Slash sys_mount() and add three helper functions: mount_update(),
mount_getargs(), and mount_domount() to handle three main things it can do. This makes the code more readable and removes the horrible goto mess that was lurking there since forever... it also makes it easier to implement a security policy for that code.
This commit is contained in:
elad
parent
e76d290058
commit
97b434c554
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@ -1,4 +1,4 @@
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/* $NetBSD: vfs_syscalls.c,v 1.282 2006/12/24 08:54:55 elad Exp $ */
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/* $NetBSD: vfs_syscalls.c,v 1.283 2006/12/24 12:43:17 elad Exp $ */
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/*
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* Copyright (c) 1989, 1993
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@ -37,7 +37,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.282 2006/12/24 08:54:55 elad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.283 2006/12/24 12:43:17 elad Exp $");
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#include "opt_compat_netbsd.h"
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#include "opt_compat_43.h"
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@ -104,6 +104,13 @@ static int rename_files(const char *, const char *, struct lwp *, int);
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void checkdirs(struct vnode *);
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static int mount_update(struct lwp *, struct vnode *, const char *, int,
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void *, struct nameidata *);
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static int mount_domount(struct lwp *, struct vnode *, const char *,
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const char *, int, void *, struct nameidata *);
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static int mount_getargs(struct lwp *, struct vnode *, const char *, int,
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void *, struct nameidata *);
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int dovfsusermount = 0;
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/*
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@ -138,128 +145,161 @@ const int nmountcompatnames = sizeof(mountcompatnames) /
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sizeof(mountcompatnames[0]);
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#endif /* COMPAT_09 || COMPAT_43 */
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/* ARGSUSED */
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int
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sys_mount(struct lwp *l, void *v, register_t *retval)
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mount_update(struct lwp *l, struct vnode *vp, const char *path, int flags,
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void *data, struct nameidata *ndp)
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{
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struct sys_mount_args /* {
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syscallarg(const char *) type;
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syscallarg(const char *) path;
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syscallarg(int) flags;
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syscallarg(void *) data;
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} */ *uap = v;
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struct vnode *vp;
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struct mount *mp;
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int error, flag = 0;
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char fstypename[MFSNAMELEN];
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struct vattr va;
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struct nameidata nd;
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struct vfsops *vfs;
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int error = 0, saved_flags;
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/*
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* if MNT_GETARGS is specified, it should be only flag.
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*/
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mp = vp->v_mount;
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saved_flags = mp->mnt_flag;
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if ((SCARG(uap, flags) & MNT_GETARGS) != 0 &&
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(SCARG(uap, flags) & ~MNT_GETARGS) != 0) {
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return EINVAL;
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/* We can't operate on VROOT here. */
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if ((vp->v_flag & VROOT) == 0) {
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vput(vp);
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error = EINVAL;
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goto out;
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}
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if (dovfsusermount == 0 && (SCARG(uap, flags) & MNT_GETARGS) == 0 &&
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(error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
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&l->l_acflag)))
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return (error);
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/*
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* Get vnode to be covered
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* We only allow the filesystem to be reloaded if it
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* is currently mounted read-only.
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*/
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE,
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SCARG(uap, path), l);
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if ((error = namei(&nd)) != 0)
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return (error);
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vp = nd.ni_vp;
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if (flags & MNT_RELOAD &&
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!(mp->mnt_flag & MNT_RDONLY)) {
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error = EOPNOTSUPP; /* Needs translation */
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goto out;
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}
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/*
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* A lookup in VFS_MOUNT might result in an attempt to
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* lock this vnode again, so make the lock recursive.
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* In "highly secure" mode, don't let the caller do anything
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* but downgrade a filesystem from read-write to read-only.
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* (see also below; MNT_UPDATE or MNT_GETARGS is required.)
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*/
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_SETRECURSE);
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if (SCARG(uap, flags) & (MNT_UPDATE | MNT_GETARGS)) {
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if ((vp->v_flag & VROOT) == 0) {
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vput(vp);
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return (EINVAL);
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if (securelevel >= 2 &&
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flags !=
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(mp->mnt_flag | MNT_RDONLY |
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MNT_RELOAD | MNT_FORCE | MNT_UPDATE)) {
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error = EPERM;
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goto out;
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}
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mp->mnt_flag |= flags &
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(MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_GETARGS);
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/*
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* Only root, or the user that did the original mount is
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* permitted to update it.
