From 07e05fd6e95ab445ebe48840c81a027dbace3b8e Mon Sep 17 00:00:00 2001 From: Nikita Sivukhin Date: Fri, 5 Jan 2024 11:25:21 +0400 Subject: [PATCH] http2: remove suspicious uint32->v conversion in frame code Function maxHeaderStringLen(...) uses uint32(int(v)) == v check to validate if length will fit in the int type. This check is a no-op on any architecture because int type always has at least 32 bits, so we can potentially encounter negative return values from maxHeaderStringLen(...) function. This can be bad as this outcome clearly breaks code intention and maybe some further code invariants. This patch replaces uint32(int(v)) == v check with more robust and simpler int(v) > 0 validation which is correct for our case when we operating with uint32 Fixes golang/go#64961 Change-Id: I31f95709df9d25593ade3200696ac5cef9f88652 Reviewed-on: https://go-review.googlesource.com/c/net/+/554235 Auto-Submit: Dmitri Shuralyov Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Dmitri Shuralyov --- http2/frame.go | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/http2/frame.go b/http2/frame.go index c1f6b90dc3..e2b298d859 100644 --- a/http2/frame.go +++ b/http2/frame.go @@ -1510,13 +1510,12 @@ func (mh *MetaHeadersFrame) checkPseudos() error { } func (fr *Framer) maxHeaderStringLen() int { - v := fr.maxHeaderListSize() - if uint32(int(v)) == v { - return int(v) + v := int(fr.maxHeaderListSize()) + if v < 0 { + // If maxHeaderListSize overflows an int, use no limit (0). + return 0 } - // They had a crazy big number for MaxHeaderBytes anyway, - // so give them unlimited header lengths: - return 0 + return v } // readMetaFrame returns 0 or more CONTINUATION frames from fr and