0766f278d8
Most kernel memory that is allocated after boot does not need to be executable. There are a few exceptions. For example, kernel modules do need executable memory, but they don't use UMA or malloc(9). The BPF JIT compiler also needs executable memory and did use malloc(9) until r317072. (Note that a side effect of r316767 was that the "small allocation" path in UMA on amd64 already returned non-executable memory. This meant that some calls to malloc(9) or the UMA zone(9) allocator could return executable memory, while others could return non-executable memory. This change makes the behavior consistent.) This change makes malloc(9) return non-executable memory unless the new M_EXEC flag is specified. After this change, the UMA zone(9) allocator will always return non-executable memory, and a KASSERT will catch attempts to use the M_EXEC flag to allocate executable memory using uma_zalloc() or its variants. Allocations that do need executable memory have various choices. They may use the M_EXEC flag to malloc(9), or they may use a different VM interfact to obtain executable pages. Now that malloc(9) again allows executable allocations, this change also reverts most of r317072. PR: 228927 Reviewed by: alc, kib, markj, jhb (previous version) Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D15691
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
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* Copyright (C) 2005-2017 Jung-uk Kim <jkim@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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*
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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 Politecnico di Torino nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#ifdef _KERNEL
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#include "opt_bpf.h"
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/sysctl.h>
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#else
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#endif
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#include <net/bpf.h>
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#include <net/bpf_jitter.h>
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static u_int bpf_jit_accept_all(u_char *, u_int, u_int);
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#ifdef _KERNEL
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MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
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SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW, 0, "BPF JIT compiler");
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int bpf_jitter_enable = 1;
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SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
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&bpf_jitter_enable, 0, "enable BPF JIT compiler");
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#endif
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bpf_jit_filter *
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bpf_jitter(struct bpf_insn *fp, int nins)
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{
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bpf_jit_filter *filter;
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/* Allocate the filter structure. */
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#ifdef _KERNEL
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filter = (struct bpf_jit_filter *)malloc(sizeof(*filter),
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M_BPFJIT, M_NOWAIT);
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#else
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filter = (struct bpf_jit_filter *)malloc(sizeof(*filter));
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#endif
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if (filter == NULL)
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return (NULL);
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/* No filter means accept all. */
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if (fp == NULL || nins == 0) {
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filter->func = bpf_jit_accept_all;
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return (filter);
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}
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/* Create the binary. */
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if ((filter->func = bpf_jit_compile(fp, nins, &filter->size)) == NULL) {
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#ifdef _KERNEL
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free(filter, M_BPFJIT);
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#else
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free(filter);
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#endif
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return (NULL);
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}
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return (filter);
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}
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void
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bpf_destroy_jit_filter(bpf_jit_filter *filter)
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{
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#ifdef _KERNEL
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if (filter->func != bpf_jit_accept_all)
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free(filter->func, M_BPFJIT);
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free(filter, M_BPFJIT);
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#else
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if (filter->func != bpf_jit_accept_all)
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munmap(filter->func, filter->size);
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free(filter);
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#endif
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}
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static u_int
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bpf_jit_accept_all(__unused u_char *p, __unused u_int wirelen,
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__unused u_int buflen)
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{
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return ((u_int)-1);
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}
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