{"id":52034,"date":"2024-12-03T16:13:41","date_gmt":"2024-12-03T08:13:41","guid":{"rendered":"https:\/\/fwq.ai\/blog\/52034\/"},"modified":"2024-12-03T16:13:41","modified_gmt":"2024-12-03T08:13:41","slug":"linux-nx%e6%8c%87%e7%9a%84%e6%98%af%e4%bb%80%e4%b9%88","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/52034\/","title":{"rendered":"linux nx\u6307\u7684\u662f\u4ec0\u4e48"},"content":{"rendered":"

<\/b> <\/p>\n

linux nx\u6307\u7684\u662f\u4ec0\u4e48<\/h1>\n

\u4eca\u5929\u7c73\u4e91\u7ed9\u5927\u5bb6\u5e26\u6765\u4e86\u300alinux nx\u6307\u7684\u662f\u4ec0\u4e48\u300b<\/span>\uff0c\u5176\u4e2d\u6d89\u53ca\u5230\u7684\u77e5\u8bc6\u70b9\u5305\u62ec<\/span>\u7b49\u7b49\uff0c\u65e0\u8bba\u4f60\u662f\u5c0f\u767d\u8fd8\u662f\u8001\u624b\uff0c\u90fd\u9002\u5408\u770b\u4e00\u770b\u54e6~\u6709\u597d\u7684\u5efa\u8bae\u4e5f\u6b22\u8fce\u5927\u5bb6\u5728\u8bc4\u8bba\u7559\u8a00\uff0c\u82e5\u662f\u770b\u5b8c\u6709\u6240\u6536\u83b7\uff0c\u4e5f\u5e0c\u671b\u5927\u5bb6\u80fd\u591a\u591a\u70b9\u8d5e\u652f\u6301\u5440\uff01\u4e00\u8d77\u52a0\u6cb9\u5b66\u4e60~<\/p>\n<\/p>\n

\n

linux nx\u662f\u6307\u201cNo-eXecute\u201d\uff0c\u662flinux\u4e2d\u7684\u4e00\u79cd\u4fdd\u62a4\u673a\u5236\uff0c\u4e5f\u5c31\u662f\u6570\u636e\u4e0d\u53ef\u6267\u884c\uff0c\u9632\u6b62\u56e0\u4e3a\u7a0b\u5e8f\u8fd0\u884c\u51fa\u73b0\u6ea2\u51fa\u800c\u4f7f\u5f97\u653b\u51fb\u8005\u7684shellcode\u53ef\u80fd\u4f1a\u5728\u6570\u636e\u533a\u5c1d\u8bd5\u6267\u884c\u7684\u60c5\u51b5\u3002<\/p>\n<\/blockquote>\n

Linux\u7a0b\u5e8f\u5e38\u89c1\u7528\u7684\u4e00\u4e9b\u4fdd\u62a4\u673a\u5236<\/p>\n

\u4e00\u3001NX\uff08Windows\u4e2d\u7684DEP\uff09<\/h4>\n

NX<\/strong>\uff1aNo-eXecute\u3001DEP<\/strong>\uff1aData Execute Prevention<\/p>\n

    \n
  • \n

    \u4e5f\u5c31\u662f\u6570\u636e\u4e0d\u53ef\u6267\u884c\uff0c\u9632\u6b62\u56e0\u4e3a\u7a0b\u5e8f\u8fd0\u884c\u51fa\u73b0\u6ea2\u51fa\u800c\u4f7f\u5f97\u653b\u51fb\u8005\u7684shellcode\u53ef\u80fd\u4f1a\u5728\u6570\u636e\u533a\u5c1d\u8bd5\u6267\u884c\u7684\u60c5\u51b5\u3002<\/p>\n<\/li>\n

