mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
105 lines
2.5 KiB
105 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Seccomp BPF example using a macro-based generator. |
|
* |
|
* Copyright (c) 2012 The Chromium OS Authors <[email protected]> |
|
* Author: Will Drewry <[email protected]> |
|
* |
|
* The code may be used by anyone for any purpose, |
|
* and can serve as a starting point for developing |
|
* applications using prctl(PR_ATTACH_SECCOMP_FILTER). |
|
*/ |
|
|
|
#include <linux/filter.h> |
|
#include <linux/seccomp.h> |
|
#include <linux/unistd.h> |
|
#include <stdio.h> |
|
#include <string.h> |
|
#include <sys/prctl.h> |
|
#include <unistd.h> |
|
|
|
#include "bpf-helper.h" |
|
|
|
#ifndef PR_SET_NO_NEW_PRIVS |
|
#define PR_SET_NO_NEW_PRIVS 38 |
|
#endif |
|
|
|
int main(int argc, char **argv) |
|
{ |
|
struct bpf_labels l = { |
|
.count = 0, |
|
}; |
|
static const char msg1[] = "Please type something: "; |
|
static const char msg2[] = "You typed: "; |
|
char buf[256]; |
|
struct sock_filter filter[] = { |
|
/* TODO: LOAD_SYSCALL_NR(arch) and enforce an arch */ |
|
LOAD_SYSCALL_NR, |
|
SYSCALL(__NR_exit, ALLOW), |
|
SYSCALL(__NR_exit_group, ALLOW), |
|
SYSCALL(__NR_write, JUMP(&l, write_fd)), |
|
SYSCALL(__NR_read, JUMP(&l, read)), |
|
DENY, /* Don't passthrough into a label */ |
|
|
|
LABEL(&l, read), |
|
ARG(0), |
|
JNE(STDIN_FILENO, DENY), |
|
ARG(1), |
|
JNE((unsigned long)buf, DENY), |
|
ARG(2), |
|
JGE(sizeof(buf), DENY), |
|
ALLOW, |
|
|
|
LABEL(&l, write_fd), |
|
ARG(0), |
|
JEQ(STDOUT_FILENO, JUMP(&l, write_buf)), |
|
JEQ(STDERR_FILENO, JUMP(&l, write_buf)), |
|
DENY, |
|
|
|
LABEL(&l, write_buf), |
|
ARG(1), |
|
JEQ((unsigned long)msg1, JUMP(&l, msg1_len)), |
|
JEQ((unsigned long)msg2, JUMP(&l, msg2_len)), |
|
JEQ((unsigned long)buf, JUMP(&l, buf_len)), |
|
DENY, |
|
|
|
LABEL(&l, msg1_len), |
|
ARG(2), |
|
JLT(sizeof(msg1), ALLOW), |
|
DENY, |
|
|
|
LABEL(&l, msg2_len), |
|
ARG(2), |
|
JLT(sizeof(msg2), ALLOW), |
|
DENY, |
|
|
|
LABEL(&l, buf_len), |
|
ARG(2), |
|
JLT(sizeof(buf), ALLOW), |
|
DENY, |
|
}; |
|
struct sock_fprog prog = { |
|
.filter = filter, |
|
.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])), |
|
}; |
|
ssize_t bytes; |
|
bpf_resolve_jumps(&l, filter, sizeof(filter)/sizeof(*filter)); |
|
|
|
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { |
|
perror("prctl(NO_NEW_PRIVS)"); |
|
return 1; |
|
} |
|
|
|
if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog)) { |
|
perror("prctl(SECCOMP)"); |
|
return 1; |
|
} |
|
syscall(__NR_write, STDOUT_FILENO, msg1, strlen(msg1)); |
|
bytes = syscall(__NR_read, STDIN_FILENO, buf, sizeof(buf)-1); |
|
bytes = (bytes > 0 ? bytes : 0); |
|
syscall(__NR_write, STDERR_FILENO, msg2, strlen(msg2)); |
|
syscall(__NR_write, STDERR_FILENO, buf, bytes); |
|
/* Now get killed */ |
|
syscall(__NR_write, STDERR_FILENO, msg2, strlen(msg2)+2); |
|
return 0; |
|
}
|
|
|