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*/
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if (mp->mnt_stat.f_owner != kauth_cred_geteuid(l->l_cred) &&
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(error = kauth_authorize_generic(l->l_cred,
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KAUTH_GENERIC_ISSUSER, NULL)) != 0) {
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goto out;
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}
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/*
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* Do not allow NFS export by non-root users. For non-root
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* users, silently enforce MNT_NOSUID and MNT_NODEV, and
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* MNT_NOEXEC if mount point is already MNT_NOEXEC.
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*/
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if (kauth_cred_geteuid(l->l_cred) != 0) {
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if (flags & MNT_EXPORTED) {
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error = EPERM;
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goto out;
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}
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mp = vp->v_mount;
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flag = mp->mnt_flag;
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vfs = mp->mnt_op;
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/*
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* We only allow the filesystem to be reloaded if it
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* is currently mounted read-only.
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*/
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if ((SCARG(uap, flags) & MNT_RELOAD) &&
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((mp->mnt_flag & MNT_RDONLY) == 0)) {
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vput(vp);
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return (EOPNOTSUPP); /* Needs translation */
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}
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/*
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* In "highly secure" mode, don't let the caller do anything
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* but downgrade a filesystem from read-write to read-only.
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* (see also below; MNT_UPDATE or MNT_GETARGS is required.)
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*/
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if (securelevel >= 2 &&
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SCARG(uap, flags) != MNT_GETARGS &&
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SCARG(uap, flags) !=
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(mp->mnt_flag | MNT_RDONLY |
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MNT_RELOAD | MNT_FORCE | MNT_UPDATE)) {
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vput(vp);
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return (EPERM);
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}
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mp->mnt_flag |= SCARG(uap, flags) &
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(MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_GETARGS);
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/*
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* Only root, or the user that did the original mount is
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* permitted to update it.
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*/
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if ((mp->mnt_flag & MNT_GETARGS) == 0 &&
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mp->mnt_stat.f_owner != kauth_cred_geteuid(l->l_cred) &&
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(error = kauth_authorize_generic(l->l_cred,
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KAUTH_GENERIC_ISSUSER, &l->l_acflag)) != 0) {
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vput(vp);
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return (error);
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}
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/*
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* Do not allow NFS export by non-root users. For non-root
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* users, silently enforce MNT_NOSUID and MNT_NODEV, and
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* MNT_NOEXEC if mount point is already MNT_NOEXEC.
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*/
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if (kauth_cred_geteuid(l->l_cred) != 0) {
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if (SCARG(uap, flags) & MNT_EXPORTED) {
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vput(vp);
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return (EPERM);
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}
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SCARG(uap, flags) |= MNT_NOSUID | MNT_NODEV;
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if (flag & MNT_NOEXEC)
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SCARG(uap, flags) |= MNT_NOEXEC;
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}
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if (vfs_busy(mp, LK_NOWAIT, 0)) {
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vput(vp);
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return (EPERM);
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}
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goto update;
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flags |= MNT_NOSUID | MNT_NODEV;
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if (saved_flags & MNT_NOEXEC)
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flags |= MNT_NOEXEC;
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}
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if (vfs_busy(mp, LK_NOWAIT, 0)) {
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error = EPERM;
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goto out;
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}
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/*
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* Set the mount level flags.
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*/
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if (flags & MNT_RDONLY)
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mp->mnt_flag |= MNT_RDONLY;
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else if (mp->mnt_flag & MNT_RDONLY)
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mp->mnt_iflag |= IMNT_WANTRDWR;
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mp->mnt_flag &=
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~(MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
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MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOCOREDUMP |
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MNT_NOATIME | MNT_NODEVMTIME | MNT_SYMPERM | MNT_SOFTDEP);
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mp->mnt_flag |= flags &
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(MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
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MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOCOREDUMP |
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MNT_NOATIME | MNT_NODEVMTIME | MNT_SYMPERM | MNT_SOFTDEP |
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MNT_IGNORE);
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error = VFS_MOUNT(mp, path, data, ndp, l);
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#if defined(COMPAT_30) && defined(NFSSERVER)
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if (error) {
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int error2;
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/* Update failed; let's try and see if it was an
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* export request. */
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error2 = nfs_update_exports_30(mp, path, data, l);
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/* Only update error code if the export request was
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* understood but some problem occurred while
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* processing it. */
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if (error2 != EJUSTRETURN)
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error = error2;
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}
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#endif
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if (mp->mnt_iflag & IMNT_WANTRDWR)
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mp->mnt_flag &= ~MNT_RDONLY;
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if (error)
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mp->mnt_flag = saved_flags;
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mp->mnt_flag &=~
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(MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_GETARGS);
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mp->mnt_iflag &=~ IMNT_WANTRDWR;
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if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0) {
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if (mp->mnt_syncer == NULL)
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error = vfs_allocate_syncvnode(mp);
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} else {
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if (securelevel >= 2) {
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vput(vp);
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return (EPERM);
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}
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if (mp->mnt_syncer != NULL)
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vfs_deallocate_syncvnode(mp);
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}
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vfs_unbusy(mp);
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out:
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return (error);
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}
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int
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mount_domount(struct lwp *l, struct vnode *vp, const char *fstype,
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const char *path, int flags, void *data, struct nameidata *ndp)
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{
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struct mount *mp = NULL;
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struct vattr va;
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char fstypename[MFSNAMELEN];
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int error;
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/* XXX secmodel stuff. */
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if (securelevel >= 2) {
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error = EPERM;
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vput(vp);
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goto out;
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}
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/* Can't make a non-dir a mount-point (from here anyway). */
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if (vp->v_type != VDIR) {
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error = ENOTDIR;
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vput(vp);
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goto out;
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}
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/*
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* If the user is not root, ensure that they own the directory
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* onto which we are attempting to mount.