  • \n

    gcc\u9ed8\u8ba4\u5f00\u542f\uff0c\u9009\u9879\u6709\uff1a<\/p>\n<\/li>\n<\/ul>\n

    gcc -o test test.c      \/\/ \u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5f00\u542fNX\u4fdd\u62a4\ngcc -z execstack -o test test.c  \/\/ \u7981\u7528NX\u4fdd\u62a4\ngcc -z noexecstack -o test test.c  \/\/ \u5f00\u542fNX\u4fdd\u62a4<\/pre>\n
    \u4e8c\u3001PIE\uff08ASLR\uff09<\/h4>\n
    PIE<\/strong>\uff1aPosition-Independent Excutable\u3001ASLR<\/strong>\uff1aAddress Space Layout Randomization<\/p>\n
      \n
    • \n
      fpie\/fPIE\uff1a\u9700\u8981\u548c\u9009\u9879-pie<\/code>\u4e00\u8d77\u4f7f\u7528\u5f00\u542fpie\u9009\u9879\u7f16\u8bd1\u53ef\u6267\u884c\u6587\u4ef6\u4f7f\u5f97elf\u62e5\u6709\u5171\u4eab\u5e93\u5c5e\u6027\uff0c\u53ef\u4ee5\u5728\u5185\u5b58\u4efb\u4f55\u5730\u65b9\u52a0\u8f7d\u8fd0\u884c\u3002\u4e0e\u4e4b\u76f8\u4f3c\u7684\u8fd8\u6709fpic\/fPIC\uff0c\u5173\u4e8e\u5176\u8bf4\u660ehttps:\/\/gcc.gnu.org\/onlinedocs\/gcc\/Code-Gen-Options.html<\/p>\n<\/li>\n<\/ul>\n
      -fpic\n\n\tGenerate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Such code accesses all constant addresses through a global offset table (GOT). The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is not part of GCC; it is part of the operating system). If the GOT size for the linked executable exceeds a machine-specific maximum size, you get an error message from the linker indicating that -fpic does not work; in that case, recompile with -fPIC instead. (These maximums are 8k on the SPARC, 28k on AArch74 and 32k on the m68k and RS\/6000. The x86 has no such limit.)\n\n\tPosition-independent code requires special support, and therefore works only on certain machines. For the x86, GCC supports PIC for System V but not for the Sun 386i. Code generated for the IBM RS\/6000 is always position-independent.\n\n\tWhen this flag is set, the macros `__pic__` and `__PIC__` are defined to 1.\n\n-fPIC\n\n\tIf supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table.This option makes a difference on AArch74, m68k, PowerPC and SPARC.\n\n\tPosition-independent code requires special support, and therefore works only on certain machines.\n\n\tWhen this flag is set, the macros `__pic__` and `__PIC__` are defined to 2.\n\n-fpie\n-fPIE\n\n\tThese options are similar to -fpic and -fPIC, but the generated position-independent code can be only linked into executables. Usually these options are used to compile code that will be linked using the  -pie  GCC option.\n\n\t-fpie and -fPIE both define the macros `__pie__` and `__PIE__`. The macros have the value 1 for `-fpie` and 2 for `-fPIE`.<\/pre>\n
        \n
      • \n
