From 448f84a43ab14a30a6bada6ce22a6dc6e89ea85e Mon Sep 17 00:00:00 2001 From: Rob Pike Date: Tue, 15 Sep 2015 10:59:27 -0700 Subject: [PATCH] internal/obj: protect against nil addr.Sym This has been the root cause of a number of crashes caused by fuzz throwing modem noise at the assembler, which in turn attempts to print diagnostics but instead just gets crashes. Fixes #12627. Change-Id: I72c2da79d8eb240e1a37aa6140454c552b05e0f1 Reviewed-on: https://go-review.googlesource.com/14595 Reviewed-by: Ian Lance Taylor --- src/cmd/internal/obj/util.go | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/src/cmd/internal/obj/util.go b/src/cmd/internal/obj/util.go index f03eb6943f..73d33666e2 100644 --- a/src/cmd/internal/obj/util.go +++ b/src/cmd/internal/obj/util.go @@ -457,13 +457,25 @@ func Mconv(a *Addr) string { } case NAME_EXTERN: - str = fmt.Sprintf("%s%s(SB)", a.Sym.Name, offConv(a.Offset)) + if a.Sym != nil { + str = fmt.Sprintf("%s%s(SB)", a.Sym.Name, offConv(a.Offset)) + } else { + str = fmt.Sprintf("%s(SB)", offConv(a.Offset)) + } case NAME_GOTREF: - str = fmt.Sprintf("%s%s@GOT(SB)", a.Sym.Name, offConv(a.Offset)) + if a.Sym != nil { + str = fmt.Sprintf("%s%s@GOT(SB)", a.Sym.Name, offConv(a.Offset)) + } else { + str = fmt.Sprintf("%s@GOT(SB)", offConv(a.Offset)) + } case NAME_STATIC: - str = fmt.Sprintf("%s<>%s(SB)", a.Sym.Name, offConv(a.Offset)) + if a.Sym != nil { + str = fmt.Sprintf("%s<>%s(SB)", a.Sym.Name, offConv(a.Offset)) + } else { + str = fmt.Sprintf("<>%s(SB)", offConv(a.Offset)) + } case NAME_AUTO: if a.Sym != nil { -- 2.48.1