't?

IOW, can we please have a real-life use case where this happens, and
where silently "fixing" this input is TRT?  TIA.

bug#47718: Fix epa-file-insert-file-contents substring error

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

Hi Eli,

In my use case, I'm writing an elisp to show the first line of each file on dired.
It does not need to visit and read entire file. So I just try to limit by (window-width).
But if Emacs try to decrypt GPG files, then I got such error.

Regards,

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, April 12, 2021 8:57 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Lars Ingebrigtsen larsi@gnus.org
> > Date: Mon, 12 Apr 2021 10:14:34 +0200
> > Cc: 47718@debbugs.gnu.org
> > juntaka juntaka@protonmail.com writes:
> >
> > > I think substring occurs error when TO is longer than its content.
> > > This patch will fix the substring bug in epa-file-insert-file-contents.
> >
> > Thanks; applied to Emacs 28.
>
> Actually, I wonder whether this is TRT: why should we silently accept
> invalid inputs when substring itself doesn't?
>
> IOW, can we please have a real-life use case where this happens, and
> where silently "fixing" this input is TRT? TIA.

bug#47718: Fix epa-file-insert-file-contents substring error

[Eli Zaretskii]

> Date: Mon, 12 Apr 2021 12:57:28 +0000
> From: juntaka <juntaka@protonmail.com>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, "47718@debbugs.gnu.org" <47718@debbugs.gnu.org>
> 
> In my use case, I'm writing an elisp to show the first line of each file on dired.
> It does not need to visit and read entire file. So I just try to limit by (window-width).
> But if Emacs try to decrypt GPG files, then I got such error.

Doesn't that mean the problem is in your application code?

bug#47718: Fix epa-file-insert-file-contents substring error

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

> Doesn't that mean the problem is in your application code?

I think insert-file-contents should behave same regardless gpg file or not.

$ echo -n test > file
$ gpg -c file

elisp> (insert-file-contents "file" nil 0 4) ;; no error
elisp> (insert-file-contents "file" nil 0 5) ;; no error
elisp> (insert-file-contents "file.gpg" nil 0 4) ;; no error
elisp> (insert-file-contents "file.gpg" nil 0 5) ;; error

I had no chance to fix that on my side.

Best,

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, April 12, 2021 10:23 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Mon, 12 Apr 2021 12:57:28 +0000
> > From: juntaka juntaka@protonmail.com
> > Cc: Lars Ingebrigtsen larsi@gnus.org, "47718@debbugs.gnu.org" 47718@debbugs.gnu.org
> > In my use case, I'm writing an elisp to show the first line of each file on dired.
> > It does not need to visit and read entire file. So I just try to limit by (window-width).
> > But if Emacs try to decrypt GPG files, then I got such error.
>
> Doesn't that mean the problem is in your application code?

bug#47718: Fix epa-file-insert-file-contents substring error

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> Actually, I wonder whether this is TRT: why should we silently accept
> invalid inputs when substring itself doesn't?

insert-file-contents does not signal an error in this case, so
epa-file-insert-file-contents shouldn't either.

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

bug#47718: Fix epa-file-insert-file-contents substring error

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

Hi Lars,

Thank you for merging.
Yes, I will do to sign the paperwork.


‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, April 12, 2021 5:14 PM, Lars Ingebrigtsen <larsi@gnus.org> wrote:

> juntaka juntaka@protonmail.com writes:
>
> > I think substring occurs error when TO is longer than its content.
> > This patch will fix the substring bug in epa-file-insert-file-contents.
>
> Thanks; applied to Emacs 28.
>
> This change was small enough to apply without assigning copyright to the
> FSF, but for future patches you want to submit, it might make sense to
> get the paperwork started now, so that subsequent patches can be applied
> speedily. Would you be willing to sign such paperwork?
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> (domestic pets only, the antidote for overdose, milk.)
> bloggy blog: http://lars.ingebrigtsen.no

bug#47718: Fix epa-file-insert-file-contents substring error

[Lars Ingebrigtsen]

juntaka <juntaka@protonmail.com> writes:

> Yes, I will do to sign the paperwork.

Great; here's the form to get started:


Please email the following information to assign@gnu.org, and we
will send you the assignment form for your past and future changes.

Please use your full legal name (in ASCII characters) as the subject
line of the message.
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