Import NetBSD libpcap
As part of this, we import bpf_filter.c from NetBSD. Even though that file is part of the NetBSD kernel, it is also used by userland (as is clear here). Our LWIP service has its own bpf_filter.c implementation but that implementation has certain limits (e.g. on program size) that are fine for a system service but should not apply to userland. The libpcap code has a number of blocks guarded by __NetBSD__, but none of those blocks apply to MINIX 3. In particular, some of the alignment logic used for NetBSD may in fact not work in our case. Change-Id: Ib187e22d627c929e111d5d4a991c3bee3c0154cb
This commit is contained in:
David van Moolenbroek
811
sys/net/bpf_filter.c
Normal file
811
sys/net/bpf_filter.c
Normal file
@@ -0,0 +1,811 @@
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/* $NetBSD: bpf_filter.c,v 1.70 2015/02/11 12:53:15 alnsn Exp $ */
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/*-
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* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
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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 the Stanford/CMU enet packet filter,
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* (net/enet.c) distributed as part of 4.3BSD, and code contributed
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* to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
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* Berkeley Laboratory.
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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. 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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* @(#)bpf_filter.c 8.1 (Berkeley) 6/10/93
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: bpf_filter.c,v 1.70 2015/02/11 12:53:15 alnsn Exp $");
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#if 0
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#if !(defined(lint) || defined(KERNEL))
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static const char rcsid[] =
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"@(#) Header: bpf_filter.c,v 1.33 97/04/26 13:37:18 leres Exp (LBL)";
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#endif
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#endif
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/kmem.h>
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#include <sys/endian.h>
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#define __BPF_PRIVATE
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#include <net/bpf.h>
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#ifdef _KERNEL
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bpf_ctx_t *
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bpf_create(void)
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{
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return kmem_zalloc(sizeof(bpf_ctx_t), KM_SLEEP);
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}
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void
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bpf_destroy(bpf_ctx_t *bc)
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{
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kmem_free(bc, sizeof(bpf_ctx_t));
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}
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int
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bpf_set_cop(bpf_ctx_t *bc, const bpf_copfunc_t *funcs, size_t n)
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{
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bc->copfuncs = funcs;
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bc->nfuncs = n;
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return 0;
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}
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int
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bpf_set_extmem(bpf_ctx_t *bc, size_t nwords, bpf_memword_init_t preinited)
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{
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if (nwords > BPF_MAX_MEMWORDS || (preinited >> nwords) != 0) {
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return EINVAL;
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}
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bc->extwords = nwords;
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bc->preinited = preinited;
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return 0;
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}
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#endif
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#define EXTRACT_SHORT(p) be16dec(p)
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#define EXTRACT_LONG(p) be32dec(p)
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#ifdef _KERNEL
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#include <sys/mbuf.h>
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#define MINDEX(len, m, k) \
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{ \
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len = m->m_len; \
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while (k >= len) { \
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k -= len; \
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m = m->m_next; \
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if (m == 0) \
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return 0; \
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len = m->m_len; \
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} \
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}
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uint32_t m_xword(const struct mbuf *, uint32_t, int *);
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uint32_t m_xhalf(const struct mbuf *, uint32_t, int *);
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uint32_t m_xbyte(const struct mbuf *, uint32_t, int *);
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#define xword(p, k, err) m_xword((const struct mbuf *)(p), (k), (err))
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#define xhalf(p, k, err) m_xhalf((const struct mbuf *)(p), (k), (err))
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#define xbyte(p, k, err) m_xbyte((const struct mbuf *)(p), (k), (err))
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uint32_t
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m_xword(const struct mbuf *m, uint32_t k, int *err)
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{
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int len;
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u_char *cp, *np;
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struct mbuf *m0;
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*err = 1;
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MINDEX(len, m, k);
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cp = mtod(m, u_char *) + k;
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if (len - k >= 4) {
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*err = 0;
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return EXTRACT_LONG(cp);
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}
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m0 = m->m_next;
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if (m0 == 0 || (len - k) + m0->m_len < 4)
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return 0;
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*err = 0;
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np = mtod(m0, u_char *);
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switch (len - k) {
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case 1:
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return (cp[0] << 24) | (np[0] << 16) | (np[1] << 8) | np[2];
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case 2:
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return (cp[0] << 24) | (cp[1] << 16) | (np[0] << 8) | np[1];
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default:
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return (cp[0] << 24) | (cp[1] << 16) | (cp[2] << 8) | np[0];
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}
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}
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uint32_t
