{"id":51981,"date":"2024-12-03T09:18:32","date_gmt":"2024-12-03T01:18:32","guid":{"rendered":"https:\/\/fwq.ai\/blog\/51981\/"},"modified":"2024-12-03T09:18:32","modified_gmt":"2024-12-03T01:18:32","slug":"linux-uid%e7%9a%84%e4%bd%9c%e7%94%a8%e6%98%af%e4%bb%80%e4%b9%88","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/51981\/","title":{"rendered":"linux uid\u7684\u4f5c\u7528\u662f\u4ec0\u4e48"},"content":{"rendered":"

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

linux uid\u7684\u4f5c\u7528\u662f\u4ec0\u4e48<\/h1>\n

\u5b66\u4e60\u6587\u7ae0<\/span>\u8981\u52aa\u529b\uff0c\u4f46\u662f\u4e0d\u8981\u6025\uff01\u4eca\u5929\u7684\u8fd9\u7bc7\u6587\u7ae0\u300alinux uid\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\u300b<\/span>\u5c06\u4f1a\u4ecb\u7ecd\u5230<\/span>\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u60f3\u6df1\u5165\u5b66\u4e60\u6587\u7ae0<\/span>\uff0c\u53ef\u4ee5\u5173\u6ce8\u6211\uff01\u6211\u4f1a\u6301\u7eed\u66f4\u65b0\u76f8\u5173\u6587\u7ae0\u7684\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u90fd\u80fd\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n<\/p>\n

\n

linux uid\u7684\u4f5c\u7528\u662f\u6807\u8bc6\u4e00\u4e2a\u7528\u6237\uff0c\u6bcf\u4e2a\u7528\u6237\u6709\u4e00\u4e2aUID\uff1blinux\u4e2d\u6709\u4e09\u4e2aUID\u6807\u8bc6\u5206\u522b\u662f\uff1a1\u3001RUID\uff0cReal UID\uff0c\u5b9e\u9645\u7528\u6237ID\uff1b2\u3001EUID\uff0cEffective UID\uff0c\u6709\u6548\u7528\u6237ID\uff1b3\u3001SUID\uff0cSaved Set-user-ID\uff0c\u4fdd\u5b58\u7684\u8bbe\u7f6e\u7528\u6237ID\u3002<\/p>\n<\/blockquote>\n

\u4e00\u3001Linux \u4e2d\u7684UID<\/h2>\n

1.1 \u6bcf\u4e2a\u8fdb\u7a0b\u7684\u4e09\u4e2aUID\u503c<\/h3>\n

\u6bcf\u4e2a\u7528\u6237\u6709\u4e00\u4e2aUID\u3002<\/p>\n

\u5185\u6838\u4e3a\u6bcf\u4e2a\u8fdb\u7a0b\u7ef4\u62a43\u4e2aUID\u6807\u8bc6\u3002\u8fd9\u4e09\u4e2aUID\u6807\u8bc6\u5206\u522b\u662fRUID(Real UID\uff0c\u5b9e\u9645\u7528\u6237ID)<\/strong>\u3001EUID(Effective UID\uff0c\u6709\u6548\u7528\u6237ID)<\/strong>\u3001SUID(Saved Set-user-ID\uff0c\u4fdd\u5b58\u7684\u8bbe\u7f6e\u7528\u6237ID)<\/strong>\u3002<\/p>\n

    \n
  • \n

    RUID<\/strong>\uff1a\u6211\u4eec\u5f53\u524d\u4ee5\u54ea\u4e2a\u7528\u6237\u767b\u5f55\uff0c\u6211\u4eec\u8fd0\u884c\u7a0b\u5e8f\u4ea7\u751f\u8fdb\u7a0b\u7684RUID\u5c31\u662f\u8fd9\u4e2a\u7528\u6237\u7684UID\u3002<\/p>\n<\/li>\n

  • \n

    EUID<\/strong>\uff1a\u6307\u5f53\u524d\u8fdb\u7a0b\u5b9e\u9645\u4ee5\u54ea\u4e2aUID\u6765\u8fd0\u884c<\/strong>\u3002\u4e00\u822c\u60c5\u51b5\u4e0bEUID\u7b49\u4e8eRUID\uff1b\u4f46\u5982\u679c\u8fdb\u7a0b\u5bf9\u5e94\u7684\u53ef\u6267\u884c\u6587\u4ef6\u5177\u6709SUID\u6743\u9650<\/strong>\uff08\u4e5f\u5c31\u662frws\u7684s\uff09\uff0c\u90a3\u4e48\u8fdb\u7a0b\u7684EUID\u662f\u53ef\u6267\u884c\u6587\u4ef6\u7684\u6240\u6709\u8005\u7684UID<\/strong>\u3002<\/p>\n<\/li>\n

  • \n

    SUID<\/strong>\uff1aEUID\u7684\u4e00\u4e2a\u526f\u672c\uff0c\u4e0eSUID\u6743\u9650\u6709\u5173\u3002<\/p>\n<\/li>\n<\/ul>\n

