漏洞公告 | Lua v5.4.0及之前版本lsys_load()栈溢出漏洞

Posted 2021-04-10 极光无限

Lua v5.4.0及之前版本lsys_load()函数加载动态链接库时没有正确处理文件名的长度，造成栈溢出漏洞，可造成拒绝服务问题。

- 01 -

漏洞描述

Lua是一种轻量小巧的脚本语言，用标准C语言编写并以源代码形式开放。

Lua v5.4.0及之前版本lsys_load()函数加载动态链接库时没有正确处理文件名的长度，造成栈溢出漏洞，可造成拒绝服务问题。

- 02 -

影响版本

Lua <= v5.4.0

- 03 -

漏洞复现

$ git clone https://github.com/lua/lua.git$ make$ ./lua ./Stack_overflow_lsys_load.luaAddressSanitizer:DEADLYSIGNAL===================================================================90451==ERROR: AddressSanitizer: stack-overflow on address 0x7ffc56ae1e38 (pc 0x7f84c442acf7 bp 0x7ffc573773f0 sp 0x7ffc56ae1e40 T0) #0 0x7f84c442acf6 (/lib64/ld-linux-x86-64.so.2+0x7cf6) #1 0x7f84c442cd4d (/lib64/ld-linux-x86-64.so.2+0x9d4d) #2 0x7f84c44379c3 (/lib64/ld-linux-x86-64.so.2+0x149c3) #3 0x7f84c31d148e in _dl_catch_exception (/lib/x86_64-linux-gnu/libc.so.6+0x15c48e) #4 0x7f84c44372c5 (/lib64/ld-linux-x86-64.so.2+0x142c5) #5 0x7f84c34a9255 (/lib/x86_64-linux-gnu/libdl.so.2+0x1255) #6 0x7f84c31d148e in _dl_catch_exception (/lib/x86_64-linux-gnu/libc.so.6+0x15c48e) #7 0x7f84c31d151e in _dl_catch_error (/lib/x86_64-linux-gnu/libc.so.6+0x15c51e) #8 0x7f84c34a9a24 (/lib/x86_64-linux-gnu/libdl.so.2+0x1a24) #9 0x7f84c34a92e5 in dlopen (/lib/x86_64-linux-gnu/libdl.so.2+0x12e5) #10 0x7f84c36c9a33 (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x8ea33) #11 0x56529c0e5908 in lsys_load /home/test/Lua/Test_lua/lua/loadlib.c:134 #12 0x56529c0e5908 in lookforfunc /home/test/Lua/Test_lua/lua/loadlib.c:391 #13 0x56529c0e5a14 in ll_loadlib /home/test/Lua/Test_lua/lua/loadlib.c:412 #14 0x56529c09025c in luaD_call /home/test/Lua/Test_lua/lua/ldo.c:481 #15 0x56529c0b8824 in luaV_execute /home/test/Lua/Test_lua/lua/lvm.c:1614 #16 0x56529c0b8824 in luaV_execute /home/test/Lua/Test_lua/lua/lvm.c:1614 #17 0x56529c090605 in luaD_callnoyield /home/test/Lua/Test_lua/lua/ldo.c:525 #18 0x56529c08dc51 in luaD_rawrunprotected /home/test/Lua/Test_lua/lua/ldo.c:148 #19 0x56529c0911e0 in luaD_pcall /home/test/Lua/Test_lua/lua/ldo.c:749 #20 0x56529c086f8f in lua_pcallk /home/test/Lua/Test_lua/lua/lapi.c:1031 #21 0x56529c08042a in docall /home/test/Lua/Test_lua/lua/lua.c:139 #22 0x56529c08179d in handle_script /home/test/Lua/Test_lua/lua/lua.c:228 #23 0x56529c08179d in pmain /home/test/Lua/Test_lua/lua/lua.c:603 #24 0x56529c09025c in luaD_call /home/test/Lua/Test_lua/lua/ldo.c:481 #25 0x56529c090605 in luaD_callnoyield /home/test/Lua/Test_lua/lua/ldo.c:525 #26 0x56529c08dc51 in luaD_rawrunprotected /home/test/Lua/Test_lua/lua/ldo.c:148 #27 0x56529c0911e0 in luaD_pcall /home/test/Lua/Test_lua/lua/ldo.c:749 #28 0x56529c086f8f in lua_pcallk /home/test/Lua/Test_lua/lua/lapi.c:1031 #29 0x56529c07fbda in main /home/test/Lua/Test_lua/lua/lua.c:629 #30 0x7f84c309909a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) #31 0x56529c080239 in _start (/home/test/Lua/Test_lua/lua/lua+0x18239)SUMMARY: AddressSanitizer: stack-overflow (/lib64/ld-linux-x86-64.so.2+0x7cf6) ==90451==ABORTING```

- 04 -

漏洞分析

漏洞发生在package.loadlib函数中，当用package.loadlib加载一个名字很长的动态链接库时，造成栈溢出：

static void *lsys_load (lua_State *L, const char *path, int seeglb) { void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL)); ---->crash if (lib == NULL) lua_pushstring(L, dlerror()); return lib;}

- 05 -

修复建议

在加载动态链接库时限制动态链接库的长度。

- 06 -

漏洞演示

Play

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