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*/
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if ((error = VOP_GETATTR(vp, &va, l->l_cred, l)) != 0 ||
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(va.va_uid != kauth_cred_geteuid(l->l_cred) &&
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(error = kauth_authorize_generic(l->l_cred,
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KAUTH_GENERIC_ISSUSER, &l->l_acflag)) != 0)) {
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(error = kauth_authorize_generic(l->l_cred,
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KAUTH_GENERIC_ISSUSER, NULL)) != 0)) {
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vput(vp);
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return (error);
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goto out;
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}
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/*
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* Do not allow NFS export by non-root users. For non-root users,
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@ -267,23 +307,20 @@ sys_mount(struct lwp *l, void *v, register_t *retval)
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* mount point is already MNT_NOEXEC.
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*/
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if (kauth_cred_geteuid(l->l_cred) != 0) {
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if (SCARG(uap, flags) & MNT_EXPORTED) {
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if (flags & MNT_EXPORTED) {
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error = EPERM;
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vput(vp);
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return (EPERM);
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goto out;
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}
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SCARG(uap, flags) |= MNT_NOSUID | MNT_NODEV;
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flags |= MNT_NOSUID | MNT_NODEV;
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if (vp->v_mount->mnt_flag & MNT_NOEXEC)
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SCARG(uap, flags) |= MNT_NOEXEC;
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flags |= MNT_NOEXEC;
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}
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if ((error = vinvalbuf(vp, V_SAVE, l->l_cred, l, 0, 0)) != 0) {
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vput(vp);
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return (error);
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}
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if (vp->v_type != VDIR) {
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vput(vp);
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return (ENOTDIR);
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}
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error = copyinstr(SCARG(uap, type), fstypename, MFSNAMELEN, NULL);
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/*
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* Copy file-system type from userspace.
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*/
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error = copyinstr(fstype, fstypename, MFSNAMELEN, NULL);
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if (error) {
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#if defined(COMPAT_09) || defined(COMPAT_43)
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/*
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@ -292,43 +329,53 @@ sys_mount(struct lwp *l, void *v, register_t *retval)
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* string, we check to see if it matches one of the historic
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* filesystem types.
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*/
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u_long fsindex = (u_long)SCARG(uap, type);
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u_long fsindex = (u_long)fstype;
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if (fsindex >= nmountcompatnames ||
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mountcompatnames[fsindex] == NULL) {
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error = ENODEV;
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vput(vp);
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return (ENODEV);
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goto out;
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}
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strncpy(fstypename, mountcompatnames[fsindex], MFSNAMELEN);
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strlcpy(fstypename, mountcompatnames[fsindex], sizeof(fstypename));
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#else
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vput(vp);
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return (error);
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goto out;
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#endif
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}
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#ifdef COMPAT_10
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/* Accept `ufs' as an alias for `ffs'. */
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if (!strncmp(fstypename, "ufs", MFSNAMELEN))
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strncpy(fstypename, "ffs", MFSNAMELEN);
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#endif
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if ((vfs = vfs_getopsbyname(fstypename)) == NULL) {
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if ((error = vinvalbuf(vp, V_SAVE, l->l_cred, l, 0, 0)) != 0) {
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vput(vp);
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return (ENODEV);
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}
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if (vp->v_mountedhere != NULL) {
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vput(vp);
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return (EBUSY);
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goto out;
|
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}
|
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|
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/*
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* Allocate and initialize the file system.
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* Check if a file-system is not already mounted on this vnode.
