15bb1bd145
process is about to exec a sugid binary. To speed up things, use hashing for vnode allocation, like other filesystems do. This avoids walking the whole procfs node list in the revoke case too.
399 lines
9.9 KiB
C
399 lines
9.9 KiB
C
/* $NetBSD: procfs_subr.c,v 1.29 2000/01/25 21:52:04 fvdl Exp $ */
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/*
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* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
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* Copyright (c) 1993 Jan-Simon Pendry
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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#include <sys/stat.h>
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#include <miscfs/procfs/procfs.h>
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void procfs_hashins __P((struct pfsnode *));
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void procfs_hashrem __P((struct pfsnode *));
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struct vnode *procfs_hashget __P((pid_t, pfstype, struct mount *));
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LIST_HEAD(pfs_hashhead, pfsnode) *pfs_hashtbl;
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u_long ihash; /* size of hash table - 1 */
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#define PFSPIDHASH(pid) (&pfs_hashtbl[(pid) & ihash])
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struct lock pfs_hashlock;
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struct simplelock pfs_hash_slock;
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#define ISSET(t, f) ((t) & (f))
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/*
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* allocate a pfsnode/vnode pair. the vnode is
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* referenced, and locked.
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*
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* the pid, pfs_type, and mount point uniquely
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* identify a pfsnode. the mount point is needed
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* because someone might mount this filesystem
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* twice.
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*
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* all pfsnodes are maintained on a singly-linked
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* list. new nodes are only allocated when they cannot
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* be found on this list. entries on the list are
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* removed when the vfs reclaim entry is called.
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*
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* a single lock is kept for the entire list. this is
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* needed because the getnewvnode() function can block
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* waiting for a vnode to become free, in which case there
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* may be more than one process trying to get the same
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* vnode. this lock is only taken if we are going to
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* call getnewvnode, since the kernel itself is single-threaded.
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*
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* if an entry is found on the list, then call vget() to
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* take a reference. this is done because there may be
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* zero references to it and so it needs to removed from
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* the vnode free list.
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*/
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int
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procfs_allocvp(mp, vpp, pid, pfs_type)
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struct mount *mp;
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struct vnode **vpp;
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long pid;
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pfstype pfs_type;
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{
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struct pfsnode *pfs;
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struct vnode *vp;
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int error;
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do {
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if ((*vpp = procfs_hashget(pid, pfs_type, mp)) != NULL)
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return (0);
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} while (lockmgr(&pfs_hashlock, LK_EXCLUSIVE|LK_SLEEPFAIL, 0));
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if ((error = getnewvnode(VT_PROCFS, mp, procfs_vnodeop_p, vpp)) != 0) {
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*vpp = NULL;
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lockmgr(&pfs_hashlock, LK_RELEASE, 0);
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return (error);
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}
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vp = *vpp;
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MALLOC(pfs, void *, sizeof(struct pfsnode), M_TEMP, M_WAITOK);
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vp->v_data = pfs;
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pfs->pfs_pid = (pid_t) pid;
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pfs->pfs_type = pfs_type;
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pfs->pfs_vnode = vp;
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pfs->pfs_flags = 0;
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pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type);
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switch (pfs_type) {
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case Proot: /* /proc = dr-xr-xr-x */
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pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
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vp->v_type = VDIR;
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vp->v_flag = VROOT;
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break;
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case Pcurproc: /* /proc/curproc = lr-xr-xr-x */
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case Pself: /* /proc/self = lr-xr-xr-x */
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pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
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vp->v_type = VLNK;
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break;
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case Pproc: /* /proc/N = dr-xr-xr-x */
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pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
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vp->v_type = VDIR;
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break;
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case Pfile: /* /proc/N/file = -rw------- */
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case Pmem: /* /proc/N/mem = -rw------- */
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case Pregs: /* /proc/N/regs = -rw------- */
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case Pfpregs: /* /proc/N/fpregs = -rw------- */
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pfs->pfs_mode = S_IRUSR|S_IWUSR;
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vp->v_type = VREG;
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break;
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case Pctl: /* /proc/N/ctl = --w------ */
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case Pnote: /* /proc/N/note = --w------ */
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case Pnotepg: /* /proc/N/notepg = --w------ */
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pfs->pfs_mode = S_IWUSR;
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vp->v_type = VREG;
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break;
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case Pmap: /* /proc/N/map = -r--r--r-- */
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case Pstatus: /* /proc/N/status = -r--r--r-- */
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case Pcmdline: /* /proc/N/cmdline = -r--r--r-- */
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pfs->pfs_mode = S_IRUSR|S_IRGRP|S_IROTH;
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vp->v_type = VREG;
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break;
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default:
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panic("procfs_allocvp");
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}
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procfs_hashins(pfs);
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lockmgr(&pfs_hashlock, LK_RELEASE, 0);
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return (error);
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}
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int
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procfs_freevp(vp)
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struct vnode *vp;
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{
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struct pfsnode *pfs = VTOPFS(vp);
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procfs_hashrem(pfs);
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FREE(vp->v_data, M_TEMP);
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vp->v_data = 0;
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return (0);
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}
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int
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procfs_rw(v)
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void *v;
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{
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struct vop_read_args *ap = v;
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struct vnode *vp = ap->a_vp;
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struct uio *uio = ap->a_uio;
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struct proc *curp = uio->uio_procp;
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struct pfsnode *pfs = VTOPFS(vp);
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struct proc *p;
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p = PFIND(pfs->pfs_pid);
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if (p == 0)
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return (EINVAL);
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switch (pfs->pfs_type) {
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case Pregs:
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case Pfpregs:
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case Pmem:
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/*
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* Do not allow init to be modified while in secure mode; it
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* could be duped into changing the security level.