        \u533a\u522b\u5728\u4e8efpic\/fPIC\u7528\u4e8e\u5171\u4eab\u5e93\u7684\u7f16\u8bd1\uff0cfpie\/fPIE\u5219\u662fpie\u6587\u4ef6\u7f16\u8bd1\u7684\u9009\u9879\u3002\u6587\u6863\u4e2d\u8bf4 pic\uff08\u4f4d\u7f6e\u65e0\u5173\u4ee3\u7801\uff09\u751f\u6210\u7684\u5171\u4eab\u5e93\u53ea\u80fd\u94fe\u63a5\u4e8e\u53ef\u6267\u884c\u6587\u4ef6\uff0c\u4e4b\u540e\u6839\u636e\u81ea\u5df1\u7f16\u8bd1\u7b80\u5355C\u7a0b\u5e8f\uff0cpie\u6b63\u5e38\u8fd0\u884c\uff0c\u5373\u5982\u7f51\u4e0a\u8bb8\u591a\u6587\u7ae0\u8bf4\u7684 pie \u9009\u9879\u751f\u6210\u7684\u4f4d\u7f6e\u65e0\u5173\u4ee3\u7801\u53ef\u5047\u5b9a\u4e8e\u672c\u7a0b\u5e8f\uff0c\u4f46\u662f\u6211\u4e5f\u6ca1\u770b\u51fafpie\/fPIE\u6709\u5565\u533a\u522b\uff0c\u53ea\u662f\u5b8f\u5b9a\u4e49\u53ea\u4e3a1\u548c2\u7684\u533a\u522b\uff0c\u8c8c\u4f3c…
        \u7f16\u8bd1\u547d\u4ee4\uff08\u9ed8\u8ba4\u4e0d\u5f00\u542fPIE\uff09\uff1a<\/p>\n<\/li>\n<\/ul>\n
        gcc -fpie -pie -o test test.c    \/\/ \u5f00\u542fPIE\ngcc -fPIE -pie -o test test.c    \/\/ \u5f00\u542fPIE\ngcc -fpic -o test test.c         \/\/ \u5f00\u542fPIC\ngcc -fPIC -o test test.c         \/\/ \u5f00\u542fPIC\ngcc -no-pie -o test test.c       \/\/ \u5173\u95edPIE<\/pre>\n
          \n
        • \n
          \u800cASLR\uff08\u5730\u5740\u7a7a\u95f4\u968f\u673a\u5316\uff09\uff0c\u5f53\u521d\u8bbe\u8ba1\u65f6\u53ea\u8d1f\u8d23\u6808\u3001\u5e93\u3001\u5806\u7b49\u6bb5\u7684\u5730\u5740\u968f\u673a\u5316\u3002ASLR\u7684\u503c\u5b58\u4e8e\/proc\/sys\/kernel\/randomize_va_space<\/code>\u4e2d\uff0c\u5982\u4e0b\uff1a<\/p>\n<\/li>\n<\/ul>\n
          \n
          0 – \u8868\u793a\u5173\u95ed\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u968f\u673a\u5316\u3002
          1 – \u8868\u793a\u5c06mmap\u7684\u57fa\u5740\uff0cstack\u548cvdso\u9875\u9762\u968f\u673a\u5316\u3002
          2 – \u8868\u793a\u57281\u7684\u57fa\u7840\u4e0a\u589e\u52a0\u6808\uff08heap\uff09\u7684\u968f\u673a\u5316\u3002\uff08\u9ed8\u8ba4\uff09<\/p>\n<\/blockquote>\n
          \n
          \u66f4\u6539\u5176\u503c\u65b9\u5f0f\uff1aecho  0 >  \/proc\/sys\/kernel\/randomize_va_space<\/p>\n<\/blockquote>\n
          vDSO\uff1avirtual dynamic shared object\uff1b
          mmap\uff1a\u5373\u5185\u5b58\u7684\u6620\u5c04\u3002
          PIE<\/code> \u5219\u662f\u8d1f\u8d23\u53ef\u6267\u884c\u7a0b\u5e8f\u7684\u57fa\u5740\u968f\u673a\u3002
          \u4ee5\u4e0b\u6458\u81eaWiki\uff1a<\/p>\n
          \n
          Position-independent executable (PIE) implements a random base address for the main executable binary and has been in place since 2003. It provides the same address randomness to the main executable as being used for the shared libraries.<\/p>\n<\/blockquote>\n
          PIE\u4e3aASLR\u7684\u4e00\u90e8\u5206\uff0cASLR\u4e3a\u7cfb\u7edf\u529f\u80fd\uff0cPIE\u5219\u4e3a\u7f16\u8bd1\u9009\u9879\u3002
          \u6ce8\uff1a<\/strong> \u5728heap\u5206\u914d\u65f6\uff0c\u6709mmap()<\/code>\u548cbrk()<\/code>\u4e24\u79cd\u65b9\u5f0f\uff0c\u7531malloc()<\/code>\u5206\u914d\u5185\u5b58\u65f6\u8c03\u7528\uff0c\u5206\u914d\u8f83\u5c0f\u65f6brk\uff0c\u5426\u5219mmap\uff0c128k\u533a\u522b\u3002<\/p>\n
