From owner-dev-commits-src-branches@freebsd.org Wed Feb 24 01:42:06 2021 Return-Path: Delivered-To: dev-commits-src-branches@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 1154F55BE70; Wed, 24 Feb 2021 01:42:06 +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 4DldvK6th7z3GqZ; Wed, 24 Feb 2021 01:42:05 +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 D450023E4F; Wed, 24 Feb 2021 01:42:05 +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 11O1g5dD054482; Wed, 24 Feb 2021 01:42:05 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 11O1g5L6054481; Wed, 24 Feb 2021 01:42:05 GMT (envelope-from git) Date: Wed, 24 Feb 2021 01:42:05 GMT Message-Id: <202102240142.11O1g5L6054481@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 4dd124c3171d - releng/12.2 - MFC jail: Change both root and working directories in jail_attach(2) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/releng/12.2 X-Git-Reftype: branch X-Git-Commit: 4dd124c3171db9cd7fbcc49d8081de590a065d0b Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Feb 2021 01:42:06 -0000 The branch releng/12.2 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=4dd124c3171db9cd7fbcc49d8081de590a065d0b commit 4dd124c3171db9cd7fbcc49d8081de590a065d0b Author: Jamie Gritton AuthorDate: 2021-02-19 22:13:35 +0000 Commit: Mark Johnston CommitDate: 2021-02-24 01:41:57 +0000 MFC jail: Change both root and working directories in jail_attach(2) jail_attach(2) performs an internal chroot operation, leaving it up to the calling process to assure the working directory is inside the jail. Add a matching internal chdir operation to the jail's root. Also ignore kern.chroot_allow_open_directories, and always disallow the operation if there are any directory descriptors open. Approved by: so Security: CVE-2020-25582 Security: FreeBSD-SA-21:05.jail_chdir Reported by: mjg Approved by: markj, kib (cherry picked from commit d4380c0cdd0517dc038403dd5c99242ce78bdeb5) (cherry picked from commit ca9ab8ea17748a1758701fde262cb272fb757989) --- lib/libc/sys/jail.2 | 5 ++++- sys/kern/kern_descrip.c | 40 ++++++++++++++++++++++++++++++++++++---- sys/kern/kern_jail.c | 2 +- sys/sys/filedesc.h | 1 + 4 files changed, 42 insertions(+), 6 deletions(-) diff --git a/lib/libc/sys/jail.2 b/lib/libc/sys/jail.2 index 2e13a6c3a381..82c2e97d4a7b 100644 --- a/lib/libc/sys/jail.2 +++ b/lib/libc/sys/jail.2 @@ -25,7 +25,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 8, 2012 +.Dd February 19, 2021 .Dt JAIL 2 .Os .Sh NAME @@ -228,6 +228,9 @@ The system call attaches the current process to an existing jail, identified by .Fa jid . +It changes the process's root and current directories to the jail's +.Va path +directory. .Pp The .Fn jail_remove diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index cda64931779b..b61b6bc2d66e 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -3216,10 +3216,9 @@ chroot_refuse_vdir_fds(struct filedesc *fdp) } /* - * Common routine for kern_chroot() and jail_attach(). The caller is - * responsible for invoking priv_check() and mac_vnode_check_chroot() to - * authorize this operation. - */ +* The caller is responsible for invoking priv_check() and +* mac_vnode_check_chroot() to authorize this operation. +*/ int pwd_chroot(struct thread *td, struct vnode *vp) { @@ -3265,6 +3264,39 @@ pwd_chdir(struct thread *td, struct vnode *vp) vrele(oldvp); } +/* + * jail_attach(2) changes both root and working directories. + */ +int +pwd_chroot_chdir(struct thread *td, struct vnode *vp) +{ + struct filedesc *fdp; + struct vnode *oldvrp, *oldvcp; + int error; + + fdp = td->td_proc->p_fd; + FILEDESC_XLOCK(fdp); + error = chroot_refuse_vdir_fds(fdp); + if (error != 0) { + FILEDESC_XUNLOCK(fdp); + return (error); + } + oldvrp = fdp->fd_rdir; + vrefact(vp); + fdp->fd_rdir = vp; + oldvcp = fdp->fd_cdir; + vrefact(vp); + fdp->fd_cdir = vp; + if (fdp->fd_jdir == NULL) { + vrefact(vp); + fdp->fd_jdir = vp; + } + FILEDESC_XUNLOCK(fdp); + vrele(oldvrp); + vrele(oldvcp); + return (0); +} + /* * Scan all active processes and prisons to see if any of them have a current * or root directory of `olddp'. If so, replace them with the new mount point. diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c index b4a20b4d29e9..46b43fa7bbc2 100644 --- a/sys/kern/kern_jail.c +++ b/sys/kern/kern_jail.c @@ -2437,7 +2437,7 @@ do_jail_attach(struct thread *td, struct prison *pr) goto e_unlock; #endif VOP_UNLOCK(pr->pr_root, 0); - if ((error = pwd_chroot(td, pr->pr_root))) + if ((error = pwd_chroot_chdir(td, pr->pr_root))) goto e_revert_osd; newcred = crget(); diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h index db5debcfe7c8..ca85f49d7997 100644 --- a/sys/sys/filedesc.h +++ b/sys/sys/filedesc.h @@ -243,6 +243,7 @@ fd_modified(struct filedesc *fdp, int fd, seq_t seq) /* cdir/rdir/jdir manipulation functions. */ void pwd_chdir(struct thread *td, struct vnode *vp); int pwd_chroot(struct thread *td, struct vnode *vp); +int pwd_chroot_chdir(struct thread *td, struct vnode *vp); void pwd_ensure_dirs(void); #endif /* _KERNEL */