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我最近在Linux中尝试共享库注入，并决定编写自己的程序来完成它（而不是使用GDB来注入库）。共享库注入：_dl_relocate_object段错误
我的程序使用pthread用程序集代码覆盖加载的程序程序（0x40000-0x400025）的第一个0x25字节，为文件名分配空间并调用dlopen。一旦完成所有这些，它将恢复程序状态并从中分离。
这里的组件：
global inject_library
global nullsub
section .data
section .text
inject_library:
; rdi -> Pointer to malloc()
; rsi -> Pointer to free()
; rdx -> Pointer to dlopen()
; rcx -> Size of the path to the .so to load
; Create a new stack frame
push rbp
; Save rbx because we're using it as scratch space
push rbx
; Save addresses of free & dlopen on the stack
push rsi
push rdx
; Move the pointer to malloc into rbx
mov rbx, rdi
; Move the size of the path as the first argument to malloc
mov rdi, rcx
; Call malloc(so_path_size)
call rbx
; Stop so that we can see what's happening from the injector process
int 0x3
; Move the pointer to dlopen into rbx
pop rbx
; Move the malloc'd space (now containing the path) to rdi for the first argument
mov rdi, rax
; Push rax because it'll be overwritten
push rax
; Second argument to dlopen (RTLD_NOW)
mov rsi, 0x2
; Call dlopen(path_to_library, RTLD_NOW)
call rbx
; Pass control to the injector
int 0x3
; Finally, begin free-ing the malloc'd area
pop rdi
; Get the address of free into rbx
pop rbx
; Call free(path_to_library)
call rbx
; Restore rbx
pop rbx
; Destory the stack frame
pop rbp
; We're done
int 0x3
retn
nullsub:
retn
还有一个C程序调用该汇编程序，并使用并行线程来处理这些断点。
这种设置对于如下所示的小型单线程程序来说工作得很好。
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main(int argc, char* argv) {
pid_t my_pid = getpid();
printf("PID: %ld\n", my_pid);
getchar();
return 0;
}
我以前只是在它的构造做puts("Hi");简单的共享库。如上所述，这里的一切都完美无缺。但是，当我尝试将相同的库注入一个更大的（外部，闭源程序）时，我遇到了段错误。
这里的回溯：
#0 0x00007f6a7985d64d in _dl_relocate_object (scope=0x21fbc08, [email protected]=0, [email protected]=0)
at dl-reloc.c:259
#1 0x00007f6a79865723 in dl_open_worker ([email protected]=0x7fff82d7cbf8) at dl-open.c:424
#2 0x00007f6a793cf5d4 in __GI__dl_catch_error ([email protected]=0x7fff82d7cbe8, [email protected]=0x7fff82d7cbf0,
[email protected]=0x7fff82d7cbe7, [email protected]=0x7f6a798654c0 <dl_open_worker>, [email protected]=0x7fff82d7cbf8)
at dl-error-skeleton.c:198
#3 0x00007f6a79865069 in _dl_open (file=0x21fb830 "/home/umang/code/insertion/test_library.so", mode=-2147483646, caller_dlopen=0x40001a, nsid=-2,
argc=<optimized out>, argv=<optimized out>, env=0x7fff82d7cfe8) at dl-open.c:649
#4 0x00007f6a7964ef96 in dlopen_doit ([email protected]=0x7fff82d7ce08) at dlopen.c:66
#5 0x00007f6a793cf5d4 in __GI__dl_catch_error ([email protected]=0x7f6a798510f0 <last_result+16>,
[email protected]=0x7f6a798510f8 <last_result+24>, [email protected]=0x7f6a798510e8 <last_result+8>,
[email protected]=0x7f6a7964ef40 <dlopen_doit>, [email protected]=0x7fff82d7ce08) at dl-error-skeleton.c:198
#6 0x00007f6a7964f665 in _dlerror_run ([email protected]=0x7f6a7964ef40 <dlopen_doit>, [email protected]=0x7fff82d7ce08) at dlerror.c:163
#7 0x00007f6a7964f021 in __dlopen (file=<optimized out>, mode=<optimized out>) at dlopen.c:87
#8 0x000000000040001a in ??()
#9 0x00000000021fb830 in ??()
#10 0x00007f6a79326a90 in ??() at malloc.c:3071 from /lib64/libc.so.6
#11 0x00007f6a796488a0 in ??() from /lib64/libc.so.6
#12 0x0000000000000d68 in ??()
#13 0x00007f6a7931e938 in _IO_new_file_underflow (fp=0x7f6a7964efe0 <__dlopen>) at fileops.c:600
#14 0x00007f6a7931fa72 in __GI__IO_default_uflow (fp=0x7f6a796488a0 <_IO_2_1_stdin_>) at genops.c:404
#15 0x00007f6a7931a20d in getchar() at getchar.c:37
#16 0x00000000004005d7 in main()
这回溯告诉我出事（可怕的）错误的dlopen通话。具体来说，错误在于glibc dl-reloc.c:259。
下面是可疑的glibc代码。
254 l->l_lookup_cache.value = _lr; })) \
255 : l)
256
257 #include "dynamic-link.h"
258
259 ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
260
261 #ifndef PROF
262 if (__glibc_unlikely (consider_profiling)
263 && l->l_info[DT_PLTRELSZ] != NULL)
ELF_DYNAMIC_RELOCATE是dynamic-link.h定义如下宏 -
/* This can't just be an inline function because GCC is too dumb
to inline functions containing inlines themselves. */
# define ELF_DYNAMIC_RELOCATE(map, lazy, consider_profile, skip_ifunc) \
do { \
int edr_lazy = elf_machine_runtime_setup ((map), (lazy), \
(consider_profile)); \
ELF_DYNAMIC_DO_REL ((map), edr_lazy, skip_ifunc); \
ELF_DYNAMIC_DO_RELA ((map), edr_lazy, skip_ifunc); \
} while (0)
#endif
elf_machine_runtime_setup回报就好了，所以我假设问题在于ELF_DYNAMIC_DO_REL。这是提到的宏的source。这里的问题在于被调用的方法是内联的，因此GDB只显示宏名称而不显示底层的源代码。
在GDB使用ni，我看到以下后elf_machine_runtime_setup回报：
ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
步进通过装配，段错误下面的指令后会发生：movaps %xmm0,-0x70(%rbp)。
info local是没有多大帮助：
(gdb) info local
ranges = {{start = 140072440991568, size = 0, nrelative = 0, lazy = 670467104}, {start = 0, size = 140072438891376, nrelative = 140072441065920,
lazy = 672664367}}
textrels = 0x0
errstring = 0x0
lazy = <optimized out>
skip_ifunc = 0
有趣的是，当我用GDB注入共享库（使用此代码，我发现某处净），该库加载完美。
sudo gdb -n -q -batch \
-ex "attach $pid" \
-ex "set \$dlopen = (void*(*)(char*, int)) dlopen" \
-ex "call \$dlopen(\"$(pwd)/libexample.so\", 1)" \
-ex "detach" \
-ex "quit"
)"
在此先感谢！
有没有可能GDB正在做的事情（说停止所有其他线程），我不是？ –