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From c1ba6f54d32b707ca6d91cb3257ce9de82876b6f Mon Sep 17 00:00:00 2001
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From: Nick Wellnhofer <wellnhofer@aevum.de>
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Date: Sat, 15 Aug 2020 18:32:29 +0200
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Subject: [PATCH] Revert "Do not URI escape in server side includes"
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This reverts commit 960f0e275616cadc29671a218d7fb9b69eb35588.
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This commit introduced
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- an infinite loop, found by OSS-Fuzz, which could be easily fixed.
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- an algorithm with quadratic runtime
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- a security issue, see
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https://bugzilla.gnome.org/show_bug.cgi?id=769760
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A better approach is to add an option not to escape URLs at all
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which libxml2 should have possibly done in the first place.
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---
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HTMLtree.c | 49 +++++++++++--------------------------------------
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1 file changed, 11 insertions(+), 38 deletions(-)
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diff --git a/HTMLtree.c b/HTMLtree.c
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index 8d236bb3..cdb7f86a 100644
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--- a/HTMLtree.c
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+++ b/HTMLtree.c
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@@ -706,49 +706,22 @@ htmlAttrDumpOutput(xmlOutputBufferPtr buf, xmlDocPtr doc, xmlAttrPtr cur,
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(!xmlStrcasecmp(cur->name, BAD_CAST "src")) ||
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((!xmlStrcasecmp(cur->name, BAD_CAST "name")) &&
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(!xmlStrcasecmp(cur->parent->name, BAD_CAST "a"))))) {
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+ xmlChar *escaped;
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xmlChar *tmp = value;
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- /* xmlURIEscapeStr() escapes '"' so it can be safely used. */
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- xmlBufCCat(buf->buffer, "\"");
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while (IS_BLANK_CH(*tmp)) tmp++;
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- /* URI Escape everything, except server side includes. */
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- for ( ; ; ) {
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- xmlChar *escaped;
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- xmlChar endChar;
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- xmlChar *end = NULL;
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- xmlChar *start = (xmlChar *)xmlStrstr(tmp, BAD_CAST "
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- if (start != NULL) {
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- end = (xmlChar *)xmlStrstr(tmp, BAD_CAST "-->");
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- if (end != NULL) {
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- *start = '\0';
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- }
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- }
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-
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- /* Escape the whole string, or until start (set to '\0'). */
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- escaped = xmlURIEscapeStr(tmp, BAD_CAST"@/:=?;#%&,+");
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- if (escaped != NULL) {
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- xmlBufCat(buf->buffer, escaped);
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- xmlFree(escaped);
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- } else {
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- xmlBufCat(buf->buffer, tmp);
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- }
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-
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- if (end == NULL) { /* Everything has been written. */
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- break;
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- }
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-
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- /* Do not escape anything within server side includes. */
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- *start = '<'; /* Restore the first character of "
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- end += 3; /* strlen("-->") */
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- endChar = *end;
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- *end = '\0';
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- xmlBufCat(buf->buffer, start);
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- *end = endChar;
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- tmp = end;
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+ /*
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+ * the < and > have already been escaped at the entity level
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+ * And doing so here breaks server side includes
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+ */
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+ escaped = xmlURIEscapeStr(tmp, BAD_CAST"@/:=?;#%&,+<>");
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+ if (escaped != NULL) {
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+ xmlBufWriteQuotedString(buf->buffer, escaped);
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+ xmlFree(escaped);
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+ } else {
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+ xmlBufWriteQuotedString(buf->buffer, value);
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}
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-
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- xmlBufCCat(buf->buffer, "\"");
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} else {
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xmlBufWriteQuotedString(buf->buffer, value);
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}
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--
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GitLab
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