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m_xhalf(const struct mbuf *m, uint32_t k, int *err)
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{
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int len;
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u_char *cp;
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struct mbuf *m0;
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*err = 1;
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MINDEX(len, m, k);
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cp = mtod(m, u_char *) + k;
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if (len - k >= 2) {
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*err = 0;
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return EXTRACT_SHORT(cp);
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}
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m0 = m->m_next;
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if (m0 == 0)
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return 0;
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*err = 0;
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return (cp[0] << 8) | mtod(m0, u_char *)[0];
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}
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uint32_t
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m_xbyte(const struct mbuf *m, uint32_t k, int *err)
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{
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int len;
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*err = 1;
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MINDEX(len, m, k);
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*err = 0;
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return mtod(m, u_char *)[k];
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}
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#else /* _KERNEL */
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#include <stdlib.h>
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#endif /* !_KERNEL */
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#include <net/bpf.h>
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/*
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* Execute the filter program starting at pc on the packet p
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* wirelen is the length of the original packet
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* buflen is the amount of data present
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*/
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#ifdef _KERNEL
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u_int
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bpf_filter(const struct bpf_insn *pc, const u_char *p, u_int wirelen,
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u_int buflen)
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{
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uint32_t mem[BPF_MEMWORDS];
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bpf_args_t args = {
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.pkt = p,
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.wirelen = wirelen,
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.buflen = buflen,
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.mem = mem,
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.arg = NULL
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};
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return bpf_filter_ext(NULL, pc, &args);
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}
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u_int
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bpf_filter_ext(const bpf_ctx_t *bc, const struct bpf_insn *pc, bpf_args_t *args)
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#else
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u_int
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bpf_filter(const struct bpf_insn *pc, const u_char *p, u_int wirelen,
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u_int buflen)
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#endif
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{
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uint32_t A, X, k;
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#ifndef _KERNEL
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uint32_t mem[BPF_MEMWORDS];
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bpf_args_t args_store = {
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.pkt = p,
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.wirelen = wirelen,
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.buflen = buflen,
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.mem = mem,
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.arg = NULL
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};
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bpf_args_t * const args = &args_store;
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#else
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const uint8_t * const p = args->pkt;
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#endif
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if (pc == 0) {
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/*
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* No filter means accept all.
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*/
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return (u_int)-1;
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}
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/*
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* Note: safe to leave memwords uninitialised, as the validation
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* step ensures that it will not be read, if it was not written.
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*/
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A = 0;
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X = 0;
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--pc;
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for (;;) {
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++pc;
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switch (pc->code) {
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default:
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#ifdef _KERNEL
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return 0;
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#else
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abort();
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/*NOTREACHED*/
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#endif
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case BPF_RET|BPF_K:
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return (u_int)pc->k;
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case BPF_RET|BPF_A:
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return (u_int)A;
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case BPF_LD|BPF_W|BPF_ABS:
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k = pc->k;
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if (k > args->buflen ||
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sizeof(int32_t) > args->buflen - k) {
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#ifdef _KERNEL
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int merr;
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if (args->buflen != 0)
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return 0;
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A = xword(args->pkt, k, &merr);
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if (merr != 0)
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return 0;
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continue;
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#else
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return 0;
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#endif
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}
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A = EXTRACT_LONG(&p[k]);
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continue;
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case BPF_LD|BPF_H|BPF_ABS:
