From owner-svn-src-all@FreeBSD.ORG Fri Aug 22 08:19:08 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id C0F3F4FD; Fri, 22 Aug 2014 08:19:08 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A0E1A335D; Fri, 22 Aug 2014 08:19:08 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id s7M8J8r4096258; Fri, 22 Aug 2014 08:19:08 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id s7M8J8v0096257; Fri, 22 Aug 2014 08:19:08 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201408220819.s7M8J8v0096257@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Fri, 22 Aug 2014 08:19:08 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r270321 - head/sys/kern X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Aug 2014 08:19:08 -0000 Author: kib Date: Fri Aug 22 08:19:08 2014 New Revision: 270321 URL: http://svnweb.freebsd.org/changeset/base/270321 Log: Ensure that sigaction flags for signal, which disposition is reset to ignored or default, are not leaking. Apparently, there exists code which relies on SA_SIGINFO not reported for SIG_DFL or SIG_IGN. In kern_sigaction, ignore flags when resetting. Encapsulate the flag and disposition testing into helper sigact_flag_test(). On exec, and when delivering signal with SA_RESETHAND flag set, signals are reset automatically. Use new helper sigdflt(), which removes duplicated code and corrects all flag bits for the signal. For proc0, set sigintr bit for all ignored signals. Ignored signals are consumed in tdsendsignal() and not delivered to the victim thread at all. Reported and tested by: royger Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/kern/kern_sig.c Modified: head/sys/kern/kern_sig.c ============================================================================== --- head/sys/kern/kern_sig.c Fri Aug 22 07:52:47 2014 (r270320) +++ head/sys/kern/kern_sig.c Fri Aug 22 08:19:08 2014 (r270321) @@ -621,6 +621,15 @@ sig_ffs(sigset_t *set) return (0); } +static bool +sigact_flag_test(struct sigaction *act, int flag) +{ + + return ((act->sa_flags & flag) != 0 && + (__sighandler_t *)act->sa_sigaction != SIG_IGN && + (__sighandler_t *)act->sa_sigaction != SIG_DFL); +} + /* * kern_sigaction * sigaction @@ -683,7 +692,7 @@ kern_sigaction(td, sig, act, oact, flags ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); - if (act->sa_flags & SA_SIGINFO) { + if (sigact_flag_test(act, SA_SIGINFO)) { ps->ps_sigact[_SIG_IDX(sig)] = (__sighandler_t *)act->sa_sigaction; SIGADDSET(ps->ps_siginfo, sig); @@ -691,19 +700,19 @@ kern_sigaction(td, sig, act, oact, flags ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; SIGDELSET(ps->ps_siginfo, sig); } - if (!(act->sa_flags & SA_RESTART)) + if (!sigact_flag_test(act, SA_RESTART)) SIGADDSET(ps->ps_sigintr, sig); else SIGDELSET(ps->ps_sigintr, sig); - if (act->sa_flags & SA_ONSTACK) + if (sigact_flag_test(act, SA_ONSTACK)) SIGADDSET(ps->ps_sigonstack, sig); else SIGDELSET(ps->ps_sigonstack, sig); - if (act->sa_flags & SA_RESETHAND) + if (sigact_flag_test(act, SA_RESETHAND)) SIGADDSET(ps->ps_sigreset, sig); else SIGDELSET(ps->ps_sigreset, sig); - if (act->sa_flags & SA_NODEFER) + if (sigact_flag_test(act, SA_NODEFER)) SIGADDSET(ps->ps_signodefer, sig); else SIGDELSET(ps->ps_signodefer, sig); @@ -904,14 +913,36 @@ siginit(p) PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); - for (i = 1; i <= NSIG; i++) - if (sigprop(i) & SA_IGNORE && i != SIGCONT) + for (i = 1; i <= NSIG; i++) { + if (sigprop(i) & SA_IGNORE && i != SIGCONT) { SIGADDSET(ps->ps_sigignore, i); + SIGADDSET(ps->ps_sigintr, i); + } + } mtx_unlock(&ps->ps_mtx); PROC_UNLOCK(p); } /* + * Reset specified signal to the default disposition. + */ +static void +sigdflt(struct sigacts *ps, int sig) +{ + + mtx_assert(&ps->ps_mtx, MA_OWNED); + SIGDELSET(ps->ps_sigcatch, sig); + if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT) + SIGADDSET(ps->ps_sigignore, sig); + ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; + SIGDELSET(ps->ps_siginfo, sig); + SIGADDSET(ps->ps_sigintr, sig); + SIGDELSET(ps->ps_sigonstack, sig); + SIGDELSET(ps->ps_sigreset, sig); + SIGDELSET(ps->ps_signodefer, sig); +} + +/* * Reset signals for an exec of the specified process. */ void @@ -932,13 +963,9 @@ execsigs(struct proc *p) mtx_lock(&ps->ps_mtx); while (SIGNOTEMPTY(ps->ps_sigcatch)) { sig = sig_ffs(&ps->ps_sigcatch); - SIGDELSET(ps->ps_sigcatch, sig); - if (sigprop(sig) & SA_IGNORE) { - if (sig != SIGCONT) - SIGADDSET(ps->ps_sigignore, sig); + sigdflt(ps, sig); + if ((sigprop(sig) & SA_IGNORE) != 0) sigqueue_delete_proc(p, sig); - } - ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } /* * Reset stack state to the user stack. @@ -1892,16 +1919,8 @@ trapsignal(struct thread *td, ksiginfo_t SIGADDSET(mask, sig); kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); - if (SIGISMEMBER(ps->ps_sigreset, sig)) { - /* - * See kern_sigaction() for origin of this code. - */ - SIGDELSET(ps->ps_sigcatch, sig); - if (sig != SIGCONT && - sigprop(sig) & SA_IGNORE) - SIGADDSET(ps->ps_sigignore, sig); - ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; - } + if (SIGISMEMBER(ps->ps_sigreset, sig)) + sigdflt(ps, sig); mtx_unlock(&ps->ps_mtx); } else { /* @@ -2844,16 +2863,8 @@ postsig(sig) kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); - if (SIGISMEMBER(ps->ps_sigreset, sig)) { - /* - * See kern_sigaction() for origin of this code. - */ - SIGDELSET(ps->ps_sigcatch, sig); - if (sig != SIGCONT && - sigprop(sig) & SA_IGNORE) - SIGADDSET(ps->ps_sigignore, sig); - ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; - } + if (SIGISMEMBER(ps->ps_sigreset, sig)) + sigdflt(ps, sig); td->td_ru.ru_nsignals++; if (p->p_sig == sig) { p->p_code = 0;