From: Zdenek Dohnal <zdohnal@redhat.com>
Date: Fri, 1 Sep 2023 14:47:29 +0000 (+0200)
Subject: raster-interpret.c: Fix CVE-2023-4504
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a9a7daa77699bd58001c25df8a61a8029a217ddf;p=thirdparty%2Fcups.git

raster-interpret.c: Fix CVE-2023-4504

We didn't check for end of buffer if it looks there is an escaped
character - check for NULL terminator there and if found, return NULL
as return value and in `ptr`, because a lone backslash is not
a valid PostScript character.
---

diff --git a/cups/raster-interpret.c b/cups/raster-interpret.c
index 6fcf731b57..011c8038c5 100644
--- a/cups/raster-interpret.c
+++ b/cups/raster-interpret.c
@@ -1116,7 +1116,19 @@ scan_ps(_cups_ps_stack_t *st,		/* I  - Stack */
 
 	    cur ++;
 
-            if (*cur == 'b')
+	   /*
+	    * Return NULL if we reached NULL terminator, a lone backslash
+            * is not a valid character in PostScript.
+	    */
+
+	    if (!*cur)
+	    {
+	      *ptr = NULL;
+
+	      return (NULL);
+	    }
+
+	    if (*cur == 'b')
 	      *valptr++ = '\b';
 	    else if (*cur == 'f')
 	      *valptr++ = '\f';