43 lines
1.5 KiB
Diff
43 lines
1.5 KiB
Diff
From ede41d1e186ed2aba88a06e84cac839b770af3a1 Mon Sep 17 00:00:00 2001
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From: Sebastian Pipping <sebastian@pipping.org>
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Date: Wed, 26 Jan 2022 02:36:43 +0100
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Subject: [PATCH 1/2] lib: Prevent integer overflow in doProlog
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(CVE-2022-23990)
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The change from "int nameLen" to "size_t nameLen"
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addresses the overflow on "nameLen++" in code
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"for (; name[nameLen++];)" right above the second
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change in the patch.
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---
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expat/lib/xmlparse.c | 10 ++++++++--
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1 file changed, 8 insertions(+), 2 deletions(-)
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diff --git a/lib/xmlparse.c b/lib/xmlparse.c
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index 5ce31402..d1d17005 100644
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--- a/lib/xmlparse.c
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+++ b/lib/xmlparse.c
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@@ -5372,7 +5372,7 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
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if (dtd->in_eldecl) {
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ELEMENT_TYPE *el;
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const XML_Char *name;
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- int nameLen;
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+ size_t nameLen;
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const char *nxt
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= (quant == XML_CQUANT_NONE ? next : next - enc->minBytesPerChar);
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int myindex = nextScaffoldPart(parser);
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@@ -5388,7 +5388,13 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
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nameLen = 0;
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for (; name[nameLen++];)
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;
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- dtd->contentStringLen += nameLen;
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+
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+ /* Detect and prevent integer overflow */
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+ if (nameLen > UINT_MAX - dtd->contentStringLen) {
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+ return XML_ERROR_NO_MEMORY;
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+ }
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+
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+ dtd->contentStringLen += (unsigned)nameLen;
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if (parser->m_elementDeclHandler)
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handleDefault = XML_FALSE;
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}
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