cmd/buildid: reject rewriting legacy buildids

This resolves legacy go binaries crashing the buildid tool when the -w flag is specified.

Fixes #50809

Change-Id: I55a866f285a3c2cebcf2cdbb9cc30e5078e1d18f
GitHub-Last-Rev: 7169a58fd7ba17fdeb8037cef3f50080169dc137
GitHub-Pull-Request: golang/go#53163
Reviewed-on: https://go-review.googlesource.com/c/go/+/409535
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

diff --git a/src/cmd/buildid/buildid.go b/src/cmd/buildid/buildid.go
index 8e02a7ae109611488417ab480cd47288de45d81a..72ad80dbbba02f094aaac43d1e924c5fdf9b39f9 100644 (file)
--- a/src/cmd/buildid/buildid.go
+++ b/src/cmd/buildid/buildid.go
@@ -53,6 +53,11 @@ func main() {
                log.Fatal(err)
        }
 
+       // <= go 1.7 doesn't embed the contentID or actionID, so no slash is present
+       if !strings.Contains(id, "/") {
+               log.Fatalf("%s: build ID is a legacy format...binary too old for this tool", file)
+       }
+
        newID := id[:strings.LastIndex(id, "/")] + "/" + buildid.HashToString(hash)
        if len(newID) != len(id) {
                log.Fatalf("%s: build ID length mismatch %q vs %q", file, id, newID)