16.11.2024 04:10, Kuniyuki Iwashima пишет:
Now this allows sending pidfd without SO_PASSPIDFD, so you need to
add a validation for "if (!msg->msg_control)" in __scm_recv_common().
Will do, thanks.
Btw don't we need MSG_CTRUNC in
such case even if "msg_control"exists? Or the established practice is to
just drop cmsg silently? I mean, something like the below: ---
a/include/net/scm.h +++ b/include/net/scm.h @@ -176,12 +176,19 @@ static
inline bool __scm_recv_common(struct socket *sock, struct msghdr *msg,
if (!msg->msg_control) { if (test_bit(SOCK_PASSCRED, &sock->flags) ||
test_bit(SOCK_PASSPIDFD, &sock->flags) || - scm->fp ||
scm_has_secdata(sock)) + scm->fp || scm_has_secdata(sock) || +
scm->pidfd_flags) msg->msg_flags |= MSG_CTRUNC; scm_destroy(scm); return
false; } + if (!test_bit(SOCK_PASSPIDFD, &sock->flags) &&
scm->pidfd_flags) { + msg->msg_flags |= MSG_CTRUNC; + scm_destroy(scm);
+ return false; + } + if (test_bit(SOCK_PASSCRED, &sock->flags)) {
struct user_namespace *current_ns = current_user_ns(); struct ucred
ucreds = {
