From owner-dev-commits-src-all@freebsd.org Mon Sep 27 17:12:53 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 8B54C66C35E; Mon, 27 Sep 2021 17:12:53 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4HJ8N53P2mz3w2Q; Mon, 27 Sep 2021 17:12:53 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 55C1215014; Mon, 27 Sep 2021 17:12:53 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 18RHCrhe041754; Mon, 27 Sep 2021 17:12:53 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 18RHCrTl041753; Mon, 27 Sep 2021 17:12:53 GMT (envelope-from git) Date: Mon, 27 Sep 2021 17:12:53 GMT Message-Id: <202109271712.18RHCrTl041753@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Konstantin Belousov Subject: git: b1e2f063ae91 - main - amd64 sendsig: fix context corruption MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kib X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: b1e2f063ae912dc5b7a7f6638ccb3aff14f299cf Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Sep 2021 17:12:53 -0000 The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=b1e2f063ae912dc5b7a7f6638ccb3aff14f299cf commit b1e2f063ae912dc5b7a7f6638ccb3aff14f299cf Author: Konstantin Belousov AuthorDate: 2021-09-27 16:57:25 +0000 Commit: Konstantin Belousov CommitDate: 2021-09-27 17:12:46 +0000 amd64 sendsig: fix context corruption Drop fpstate only after copying out xfpustate from the thread usermode save area. Otherwise a context switch between get_fpcontext(), which now returns the pointer directly into user save area, and copyout, would cause reinit of the save area, loosing user registers. Reported, reviewed, and tested by: markj Sponsored by: The FreeBSD Foundation MFC after: 3 days Differential revision: https://reviews.freebsd.org/D32159 --- sys/amd64/amd64/exec_machdep.c | 2 +- sys/amd64/ia32/ia32_signal.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/amd64/amd64/exec_machdep.c b/sys/amd64/amd64/exec_machdep.c index d605f080871a..b93fe7c4b3c7 100644 --- a/sys/amd64/amd64/exec_machdep.c +++ b/sys/amd64/amd64/exec_machdep.c @@ -143,7 +143,6 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) bcopy(regs, &sf.sf_uc.uc_mcontext.mc_rdi, sizeof(*regs)); sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ get_fpcontext(td, &sf.sf_uc.uc_mcontext, &xfpusave, &xfpusave_len); - fpstate_drop(td); update_pcb_bases(pcb); sf.sf_uc.uc_mcontext.mc_fsbase = pcb->pcb_fsbase; sf.sf_uc.uc_mcontext.mc_gsbase = pcb->pcb_gsbase; @@ -203,6 +202,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sigexit(td, SIGILL); } + fpstate_drop(td); regs->tf_rsp = (long)sfp; regs->tf_rip = p->p_sysent->sv_sigcode_base; regs->tf_rflags &= ~(PSL_T | PSL_D); diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c index ab7100f5b9fb..6c879eccfc77 100644 --- a/sys/amd64/ia32/ia32_signal.c +++ b/sys/amd64/ia32/ia32_signal.c @@ -607,7 +607,6 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sf.sf_uc.uc_mcontext.mc_gs = regs->tf_gs; sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ ia32_get_fpcontext(td, &sf.sf_uc.uc_mcontext, &xfpusave, &xfpusave_len); - fpstate_drop(td); sf.sf_uc.uc_mcontext.mc_fsbase = td->td_pcb->pcb_fsbase; sf.sf_uc.uc_mcontext.mc_gsbase = td->td_pcb->pcb_gsbase; @@ -661,6 +660,7 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sigexit(td, SIGILL); } + fpstate_drop(td); regs->tf_rsp = (uintptr_t)sfp; regs->tf_rip = p->p_sysent->sv_sigcode_base; regs->tf_rflags &= ~(PSL_T | PSL_D);