ghostscript: fix CVE-2020-15900

(From OE-Core rev: a58aa3017925617da1eec732a0e68bfda83410a1)

Signed-off-by: Lee Chee Yang <chee.yang.lee@intel.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/ghostscript/ghostscript/CVE-2020-15900.patch

@@ -0,0 +1,54 @@
+From 5d499272b95a6b890a1397e11d20937de000d31b Mon Sep 17 00:00:00 2001
+From: Ray Johnston <ray.johnston@artifex.com>
+Date: Wed, 22 Jul 2020 09:57:54 -0700
+Subject: [PATCH] Bug 702582, CVE 2020-15900 Memory Corruption in Ghostscript
+ 9.52
+
+Fix the 'rsearch' calculation for the 'post' size to give the correct
+size.  Previous calculation would result in a size that was too large,
+and could underflow to max uint32_t. Also fix 'rsearch' to return the
+correct 'pre' string with empty string match.
+
+A future change may 'undefine' this undocumented, non-standard operator
+during initialization as we do with the many other non-standard internal
+PostScript operators and procedures.
+
+Upstream-Status: Backport [https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=5d499272b95a6b890a1397e11d20937de000d31b]
+CVE: CVE-2020-15900
+Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
+---
+ psi/zstring.c | 17 +++++++++++------
+ 1 file changed, 11 insertions(+), 6 deletions(-)
+
+diff --git a/psi/zstring.c b/psi/zstring.c
+index 33662dafa..58e1af2b3 100644
+--- a/psi/zstring.c
++++ b/psi/zstring.c
+@@ -142,13 +142,18 @@ search_impl(i_ctx_t *i_ctx_p, bool forward)
+     return 0;
+ found:
+     op->tas.type_attrs = op1->tas.type_attrs;
+-    op->value.bytes = ptr;
+-    r_set_size(op, size);
++    op->value.bytes = ptr;				/* match */
++    op->tas.rsize = size;				/* match */
+     push(2);
+-    op[-1] = *op1;
+-    r_set_size(op - 1, ptr - op[-1].value.bytes);
+-    op1->value.bytes = ptr + size;
+-    r_set_size(op1, count + (!forward ? (size - 1) : 0));
++    op[-1] = *op1;					/* pre */
++    op[-3].value.bytes = ptr + size;			/* post */
++    if (forward) {
++        op[-1].tas.rsize = ptr - op[-1].value.bytes;	/* pre */
++        op[-3].tas.rsize = count;			/* post */
++    } else {
++        op[-1].tas.rsize = count;			/* pre */
++        op[-3].tas.rsize -= count + size;		/* post */
++    }
+     make_true(op);
+     return 0;
+ }
+-- 
+2.17.1
+

meta/recipes-extended/ghostscript/ghostscript_9.50.bb

@@ -26,6 +26,7 @@ SRC_URI_BASE = "https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/d
                 file://avoid-host-contamination.patch \
                 file://mkdir-p.patch \
                 file://CVE-2019-14869-0001.patch \
+                file://CVE-2020-15900.patch \
 "
 
 SRC_URI = "${SRC_URI_BASE} \