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*/
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mp = (struct mount *)malloc((u_long)sizeof(struct mount),
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M_MOUNT, M_WAITOK);
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memset((char *)mp, 0, (u_long)sizeof(struct mount));
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if (vp->v_mountedhere != NULL) {
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error = EBUSY;
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vput(vp);
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goto out;
|
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}
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|
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#ifdef COMPAT_10
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/* Accept `ufs' as an alias for `ffs'. */
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if (strncmp(fstype, "ufs", MFSNAMELEN) == 0)
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fstype = "ffs";
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#endif
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mp = malloc(sizeof(*mp), M_MOUNT, M_WAITOK|M_ZERO);
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|
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if ((mp->mnt_op = vfs_getopsbyname(fstype)) == NULL) {
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free(mp, M_MOUNT);
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error = ENODEV;
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vput(vp);
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goto out;
|
||||
}
|
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|
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lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
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simple_lock_init(&mp->mnt_slock);
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(void)vfs_busy(mp, LK_NOWAIT, 0);
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mp->mnt_op = vfs;
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vfs->vfs_refcount++;
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||||
|
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mp->mnt_op->vfs_refcount++;
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mp->mnt_vnodecovered = vp;
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mp->mnt_stat.f_owner = kauth_cred_geteuid(l->l_cred);
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mp->mnt_unmounter = NULL;
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||||
|
|
@ -339,66 +386,10 @@ sys_mount(struct lwp *l, void *v, register_t *retval)
|
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* The underlying file system may refuse the mount for
|
||||
* various reasons. Allow the user to force it to happen.
|
||||
*/
|
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mp->mnt_flag |= SCARG(uap, flags) & MNT_FORCE;
|
||||
update:
|
||||
if ((SCARG(uap, flags) & MNT_GETARGS) == 0) {
|
||||
/*
|
||||
* Set the mount level flags.
|
||||
*/
|
||||
if (SCARG(uap, flags) & MNT_RDONLY)
|
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mp->mnt_flag |= MNT_RDONLY;
|
||||
else if (mp->mnt_flag & MNT_RDONLY)
|
||||
mp->mnt_iflag |= IMNT_WANTRDWR;
|
||||
mp->mnt_flag &=
|
||||
~(MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
|
||||
MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOCOREDUMP |
|
||||
MNT_NOATIME | MNT_NODEVMTIME | MNT_SYMPERM | MNT_SOFTDEP);
|
||||
mp->mnt_flag |= SCARG(uap, flags) &
|
||||
(MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
|
||||
MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOCOREDUMP |
|
||||
MNT_NOATIME | MNT_NODEVMTIME | MNT_SYMPERM | MNT_SOFTDEP |
|
||||
MNT_IGNORE);
|
||||
}
|
||||
/*
|
||||
* Mount the filesystem.
|
||||
*/
|
||||
error = VFS_MOUNT(mp, SCARG(uap, path), SCARG(uap, data), &nd, l);
|
||||
if (mp->mnt_flag & (MNT_UPDATE | MNT_GETARGS)) {
|
||||
VOP_UNLOCK(vp, 0);
|
||||
#if defined(COMPAT_30) && defined(NFSSERVER)
|
||||
if (mp->mnt_flag & MNT_UPDATE && error != 0) {
|
||||
int error2;
|
||||
mp->mnt_flag |= flags & MNT_FORCE;
|
||||
|
||||
/* Update failed; let's try and see if it was an
|
||||
* export request. */
|
||||
error2 = nfs_update_exports_30(mp, SCARG(uap, path),
|
||||
SCARG(uap, data), l);
|
||||
error = VFS_MOUNT(mp, path, data, ndp, l);
|
||||
|
||||
/* Only update error code if the export request was
|
||||
* understood but some problem occurred while
|
||||
* processing it. */
|
||||
if (error2 != EJUSTRETURN)
|
||||
error = error2;
|
||||
}
|
||||
#endif
|
||||
if (mp->mnt_iflag & IMNT_WANTRDWR)
|
||||
mp->mnt_flag &= ~MNT_RDONLY;
|
||||
if (error)
|
||||
mp->mnt_flag = flag;
|
||||
mp->mnt_flag &=~
|
||||
(MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_GETARGS);
|
||||
mp->mnt_iflag &=~ IMNT_WANTRDWR;
|
||||
if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0) {
|
||||
if (mp->mnt_syncer == NULL)
|
||||
error = vfs_allocate_syncvnode(mp);
|
||||
} else {
|
||||
if (mp->mnt_syncer != NULL)
|
||||
vfs_deallocate_syncvnode(mp);
|
||||
}
|
||||
vfs_unbusy(mp);
|
||||
vrele(vp);
|
||||
return (error);
|
||||
}
|
||||
/*
|
||||
* Put the new filesystem on the mount list after root.
