{"id":114,"date":"2019-07-11T18:43:32","date_gmt":"2019-07-11T09:43:32","guid":{"rendered":"http:\/\/www.space4u.co.kr\/wp\/?p=114"},"modified":"2019-07-11T18:43:34","modified_gmt":"2019-07-11T09:43:34","slug":"gcc-%ec%8a%a4%ed%85%8d-%ea%b9%a8%ec%a7%80%eb%8a%94%ea%b1%b0-%ea%b2%80%ec%82%ac%ed%95%98%ea%b8%b0","status":"publish","type":"post","link":"http:\/\/www.space4u.co.kr\/wp\/?p=114","title":{"rendered":"gcc \uc2a4\ud14d \uae68\uc9c0\ub294\uac70 \uac80\uc0ac\ud558\uae30"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code>\uc2a4\ud14d \uae68\uc9c0\ub294\uac70 \uac80\uc0ac linux ubuntu <\/code><\/pre>\n\n\n\n<pre class=\"wp-block-preformatted\">\ucd9c\ucc98 : <a href=\"http:\/\/stackoverflow.com\/questions\/1345670\/stack-smashing-detected\">http:\/\/stackoverflow.com\/questions\/1345670\/stack-smashing-detected<\/a><\/pre>\n\n\n\n<pre class=\"wp-block-preformatted\"><code>ab@cd-x:$ cat test_overflow.c \n#include &lt;stdio.h>\n#include &lt;string.h>\n\nint check_password(char *password){\n\u00a0 \u00a0 int flag = 0;\n\u00a0 \u00a0 char buffer[20];\n\u00a0 \u00a0 strcpy(buffer, password);\n\n\u00a0 \u00a0 if(strcmp(buffer, \"mypass\") == 0){\n\u00a0 \u00a0 \u00a0 \u00a0 flag = 1;\n\u00a0 \u00a0 }\n\u00a0 \u00a0 if(strcmp(buffer, \"yourpass\") == 0){\n\u00a0 \u00a0 \u00a0 \u00a0 flag = 1;\n\u00a0 \u00a0 }\n\u00a0 \u00a0 return flag;\n}\n\nint main(int argc, char *argv[]){\n\u00a0 \u00a0 if(argc >= 2){\n\u00a0 \u00a0 \u00a0 \u00a0 if(check_password(argv[1])){\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 printf(\"%s\", \"Access grainted\\n\");\n\u00a0 \u00a0 \u00a0 \u00a0 }else{\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 printf(\"%s\", \"Access denined\\n\");\n\u00a0 \u00a0 \u00a0 \u00a0 }\n\u00a0 \u00a0 }else{\n\u00a0 \u00a0 \u00a0 \u00a0 printf(\"%s\", \"Please enter password!\\n\");\n\u00a0 \u00a0 }\n}\nab@cd-x:$ gcc -g -fno-stack-protector test_overflow.c \nab@cd-x:$ .\/a.out mypass\nAccess grainted\nab@cd-x:$ .\/a.out yourpass\nAccess grainted\nab@cd-x:$ .\/a.out wepass\nAccess denined\nab@cd-x:$ .\/a.out wepassssssssssssssssss\nAccess grainted\n\nab@cd-x:$ gcc -g -fstack-protector test_overflow.c \nab@cd-x:$ .\/a.out wepass\nAccess denined\nab@cd-x:$ .\/a.out mypass\nAccess grainted\nab@cd-x:$ .\/a.out yourpass\nAccess grainted\nab@cd-x:$ .\/a.out wepassssssssssssssssss\n*** stack smashing detected ***: .\/a.out terminated\n======= Backtrace: =========\n\/lib\/tls\/i686\/cmov\/libc.so.6(__fortify_fail+0x48)[0xce0ed8]\n\/lib\/tls\/i686\/cmov\/libc.so.6(__fortify_fail+0x0)[0xce0e90]\n.\/a.out[0x8048524]\n.\/a.out[0x8048545]\n\/lib\/tls\/i686\/cmov\/libc.so.6(__libc_start_main+0xe6)[0xc16b56]\n.