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k = pc->k;
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if (k > args->buflen ||
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sizeof(int16_t) > args->buflen - k) {
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#ifdef _KERNEL
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int merr;
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if (args->buflen != 0)
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return 0;
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A = xhalf(args->pkt, k, &merr);
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if (merr != 0)
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return 0;
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continue;
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#else
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return 0;
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#endif
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}
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A = EXTRACT_SHORT(&p[k]);
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continue;
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case BPF_LD|BPF_B|BPF_ABS:
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k = pc->k;
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if (k >= args->buflen) {
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#ifdef _KERNEL
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int merr;
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if (args->buflen != 0)
|
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return 0;
|
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A = xbyte(args->pkt, k, &merr);
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if (merr != 0)
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return 0;
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continue;
|
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#else
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return 0;
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#endif
|
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}
|
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A = p[k];
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continue;
|
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case BPF_LD|BPF_W|BPF_LEN:
|
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A = args->wirelen;
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continue;
|
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case BPF_LDX|BPF_W|BPF_LEN:
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X = args->wirelen;
|
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continue;
|
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|
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case BPF_LD|BPF_W|BPF_IND:
|
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k = X + pc->k;
|
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if (k < X || k >= args->buflen ||
|
||||
sizeof(int32_t) > args->buflen - k) {
|
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#ifdef _KERNEL
|
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int merr;
|
||||
|
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if (k < X || args->buflen != 0)
|
||||
return 0;
|
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A = xword(args->pkt, k, &merr);
|
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if (merr != 0)
|
||||
return 0;
|
||||
continue;
|
||||
#else
|
||||
return 0;
|
||||
#endif
|
||||
}
|
||||
A = EXTRACT_LONG(&p[k]);
|
||||
continue;
|
||||
|
||||
case BPF_LD|BPF_H|BPF_IND:
|
||||
k = X + pc->k;
|
||||
if (k < X || k >= args->buflen ||
|
||||
sizeof(int16_t) > args->buflen - k) {
|
||||
#ifdef _KERNEL
|
||||
int merr;
|
||||
|
||||
if (k < X || args->buflen != 0)
|
||||
return 0;
|
||||
A = xhalf(args->pkt, k, &merr);
|
||||
if (merr != 0)
|
||||
return 0;
|
||||
continue;
|
||||
#else
|
||||
return 0;
|
||||
#endif
|
||||
}
|
||||
A = EXTRACT_SHORT(&p[k]);
|
||||
continue;
|
||||
|
||||
case BPF_LD|BPF_B|BPF_IND:
|
||||
k = X + pc->k;
|
||||
if (k < X || k >= args->buflen) {
|
||||
#ifdef _KERNEL
|
||||
int merr;
|
||||
|
||||
if (k < X || args->buflen != 0)
|
||||
return 0;
|
||||
A = xbyte(args->pkt, k, &merr);
|
||||
if (merr != 0)
|
||||
return 0;
|
||||
continue;
|
||||
#else
|
||||
return 0;
|
||||
#endif
|
||||
}
|
||||
A = p[k];
|
||||
continue;
|
||||
|
||||
case BPF_LDX|BPF_MSH|BPF_B:
|
||||
k = pc->k;
|
||||
if (k >= args->buflen) {
|
||||
#ifdef _KERNEL
|
||||
int merr;
|
||||
|
||||
if (args->buflen != 0)
|
||||
return 0;
|
||||
X = (xbyte(args->pkt, k, &merr) & 0xf) << 2;
|
||||
if (merr != 0)
|
||||
return 0;
|
||||
continue;
|
||||
#else
|
||||
return 0;
|
||||
#endif
|
||||
}
|
||||
X = (p[pc->k] & 0xf) << 2;
|
||||
continue;
|
||||
|
||||
case BPF_LD|BPF_IMM:
|
||||
A = pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_LDX|BPF_IMM:
|
||||
X = pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_LD|BPF_MEM:
|
||||
A = args->mem[pc->k];
|
||||
continue;
|
||||
|
||||
case BPF_LDX|BPF_MEM:
|
||||
X = args->mem[pc->k];
|
||||
continue;
|
||||
|
||||
case BPF_ST:
|
||||
args->mem[pc->k] = A;
|
||||
continue;
|
||||
|
||||
case BPF_STX:
|
||||
args->mem[pc->k] = X;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JA:
|
||||
pc += pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JGT|BPF_K:
|
||||
pc += (A > pc->k) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JGE|BPF_K:
|
||||
pc += (A >= pc->k) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JEQ|BPF_K:
|
||||
pc += (A == pc->k) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JSET|BPF_K:
|
||||
pc += (A & pc->k) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JGT|BPF_X:
|
||||
pc += (A > X) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JGE|BPF_X:
|
||||
pc += (A >= X) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JEQ|BPF_X:
|
||||
pc += (A == X) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_JMP|BPF_JSET|BPF_X:
|
||||
pc += (A & X) ? pc->jt : pc->jf;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_ADD|BPF_X:
|
||||
A += X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_SUB|BPF_X:
|
||||
A -= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_MUL|BPF_X:
|
||||
A *= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_DIV|BPF_X:
|
||||
if (X == 0)
|
||||
return 0;
|
||||
A /= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_MOD|BPF_X:
|
||||
if (X == 0)
|
||||
return 0;
|
||||
A %= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_AND|BPF_X:
|
||||
A &= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_OR|BPF_X:
|
||||
A |= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_XOR|BPF_X:
|
||||
A ^= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_LSH|BPF_X:
|
||||
A <<= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_RSH|BPF_X:
|
||||
A >>= X;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_ADD|BPF_K:
|
||||
A += pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_SUB|BPF_K:
|
||||
A -= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_MUL|BPF_K:
|
||||
A *= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_DIV|BPF_K:
|
||||
A /= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_MOD|BPF_K:
|
||||
A %= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_AND|BPF_K:
|
||||
A &= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_OR|BPF_K:
|
||||
A |= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_XOR|BPF_K:
|
||||
A ^= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_LSH|BPF_K:
|
||||
A <<= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_RSH|BPF_K:
|
||||
A >>= pc->k;
|
||||
continue;
|
||||
|
||||
case BPF_ALU|BPF_NEG:
|
||||
A = -A;
|
||||
continue;
|
||||
|
||||
case BPF_MISC|BPF_TAX:
|
||||
X = A;
|
||||
continue;
|
||||
|
||||
case BPF_MISC|BPF_TXA:
|
||||
A = X;
|
||||
continue;
|
||||
|
||||
case BPF_MISC|BPF_COP:
|
||||
#ifdef _KERNEL
|
||||
if (pc->k < bc->nfuncs) {
|
||||
const bpf_copfunc_t fn = bc->copfuncs[pc->k];
|
||||
A = fn(bc, args, A);
|
||||
continue;
|
||||
}
|
||||
#endif
|
||||
return 0;
|
||||
|
||||
case BPF_MISC|BPF_COPX:
|
||||
#ifdef _KERNEL
|
||||
if (X < bc->nfuncs) {
|
||||
const bpf_copfunc_t fn = bc->copfuncs[X];
|
||||
A = fn(bc, args, A);
|
||||
continue;
|
||||
}
|
||||
#endif
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Return true if the 'fcode' is a valid filter program.
