From owner-dev-commits-src-all@freebsd.org Tue Apr 13 21:42:39 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 E742B5ED249; Tue, 13 Apr 2021 21:42:39 +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 4FKfGR1FcSz3Pj8; Tue, 13 Apr 2021 21:42:39 +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 D2793126A5; Tue, 13 Apr 2021 21:42:38 +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 13DLgcRK099233; Tue, 13 Apr 2021 21:42:38 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 13DLgc9B099232; Tue, 13 Apr 2021 21:42:38 GMT (envelope-from git) Date: Tue, 13 Apr 2021 21:42:38 GMT Message-Id: <202104132142.13DLgc9B099232@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: b261bb4057f4 - main - vfs: Add KASAN state transitions for vnodes 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/main X-Git-Reftype: branch X-Git-Commit: b261bb4057f4abbc1366e4af8e9e4081d039be4a 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: Tue, 13 Apr 2021 21:42:40 -0000 The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=b261bb4057f4abbc1366e4af8e9e4081d039be4a commit b261bb4057f4abbc1366e4af8e9e4081d039be4a Author: Mark Johnston AuthorDate: 2021-04-13 21:40:11 +0000 Commit: Mark Johnston CommitDate: 2021-04-13 21:42:21 +0000 vfs: Add KASAN state transitions for vnodes vnodes are a bit special in that they may exist on per-CPU lists even while free. Add a KASAN-only destructor that poisons regions of each vnode that are not expected to be accessed after a free. MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D29459 --- sys/kern/vfs_subr.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 64 insertions(+), 2 deletions(-) diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index af12252e8a88..2be3a81ad799 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$"); #include #include +#include #include #include #include @@ -527,6 +528,54 @@ vn_free_marker(struct vnode *vp) free(vp, M_VNODE_MARKER); } +#ifdef KASAN +static int +vnode_ctor(void *mem, int size, void *arg __unused, int flags __unused) +{ + kasan_mark(mem, size, roundup2(size, UMA_ALIGN_PTR + 1), 0); + return (0); +} + +static void +vnode_dtor(void *mem, int size, void *arg __unused) +{ + size_t end1, end2, off1, off2; + + _Static_assert(offsetof(struct vnode, v_vnodelist) < + offsetof(struct vnode, v_dbatchcpu), + "KASAN marks require updating"); + + off1 = offsetof(struct vnode, v_vnodelist); + off2 = offsetof(struct vnode, v_dbatchcpu); + end1 = off1 + sizeof(((struct vnode *)NULL)->v_vnodelist); + end2 = off2 + sizeof(((struct vnode *)NULL)->v_dbatchcpu); + + /* + * Access to the v_vnodelist and v_dbatchcpu fields are permitted even + * after the vnode has been freed. Try to get some KASAN coverage by + * marking everything except those two fields as invalid. Because + * KASAN's tracking is not byte-granular, any preceding fields sharing + * the same 8-byte aligned word must also be marked valid. + */ + + /* Handle the area from the start until v_vnodelist... */ + off1 = rounddown2(off1, KASAN_SHADOW_SCALE); + kasan_mark(mem, off1, off1, KASAN_UMA_FREED); + + /* ... then the area between v_vnodelist and v_dbatchcpu ... */ + off1 = roundup2(end1, KASAN_SHADOW_SCALE); + off2 = rounddown2(off2, KASAN_SHADOW_SCALE); + if (off2 > off1) + kasan_mark((void *)((char *)mem + off1), off2 - off1, + off2 - off1, KASAN_UMA_FREED); + + /* ... and finally the area from v_dbatchcpu to the end. */ + off2 = roundup2(end2, KASAN_SHADOW_SCALE); + kasan_mark((void *)((char *)mem + off2), size - off2, size - off2, + KASAN_UMA_FREED); +} +#endif /* KASAN */ + /* * Initialize a vnode as it first enters the zone. */ @@ -592,6 +641,8 @@ vnode_fini(void *mem, int size) mtx_destroy(&vp->v_interlock); bo = &vp->v_bufobj; rw_destroy(BO_LOCKPTR(bo)); + + kasan_mark(mem, size, size, 0); } /* @@ -619,6 +670,8 @@ static void vntblinit(void *dummy __unused) { struct vdbatch *vd; + uma_ctor ctor; + uma_dtor dtor; int cpu, physvnodes, virtvnodes; u_int i; @@ -658,9 +711,18 @@ vntblinit(void *dummy __unused) TAILQ_INSERT_HEAD(&vnode_list, vnode_list_free_marker, v_vnodelist); vnode_list_reclaim_marker = vn_alloc_marker(NULL); TAILQ_INSERT_HEAD(&vnode_list, vnode_list_reclaim_marker, v_vnodelist); - vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL, - vnode_init, vnode_fini, UMA_ALIGN_PTR, 0); + +#ifdef KASAN + ctor = vnode_ctor; + dtor = vnode_dtor; +#else + ctor = NULL; + dtor = NULL; +#endif + vnode_zone = uma_zcreate("VNODE", sizeof(struct vnode), ctor, dtor, + vnode_init, vnode_fini, UMA_ALIGN_PTR, UMA_ZONE_NOKASAN); uma_zone_set_smr(vnode_zone, vfs_smr); + /* * Preallocate enough nodes to support one-per buf so that * we can not fail an insert. reassignbuf() callers can not