Bash脚本实现实时监测登录

#!/bin/bash
# 作者: 阿杰
# 用途: 实时检测登录日志,统计异常登录
# 脚本名称: watch_secure.sh
# 用法: bash watch_seacure.sh

# 日志记录
log_err() {
  printf "[$(date +'%y-%m-%dt%h:%m:%s')]: \033[31merror: \033[0m$@\n"
}

log_info() {
  printf "[$(date +'%y-%m-%dt%h:%m:%s')]: \033[32minfo: \033[0m$@\n"
}

log_warning() {
  printf "[$(date +'%y-%m-%dt%h:%m:%s')]: \033[33mwarning: \033[0m$@\n"
}

# 初始化map
declare -a securemap

init() {
    # 行数记录文件
    line_file_name="conf/line_file.txt"
    # inode存储文件
    inode_file="conf/inode.txt"
    # 认证失败文件记录
    ssh_auth_failed_file="conf/ssh_auth_failed.csv"

    # 文件列表
    file_array=("$line_file_name" "$inode_file" "$ssh_auth_failed_file")
    # inode 文件状态
    inode_file_status=0
    # 控制是否进行写入 0为可写，1为不可写
    write_status=1

    onesecurekey=""

    {
        if [ ! -d "conf" ];then
            mkdir conf
        fi
        # 检查文件是否存在
        for file in ${file_array[@]};do
            check_file_exists $file
        done
        line=$(cat $line_file_name)
        if [ -z "$line" ];then
            line=0
        fi
        # 认证失败文件第一次创建
        if [ $(wc -l < $ssh_auth_failed_file) -eq 0 ];then
            # 时间以月天为单位(none为空账号或不存在账号)
            echo "登录认证失败时间,源ip地址,登录账号,连接认证失败次数" > $ssh_auth_failed_file
        fi

    }

    file_name="/var/log/secure"
    if [ -z "$(rpm -qa | grep 'inotify-tools')" ];then
        yum install -y inotify-tools > /dev/null 2>&1
        if [ $? -ne 0 ];then
            log_err "[init] inotify-tools 安装失败!"
        fi
    fi


}
# 检查文件是否存在，不存在则创建
check_file_exists() {
    local file_name=$1
    if [ ! -f "$file_name" ];then
        touch $file_name
        if [ $? -ne 0 ];then
            log_err "[check_file_exists] file: $file_name 文件创建失败!"
        fi
    fi
}



# 监听文件事件
watch_file() {
    inotifywait -mrq --format '%e' --event create,delete,modify $file_name | while read event ;do
        case "$event" in
        modify)
            start_read_file
        ;;
        # 文件被删除或重新创建
        create|delete)
            # 重置文件行数
            line=0
            > $line_file_name
            check
        ;;
        *)
            log_warning "[watch_file] watch file event: $event"
        ;;
        esac
    done
}

# 只读一行
read_line_file() {
    ((line++))
    echo $line > $line_file_name
    # 不是指定数据退出
    if [ $(sed -n "$line p" $file_name  | grep 'pam_unix(sshd:auth): authentication failure;' | wc -l ) -ne 1 ];then
        return
    fi
    # 控制是否进行写入
    write_status=0
    onesecurekey=$(sed -n "$line p" $file_name  |awk -v datenow=$(date +"%y") '{
        split($0,rhost,"rhost=")
        split(rhost[2],rhost," ")
        split($0,user," user=")
        if (length(user[2])==0) {
            user[2]="none"
        }
        print datenow":"$1":"$2","rhost[1]","user[2]
    }')
    log_info "[read_line_file] line: $line data:[$onesecurekey]"

    send_map $onesecurekey
}

# 往map中塞入数据
send_map() {
    local key=$1
    if [ -n ${securemap[$key]} ];then
        securemap[$key]=`expr ${securemap[$key]} + 1`
    else
        securemap[$key]=1
    fi
}

wirte_all_secure() {
    for key in ${!securemap[@]};do
        write_one_secure $key
    done
}

write_one_secure() {
    local key="$@"
    local data=$(grep -w -n "$key" $ssh_auth_failed_file)
    if [ -n "$data" ];then
        local i=$(echo $data | awk -f: '{print $1}')
        local a=$(echo $data | awk -f, '{print $nf}')
        sed -i "${i} s#$a#${securemap[$key]}#" $ssh_auth_failed_file
        if [ $? -ne 0 ];then
            log_err "[write_secure] 写 $ssh_auth_failed_file 文件失败! data:[$key,${securemap[$key]}]"
        fi
    else
        # 新数据
        echo "$key,${securemap[$key]}" >> $ssh_auth_failed_file
        if [ $? -ne 0 ];then
            log_err "[write_secure] 写 $ssh_auth_failed_file 文件失败! data:[$key,${securemap[$key]}]"
        fi
    fi
    log_info "[write_secure] line: $line status: $write_status data:[$key,${securemap[$key]}]"
}



# 启动前应先检查是否读取过
check() {
    # 检查预存inode是否一致
    check_secure_file_inode
}

# 检查登录日志inode是否一致
check_secure_file_inode() {
    inode=$(ls -i $file_name | awk '{print $1}')
    inode_file_data="$(cat $inode_file)"
    if [ -n "$inode_file_data" ]; then
        if [ $inode -ne $inode_file_data ];then
            log_warning "[check_secure_file_inode] secure file inode is inconsistency"
            # inode不一致,重置
            echo "$inode" > $inode_file
            inode_file_status=1
        else
           inode_file_status=0
        fi
    else
        # 第一次读取
        echo "$inode" > $inode_file
        inode_file_status=1
    fi
}

# 开始读取文件
start_read_file() {
    # 第一次读取
    if [ $inode_file_status -eq 1 ] ;then
        # 使用循环将历史内容读取
        while true;do
            if [ $line -eq $(wc -l < $file_name) ];then
                break
            fi
            read_line_file
        done
        wirte_all_secure
    elif [  $line -ne $(wc -l < $file_name) ];then
        # 使用循环将行数对齐
        while true;do
            if [ $line -eq $(wc -l < $file_name) ];then
                break
            fi
            read_line_file
            if [ $write_status -eq 0 ];then
                write_one_secure $onesecurekey
            fi
            # 状态设置为1
            write_status=1
        done
    # else
    #     read_line_file
    #     if [ $write_status -eq 0 ];then
    #         write_one_secure $onesecurekey
    #     fi
    #     # 状态设置为1
    #     write_status=1
    fi
}

test_main() {
    init
    check_secure_file_inode

}

main() {
    # 初始化
    init
    # 内容检查
    check
    start_read_file
    log_info "[main] watch secure startd"
    watch_file
}

main