Andrew Geissler | c9f7865 | 2020-09-18 14:11:35 -0500 | [diff] [blame^] | 1 | From 50f06b3efb638efb0abd95dc62dca05ae67882c2 Mon Sep 17 00:00:00 2001 |
| 2 | From: Nick Wellnhofer <wellnhofer@aevum.de> |
| 3 | Date: Fri, 7 Aug 2020 21:54:27 +0200 |
| 4 | Subject: [PATCH] Fix out-of-bounds read with 'xmllint --htmlout' |
| 5 | |
| 6 | Make sure that truncated UTF-8 sequences don't cause an out-of-bounds |
| 7 | array access. |
| 8 | |
| 9 | Thanks to @SuhwanSong and the Agency for Defense Development (ADD) for |
| 10 | the report. |
| 11 | |
| 12 | Fixes #178. |
| 13 | |
| 14 | CVE: CVE-2020-24977 |
| 15 | Upstream-Status: Backport [https://gitlab.gnome.org/GNOME/libxml2/-/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2] |
| 16 | |
| 17 | Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> |
| 18 | --- |
| 19 | xmllint.c | 6 ++++++ |
| 20 | 1 file changed, 6 insertions(+) |
| 21 | |
| 22 | diff --git a/xmllint.c b/xmllint.c |
| 23 | index f6a8e463..c647486f 100644 |
| 24 | --- a/xmllint.c |
| 25 | +++ b/xmllint.c |
| 26 | @@ -528,6 +528,12 @@ static void |
| 27 | xmlHTMLEncodeSend(void) { |
| 28 | char *result; |
| 29 | |
| 30 | + /* |
| 31 | + * xmlEncodeEntitiesReentrant assumes valid UTF-8, but the buffer might |
| 32 | + * end with a truncated UTF-8 sequence. This is a hack to at least avoid |
| 33 | + * an out-of-bounds read. |
| 34 | + */ |
| 35 | + memset(&buffer[sizeof(buffer)-4], 0, 4); |
| 36 | result = (char *) xmlEncodeEntitiesReentrant(NULL, BAD_CAST buffer); |
| 37 | if (result) { |
| 38 | xmlGenericError(xmlGenericErrorContext, "%s", result); |
| 39 | -- |
| 40 | 2.17.1 |
| 41 | |