81 lines
2.6 KiB
Diff
81 lines
2.6 KiB
Diff
From 0f112d02890c218965235b8d1c42573fcaeec051 Mon Sep 17 00:00:00 2001
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From: Nick Wellnhofer <wellnhofer@aevum.de>
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Date: Fri, 24 Feb 2023 18:00:03 +0100
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Subject: [PATCH] malloc-fail: Fix use-after-free related to
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xmlXPathNodeSetFilter
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Found with libFuzzer, see #344.
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Reference:https://github.com/GNOME/libxml2/commit/0f112d02890c218965235b8d1c42573fcaeec051
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Conflict:xpath.c
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---
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xpath.c | 21 +++++++++++++++++++--
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1 file changed, 19 insertions(+), 2 deletions(-)
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diff --git a/xpath.c b/xpath.c
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index 7f2c92a..d63bdd7 100644
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--- a/xpath.c
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+++ b/xpath.c
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@@ -12876,6 +12876,7 @@ xmlXPathCompOpEvalFilterFirst(xmlXPathParserContextPtr ctxt,
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{
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int total = 0;
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xmlXPathCompExprPtr comp;
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+ xmlXPathObjectPtr obj;
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xmlNodeSetPtr set;
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CHECK_ERROR0;
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@@ -12943,13 +12944,20 @@ xmlXPathCompOpEvalFilterFirst(xmlXPathParserContextPtr ctxt,
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}
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#endif /* LIBXML_XPTR_ENABLED */
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+ /*
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+ * In case of errors, xmlXPathNodeSetFilter can pop additional nodes from
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+ * the stack. We have to temporarily remove the nodeset object from the
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+ * stack to avoid freeing it prematurely.
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+ */
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CHECK_TYPE0(XPATH_NODESET);
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- set = ctxt->value->nodesetval;
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+ obj = valuePop(ctxt);
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+ set = obj->nodesetval;
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if (set != NULL) {
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xmlXPathNodeSetFilter(ctxt, set, op->ch2, 1, 1, 1);
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if (set->nodeNr > 0)
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*first = set->nodeTab[0];
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}
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+ valuePush(ctxt, obj);
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return (total);
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}
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@@ -13247,6 +13255,7 @@ xmlXPathCompOpEval(xmlXPathParserContextPtr ctxt, xmlXPathStepOpPtr op)
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break;
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case XPATH_OP_PREDICATE:
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case XPATH_OP_FILTER:{
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+ xmlXPathObjectPtr obj;
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xmlNodeSetPtr set;
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/*
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@@ -13361,11 +13370,19 @@ xmlXPathCompOpEval(xmlXPathParserContextPtr ctxt, xmlXPathStepOpPtr op)
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}
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#endif /* LIBXML_XPTR_ENABLED */
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+ /*
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+ * In case of errors, xmlXPathNodeSetFilter can pop additional
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+ * nodes from the stack. We have to temporarily remove the
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+ * nodeset object from the stack to avoid freeing it
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+ * prematurely.
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+ */
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CHECK_TYPE0(XPATH_NODESET);
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- set = ctxt->value->nodesetval;
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+ obj = valuePop(ctxt);
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+ set = obj->nodesetval;
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if (set != NULL)
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xmlXPathNodeSetFilter(ctxt, set, op->ch2,
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1, set->nodeNr, 1);
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+ valuePush(ctxt, obj);
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break;
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}
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case XPATH_OP_SORT:
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--
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2.27.0
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