69 строки
1.8 KiB
C
69 строки
1.8 KiB
C
|
/*
|
||
|
|
* Naive system call dropper built on seccomp_filter.
|
||
|
|
*
|
||
|
|
* Copyright (c) 2012 The Chromium OS Authors <chromium-os-dev@chromium.org>
|
||
|
|
* Author: Will Drewry <wad@chromium.org>
|
||
|
|
*
|
||
|
|
* The code may be used by anyone for any purpose,
|
||
|
|
* and can serve as a starting point for developing
|
||
|
|
* applications using prctl(PR_SET_SECCOMP, 2, ...).
|
||
|
|
*
|
||
|
|
* When run, returns the specified errno for the specified
|
||
|
|
* system call number against the given architecture.
|
||
|
|
*
|
||
|
|
* Run this one as root as PR_SET_NO_NEW_PRIVS is not called.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <errno.h>
|
||
|
|
#include <linux/audit.h>
|
||
|
|
#include <linux/filter.h>
|
||
|
|
#include <linux/seccomp.h>
|
||
|
|
#include <linux/unistd.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <sys/prctl.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
static int install_filter(int nr, int arch, int error)
|
||
|
|
{
|
||
|
|
struct sock_filter filter[] = {
|
||
|
|
BPF_STMT(BPF_LD+BPF_W+BPF_ABS,
|
||
|
|
(offsetof(struct seccomp_data, arch))),
|
||
|
|
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, arch, 0, 3),
|
||
|
|
BPF_STMT(BPF_LD+BPF_W+BPF_ABS,
|
||
|
|
(offsetof(struct seccomp_data, nr))),
|
||
|
|
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, nr, 0, 1),
|
||
|
|
BPF_STMT(BPF_RET+BPF_K,
|
||
|
|
SECCOMP_RET_ERRNO|(error & SECCOMP_RET_DATA)),
|
||
|
|
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
|
||
|
|
};
|
||
|
|
struct sock_fprog prog = {
|
||
|
|
.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
|
||
|
|
.filter = filter,
|
||
|
|
};
|
||
|
|
if (prctl(PR_SET_SECCOMP, 2, &prog)) {
|
||
|
|
perror("prctl");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char **argv)
|
||
|
|
{
|
||
|
|
if (argc < 5) {
|
||
|
|
fprintf(stderr, "Usage:\n"
|
||
|
|
"dropper <syscall_nr> <arch> <errno> <prog> [<args>]\n"
|
||
|
|
"Hint: AUDIT_ARCH_I386: 0x%X\n"
|
||
|
|
" AUDIT_ARCH_X86_64: 0x%X\n"
|
||
|
|
"\n", AUDIT_ARCH_I386, AUDIT_ARCH_X86_64);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
if (install_filter(strtol(argv[1], NULL, 0), strtol(argv[2], NULL, 0),
|
||
|
|
strtol(argv[3], NULL, 0)))
|
||
|
|
return 1;
|
||
|
|
execv(argv[4], &argv[4]);
|
||
|
|
printf("Failed to execv\n");
|
||
|
|
return 255;
|
||
|
|
}
|