fix: improve buffer handling in QUIC client hello processing

j2rong4cn · j2rong4cn · commit f07ddba70ceb · 2025-11-11T15:55:04.000+08:00
diff --git a/common/sniff/quic.go b/common/sniff/quic.go
@@ -230,11 +230,12 @@ sniff:
 
 			start := int(5 + offset)
 			end := start + int(length)
-			if ja3DataBuf.Len() < end {
+			bufLen := ja3DataBuf.Len()
+			if bufLen < end {
 				if ja3DataBuf.Cap() < end {
 					return io.ErrShortBuffer
 				}
-				ja3DataBuf.Truncate(end)
+				ja3DataBuf.WriteZeroN(end - bufLen)
 			}
 
 			_, err = decryptedReader.Read(ja3DataBuf.Range(start, end))

Original file line number	Diff line number	Diff line change
`@@ -230,11 +230,12 @@ sniff:`
`230`	`230`
`231`	`231`	`start := int(5 + offset)`
`232`	`232`	`end := start + int(length)`
`233`		`- if ja3DataBuf.Len() < end {`
	`233`	`+ bufLen := ja3DataBuf.Len()`
	`234`	`+ if bufLen < end {`
`234`	`235`	`if ja3DataBuf.Cap() < end {`
`235`	`236`	`return io.ErrShortBuffer`
`236`	`237`	`}`
`237`		`- ja3DataBuf.Truncate(end)`
	`238`	`+ ja3DataBuf.WriteZeroN(end - bufLen)`
`238`	`239`	`}`
`239`	`240`
`240`	`241`	`_, err = decryptedReader.Read(ja3DataBuf.Range(start, end))`