blob: 8adaac53207ca4688281e35e7f38182d25b0b9c4 [file] [log] [blame]
/*
* Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "defs.h"
#ifdef HAVE_LINUX_SECCOMP_H
# include <linux/seccomp.h>
#endif
#ifndef SECCOMP_SET_MODE_STRICT
# define SECCOMP_SET_MODE_STRICT 1
#endif
#ifndef SECCOMP_SET_MODE_FILTER
# define SECCOMP_SET_MODE_FILTER 1
#endif
#include "xlat/seccomp_ops.h"
#ifndef SECCOMP_FILTER_FLAG_TSYNC
# define SECCOMP_FILTER_FLAG_TSYNC 1
#endif
#include "xlat/seccomp_filter_flags.h"
#ifdef HAVE_LINUX_FILTER_H
# include <linux/filter.h>
# include "xlat/bpf_class.h"
# include "xlat/bpf_miscop.h"
# include "xlat/bpf_mode.h"
# include "xlat/bpf_op_alu.h"
# include "xlat/bpf_op_jmp.h"
# include "xlat/bpf_rval.h"
# include "xlat/bpf_size.h"
# include "xlat/bpf_src.h"
# ifndef SECCOMP_RET_ACTION
# define SECCOMP_RET_ACTION 0x7fff0000U
# endif
# include "xlat/seccomp_ret_action.h"
#endif
struct bpf_filter {
uint16_t code;
uint8_t jt;
uint8_t jf;
uint32_t k;
};
#ifdef HAVE_LINUX_FILTER_H
static void
decode_bpf_code(uint16_t code)
{
uint16_t i = code & ~BPF_CLASS(code);
printxval(bpf_class, BPF_CLASS(code), "BPF_???");
switch (BPF_CLASS(code)) {
case BPF_LD:
case BPF_LDX:
tprints(" | ");
printxval(bpf_size, BPF_SIZE(code), "BPF_???");
tprints(" | ");
printxval(bpf_mode, BPF_MODE(code), "BPF_???");
break;
case BPF_ST:
case BPF_STX:
if (i)
tprintf(" | %#x /* %s */", i, "BPF_???");
break;
case BPF_ALU:
tprints(" | ");
printxval(bpf_src, BPF_SRC(code), "BPF_???");
tprints(" | ");
printxval(bpf_op_alu, BPF_OP(code), "BPF_???");
break;
case BPF_JMP:
tprints(" | ");
printxval(bpf_src, BPF_SRC(code), "BPF_???");
tprints(" | ");
printxval(bpf_op_jmp, BPF_OP(code), "BPF_???");
break;
case BPF_RET:
tprints(" | ");
printxval(bpf_rval, BPF_RVAL(code), "BPF_???");
i &= ~BPF_RVAL(code);
if (i)
tprintf(" | %#x /* %s */", i, "BPF_???");
break;
case BPF_MISC:
tprints(" | ");
printxval(bpf_miscop, BPF_MISCOP(code), "BPF_???");
i &= ~BPF_MISCOP(code);
if (i)
tprintf(" | %#x /* %s */", i, "BPF_???");
break;
}
}
static void
decode_bpf_stmt(const struct bpf_filter *filter)
{
#ifdef HAVE_LINUX_FILTER_H
tprints("BPF_STMT(");
decode_bpf_code(filter->code);
tprints(", ");
if (BPF_CLASS(filter->code) == BPF_RET) {
unsigned int action = SECCOMP_RET_ACTION & filter->k;
unsigned int data = filter->k & ~action;
printxval(seccomp_ret_action, action, "SECCOMP_RET_???");
if (data)
tprintf(" | %#x)", data);
else
tprints(")");
} else {
tprintf("%#x)", filter->k);
}
#else
tprintf("BPF_STMT(%#x, %#x)", filter->code, filter->k);
#endif /* HAVE_LINUX_FILTER_H */
}
static void
decode_bpf_jump(const struct bpf_filter *filter)
{
#ifdef HAVE_LINUX_FILTER_H
tprints("BPF_JUMP(");
decode_bpf_code(filter->code);
tprintf(", %#x, %#x, %#x)",
filter->k, filter->jt, filter->jf);
#else
tprintf("BPF_JUMP(%#x, %#x, %#x, %#x)",
filter->code, filter->k, filter->jt, filter->jf);
#endif /* HAVE_LINUX_FILTER_H */
}
static void
decode_filter(const struct bpf_filter *filter)
{
if (filter->jt || filter->jf)
decode_bpf_jump(filter);
else
decode_bpf_stmt(filter);
}
#endif /* HAVE_LINUX_FILTER_H */
#ifndef BPF_MAXINSNS
# define BPF_MAXINSNS 4096
#endif
static void
decode_fprog(struct tcb *tcp, unsigned short len, unsigned long addr)
{
if (!len || abbrev(tcp)) {
tprintf("{len = %u, filter = %#lx}", len, addr);
} else {
unsigned int i = 0;
tprints("[");
while (i < len && i < BPF_MAXINSNS) {
struct bpf_filter filter;
if (umove(tcp, addr, &filter) < 0)
break;
if (i)
tprints(", ");
decode_filter(&filter);
addr += sizeof(filter);
++i;
}
if (i < len)
tprints("...");
tprints("]");
}
}
void
print_seccomp_filter(struct tcb *tcp, unsigned long addr)
{
if (addr) {
#if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
if (current_wordsize == 4) {
struct {
unsigned short len;
uint32_t filter;
} fprog;
if (umove(tcp, addr, &fprog) < 0)
tprintf("%#lx", addr);
else
decode_fprog(tcp, fprog.len, fprog.filter);
} else {
#endif
struct {
unsigned short len;
unsigned long filter;
} fprog;
if (umove(tcp, addr, &fprog) < 0)
tprintf("%#lx", addr);
else
decode_fprog(tcp, fprog.len, fprog.filter);
#if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
}
#endif
} else {
tprints("NULL");
}
}
static void
decode_seccomp_set_mode_strict(unsigned int flags, unsigned long addr)
{
tprintf("%u, ", flags);
if (addr)
tprintf("%#lx", addr);
else
tprints("NULL");
}
int
sys_seccomp(struct tcb *tcp)
{
if (entering(tcp)) {
unsigned int op = tcp->u_arg[0];
printxval(seccomp_ops, op, "SECCOMP_SET_MODE_???");
tprints(", ");
if (op == SECCOMP_SET_MODE_FILTER) {
printflags(seccomp_filter_flags, tcp->u_arg[1],
"SECCOMP_FILTER_FLAG_???");
tprints(", ");
print_seccomp_filter(tcp, tcp->u_arg[2]);
} else {
decode_seccomp_set_mode_strict(tcp->u_arg[1],
tcp->u_arg[2]);
}
}
return 0;
}