From nobody Fri Oct 15 08:23:16 2021 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 8F08317F4D00; Fri, 15 Oct 2021 08:23:16 +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 4HVzmh2qmWz4W1G; Fri, 15 Oct 2021 08:23:16 +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 3E771233FD; Fri, 15 Oct 2021 08:23:16 +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 19F8NGi6047219; Fri, 15 Oct 2021 08:23:16 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 19F8NG16047218; Fri, 15 Oct 2021 08:23:16 GMT (envelope-from git) Date: Fri, 15 Oct 2021 08:23:16 GMT Message-Id: <202110150823.19F8NG16047218@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Marcin Wojtas Subject: git: a97d697122da - main - kern_exec: Add kern.stacktop sysctl. List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-main@freebsd.org X-BeenThere: dev-commits-src-main@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mw X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: a97d697122da2bfb0baae5f0939d118d119dae33 Auto-Submitted: auto-generated X-ThisMailContainsUnwantedMimeParts: N The branch main has been updated by mw: URL: https://cgit.FreeBSD.org/src/commit/?id=a97d697122da2bfb0baae5f0939d118d119dae33 commit a97d697122da2bfb0baae5f0939d118d119dae33 Author: Dawid Gorecki AuthorDate: 2021-10-13 19:03:37 +0000 Commit: Marcin Wojtas CommitDate: 2021-10-15 08:21:55 +0000 kern_exec: Add kern.stacktop sysctl. With stack gap enabled top of the stack is moved down by a random amount of bytes. Because of that some multithreaded applications which use kern.usrstack sysctl to calculate address of stacks for their threads can fail. Add kern.stacktop sysctl, which can be used to retrieve address of the stack after stack gap is applied to it. Returns value identical to kern.usrstack for processes which have no stack gap. Reviewed by: kib Obtained from: Semihalf Sponsored by: Stormshield MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D31897 --- sys/kern/kern_exec.c | 31 ++++++++++++++++++++++++++++++- sys/sys/sysctl.h | 1 + 2 files changed, 31 insertions(+), 1 deletion(-) diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c index 9dceebdd8441..a9998471dd14 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -119,6 +119,7 @@ SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); +static int sysctl_kern_stacktop(SYSCTL_HANDLER_ARGS); static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); static int do_execve(struct thread *td, struct image_args *args, struct mac *mac_p, struct vmspace *oldvmspace); @@ -133,6 +134,10 @@ SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", "Top of process stack"); +SYSCTL_PROC(_kern, KERN_STACKTOP, stacktop, CTLTYPE_ULONG | CTLFLAG_RD | + CTLFLAG_CAPRD | CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_stacktop, "LU", + "Top of process stack with stack gap."); + SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_stackprot, "I", "Stack memory permissions"); @@ -191,7 +196,31 @@ sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) #endif error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, sizeof(p->p_sysent->sv_usrstack)); - return error; + return (error); +} + +static int +sysctl_kern_stacktop(SYSCTL_HANDLER_ARGS) +{ + vm_offset_t stacktop; + struct proc *p; + int error; + + p = curproc; +#ifdef SCTL_MASK32 + if (req->flags & SCTL_MASK32) { + unsigned int val; + + val = (unsigned int)(p->p_sysent->sv_usrstack - + p->p_vmspace->vm_stkgap); + error = SYSCTL_OUT(req, &val, sizeof(val)); + } else +#endif + { + stacktop = p->p_sysent->sv_usrstack - p->p_vmspace->vm_stkgap; + error = SYSCTL_OUT(req, &stacktop, sizeof(stacktop)); + } + return (error); } static int diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h index 71a34652ff44..b455fec7209f 100644 --- a/sys/sys/sysctl.h +++ b/sys/sys/sysctl.h @@ -976,6 +976,7 @@ TAILQ_HEAD(sysctl_ctx_list, sysctl_ctx_entry); #define KERN_HOSTUUID 36 /* string: host UUID identifier */ #define KERN_ARND 37 /* int: from arc4rand() */ #define KERN_MAXPHYS 38 /* int: MAXPHYS value */ +#define KERN_STACKTOP 39 /* int: USRSTACK - stack gap */ /* * KERN_PROC subtypes */