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591b09b486
Otherwise accept filters compiled into the kernel do not preempt preloaded accept filter modules. Then, the preloaded file registers its accept filter module before the kernel, and the kernel's attempt fails since duplicate accept filter list entries are not permitted. This causes the preloaded file's module to be released, since module_register_init() does a lookup by name, so the preloaded file is unloaded, and the accept filter's callback points to random memory since preload_delete_name() unmaps the file on x86 as of r336505. Add a new ACCEPT_FILTER_DEFINE macro which wraps the accept filter and module definitions, and ensures that a module version is defined. PR: 245870 Reported by: Thomas von Dein <freebsd@daemon.de> MFC after: 2 weeks Sponsored by: The FreeBSD Foundation
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 2007 David Malone <dwmalone@FreeBSD.org>
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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#define ACCEPT_FILTER_MOD
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/mbuf.h>
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#include <sys/module.h>
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#include <sys/signalvar.h>
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#include <sys/sysctl.h>
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#include <sys/socketvar.h>
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/* check for full DNS request */
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static int sohasdns(struct socket *so, void *arg, int waitflag);
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ACCEPT_FILTER_DEFINE(accf_dns, "dnsready", sohasdns, NULL, NULL, 1);
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struct packet {
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struct mbuf *m; /* Current mbuf. */
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struct mbuf *n; /* nextpkt mbuf. */
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unsigned long moff; /* Offset of the beginning of m. */
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unsigned long offset; /* Which offset we are working at. */
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unsigned long len; /* The number of bytes we have to play with. */
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};
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#define DNS_OK 0
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#define DNS_WAIT -1
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#define DNS_RUN -2
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/* check we can skip over various parts of DNS request */
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static int skippacket(struct sockbuf *sb);
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static int
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sohasdns(struct socket *so, void *arg, int waitflag)
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{
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struct sockbuf *sb = &so->so_rcv;
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/* If the socket is full, we're ready. */
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if (sbused(sb) >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax)
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goto ready;
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/* Check to see if we have a request. */
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if (skippacket(sb) == DNS_WAIT)
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return (SU_OK);
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ready:
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return (SU_ISCONNECTED);
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}
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#define GET8(p, val) do { \
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if (p->offset < p->moff) \
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return DNS_RUN; \
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while (p->offset >= p->moff + p->m->m_len) { \
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p->moff += p->m->m_len; \
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p->m = p->m->m_next; \
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if (p->m == NULL) { \
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p->m = p->n; \
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p->n = p->m->m_nextpkt; \
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} \
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if (p->m == NULL) \
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return DNS_WAIT; \
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} \
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val = *(mtod(p->m, unsigned char *) + (p->offset - p->moff)); \
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p->offset++; \
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} while (0)
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#define GET16(p, val) do { \
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unsigned int v0, v1; \
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GET8(p, v0); \
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GET8(p, v1); \
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val = v0 * 0x100 + v1; \
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} while (0)
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static int
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skippacket(struct sockbuf *sb) {
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unsigned long packlen;
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struct packet q, *p = &q;
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if (sbavail(sb) < 2)
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return DNS_WAIT;
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q.m = sb->sb_mb;
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q.n = q.m->m_nextpkt;
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q.moff = 0;
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q.offset = 0;
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q.len = sbavail(sb);
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GET16(p, packlen);
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if (packlen + 2 > q.len)
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return DNS_WAIT;
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return DNS_OK;
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}
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