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XSS: reduce false positives on JavaScript GEHs (#151) #153

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XSS: reduce false positives on JavaScript GEHs (#151) #153

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94 changes: 91 additions & 3 deletions src/libinjection_xss.c
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Original file line number Diff line number Diff line change
Expand Up @@ -210,6 +210,72 @@ static const char* BLACKTAG[] = {
, NULL
};

/* Blacklist of known JS GlobalEventHandlers */
static const char* BLACKGEH[] = {
"ONABORT"
, "ONANIMATIONCANCEL"
, "ONANIMATIONEND"
, "ONANIMATIONITERATION"
, "ONAUXCLICK"
, "ONBLUR"
, "ONCANCEL"
, "ONCANPLAY"
, "ONCANPLAYTHROUGH"
, "ONCHANGE"
, "ONCLICK"
, "ONCLOSE"
, "ONCONTEXTMENU"
, "ONCUECHANGE"
, "ONDBLCLICK"
, "ONDURATIONCHANGE"
, "ONENDED"
, "ONERROR"
, "ONFOCUS"
, "ONFORMDATA"
, "ONGOTPOINTERCAPTURE"
, "ONINPUT"
, "ONINVALID"
, "ONKEYDOWN"
, "ONKEYPRESS"
, "ONKEYUP"
, "ONLOAD"
, "ONLOADEDDATA"
, "ONLOADEDMETADATA"
, "ONLOADEND"
, "ONLOADSTART"
, "ONLOSTPOINTERCAPTURE"
, "ONMOUSEDOWN"
, "ONMOUSEENTER"
, "ONMOUSELEAVE"
, "ONMOUSEMOVE"
, "ONMOUSEOUT"
, "ONMOUSEOVER"
, "ONMOUSEUP"
, "ONPAUSE"
, "ONPLAY"
, "ONPLAYING"
, "ONPOINTERCANCEL"
, "ONPOINTERDOWN"
, "ONPOINTERENTER"
, "ONPOINTERLEAVE"
, "ONPOINTERMOVE"
, "ONPOINTEROUT"
, "ONPOINTEROVER"
, "ONPOINTERUP"
, "ONRESET"
, "ONRESIZE"
, "ONSCROLL"
, "ONSELECT"
, "ONSELECTIONCHANGE"
, "ONSELECTSTART"
, "ONSUBMIT"
, "ONTOUCHCANCEL"
, "ONTOUCHSTART"
, "ONTRANSITIONCANCEL"
, "ONTRANSITIONEND"
, "ONWHEEL"
, NULL
};

static int cstrcasecmp_with_null(const char *a, const char *b, size_t n)
{
Expand Down Expand Up @@ -332,6 +398,27 @@ static int is_black_tag(const char* s, size_t len)
return 0;
}

static int is_black_geh(const char* s, size_t len)
{
const char** black;

if (len < 3) {
return 0;
}

black = BLACKGEH;
while (*black != NULL) {
if (cstrcasecmp_with_null(*black, s, len) == 0) {
/* printf("Got black event handler %s\n", *black); */
return 1;
}
black+= 1;
}

return 0;
}


static attribute_t is_black_attr(const char* s, size_t len)
{
stringtype_t* black;
Expand All @@ -344,10 +431,11 @@ static attribute_t is_black_attr(const char* s, size_t len)
/* JavaScript on.* */
if ((s[0] == 'o' || s[0] == 'O') && (s[1] == 'n' || s[1] == 'N')) {
/* printf("Got JavaScript on- attribute name\n"); */
return TYPE_BLACK;
}


if (is_black_geh(s, len)) {
return TYPE_BLACK;
}
}

/* XMLNS can be used to create arbitrary tags */
if (cstrcasecmp_with_null("XMLNS", s, 5) == 0 || cstrcasecmp_with_null("XLINK", s, 5) == 0) {
Expand Down