libxml2: Fix CVE-2026-86143

This patch applies the upstream fix as referenced in [2], using the commit shown in [1]. [1] https://github.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35 [2] https://nvd.nist.gov/vuln/detail/CVE-2026-86143 (From OE-Core rev: fb571abf1473c04b869360faab38409471ab06c6) Signed-off-by: Hetvi Thakar <hthakar@cisco.com> Signed-off-by: Yoann Congal <yoann.congal@smile.fr> Signed-off-by: Paul Barker <paul@pbarker.dev>
2026-10-21 06:48:18 +00:00 · 2026-10-19 09:03:17 +01:00
1 parent d32be85b6a
commit ef8931543a
@@ -0,0 +1,96 @@
+From 83259eee08067b547d2aaedd436504939b2c343b Mon Sep 17 00:00:00 2001
+From: Daniel Garcia Moreno <daniel.garcia@suse.com>
+Date: Mon, 4 May 2026 09:54:34 +0200
+Subject: [PATCH] xmlIO: Check for int overflow before calling writecallback
+
+Fix https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1111
+
+CVE: CVE-2026-86143
+Upstream-Status: Backport [https://github.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35]
+
+Backport Changes:
+- Change nbchars to size_t in both Scarthgap write functions before assigning
+  the size_t result of xmlBufUse(). Add the INT_MAX guard to both
+  xmlOutputBufferWrite() callback paths. The upstream commit assumes earlier
+  refactoring that changed nbchars to size_t and routed
+  xmlOutputBufferWriteEscape() through the protected write path; the existing
+  flush guards are retained.
+
+(cherry picked from commit 90f293ba74d28b1d570920382e707586f68ebf35)
+Signed-off-by: Hetvi Thakar <hthakar@cisco.com>
+---
+ xmlIO.c | 26 ++++++++++++++++++----
+ 1 file changed, 22 insertions(+), 4 deletions(-)
+
+diff --git a/xmlIO.c b/xmlIO.c
+index 95d27157..de227d8c 100644
+--- a/xmlIO.c
+++ b/xmlIO.c
+@@ -3318,7 +3318,7 @@
+  */
+ int
+ xmlOutputBufferWrite(xmlOutputBufferPtr out, int len, const char *buf) {
+-    int nbchars = 0; /* number of chars to output to I/O */
+    size_t nbchars = 0; /* number of chars to output to I/O */
+     int ret;         /* return from function call */
+     int written = 0; /* number of char written to I/O so far */
+     int chunk;       /* number of byte current processed from buf */
+@@ -3378,6 +3378,10 @@
+             if ((nbchars < MINLEN) && (len <= 0))
+                 goto done;
+ 
+            if (nbchars >= INT_MAX) {
+                out->error = XML_ERR_INTERNAL_ERROR;
+                return(-1);
+            }
+ 	    /*
+ 	     * second write the stuff to the I/O channel
+ 	     */
+@@ -3487,7 +3491,7 @@
+ int
+ xmlOutputBufferWriteEscape(xmlOutputBufferPtr out, const xmlChar *str,
+                            xmlCharEncodingOutputFunc escaping) {
+-    int nbchars = 0; /* number of chars to output to I/O */
+    size_t nbchars = 0; /* number of chars to output to I/O */
+     int ret;         /* return from function call */
+     int written = 0; /* number of char written to I/O so far */
+     int oldwritten=0;/* loop guard */
+@@ -3572,6 +3576,10 @@
+             if ((nbchars < MINLEN) && (len <= 0))
+                 goto done;
+ 
+            if (nbchars >= INT_MAX) {
+                out->error = XML_ERR_INTERNAL_ERROR;
+                return(-1);
+            }
+ 	    /*
+ 	     * second write the stuff to the I/O channel
+ 	     */
+@@ -3667,15 +3675,25 @@
+      */
+     if ((out->conv != NULL) && (out->encoder != NULL) &&
+ 	(out->writecallback != NULL)) {
+        size_t bufsize = xmlBufUse(out->conv);
+        if (bufsize >= INT_MAX) {
+            out->error = XML_ERR_INTERNAL_ERROR;
+            return(-1);
+        }
+ 	ret = out->writecallback(out->context,
+                                  (const char *)xmlBufContent(out->conv),
+-                                 xmlBufUse(out->conv));
+                                 bufsize);
+ 	if (ret >= 0)
+ 	    xmlBufShrink(out->conv, ret);
+     } else if (out->writecallback != NULL) {
+        size_t bufsize = xmlBufUse(out->buffer);
+        if (bufsize >= INT_MAX) {
+            out->error = XML_ERR_INTERNAL_ERROR;
+            return(-1);
+        }
+ 	ret = out->writecallback(out->context,
+                                  (const char *)xmlBufContent(out->buffer),
+-                                 xmlBufUse(out->buffer));
+                                 bufsize);
+ 	if (ret >= 0)
+ 	    xmlBufShrink(out->buffer, ret);
+     }
@@ -37,6 +37,7 @@ SRC_URI += "http://www.w3.org/XML/Test/xmlts20130923.tar;subdir=${BP};name=testt
           file://CVE-2026-86140.patch \
           file://CVE-2026-86141.patch \
           file://CVE-2026-86142.patch \
+           file://CVE-2026-86143.patch \
           "

 SRC_URI[archive.sha256sum] = "c3d8c0c34aa39098f66576fe51969db12a5100b956233dc56506f7a8679be995"