|
||||
* The constraints are that each jump be forward and to a valid
|
||||
* code, that memory accesses are within valid ranges (to the
|
||||
* extent that this can be checked statically; loads of packet
|
||||
* data have to be, and are, also checked at run time), and that
|
||||
* the code terminates with either an accept or reject.
|
||||
*
|
||||
* The kernel needs to be able to verify an application's filter code.
|
||||
* Otherwise, a bogus program could easily crash the system.
|
||||
*/
|
||||
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
|
||||
int
|
||||
bpf_validate(const struct bpf_insn *f, int signed_len)
|
||||
{
|
||||
return bpf_validate_ext(NULL, f, signed_len);
|
||||
}
|
||||
|
||||
int
|
||||
bpf_validate_ext(const bpf_ctx_t *bc, const struct bpf_insn *f, int signed_len)
|
||||
#else
|
||||
int
|
||||
bpf_validate(const struct bpf_insn *f, int signed_len)
|
||||
#endif
|
||||
{
|
||||
u_int i, from, len, ok = 0;
|
||||
const struct bpf_insn *p;
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
bpf_memword_init_t *mem, invalid;
|
||||
size_t size;
|
||||
const size_t extwords = bc ? bc->extwords : 0;
|
||||
const size_t memwords = extwords ? extwords : BPF_MEMWORDS;
|
||||
const bpf_memword_init_t preinited = extwords ? bc->preinited : 0;
|
||||
#else
|
||||
const size_t memwords = BPF_MEMWORDS;
|
||||
#endif
|
||||
|
||||
len = (u_int)signed_len;
|
||||
if (len < 1)
|
||||
return 0;
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
if (len > BPF_MAXINSNS)
|
||||
return 0;
|
||||
#endif
|
||||
if (f[len - 1].code != (BPF_RET|BPF_K) &&
|
||||
f[len - 1].code != (BPF_RET|BPF_A)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
/* Note: only the pre-initialised is valid on startup */
|
||||
mem = kmem_zalloc(size = sizeof(*mem) * len, KM_SLEEP);
|
||||
invalid = ~preinited;
|
||||
#endif
|
||||
|
||||
for (i = 0; i < len; ++i) {
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
/* blend in any invalid bits for current pc */
|
||||
invalid |= mem[i];
|
||||
#endif
|
||||
p = &f[i];
|
||||
switch (BPF_CLASS(p->code)) {
|
||||
/*
|
||||
* Check that memory operations use valid addresses.
|
||||
*/
|
||||
case BPF_LD:
|
||||
case BPF_LDX:
|
||||
switch (BPF_MODE(p->code)) {
|
||||
case BPF_MEM:
|
||||
/*
|
||||
* There's no maximum packet data size
|
||||
* in userland. The runtime packet length
|
||||
* check suffices.
|
||||
*/
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
/*
|
||||
* More strict check with actual packet length
|
||||
* is done runtime.