          \u4e09\u3001Canary\uff08\u6808\u4fdd\u62a4\uff09<\/h4>\n
          \u2003\u2003Canary\u5bf9\u4e8e\u6808\u7684\u4fdd\u62a4\uff0c\u5728\u51fd\u6570\u6bcf\u4e00\u6b21\u6267\u884c\u65f6\uff0c\u5728\u6808\u4e0a\u968f\u673a\u4ea7\u751f\u4e00\u4e2aCanary\u503c\u3002\u4e4b\u540e\u5f53\u51fd\u6570\u6267\u884c\u7ed3\u675f\u8fd4\u56de\u65f6\u68c0\u6d4bCanary\u503c\uff0c\u82e5\u4e0d\u4e00\u81f4\u7cfb\u7edf\u5219\u62a5\u51fa\u5f02\u5e38\u3002<\/p>\n
            \n
          • \n
            Wiki\uff1a<\/p>\n<\/li>\n
          • \n
            Canaries<\/em> or canary words<\/em> are known values that are placed between a buffer and control data on the stack to monitor buffer overflows. When the buffer overflows, the first data to be corrupted will usually be the canary, and a failed verification of the canary data will therefore alert of an overflow, which can then be handled, for example, by invalidating the corrupted data. A canary value should not be confused with a sentinel value.<\/p>\n<\/li>\n<\/ul>\n
            \u2003\u2003\u5982\u4e0a\u6240\u8ff0\uff0cCanary\u503c\u7f6e\u4e8e\u7f13\u51b2\u533a\u548c\u63a7\u5236\u6570\u636e\u4e4b\u95f4\uff0c\u5f53\u7f13\u51b2\u533a\u6ea2\u51fa\uff0c\u8be5\u503c\u88ab\u8986\u5199\uff0c\u4ece\u800c\u53ef\u4ee5\u68c0\u6d4b\u4ee5\u5224\u65ad\u662f\u5426\u8fd0\u884c\u51fa\u9519\u6216\u662f\u53d7\u5230\u653b\u51fb\u3002\u7f13\u89e3\u7f13\u51b2\u533a\u6ea2\u51fa\u653b\u51fb\u3002<\/p>\n
              \n
            • \n
              \u7f16\u8bd1\u9009\u9879\uff1a<\/p>\n<\/li>\n<\/ul>\n
              gcc -o test test.c                       \/\/\u9ed8\u8ba4\u5173\u95ed\ngcc -fno-stack-protector -o test test.c  \/\/\u7981\u7528\u6808\u4fdd\u62a4\ngcc -fstack-protector -o test test.c     \/\/\u542f\u7528\u5806\u6808\u4fdd\u62a4\uff0c\u4e0d\u8fc7\u53ea\u4e3a\u5c40\u90e8\u53d8\u91cf\u4e2d\u542b\u6709 char \u6570\u7ec4\u7684\u51fd\u6570\u63d2\u5165\u4fdd\u62a4\u4ee3\u7801\ngcc -fstack-protector-all -o test test.c \/\/\u542f\u7528\u5806\u6808\u4fdd\u62a4\uff0c\u4e3a\u6240\u6709\u51fd\u6570\u63d2\u5165\u4fdd\u62a4\u4ee3\u7801<\/pre>\n
              \u56db\u3001RELRO\uff08RELocation Read Only\uff09<\/h4>\n
              \u5728Linux\u4e2d\u6709\u4e24\u79cdRELRO\u6a21\u5f0f\uff1a\u201dPartial RELRO\u201c<\/code> \u548c \u201dFull RELRO\u201c<\/code>\u3002Linux\u4e2dPartical RELRO\u9ed8\u8ba4\u5f00\u542f\u3002<\/p>\n
              Partial RELRO\uff1a<\/strong><\/p>\n
                \n
              • \n
                \u7f16\u8bd1\u547d\u4ee4\uff1a
                gcc -o test test.c  \/\/ \u9ed8\u8ba4\u90e8\u5206\u5f00\u542f
                gcc -Wl,-z,relro -o test test.c \/\/ \u5f00\u542f\u90e8\u5206RELRO
                gcc -z lazy -o test test.c \/\/ \u90e8\u5206\u5f00\u542f<\/p>\n<\/li>\n
              • \n
