Fix SIGSEGV on double free for Cred object

lhchavez · lhchavez · commit 707a03b58173 · 2020-08-16T07:19:20.000-07:00
This change removes the Go finalizer when passing ownership to libgit2. Fixes: #553 (cherry picked from commit 0843b82)
diff --git a/remote.go b/remote.go
@@ -248,6 +248,10 @@ func credentialsCallback(_cred **C.git_cred, _url *C.char, _username_from_url *C
 	ret, cred := callbacks.CredentialsCallback(url, username_from_url, (CredType)(allowed_types))
 	if cred != nil {
 		*_cred = cred.ptr
+
+		// have transferred ownership to libgit, 'forget' the native pointer
+		cred.ptr = nil
+		runtime.SetFinalizer(cred, nil)
 	}
 	return int(ret)
 }

Original file line number	Diff line number	Diff line change
`@@ -248,6 +248,10 @@ func credentialsCallback(_cred *C.git_cred, _url C.char, _username_from_url *C`
`248`	`248`	`ret, cred := callbacks.CredentialsCallback(url, username_from_url, (CredType)(allowed_types))`
`249`	`249`	`if cred != nil {`
`250`	`250`	`*_cred = cred.ptr`
	`251`	`+`
	`252`	`+ // have transferred ownership to libgit, 'forget' the native pointer`
	`253`	`+ cred.ptr = nil`
	`254`	`+ runtime.SetFinalizer(cred, nil)`
`251`	`255`	`}`
`252`	`256`	`return int(ret)`
`253`	`257`	`}`