230 lines
5.7 KiB
C
230 lines
5.7 KiB
C
/*
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* Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.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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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT 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 OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "defs.h"
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#ifdef HAVE_LINUX_SECCOMP_H
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# include <linux/seccomp.h>
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#endif
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#include "xlat/seccomp_ops.h"
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#include "xlat/seccomp_filter_flags.h"
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#ifdef HAVE_LINUX_FILTER_H
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# include <linux/filter.h>
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# include "xlat/bpf_class.h"
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# include "xlat/bpf_miscop.h"
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# include "xlat/bpf_mode.h"
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# include "xlat/bpf_op_alu.h"
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# include "xlat/bpf_op_jmp.h"
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# include "xlat/bpf_rval.h"
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# include "xlat/bpf_size.h"
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# include "xlat/bpf_src.h"
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# ifndef SECCOMP_RET_ACTION
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# define SECCOMP_RET_ACTION 0x7fff0000U
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# endif
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# include "xlat/seccomp_ret_action.h"
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#endif
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struct bpf_filter {
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uint16_t code;
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uint8_t jt;
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uint8_t jf;
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uint32_t k;
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};
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#ifdef HAVE_LINUX_FILTER_H
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static void
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decode_bpf_code(uint16_t code)
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{
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uint16_t i = code & ~BPF_CLASS(code);
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printxval(bpf_class, BPF_CLASS(code), "BPF_???");
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switch (BPF_CLASS(code)) {
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case BPF_LD:
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case BPF_LDX:
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tprints("|");
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printxval(bpf_size, BPF_SIZE(code), "BPF_???");
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tprints("|");
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printxval(bpf_mode, BPF_MODE(code), "BPF_???");
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break;
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case BPF_ST:
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case BPF_STX:
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if (i)
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tprintf("|%#x /* %s */", i, "BPF_???");
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break;
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case BPF_ALU:
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tprints("|");
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printxval(bpf_src, BPF_SRC(code), "BPF_???");
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tprints("|");
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printxval(bpf_op_alu, BPF_OP(code), "BPF_???");
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break;
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case BPF_JMP:
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tprints("|");
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printxval(bpf_src, BPF_SRC(code), "BPF_???");
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tprints("|");
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printxval(bpf_op_jmp, BPF_OP(code), "BPF_???");
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break;
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case BPF_RET:
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tprints("|");
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printxval(bpf_rval, BPF_RVAL(code), "BPF_???");
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i &= ~BPF_RVAL(code);
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if (i)
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tprintf("|%#x /* %s */", i, "BPF_???");
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break;
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case BPF_MISC:
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tprints("|");
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printxval(bpf_miscop, BPF_MISCOP(code), "BPF_???");
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i &= ~BPF_MISCOP(code);
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if (i)
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tprintf("|%#x /* %s */", i, "BPF_???");
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break;
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}
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}
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#endif /* HAVE_LINUX_FILTER_H */
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static void
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decode_bpf_stmt(const struct bpf_filter *filter)
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{
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#ifdef HAVE_LINUX_FILTER_H
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tprints("BPF_STMT(");
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decode_bpf_code(filter->code);
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tprints(", ");
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if (BPF_CLASS(filter->code) == BPF_RET) {
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unsigned int action = SECCOMP_RET_ACTION & filter->k;
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unsigned int data = filter->k & ~action;
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printxval(seccomp_ret_action, action, "SECCOMP_RET_???");
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if (data)
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tprintf("|%#x)", data);
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else
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tprints(")");
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} else {
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tprintf("%#x)", filter->k);
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}
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#else
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tprintf("BPF_STMT(%#x, %#x)", filter->code, filter->k);
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#endif /* HAVE_LINUX_FILTER_H */
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}
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static void
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decode_bpf_jump(const struct bpf_filter *filter)
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{
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#ifdef HAVE_LINUX_FILTER_H
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tprints("BPF_JUMP(");
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decode_bpf_code(filter->code);
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tprintf(", %#x, %#x, %#x)",
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filter->k, filter->jt, filter->jf);
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#else
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tprintf("BPF_JUMP(%#x, %#x, %#x, %#x)",
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filter->code, filter->k, filter->jt, filter->jf);
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#endif /* HAVE_LINUX_FILTER_H */
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}
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#ifndef BPF_MAXINSNS
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# define BPF_MAXINSNS 4096
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#endif
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static bool
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print_bpf_filter(struct tcb *tcp, void *elem_buf, size_t elem_size, void *data)
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{
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const struct bpf_filter *filter = elem_buf;
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unsigned int *pn = data;
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if ((*pn)++ >= BPF_MAXINSNS) {
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tprints("...");
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return false;
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}
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if (filter->jt || filter->jf)
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decode_bpf_jump(filter);
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else
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decode_bpf_stmt(filter);
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return true;
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}
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void
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print_seccomp_fprog(struct tcb *const tcp, const kernel_ulong_t addr,
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const unsigned short len)
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{
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if (abbrev(tcp)) {
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printaddr(addr);
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} else {
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unsigned int insns = 0;
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struct bpf_filter filter;
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print_array(tcp, addr, len, &filter, sizeof(filter),
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umoven_or_printaddr, print_bpf_filter, &insns);
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}
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}
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#include "seccomp_fprog.h"
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void
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print_seccomp_filter(struct tcb *const tcp, const kernel_ulong_t addr)
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{
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struct seccomp_fprog fprog;
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if (fetch_seccomp_fprog(tcp, addr, &fprog)) {
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tprintf("{len=%hu, filter=", fprog.len);
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print_seccomp_fprog(tcp, fprog.filter, fprog.len);
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tprints("}");
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}
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}
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static void
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decode_seccomp_set_mode_strict(const unsigned int flags,
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const kernel_ulong_t addr)
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{
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tprintf("%u, ", flags);
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printaddr(addr);
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}
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SYS_FUNC(seccomp)
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{
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unsigned int op = tcp->u_arg[0];
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printxval(seccomp_ops, op, "SECCOMP_SET_MODE_???");
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tprints(", ");
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if (op == SECCOMP_SET_MODE_FILTER) {
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printflags(seccomp_filter_flags, tcp->u_arg[1],
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"SECCOMP_FILTER_FLAG_???");
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tprints(", ");
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print_seccomp_filter(tcp, tcp->u_arg[2]);
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} else {
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decode_seccomp_set_mode_strict(tcp->u_arg[1],
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tcp->u_arg[2]);
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}
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return RVAL_DECODED;
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}
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