|
||||
*/
|
||||
if (p->k >= memwords)
|
||||
goto out;
|
||||
/* check for current memory invalid */
|
||||
if (invalid & BPF_MEMWORD_INIT(p->k))
|
||||
goto out;
|
||||
#endif
|
||||
break;
|
||||
case BPF_ABS:
|
||||
case BPF_IND:
|
||||
case BPF_MSH:
|
||||
case BPF_IMM:
|
||||
case BPF_LEN:
|
||||
break;
|
||||
default:
|
||||
goto out;
|
||||
}
|
||||
break;
|
||||
case BPF_ST:
|
||||
case BPF_STX:
|
||||
if (p->k >= memwords)
|
||||
goto out;
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
/* validate the memory word */
|
||||
invalid &= ~BPF_MEMWORD_INIT(p->k);
|
||||
#endif
|
||||
break;
|
||||
case BPF_ALU:
|
||||
switch (BPF_OP(p->code)) {
|
||||
case BPF_ADD:
|
||||
case BPF_SUB:
|
||||
case BPF_MUL:
|
||||
case BPF_OR:
|
||||
case BPF_XOR:
|
||||
case BPF_AND:
|
||||
case BPF_LSH:
|
||||
case BPF_RSH:
|
||||
case BPF_NEG:
|
||||
break;
|
||||
case BPF_DIV:
|
||||
case BPF_MOD:
|
||||
/*
|
||||
* Check for constant division by 0.
|
||||
*/
|
||||
if (BPF_SRC(p->code) == BPF_K && p->k == 0)
|
||||
goto out;
|
||||
break;
|
||||
default:
|
||||
goto out;
|
||||
}
|
||||
break;
|
||||
case BPF_JMP:
|
||||
/*
|
||||
* Check that jumps are within the code block,
|
||||
* and that unconditional branches don't go
|
||||
* backwards as a result of an overflow.
|
||||
* Unconditional branches have a 32-bit offset,
|
||||
* so they could overflow; we check to make
|
||||
* sure they don't. Conditional branches have
|
||||
* an 8-bit offset, and the from address is <=
|
||||
* BPF_MAXINSNS, and we assume that BPF_MAXINSNS
|
||||
* is sufficiently small that adding 255 to it
|
||||
* won't overflow.
|
||||
*
|
||||
* We know that len is <= BPF_MAXINSNS, and we
|
||||
* assume that BPF_MAXINSNS is < the maximum size
|
||||
* of a u_int, so that i + 1 doesn't overflow.
|
||||
*
|
||||
* For userland, we don't know that the from
|
||||
* or len are <= BPF_MAXINSNS, but we know that
|
||||
* from <= len, and, except on a 64-bit system,
|
||||
* it's unlikely that len, if it truly reflects
|
||||
* the size of the program we've been handed,
|
||||
* will be anywhere near the maximum size of
|
||||
* a u_int. We also don't check for backward
|
||||
* branches, as we currently support them in
|
||||
* userland for the protochain operation.
|
||||
*/
|
||||
from = i + 1;
|
||||
switch (BPF_OP(p->code)) {
|
||||
case BPF_JA:
|
||||
if (from + p->k >= len)
|
||||
goto out;
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
if (from + p->k < from)
|
||||
goto out;
|
||||
/*
|
||||
* mark the currently invalid bits for the
|
||||
* destination
|
||||
*/
|
||||
mem[from + p->k] |= invalid;
|
||||
invalid = 0;
|
||||
#endif
|
||||
break;
|
||||
case BPF_JEQ:
|
||||
case BPF_JGT:
|
||||
case BPF_JGE:
|
||||
case BPF_JSET:
|
||||
if (from + p->jt >= len || from + p->jf >= len)
|
||||
goto out;
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
/*
|
||||
* mark the currently invalid bits for both
|
||||
* possible jump destinations
|
||||
*/
|
||||
mem[from + p->jt] |= invalid;
|
||||
mem[from + p->jf] |= invalid;
|
||||
invalid = 0;
|
||||
#endif
|
||||
break;
|
||||
default:
|
||||
goto out;
|
||||
}
|
||||
break;
|
||||
case BPF_RET:
|
||||
break;
|
||||
case BPF_MISC:
|
||||
switch (BPF_MISCOP(p->code)) {
|
||||
case BPF_COP:
|
||||
case BPF_COPX:
|
||||
/* In-kernel COP use only. */
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
if (bc == NULL || bc->copfuncs == NULL)
|
||||
goto out;
|
||||
if (BPF_MISCOP(p->code) == BPF_COP &&
|
||||
p->k >= bc->nfuncs) {
|
||||
goto out;
|
||||
}
|
||||
break;
|
||||
#else
|
||||
goto out;
|
||||
#endif
|
||||
default:
|
||||
break;
|
||||
}
|
||||
break;
|
||||
default:
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
ok = 1;
|
||||
out:
|
||||
#if defined(KERNEL) || defined(_KERNEL)
|
||||
kmem_free(mem, size);
|
||||
#endif
|
||||
return ok;
|
||||
}
|
||||
Reference in New Issue
Block a user