                \u8be5ELF\u6587\u4ef6\u7684\u5404\u4e2a\u90e8\u5206\u88ab\u91cd\u65b0\u6392\u5e8f\u3002\u5185\u6570\u636e\u6bb5\uff08internal data sections\uff09\uff08\u5982.got\uff0c.dtors\u7b49\uff09\u7f6e\u4e8e\u7a0b\u5e8f\u6570\u636e\u6bb5\uff08program’s data sections\uff09\uff08\u5982.data\u548c.bss\uff09\u4e4b\u524d\uff1b<\/p>\n<\/li>\n
              • \n
                \u65e0 plt \u6307\u5411\u7684GOT\u662f\u53ea\u8bfb\u7684\uff1b<\/p>\n<\/li>\n
              • \n
                GOT\u8868\u53ef\u5199\uff08\u5e94\u8be5\u662f\u4e0e\u4e0a\u9762\u6709\u6240\u533a\u522b\u7684\uff09\u3002<\/p>\n<\/li>\n<\/ul>\n
                Full RELRO\uff1a<\/strong><\/p>\n
                  \n
                • \n
                  \u7f16\u8bd1\u547d\u4ee4\uff1a
                  gcc -Wl,-z,relro,-z,now -o test test.c    \/\/ \u5f00\u542fFull RELRO
                  gcc -z now -o test test.c  \/\/ \u5168\u90e8\u5f00\u542f<\/p>\n<\/li>\n
                • \n
                  \u652f\u6301Partial\u6a21\u5f0f\u7684\u6240\u6709\u529f\u80fd\uff1b<\/p>\n<\/li>\n
                • \n
                  \u6574\u4e2aGOT\u8868\u6620\u5c04\u4e3a\u53ea\u8bfb\u7684\u3002<\/p>\n<\/li>\n<\/ul>\n
                  \n
                  gcc -z norelro -o a a.c \/\/ RELRO\u5173\u95ed\uff0c\u5373No RELRO<\/p>\n<\/blockquote>\n
                  Note\uff1a<\/strong><\/p>\n
                    \n
                  • \n
                    .dtors\uff1a\u5f53\u5b9a\u4e49\u6709.dtors\u7684\u5171\u4eab\u5e93\u88ab\u52a0\u8f7d\u65f6\u8c03\u7528\uff1b<\/p>\n<\/li>\n
                  • \n
                    \u5728bss\u6216\u6570\u636e\u6ea2\u51fa\u9519\u8bef\u7684\u60c5\u51b5\u4e0b\uff0cPartial\u548cFull RELRO\u4fdd\u62a4ELF\u5185\u6570\u636e\u6bb5\u4e0d\u88ab\u8986\u76d6\u3002 \u4f46\u53ea\u6709Full RELRO\u53ef\u4ee5\u7f13\u89e3GOT\u8868\u8986\u5199\u653b\u51fb\uff0c\u4f46\u662f\u76f8\u6bd4\u8f83\u800c\u8a00\u5f00\u9500\u8f83\u5927\uff0c\u56e0\u4e3a\u7a0b\u5e8f\u5728\u542f\u52a8\u4e4b\u524d\u9700\u8981\u89e3\u6790\u6240\u6709\u7684\u7b26\u53f7\u3002<\/p>\n<\/li>\n<\/ul>\n
                    \u4eca\u5929\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u5e0c\u671b\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff1b\u5173\u4e8e\u6587\u7ae0\u7684\u6280\u672f\u77e5\u8bc6\u6211\u4eec\u4f1a\u4e00\u70b9\u70b9\u6df1\u5165\u4ecb\u7ecd\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\uff0c\u4e00\u8d77\u5b66\u4e60\u7f16\u7a0b~<\/p>\n","protected":false},"excerpt":{"rendered":"
                    linux nx\u6307\u7684\u662f\u4ec0\u4e48 \u4eca\u5929\u7c73\u4e91\u7ed9\u5927\u5bb6\u5e26\u6765\u4e86\u300alinux nx\u6307\u7684\u662f\u4ec0\u4e48\u300b\uff0c\u5176\u4e2d\u6d89\u53ca\u5230\u7684\u77e5\u8bc6\u70b9\u5305\u62ec\u7b49\u7b49\uff0c\u65e0\u8bba\u4f60\u662f\u5c0f\u767d\u8fd8\u662f\u8001\u624b\uff0c\u90fd\u9002\u5408\u770b\u4e00\u770b\u54e6~\u6709\u597d\u7684\u5efa\u8bae\u4e5f\u6b22\u8fce\u5927\u5bb6\u5728\u8bc4\u8bba\u7559\u8a00\uff0c\u82e5\u662f\u770b\u5b8c\u6709\u6240\u6536\u83b7\uff0c\u4e5f\u5e0c\u671b\u5927\u5bb6\u80fd\u591a\u591a\u70b9\u8d5e\u652f\u6301\u5440\uff01\u4e00\u8d77\u52a0\u6cb9\u5b66\u4e60~ linux nx\u662f\u6307\u201cNo-eXecute\u201d\uff0c\u662flinux\u4e2d\u7684\u4e00\u79cd\u4fdd\u62a4\u673a\u5236\uff0c\u4e5f\u5c31\u662f\u6570\u636e\u4e0d\u53ef\u6267\u884c\uff0c\u9632\u6b62\u56e0\u4e3a\u7a0b\u5e8f\u8fd0\u884c\u51fa\u73b0\u6ea2\u51fa\u800c\u4f7f\u5f97\u653b\u51fb\u8005\u7684shellcode\u53ef\u80fd\u4f1a\u5728\u6570\u636e\u533a\u5c1d\u8bd5\u6267\u884c\u7684\u60c5\u51b5\u3002 Linux\u7a0b\u5e8f\u5e38\u89c1\u7528\u7684\u4e00\u4e9b\u4fdd\u62a4\u673a\u5236 \u4e00\u3001NX\uff08Windows\u4e2d\u7684DEP\uff09 NX\uff1aNo-eXecute\u3001DEP\uff1aData Execute Prevention \u4e5f\u5c31\u662f\u6570\u636e\u4e0d\u53ef\u6267\u884c\uff0c\u9632\u6b62\u56e0\u4e3a\u7a0b\u5e8f\u8fd0\u884c\u51fa\u73b0\u6ea2\u51fa\u800c\u4f7f\u5f97\u653b\u51fb\u8005\u7684shellcode\u53ef\u80fd\u4f1a\u5728\u6570\u636e\u533a\u5c1d\u8bd5\u6267\u884c\u7684\u60c5\u51b5\u3002 gcc\u9ed8\u8ba4\u5f00\u542f\uff0c\u9009\u9879\u6709\uff1a gcc -o test test.c      \/\/ \u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5f00\u542fNX\u4fdd\u62a4 gcc -z execstack -o test test.c  \/\/ \u7981\u7528NX\u4fdd\u62a4 gcc -z noexecstack -o test test.c  \/\/ \u5f00\u542fNX\u4fdd\u62a4 \u4e8c\u3001PIE\uff08ASLR\uff09 PIE\uff1aPosition-Independent Excutable\u3001ASLR\uff1aAddress Space Layout Randomization fpie\/fPIE\uff1a\u9700\u8981\u548c\u9009\u9879-pie\u4e00\u8d77\u4f7f\u7528\u5f00\u542fpie\u9009\u9879\u7f16\u8bd1\u53ef\u6267\u884c\u6587\u4ef6\u4f7f\u5f97elf\u62e5\u6709\u5171\u4eab\u5e93\u5c5e\u6027\uff0c\u53ef\u4ee5\u5728\u5185\u5b58\u4efb\u4f55\u5730\u65b9\u52a0\u8f7d\u8fd0\u884c\u3002\u4e0e\u4e4b\u76f8\u4f3c\u7684\u8fd8\u6709fpic\/fPIC\uff0c\u5173\u4e8e\u5176\u8bf4\u660ehttps:\/\/gcc.gnu.org\/onlinedocs\/gcc\/Code-Gen-Options.html -fpic Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Such code accesses all constant addresses through a global offset table (GOT). The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is not part of GCC; it is part of the operating system). If the GOT size for the linked executable exceeds a machine-specific maximum size, you get an error message from the linker indicating that -fpic does not work; in that case, recompile with -fPIC instead. (These maximums are 8k on the SPARC, 28k on AArch74 and 32k on the m68k and RS\/6000. The x86 has no such limit.) Position-independent code requires special support, and therefore works only on certain machines. For the x86, GCC supports PIC for System V but not for the Sun 386i. Code generated for the IBM RS\/6000 is always position-independent. When this flag is set, the macros `__pic__` and `__PIC__` are defined to 1. -fPIC If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table.This option makes a difference on AArch74, m68k, PowerPC and SPARC. Position-independent code requires