我有以下的C应用程序:
#include <stdio.h>
void smash()
{
int i;
char buffer[16];
for(i = 0; i < 17; i++) // <-- exceeds the limit of the buffer
{
buffer[i] = i;
}
}
int main()
{
printf("Starting\n");
smash();
return 0;
}
我使用以下版本的gcc进行交叉编译:
armv5l-linux-gnueabi-gcc -v
Using built-in specs.
Target: armv5l-linux-gnueabi
Configured with: /home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/gcc-4.4.1/gcc-4.4.1/configure --target=armv5l-linux-gnueabi --host=i486-linux-gnu --build=i486-linux-gnu --prefix=/home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/toolchain --with-sysroot=/home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/toolchain --with-headers=/home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/toolchain/include --enable-languages=c,c++ --with-gmp=/home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/gmp-5.0.0/gmp-host-install --with-mpfr=/home/tarjeif/svn/builder/build_armv5l-linux-gnueabi/mpfr-2.4.2/mpfr-host-install --disable-nls --disable-libgcj --disable-libmudflap --disable-libssp --disable-libgomp --enable-checking=release --with-system-zlib --with-arch=armv5t --with-gnu-as --with-gnu-ld --enable-shared --enable-symvers=gnu --enable-__cxa_atexit --disable-nls --without-fp --enable-threads
Thread model: posix
gcc version 4.4.1 (GCC)
这样调用:
armv5l-linux-gnueabi-gcc -ggdb3 -fstack-protector-all -O0 test.c
在目标上运行时,它会输出:
Starting
*** stack smashing detected ***: ./a.out terminated
Aborted (core dumped)
我使用gdb加载生成的核心转储,得到以下回溯信息:
GNU gdb (GDB) 7.0.1
Copyright (C) 2009 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 "--host=i486-linux-gnu --target=armv5l-linux-gnueabi".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/andersn/workspace/stacktest/a.out...done.
Reading symbols from /home/andersn/workspace/stacktest/linux/toolchain/lib/libc.so.6...done.
Loaded symbols for /home/andersn/workspace/stacktest/linux/toolchain/lib/libc.so.6
Reading symbols from /home/andersn/workspace/stacktest/linux/toolchain/lib/ld-linux.so.3...done.
Loaded symbols for /home/andersn/workspace/stacktest/linux/toolchain/lib/ld-linux.so.3
Reading symbols from /home/andersn/workspace/stacktest/linux/toolchain /lib/libgcc_s.so.1...done.
Loaded symbols for /home/andersn/workspace/stacktest/linux/toolchain/lib/libgcc_s.so.1
Core was generated by `./a.out'.
Program terminated with signal 6, Aborted.
#0 0x40052d4c in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:67
67 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
in ../nptl/sysdeps/unix/sysv/linux/raise.c
(gdb) bt
#0 0x40052d4c in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:67
#1 0x40054244 in *__GI_abort () at abort.c:92
#2 0x40054244 in *__GI_abort () at abort.c:92
#3 0x40054244 in *__GI_abort () at abort.c:92
#4 0x40054244 in *__GI_abort () at abort.c:92
#5 0x40054244 in *__GI_abort () at abort.c:92
#6 0x40054244 in *__GI_abort () at abort.c:92
... and so on ...
现在,问题来了: 我通过GDB完全找不到导致堆栈溢出的函数,尽管smash()函数没有覆盖堆栈的任何结构数据,仅覆盖了堆栈保护本身。我该怎么办?