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 <iant@golang.org>
diff --git a/src/cmd/internal/obj/util.go b/src/cmd/internal/obj/util.go
index f03eb69..73d3366 100644
--- a/src/cmd/internal/obj/util.go
+++ b/src/cmd/internal/obj/util.go
@@ -457,13 +457,25 @@
}
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 {
