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Limit recursion depth in xmlXPathOptimizeExpression

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This commit is contained in:
Nick Wellnhofer 2019-04-20 17:01:19 +02:00
parent 93a1d22380
commit 012f8e9284
1 changed files with 25 additions and 8 deletions
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33
xpath.c
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@ -14654,8 +14654,12 @@ xmlXPathTryStreamCompile(xmlXPathContextPtr ctxt, const xmlChar *str) {
#endif /* XPATH_STREAMING */
static void
xmlXPathOptimizeExpression(xmlXPathCompExprPtr comp, xmlXPathStepOpPtr op)
xmlXPathOptimizeExpression(xmlXPathParserContextPtr pctxt,
xmlXPathStepOpPtr op)
{
xmlXPathCompExprPtr comp = pctxt->comp;
xmlXPathContextPtr ctxt;
/*
* Try to rewrite "descendant-or-self::node()/foo" to an optimized
* internal representation.
@ -14711,10 +14715,18 @@ xmlXPathOptimizeExpression(xmlXPathCompExprPtr comp, xmlXPathStepOpPtr op)
return;
/* Recurse */
ctxt = pctxt->context;
if (ctxt != NULL) {
if (ctxt->depth >= ctxt->maxDepth)
return;
ctxt->depth += 1;
}
if (op->ch1 != -1)
xmlXPathOptimizeExpression(comp, &comp->steps[op->ch1]);
xmlXPathOptimizeExpression(pctxt, &comp->steps[op->ch1]);
if (op->ch2 != -1)
xmlXPathOptimizeExpression(comp, &comp->steps[op->ch2]);
xmlXPathOptimizeExpression(pctxt, &comp->steps[op->ch2]);
if (ctxt != NULL)
ctxt->depth -= 1;
}
/**
@ -14764,6 +14776,11 @@ xmlXPathCtxtCompile(xmlXPathContextPtr ctxt, const xmlChar *str) {
comp = NULL;
} else {
comp = pctxt->comp;
if ((comp->nbStep > 1) && (comp->last >= 0)) {
if (ctxt != NULL)
ctxt->depth = 0;
xmlXPathOptimizeExpression(pctxt, &comp->steps[comp->last]);
}
pctxt->comp = NULL;
}
xmlXPathFreeParserContext(pctxt);
@ -14774,9 +14791,6 @@ xmlXPathCtxtCompile(xmlXPathContextPtr ctxt, const xmlChar *str) {
comp->string = xmlStrdup(str);
comp->nb = 0;
#endif
if ((comp->nbStep > 1) && (comp->last >= 0)) {
xmlXPathOptimizeExpression(comp, &comp->steps[comp->last]);
}
}
return(comp);
}
@ -14942,9 +14956,12 @@ xmlXPathEvalExpr(xmlXPathParserContextPtr ctxt) {
if (*ctxt->cur != 0)
XP_ERROR(XPATH_EXPR_ERROR);
if ((ctxt->comp->nbStep > 1) && (ctxt->comp->last >= 0))
xmlXPathOptimizeExpression(ctxt->comp,
if ((ctxt->comp->nbStep > 1) && (ctxt->comp->last >= 0)) {
if (ctxt->context != NULL)
ctxt->context->depth = 0;
xmlXPathOptimizeExpression(ctxt,
&ctxt->comp->steps[ctxt->comp->last]);
}
}
xmlXPathRunEval(ctxt, 0);