\/a.out[0x8048411]\n======= Memory map: ========\n007d9000-007f5000 r-xp 00000000 08:06 5776 \u00a0 \u00a0 \u00a0 \/lib\/libgcc_s.so.1\n007f5000-007f6000 r--p 0001b000 08:06 5776 \u00a0 \u00a0 \u00a0 \/lib\/libgcc_s.so.1\n007f6000-007f7000 rw-p 0001c000 08:06 5776 \u00a0 \u00a0 \u00a0 \/lib\/libgcc_s.so.1\n0090a000-0090b000 r-xp 00000000 00:00 0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0[vdso]\n00c00000-00d3e000 r-xp 00000000 08:06 1183 \u00a0 \u00a0 \u00a0 \/lib\/tls\/i686\/cmov\/libc-2.10.1.so\n00d3e000-00d3f000 ---p 0013e000 08:06 1183 \u00a0 \u00a0 \u00a0 \/lib\/tls\/i686\/cmov\/libc-2.10.1.so\n00d3f000-00d41000 r--p 0013e000 08:06 1183 \u00a0 \u00a0 \u00a0 \/lib\/tls\/i686\/cmov\/libc-2.10.1.so\n00d41000-00d42000 rw-p 00140000 08:06 1183 \u00a0 \u00a0 \u00a0 \/lib\/tls\/i686\/cmov\/libc-2.10.1.so\n00d42000-00d45000 rw-p 00000000 00:00 0 \n00e0c000-00e27000 r-xp 00000000 08:06 4213 \u00a0 \u00a0 \u00a0 \/lib\/ld-2.10.1.so\n00e27000-00e28000 r--p 0001a000 08:06 4213 \u00a0 \u00a0 \u00a0 \/lib\/ld-2.10.1.so\n00e28000-00e29000 rw-p 0001b000 08:06 4213 \u00a0 \u00a0 \u00a0 \/lib\/ld-2.10.1.so\n08048000-08049000 r-xp 00000000 08:05 1056811 \u00a0 \u00a0\/dos\/hacking\/test\/a.out\n08049000-0804a000 r--p 00000000 08:05 1056811 \u00a0 \u00a0\/dos\/hacking\/test\/a.out\n0804a000-0804b000 rw-p 00001000 08:05 1056811 \u00a0 \u00a0\/dos\/hacking\/test\/a.out\n08675000-08696000 rw-p 00000000 00:00 0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0[heap]\nb76fe000-b76ff000 rw-p 00000000 00:00 0 \nb7717000-b7719000 rw-p 00000000 00:00 0 \nbfc1c000-bfc31000 rw-p 00000000 00:00 0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0[stack]\nAborted\nab@cd-x:$ <\/code> <\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\ucd9c\ucc98 : http:\/\/stackoverflow.com\/questions\/1345670\/stack-smashing-detected ab@cd-x:$ cat test_overflow.c #include &lt;stdio.h> #include &lt;string.h> int check_password(char *password){ \u00a0 \u00a0 int flag = 0; \u00a0 \u00a0 char buffer[20]; \u00a0 \u00a0&#8230;<\/p>\n<div class=\"more-link-wrapper\"><a class=\"more-link\" href=\"http:\/\/www.space4u.co.kr\/wp\/?p=114\">\ub354 \uc77d\uae30<span class=\"screen-reader-text\">gcc \uc2a4\ud14d \uae68\uc9c0\ub294\uac70 \uac80\uc0ac\ud558\uae30<\/span> <i class=\"fas fa-angle-right\"><\/i><\/a><\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[83,81,82],"aioseo_notices":[],"_links":{"self":[{"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/posts\/114"}],"collection":[{"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=114"}],"version-history":[{"count":1,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/posts\/114\/revisions"}],"predecessor-version":[{"id":115,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=\/wp\/v2\/posts\/114\/revisions\/115"}],"wp:attachment":[{"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=114"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=114"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.space4u.co.kr\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}