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From: Chris Liddell <chris.liddell@artifex.com>
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Date: Tue, 21 Aug 2018 19:17:51 +0000 (+0100)
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Subject: Bug 699658: Fix handling of pre-SAFER opened files.
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Bug 699658: Fix handling of pre-SAFER opened files.
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Temp files opened for writing before SAFER is engaged are not subject to the
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SAFER restrictions - that is handled by recording in a dictionary, and
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checking that as part of the permissions checks.
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By adding a custom error handler for invalidaccess, that allowed the filename
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to be added to the dictionary (despite the attempted open throwing the error)
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thus meaning subsequent accesses were erroneously permitted.
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https://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=a054156d425b4dbdaaa9fda4b5f1182b27598c2b
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---
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diff -up a/Resource/Init/gs_init.ps.cve-2018-16539 b/Resource/Init/gs_init.ps
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--- a/Resource/Init/gs_init.ps.cve-2018-16539 2018-11-14 16:34:23.268867657 +0100
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+++ b/Resource/Init/gs_init.ps 2018-11-14 16:36:38.765552576 +0100
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@@ -2015,6 +2015,19 @@ readonly def
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concatstrings concatstrings .generate_dir_list_templates
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} if
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]
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+ /PermitFileWriting [
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+ currentuserparams /PermitFileWriting get aload pop
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+ (TMPDIR) getenv not
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+ {
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+ (TEMP) getenv not
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+ {
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+ (TMP) getenv not
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+ {
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+ (/temp) (/tmp)
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+ } if
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+ } if
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+ } if
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+ ]
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/LockFilePermissions //true
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>> setuserparams
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}
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@@ -2062,7 +2075,9 @@ readonly def
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% the file can be deleted later, even if SAFER is set.
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/.tempfile {
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.tempfile % filename file
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- //SAFETY /tempfiles get 2 .argindex //true .forceput
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+ //SAFETY /safe get not { % only add the filename if we're not yet safe
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+ //SAFETY /tempfiles get 2 .argindex //true .forceput
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+ } if
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} .bind executeonly odef
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% If we are running in SAFER mode, lock things down
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