Messages in this thread | | | Date | Mon, 20 Mar 2006 13:36:36 -0800 | From | Chris Wright <> | Subject | Re: [PATCH] scm: fold __scm_send() into scm_send() |
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* Chris Wright (chrisw@sous-sol.org) wrote: > * Ingo Oeser (netdev@axxeo.de) wrote: > > Hi Chris, > > > > Andrew Morton wrote: > > > Ingo Oeser <ioe-lkml@rameria.de> wrote: > > > > > > > > -int scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) > > > > -{ > > > > - struct task_struct *p = current; > > > > - scm->creds = (struct ucred) { > > > > - .uid = p->uid, > > > > - .gid = p->gid, > > > > - .pid = p->tgid > > > > - }; > > > > - scm->fp = NULL; > > > > - scm->sid = security_sk_sid(sock->sk, NULL, 0); > > > > - scm->seq = 0; > > > > - if (msg->msg_controllen <= 0) > > > > - return 0; > > > > - return __scm_send(sock, msg, scm); > > > > -} > > > > > > It's worth noting that scm_send() will call security_sk_sid() even if > > > (msg->msg_controllen <= 0). > > > > Chris, do you know if this is needed in this case? > > This whole thing is looking broken. I'm still trying to find the original > patch which caused the series of broken patches on top.
OK, it starts here from Catherine's patch:
include/net/scm.h::scm_recv() + if (test_bit(SOCK_PASSSEC, &sock->flags)) { + err = security_sid_to_context(scm->sid, &scontext, &scontext_len); + if (!err) + put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, scontext_len, scontext); + }
Catherine, the security_sid_to_context() is a raw SELinux function which crept into core code and should not have been there. The fallout fixes included conditionally exporting security_sid_to_context, and finally scm_send/recv unlining. The end result in -mm looks broken to me. Specifically, it now does:
ucred->uid = tsk->uid; ucred->gid = tsk->gid; ucred->pid = tsk->tgid; scm->fp = NULL; scm->seq = 0; if (msg->msg_controllen <= 0) return 0;
scm->sid = security_sk_sid(sock->sk, NULL, 0);
The point of Catherine's original patch was to make sure there's always a security identifier associated with AF_UNIX messages. So receiver can always check it (same as having credentials even w/out sender control message passing them). Now we will have garbage for sid.
thanks, -chris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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