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*/
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if (uio->uio_rw == UIO_WRITE &&
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p == initproc && securelevel > -1)
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return (EPERM);
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break;
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default:
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break;
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}
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switch (pfs->pfs_type) {
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case Pnote:
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case Pnotepg:
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return (procfs_donote(curp, p, pfs, uio));
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case Pregs:
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return (procfs_doregs(curp, p, pfs, uio));
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case Pfpregs:
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return (procfs_dofpregs(curp, p, pfs, uio));
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case Pctl:
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return (procfs_doctl(curp, p, pfs, uio));
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case Pstatus:
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return (procfs_dostatus(curp, p, pfs, uio));
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case Pmap:
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return (procfs_domap(curp, p, pfs, uio));
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case Pmem:
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return (procfs_domem(curp, p, pfs, uio));
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case Pcmdline:
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return (procfs_docmdline(curp, p, pfs, uio));
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default:
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return (EOPNOTSUPP);
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}
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}
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/*
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* Get a string from userland into (buf). Strip a trailing
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* nl character (to allow easy access from the shell).
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* The buffer should be *buflenp + 1 chars long. vfs_getuserstr
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* will automatically add a nul char at the end.
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*
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* Returns 0 on success or the following errors
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*
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* EINVAL: file offset is non-zero.
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* EMSGSIZE: message is longer than kernel buffer
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* EFAULT: user i/o buffer is not addressable
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*/
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int
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vfs_getuserstr(uio, buf, buflenp)
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struct uio *uio;
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char *buf;
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int *buflenp;
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{
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int xlen;
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int error;
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if (uio->uio_offset != 0)
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return (EINVAL);
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xlen = *buflenp;
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/* must be able to read the whole string in one go */
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if (xlen < uio->uio_resid)
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return (EMSGSIZE);
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xlen = uio->uio_resid;
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if ((error = uiomove(buf, xlen, uio)) != 0)
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return (error);
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/* allow multiple writes without seeks */
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uio->uio_offset = 0;
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/* cleanup string and remove trailing newline */
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buf[xlen] = '\0';
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xlen = strlen(buf);
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if (xlen > 0 && buf[xlen-1] == '\n')
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buf[--xlen] = '\0';
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*buflenp = xlen;
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return (0);
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}
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vfs_namemap_t *
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vfs_findname(nm, buf, buflen)
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vfs_namemap_t *nm;
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char *buf;
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int buflen;
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{
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for (; nm->nm_name; nm++)
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if (memcmp(buf, nm->nm_name, buflen+1) == 0)
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return (nm);
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return (0);
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}
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/*
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* Initialize pfsnode hash table.
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*/
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void
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procfs_hashinit()
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{
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lockinit(&pfs_hashlock, PINOD, "pfs_hashlock", 0, 0);
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pfs_hashtbl = hashinit(desiredvnodes / 4, M_UFSMNT, M_WAITOK, &ihash);
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simple_lock_init(&pfs_hash_slock);
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}
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struct vnode *
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procfs_hashget(pid, type, mp)
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pid_t pid;
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pfstype type;
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struct mount *mp;
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{
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struct pfsnode *pp;
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struct vnode *vp;
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loop:
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simple_lock(&pfs_hash_slock);
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for (pp = PFSPIDHASH(pid)->lh_first; pp; pp = pp->pfs_hash.le_next) {
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vp = PFSTOV(pp);
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if (pid == pp->pfs_pid && pp->pfs_type == type &&
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vp->v_mount == mp) {
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simple_lock(&vp->v_interlock);
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simple_unlock(&pfs_hash_slock);
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if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK))
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goto loop;
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return (vp);
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}
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}
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simple_unlock(&pfs_hash_slock);
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return (NULL);
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}
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/*
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* Insert the pfsnode into the hash table and lock it.
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*/
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void
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procfs_hashins(pp)
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struct pfsnode *pp;
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{
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struct pfs_hashhead *ppp;
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/* lock the pfsnode, then put it on the appropriate hash list */
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lockmgr(&pp->pfs_vnode->v_lock, LK_EXCLUSIVE, (struct simplelock *)0);
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simple_lock(&pfs_hash_slock);
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ppp = PFSPIDHASH(pp->pfs_pid);
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LIST_INSERT_HEAD(ppp, pp, pfs_hash);
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simple_unlock(&pfs_hash_slock);
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}
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/*
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* Remove the pfsnode from the hash table.
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*/
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void
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procfs_hashrem(pp)
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struct pfsnode *pp;
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{
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simple_lock(&pfs_hash_slock);
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LIST_REMOVE(pp, pfs_hash);
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simple_unlock(&pfs_hash_slock);
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}
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void
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procfs_revoke_vnodes(p, arg)
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struct proc *p;
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void *arg;
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{
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struct pfsnode *pfs, *pnext;
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struct vnode *vp;
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struct mount *mp = (struct mount *)arg;
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if (!(p->p_flag & P_SUGID))
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return;
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for (pfs = PFSPIDHASH(p->p_pid)->lh_first; pfs; pfs = pnext) {
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vp = PFSTOV(pfs);
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pnext = pfs->pfs_hash.le_next;
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if (vp->v_usecount > 0 && pfs->pfs_pid == p->p_pid &&
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vp->v_mount == mp)
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VOP_REVOKE(vp, REVOKEALL);
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}
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}
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