special support, and therefore works only on certain machines. When this flag is set, the macros `__pic__` and `__PIC__` are defined to 2. -fpie -fPIE These options are similar to -fpic and -fPIC, but the generated position-independent code can be only linked into executables. Usually these options are used to compile code that will be linked using the  -pie  GCC option. -fpie and -fPIE both define the macros `__pie__` and `__PIE__`. The macros have the value 1 for `-fpie` and 2 for `-fPIE`. \u533a\u522b\u5728\u4e8efpic\/fPIC\u7528\u4e8e\u5171\u4eab\u5e93\u7684\u7f16\u8bd1\uff0cfpie\/fPIE\u5219\u662fpie\u6587\u4ef6\u7f16\u8bd1\u7684\u9009\u9879\u3002\u6587\u6863\u4e2d\u8bf4 pic\uff08\u4f4d\u7f6e\u65e0\u5173\u4ee3\u7801\uff09\u751f\u6210\u7684\u5171\u4eab\u5e93\u53ea\u80fd\u94fe\u63a5\u4e8e\u53ef\u6267\u884c\u6587\u4ef6\uff0c\u4e4b\u540e\u6839\u636e\u81ea\u5df1\u7f16\u8bd1\u7b80\u5355C\u7a0b\u5e8f\uff0cpie\u6b63\u5e38\u8fd0\u884c\uff0c\u5373\u5982\u7f51\u4e0a\u8bb8\u591a\u6587\u7ae0\u8bf4\u7684 pie \u9009\u9879\u751f\u6210\u7684\u4f4d\u7f6e\u65e0\u5173\u4ee3\u7801\u53ef\u5047\u5b9a\u4e8e\u672c\u7a0b\u5e8f\uff0c\u4f46\u662f\u6211\u4e5f\u6ca1\u770b\u51fafpie\/fPIE\u6709\u5565\u533a\u522b\uff0c\u53ea\u662f\u5b8f\u5b9a\u4e49\u53ea\u4e3a1\u548c2\u7684\u533a\u522b\uff0c\u8c8c\u4f3c…\u7f16\u8bd1\u547d\u4ee4\uff08\u9ed8\u8ba4\u4e0d\u5f00\u542fPIE\uff09\uff1a gcc -fpie -pie -o test test.c    \/\/ \u5f00\u542fPIE gcc -fPIE -pie -o test test.c    \/\/ \u5f00\u542fPIE gcc -fpic -o test test.c         \/\/ \u5f00\u542fPIC gcc -fPIC -o test test.c         \/\/ \u5f00\u542fPIC gcc -no-pie -o test test.c       \/\/ \u5173\u95edPIE \u800cASLR\uff08\u5730\u5740\u7a7a\u95f4\u968f\u673a\u5316\uff09\uff0c\u5f53\u521d\u8bbe\u8ba1\u65f6\u53ea\u8d1f\u8d23\u6808\u3001\u5e93\u3001\u5806\u7b49\u6bb5\u7684\u5730\u5740\u968f\u673a\u5316\u3002ASLR\u7684\u503c\u5b58\u4e8e\/proc\/sys\/kernel\/randomize_va_space\u4e2d\uff0c\u5982\u4e0b\uff1a 0 – \u8868\u793a\u5173\u95ed\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u968f\u673a\u5316\u30021 – \u8868\u793a\u5c06mmap\u7684\u57fa\u5740\uff0cstack\u548cvdso\u9875\u9762\u968f\u673a\u5316\u30022 – \u8868\u793a\u57281\u7684\u57fa\u7840\u4e0a\u589e\u52a0\u6808\uff08heap\uff09\u7684\u968f\u673a\u5316\u3002\uff08\u9ed8\u8ba4\uff09 \u66f4\u6539\u5176\u503c\u65b9\u5f0f\uff1aecho  0 > […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-52034","post","type-post","status-publish","format-standard","hentry","category-os"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/52034","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=52034"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/52034\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=52034"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=52034"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=52034"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}