Control: tags -1 + patch On Sun, 16 Jul 2017 08:19:43 +0200 Salvatore Bonaccorso <car...@debian.org> wrote: ... > the following vulnerability was published for atril. > > CVE-2017-1000083[0]: > Evince command injection vulnerability in CBT handler ...
Please, find attached the patch backported from evince's fix. Cheers, -- Santiago
Origin: https://bugzilla.gnome.org/show_bug.cgi?id=784630 Reviewed-by: Santiago R.R. <santiag...@riseup.net> Bug-Debian: http://bugs.debian.org/868500 From 717df38fd8509bf883b70d680c9b1b3cf36732ee Mon Sep 17 00:00:00 2001 From: Bastien Nocera <had...@hadess.net> Date: Thu, 6 Jul 2017 20:02:00 +0200 Subject: [PATCH] comics: Remove support for tar and tar-like commands When handling tar files, or using a command with tar-compatible syntax, to open comic-book archives, both the archive name (the name of the comics file) and the filename (the name of a page within the archive) are quoted to not be interpreted by the shell. But the filename is completely with the attacker's control and can start with "--" which leads to tar interpreting it as a command line flag. This can be exploited by creating a CBT file (a tar archive with the .cbt suffix) with an embedded file named something like this: "--checkpoint-action=exec=bash -c 'touch ~/hacked;'.jpg" CBT files are infinitely rare (CBZ is usually used for DRM-free commercial releases, CBR for those from more dubious provenance), so removing support is the easiest way to avoid the bug triggering. All this code was rewritten in the development release for GNOME 3.26 to not shell out to any command, closing off this particular attack vector. This also removes the ability to use libarchive's bsdtar-compatible binary for CBZ (ZIP), CB7 (7zip), and CBR (RAR) formats. The first two are already supported by unzip and 7zip respectively. libarchive's RAR support is limited, so unrar is a requirement anyway. Discovered by Felix Wilhelm from the Google Security Team. https://bugzilla.gnome.org/show_bug.cgi?id=784630 -Index: atril-1.16.1/backend/comics/comics-document.c =================================================================== --- atril-1.16.1.orig/backend/comics/comics-document.c +++ atril-1.16.1/backend/comics/comics-document.c @@ -44,8 +44,7 @@ typedef enum RARLABS, GNAUNRAR, UNZIP, - P7ZIP, - TAR + P7ZIP } ComicBookDecompressType; typedef struct _ComicsDocumentClass ComicsDocumentClass; @@ -105,9 +104,6 @@ static const ComicBookDecompressCommand /* 7zip */ {NULL , "%s l -- %s" , "%s x -y %s -o%s", FALSE, OFFSET_7Z}, - - /* tar */ - {"%s -xOf" , "%s -tf %s" , NULL , FALSE, NO_OFFSET} }; static void comics_document_document_thumbnails_iface_init (EvDocumentThumbnailsInterface *iface); @@ -355,13 +351,6 @@ comics_check_decompress_command (gchar comics_document->command_usage = GNAUNRAR; return TRUE; } - comics_document->selected_command = - g_find_program_in_path ("bsdtar"); - if (comics_document->selected_command) { - comics_document->command_usage = TAR; - return TRUE; - } - } else if (g_content_type_is_a (mime_type, "application/x-cbz") || g_content_type_is_a (mime_type, "application/zip")) { /* InfoZIP's unzip program */ @@ -374,12 +363,6 @@ comics_check_decompress_command (gchar comics_document->command_usage = UNZIP; return TRUE; } - comics_document->selected_command = - g_find_program_in_path ("bsdtar"); - if (comics_document->selected_command) { - comics_document->command_usage = TAR; - return TRUE; - } } else if (g_content_type_is_a (mime_type, "application/x-cb7") || g_content_type_is_a (mime_type, "application/x-7z-compressed")) { @@ -403,27 +386,6 @@ comics_check_decompress_command (gchar comics_document->command_usage = P7ZIP; return TRUE; } - comics_document->selected_command = - g_find_program_in_path ("bsdtar"); - if (comics_document->selected_command) { - comics_document->command_usage = TAR; - return TRUE; - } - } else if (g_content_type_is_a (mime_type, "application/x-cbt") || - g_content_type_is_a (mime_type, "application/x-tar")) { - /* tar utility (Tape ARchive) */ - comics_document->selected_command = - g_find_program_in_path ("tar"); - if (comics_document->selected_command) { - comics_document->command_usage = TAR; - return TRUE; - } - comics_document->selected_command = - g_find_program_in_path ("bsdtar"); - if (comics_document->selected_command) { - comics_document->command_usage = TAR; - return TRUE; - } } else { g_set_error (error, EV_DOCUMENT_ERROR, Index: atril-1.16.1/configure.ac =================================================================== --- atril-1.16.1.orig/configure.ac +++ atril-1.16.1/configure.ac @@ -625,7 +625,7 @@ if test "x$enable_tiff" = "xyes"; then ATRIL_MIME_TYPES="${ATRIL_MIME_TYPES}image/tiff;" fi if test "x$enable_comics" = "xyes"; then - ATRIL_MIME_TYPES="${ATRIL_MIME_TYPES}application/x-cbr;application/x-cbz;application/x-cb7;application/x-cbt;application/vnd.comicbook+zip;" + ATRIL_MIME_TYPES="${ATRIL_MIME_TYPES}application/x-cbr;application/x-cbz;application/x-cb7;application/vnd.comicbook+zip;" fi if test "x$enable_pixbuf" = "xyes"; then ATRIL_MIME_TYPES="${ATRIL_MIME_TYPES}image/*;"
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