From owner-dev-commits-src-all@freebsd.org Fri Dec 25 13:47:38 2020 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 A26AC4C22A9; Fri, 25 Dec 2020 13:47:38 +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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4D2Stf2Ndyz3FF6; Fri, 25 Dec 2020 13:47:38 +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 3574F23A3C; Fri, 25 Dec 2020 13:47:38 +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 0BPDlcNW082237; Fri, 25 Dec 2020 13:47:38 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 0BPDlc8U082236; Fri, 25 Dec 2020 13:47:38 GMT (envelope-from git) Date: Fri, 25 Dec 2020 13:47:38 GMT Message-Id: <202012251347.0BPDlc8U082236@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Konstantin Belousov Subject: git: ed52452d6e52 - MFC r368772: Add ELF flag to disable ASLR stack gap. 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/stable/12 X-Git-Reftype: branch X-Git-Commit: ed52452d6e52a37409c15b13c0efca8d0b28c44e 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: Fri, 25 Dec 2020 13:47:38 -0000 The branch stable/12 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=ed52452d6e52a37409c15b13c0efca8d0b28c44e commit ed52452d6e52a37409c15b13c0efca8d0b28c44e Author: Konstantin Belousov AuthorDate: 2020-12-18 23:14:39 +0000 Commit: Konstantin Belousov CommitDate: 2020-12-25 13:44:33 +0000 MFC r368772: Add ELF flag to disable ASLR stack gap. PR: 239873 (cherry picked from commit 673e2dd652156342009930cf1f7d15623e4a543a) --- sys/compat/freebsd32/freebsd32_misc.c | 3 +-- sys/kern/imgact_elf.c | 2 -- sys/kern/kern_exec.c | 14 ++++++++++++-- sys/sys/elf_common.h | 1 + sys/sys/imgact.h | 1 + usr.bin/elfctl/elfctl.c | 1 + 6 files changed, 16 insertions(+), 6 deletions(-) diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c index 76054c8046a0..6c9ede34c1dc 100644 --- a/sys/compat/freebsd32/freebsd32_misc.c +++ b/sys/compat/freebsd32/freebsd32_misc.c @@ -3224,9 +3224,8 @@ freebsd32_copyout_strings(struct image_params *imgp) destp -= ARG_MAX - imgp->args->stringspace; destp = rounddown2(destp, sizeof(uint32_t)); + exec_stackgap(imgp, &destp); vectp = (uint32_t *)destp; - if (imgp->sysent->sv_stackgap != NULL) - imgp->sysent->sv_stackgap(imgp, (u_long *)&vectp); if (imgp->auxargs) { /* diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c index b1828591fc33..e436c34d1d1b 100644 --- a/sys/kern/imgact_elf.c +++ b/sys/kern/imgact_elf.c @@ -2757,8 +2757,6 @@ __elfN(stackgap)(struct image_params *imgp, u_long *stack_base) u_long range, rbase, gap; int pct; - if ((imgp->map_flags & MAP_ASLR) == 0) - return; pct = __elfN(aslr_stack_gap); if (pct == 0) return; diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c index cd6c231479bb..812d5e827093 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -1497,6 +1497,17 @@ exec_free_args(struct image_args *args) fdescfree_remapped(args->fdp); } +void +exec_stackgap(struct image_params *imgp, uintptr_t *dp) +{ + if (imgp->sysent->sv_stackgap == NULL || + (imgp->proc->p_fctl0 & (NT_FREEBSD_FCTL_ASLR_DISABLE | + NT_FREEBSD_FCTL_ASG_DISABLE)) != 0 || + (imgp->map_flags & MAP_ASLR) == 0) + return; + imgp->sysent->sv_stackgap(imgp, dp); +} + /* * Copy strings out to the new process address space, constructing new arg * and env vector tables. Return a pointer to the base so that it can be used @@ -1574,9 +1585,8 @@ exec_copyout_strings(struct image_params *imgp) destp -= ARG_MAX - imgp->args->stringspace; destp = rounddown2(destp, sizeof(void *)); + exec_stackgap(imgp, &destp); vectp = (char **)destp; - if (imgp->sysent->sv_stackgap != NULL) - imgp->sysent->sv_stackgap(imgp, (u_long *)&vectp); if (imgp->auxargs) { /* diff --git a/sys/sys/elf_common.h b/sys/sys/elf_common.h index b31ee6db7179..c469557a96e1 100644 --- a/sys/sys/elf_common.h +++ b/sys/sys/elf_common.h @@ -791,6 +791,7 @@ typedef struct { #define NT_FREEBSD_FCTL_STKGAP_DISABLE 0x00000004 #define NT_FREEBSD_FCTL_WXNEEDED 0x00000008 #define NT_FREEBSD_FCTL_LA48 0x00000010 +#define NT_FREEBSD_FCTL_ASG_DISABLE 0x00000020 /* ASLR STACK GAP Disable */ /* Values for n_type. Used in core files. */ #define NT_PRSTATUS 1 /* Process status. */ diff --git a/sys/sys/imgact.h b/sys/sys/imgact.h index a89907e7b60d..44bf8a1359c9 100644 --- a/sys/sys/imgact.h +++ b/sys/sys/imgact.h @@ -110,6 +110,7 @@ int exec_copyin_args(struct image_args *, char *, enum uio_seg, char **, char **); int exec_copyin_data_fds(struct thread *, struct image_args *, const void *, size_t, const int *, size_t); +void exec_stackgap(struct image_params *imgp, uintptr_t *dp); int pre_execve(struct thread *td, struct vmspace **oldvmspace); void post_execve(struct thread *td, int error, struct vmspace *oldvmspace); #endif diff --git a/usr.bin/elfctl/elfctl.c b/usr.bin/elfctl/elfctl.c index ccc1c85007ce..d18d828e151c 100644 --- a/usr.bin/elfctl/elfctl.c +++ b/usr.bin/elfctl/elfctl.c @@ -70,6 +70,7 @@ static struct ControlFeatures featurelist[] = { #ifdef NT_FREEBSD_FCTL_LA48 { "la48", NT_FREEBSD_FCTL_LA48, "amd64: Limit user VA to 48bit" }, #endif + { "aslrstkgap", NT_FREEBSD_FCTL_ASG_DISABLE, "Disable ASLR stack gap" }, }; static struct option long_opts[] = {