From: Federico Tedin <federicotedin@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Tassilo Horn <tsdh@gnu.org>, 33684@debbugs.gnu.org, jidanni@jidanni.org
Subject: bug#33684: DocView bombs out upon password protected PDFs
Date: Sat, 02 Feb 2019 17:58:00 -0300 [thread overview]
Message-ID: <875zu1x607.fsf@gmail.com> (raw)
In-Reply-To: <83pnsbyeyt.fsf@gnu.org> (Eli Zaretskii's message of "Fri, 01 Feb 2019 12:34:34 +0200")
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Here's the new version of the patch, which enables using MuPDF to open
password-protected PDF files.
One problem I encountered while writing it is that function
`doc-view-pdf->png-converter-mupdf' uses a small hack to add "draw" to
the arguments list passed to `doc-view-start-process', only when
`doc-view-pdfdraw-program' has the value "mutool". This is because the
"mudraw" command has been replaced at some point by the "mutool"
command, which requires passing "draw" as a subcommand to do the same
work. I ended up using the same hack in the new function I created, with
a reference to the original one, but I'm not sure this was the best
possible approach. Is there a cleaner way to solve this?
- Federico
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[-- Attachment #2: patch --]
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diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index df8a9fc70f..b690fb1bd6 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -183,11 +183,16 @@ doc-view-pdf->png-converter-function
(defcustom doc-view-ghostscript-options
'("-dSAFER" ;; Avoid security problems when rendering files from untrusted
;; sources.
- "-dNOPAUSE" "-sDEVICE=png16m" "-dTextAlphaBits=4"
+ "-dNOPAUSE" "-dTextAlphaBits=4"
"-dBATCH" "-dGraphicsAlphaBits=4" "-dQUIET")
"A list of options to give to ghostscript."
:type '(repeat string))
+(defcustom doc-view-ghostscript-device "png16m"
+ "Output device to give to ghostscript."
+ :type 'string
+ :version "27.1")
+
(defcustom doc-view-resolution 100
"Dots per inch resolution used to render the documents.
Higher values result in larger images."
@@ -950,16 +955,31 @@ doc-view-dvi->pdf
(list "-o" pdf dvi)
callback)))
+(defun doc-view-pdf-password-protected-ghostscript-p (pdf)
+ "Using Ghostscript, check if a PDF file is password-protected. If it
+is, return non-nil."
+ (with-temp-buffer
+ (apply #'call-process doc-view-ghostscript-program nil (current-buffer)
+ nil `(,@doc-view-ghostscript-options
+ "-sNODISPLAY"
+ ,pdf))
+ (goto-char (point-min))
+ (search-forward "This file requires a password for access." nil t)))
+
(defun doc-view-pdf->png-converter-ghostscript (pdf png page callback)
- (doc-view-start-process
- "pdf/ps->png" doc-view-ghostscript-program
- `(,@doc-view-ghostscript-options
- ,(format "-r%d" (round doc-view-resolution))
- ,@(if page `(,(format "-dFirstPage=%d" page)))
- ,@(if page `(,(format "-dLastPage=%d" page)))
- ,(concat "-sOutputFile=" png)
- ,pdf)
- callback))
+ (let ((pdf-passwd (if (doc-view-pdf-password-protected-ghostscript-p pdf)
+ (read-passwd "Enter password for PDF file: "))))
+ (doc-view-start-process
+ "pdf/ps->png" doc-view-ghostscript-program
+ `(,@doc-view-ghostscript-options
+ ,(concat "-sDEVICE=" doc-view-ghostscript-device)
+ ,(format "-r%d" (round doc-view-resolution))
+ ,@(if page `(,(format "-dFirstPage=%d" page)))
+ ,@(if page `(,(format "-dLastPage=%d" page)))
+ ,@(if pdf-passwd `(,(format "-sPDFPassword=%s" pdf-passwd)))
+ ,(concat "-sOutputFile=" png)
+ ,pdf)
+ callback)))
(defalias 'doc-view-ps->png-converter-ghostscript
'doc-view-pdf->png-converter-ghostscript)
@@ -980,17 +1000,33 @@ doc-view-djvu->tiff-converter-ddjvu
,tiff)
callback))
+(defun doc-view-pdf-password-protected-pdfdraw-p (pdf)
+ "Using MuPDF, check if a PDF file is password-protected. If it is,
+return non-nil."
+ (with-temp-buffer
+ (apply #'call-process doc-view-pdfdraw-program nil (current-buffer) nil
+ ;; FIXME: See FIXME comment in `doc-view-pdf->png-converter-mupdf'.
+ `(,@(if (string-match "mutool[^/\\]*$" doc-view-pdfdraw-program) '("draw"))
+ ,(concat "-o" null-device)
+ ;; In case PDF isn't password-protected, "draw" only one page.
+ ,pdf "1"))
+ (goto-char (point-min))
+ (search-forward "error: cannot authenticate password" nil t)))
+
(defun doc-view-pdf->png-converter-mupdf (pdf png page callback)
- (doc-view-start-process
- "pdf->png" doc-view-pdfdraw-program
- ;; FIXME: Ugly hack: recent mupdf distribution replaced "mudraw" with
- ;; "mutool draw".
- `(,@(if (string-match "mutool[^/\\]*$" doc-view-pdfdraw-program) '("draw"))
- ,(concat "-o" png)
- ,(format "-r%d" (round doc-view-resolution))
- ,pdf
- ,@(if page `(,(format "%d" page))))
- callback))
+ (let ((pdf-passwd (if (doc-view-pdf-password-protected-pdfdraw-p pdf)
+ (read-passwd "Enter password for PDF file: "))))
+ (doc-view-start-process
+ "pdf->png" doc-view-pdfdraw-program
+ ;; FIXME: Ugly hack: recent mupdf distribution replaced "mudraw" with
+ ;; "mutool draw".
+ `(,@(if (string-match "mutool[^/\\]*$" doc-view-pdfdraw-program) '("draw"))
+ ,(concat "-o" png)
+ ,(format "-r%d" (round doc-view-resolution))
+ ,@(if pdf-passwd `("-p" ,pdf-passwd))
+ ,pdf
+ ,@(if page `(,(format "%d" page))))
+ callback)))
(defun doc-view-odf->pdf-converter-unoconv (odf callback)
"Convert ODF to PDF asynchronously and call CALLBACK when finished.
next prev parent reply other threads:[~2019-02-02 20:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-09 10:52 bug#33684: DocView bombs out upon password protected PDFs 積丹尼 Dan Jacobson
2019-01-27 2:14 ` Federico Tedin
2019-02-01 9:33 ` Eli Zaretskii
2019-02-01 10:12 ` Tassilo Horn
2019-02-01 10:34 ` Eli Zaretskii
2019-02-01 10:42 ` Federico Tedin
2019-02-02 20:58 ` Federico Tedin [this message]
2019-02-03 8:40 ` Tassilo Horn
2019-02-03 16:55 ` Federico Tedin
2019-02-04 5:44 ` Tassilo Horn
2019-02-04 6:29 ` Eli Zaretskii
2019-02-04 6:52 ` Tassilo Horn
2019-02-04 15:49 ` Tassilo Horn
2019-02-04 21:24 ` Federico Tedin
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