|
||||
*/
|
||||
|
|
@ -417,15 +408,109 @@ sys_mount(struct lwp *l, void *v, register_t *retval)
|
|||
error = vfs_allocate_syncvnode(mp);
|
||||
vfs_unbusy(mp);
|
||||
(void) VFS_STATVFS(mp, &mp->mnt_stat, l);
|
||||
if ((error = VFS_START(mp, 0, l)))
|
||||
error = VFS_START(mp, 0, l);
|
||||
if (error)
|
||||
vrele(vp);
|
||||
} else {
|
||||
vp->v_mountedhere = (struct mount *)0;
|
||||
vfs->vfs_refcount--;
|
||||
vp->v_mountedhere = NULL;
|
||||
mp->mnt_op->vfs_refcount--;
|
||||
vfs_unbusy(mp);
|
||||
free(mp, M_MOUNT);
|
||||
vput(vp);
|
||||
}
|
||||
|
||||
out:
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
mount_getargs(struct lwp *l, struct vnode *vp, const char *path, int flags,
|
||||
void *data, struct nameidata *ndp)
|
||||
{
|
||||
struct mount *mp;
|
||||
int error;
|
||||
|
||||
mp = vp->v_mount;
|
||||
|
||||
if ((vp->v_flag & VROOT) == 0) {
|
||||
error = EINVAL;
|
||||
goto out;
|
||||
}
|
||||
|
||||
mp->mnt_flag |= MNT_GETARGS;
|
||||
|
||||
if (vfs_busy(mp, LK_NOWAIT, 0)) {
|
||||
error = EPERM;
|
||||
goto out;
|
||||
}
|
||||
|
||||
error = VFS_MOUNT(mp, path, data, ndp, l);
|
||||
|
||||
vfs_unbusy(mp);
|
||||
|
||||
|
||||
out:
|
||||
mp->mnt_flag &=~ MNT_GETARGS;
|
||||
return (error);
|
||||
}
|
||||
|
||||
/* ARGSUSED */
|
||||
int
|
||||
sys_mount(struct lwp *l, void *v, register_t *retval)
|
||||
{
|
||||
struct sys_mount_args /* {
|
||||
syscallarg(const char *) type;
|
||||
syscallarg(const char *) path;
|
||||
syscallarg(int) flags;
|
||||
syscallarg(void *) data;
|
||||
} */ *uap = v;
|
||||
struct vnode *vp;
|
||||
struct nameidata nd;
|
||||
int error;
|
||||
|
||||
/*
|
||||
* if MNT_GETARGS is specified, it should be only flag.
|
||||
*/
|
||||
if ((SCARG(uap, flags) & MNT_GETARGS) != 0 &&
|
||||
(SCARG(uap, flags) & ~MNT_GETARGS) != 0) {
|
||||
return EINVAL;
|
||||
}
|
||||
|
||||
/* XXX secmodel stuff. */
|
||||
if (dovfsusermount == 0 && (SCARG(uap, flags) & MNT_GETARGS) == 0 &&
|
||||
(error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
|
||||
&l->l_acflag)))
|
||||
return (error);
|
||||
|
||||
/*
|
||||
* Get vnode to be covered
|
||||
*/
|
||||
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE,
|
||||
SCARG(uap, path), l);
|
||||
if ((error = namei(&nd)) != 0)
|
||||
return (error);
|
||||
vp = nd.ni_vp;
|
||||
|
||||
/*
|
||||
* A lookup in VFS_MOUNT might result in an attempt to
|
||||
* lock this vnode again, so make the lock recursive.
|
||||
*/
|
||||
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_SETRECURSE);
|
||||
|
||||
if (SCARG(uap, flags) == MNT_GETARGS) {
|
||||
error = mount_getargs(l, vp, SCARG(uap, path),
|
||||
SCARG(uap, flags), SCARG(uap, data), &nd);
|
||||
vput(vp);
|
||||
} else if (SCARG(uap, flags) & MNT_UPDATE) {
|
||||
error = mount_update(l, vp, SCARG(uap, path),
|
||||
SCARG(uap, flags), SCARG(uap, data), &nd);
|
||||
vput(vp);
|
||||
} else {
|
||||
/* Locking is handled internally in mount_domount(). */
|
||||
error = mount_domount(l, vp, SCARG(uap, type),
|
||||
SCARG(uap, path), SCARG(uap, flags), SCARG(uap, data), &nd);
|
||||
}
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue