Remove NULs byte arrays passed to PostProcess (#14587)

PostProcess is supposed to be parsing and handling HTML fragments, but on fuzzing it appears that there is a weird issue with NUL elements that could cause a memory address error in downstream libraries. The simplest solution is to strip out the weird NULs - they should not be there in any case and would be stripped out anyway. Signed-off-by: Andrew Thornton <art27@cantab.net>
4 years ago · 7ab6c77b41
parent ec06eb112c
commit 7ab6c77b41
1 changed files with 23 additions and 1 deletions
--- a/modules/markup/html.go
+++ b/modules/markup/html.go
@ -324,8 +324,30 @@ func (ctx *postProcessCtx) postProcess(rawHTML []byte) ([]byte, error) {
 	// give a generous extra 50 bytes
 	res := make([]byte, 0, len(rawHTML)+50)
 	// prepend "<html><body>"
 	res = append(res, "<html><body>"...)
 	// Strip out nuls - they're always invalid
 	start := bytes.IndexByte(rawHTML, '\000')
 	if start >= 0 {
 		res = append(res, rawHTML[:start]...)
 		start++
 		for start < len(rawHTML) {
 			end := bytes.IndexByte(rawHTML[start:], '\000')
 			if end < 0 {
 				res = append(res, rawHTML[start:]...)
 				break
 			} else if end > 0 {
 				res = append(res, rawHTML[start:start+end]...)
 			}
 			start += end + 1
 		}
 	} else {
 		res = append(res, rawHTML...)
 	}
 	// close the tags
 	res = append(res, "</body></html>"...)
 	// parse the HTML