    1.2 \u4e8c\u8fdb\u5236\u6587\u4ef6\u7684SUID\u6743\u9650<\/h3>\n

    \u4ee5passwd\u8fd9\u4e2a\u53ef\u6267\u884c\u6587\u4ef6\u4e3a\u4f8b\u3002
    password\u6587\u4ef6\u7684\u6743\u9650\u4e3a\uff1a-rwsr-xr-x<\/code>
    passwd\u7684\u6240\u6709\u8005\u662froot\uff0c\u4f46\u662f\u5176\u4ed6\u7528\u6237\u5bf9\u4e8epasswd\u4e5f\u6709\u6267\u884c\u6743\u9650\uff0c\u5e76\u4e14passwd\u81ea\u8eab\u5177\u6709SUID\u6743\u9650\uff08rws\u7684s\uff09\u3002
    \u90a3\u4e48\uff0c\u5f53\u975eroot\u7528\u6237\u6267\u884cpasswd\u8fd9\u4e2a\u53ef\u6267\u884c\u6587\u4ef6\u7684\u65f6\u5019\uff0c\u4ea7\u751f\u7684\u8fdb\u7a0b\u7684EUID<\/strong>\uff0c\u5c31\u662froot\u7528\u6237\u7684UID<\/strong>\u3002\u6362\u8a00\u4e4b\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u4ea7\u751f\u7684\u8fdb\u7a0b\uff0c\u5b9e\u9645\u4ee5root\u7528\u6237\u7684ID\u6765\u8fd0\u884c\u4e8c\u8fdb\u5236\u6587\u4ef6\u3002<\/p>\n

    \u9700\u8981\u8bf4\u660e\u7684\u662f\uff0cSUID\u6743\u9650\u5177\u6709\u65f6\u6548\u6027<\/strong>\uff1a\u4ec5\u5728\u6267\u884c\u8be5\u6587\u4ef6\u7684\u8fc7\u7a0b\u4e2d\u6709\u6548<\/strong>\u3002<\/p>\n

    \u4e8c\u3001setuid\u3001setresuid\u51fd\u6570<\/h2>\n

    2.1 setuid\u51fd\u6570<\/h3>\n

    \u51fd\u6570\u539f\u578b\uff1aint setuid(uid_t uid);<\/p>\n

    \u5728Linux\u4e2d\uff0c setuid(uid)\u51fd\u6570\u7684\u6267\u884c\u6b65\u9aa4\u4e3a:
    \uff081\uff09\u5982\u679c\u7531Root\u6743\u9650\u8fdb\u7a0b\uff08EUID\u4e3a0\u7684\u8fdb\u7a0b\uff09\u8c03\u7528\uff0c\u5219\u5c06\u8fdb\u7a0b\u7684RUID\uff0cEUID\u548cSUID\u90fd\u8bbe\u7f6e\u4e3auid\uff0c\u8fd4\u56de0
    \uff082\uff09\u5982\u679c\u7531\u666e\u901a\u6743\u9650\u8fdb\u7a0b\u8c03\u7528\uff0c\u4e14uid\u7b49\u4e8eRUID\u6216uid\u7b49\u4e8eSUID\uff0c\u5219\u5c06\u8fdb\u7a0b\u7684EUID\u8bbe\u7f6e\u4e3auid\uff0c\u8fd4\u56de0
    \uff083\uff09\u5982\u679c\u7531\u666e\u901a\u6743\u9650\u8fdb\u7a0b\u8c03\u7528\uff0c\u4e14uid\u4e0d\u7b49\u4e8eRUID\u6216SUID\uff0c\u5219\u8bbe\u7f6eerrno\u4e3aEPERM\uff0c\u5e76\u8fd4\u56de-1\uff08\u8868\u793a\u6267\u884c\u5931\u8d25\uff09<\/p>\n

    \u4e0a\u6587\u4e2d\uff0c\u6267\u884cpassword\u7684\u8fdb\u7a0b\uff0cEUID\u662fpassword\u7684\u6240\u6709\u8005\u7684UID\uff0c\u4e5f\u5c31\u662froot\u7528\u6237\u7684UID\uff0c\u4e5f\u5c31\u662f0\u3002\u6240\u4ee5\uff0c\u5c5e\u4e8e\u60c5\u51b5\uff081\uff09\u3002<\/p>\n

    su\u6587\u4ef6\u540c\u6837\u662f-rwsr-xr-x<\/code>\u6743\u9650\u3002\u6240\u4ee5\uff0c\u5b89\u5353\u4e2d\uff0c\u666e\u901a\u8fdb\u7a0b\u901a\u8fc7Runtime.getRuntime().exec(\u201csu\u201d)\uff0c\u53d1\u8d77\u4e00\u4e2ashell\u8fdb\u7a0b\uff0c\u53bb\u6267\u884csu\u7684\u65f6\u5019\uff0c\u540c\u6837\u5c5e\u4e8e\u60c5\u51b5\uff081\uff09\u3002<\/p>\n

    2.2 setresuid\u51fd\u6570<\/h3>\n

    \u51fd\u6570\u539f\u578b\uff1aint setresuid(uid_t ruid, uid_t euid, uid_t suid);<\/p>\n

    \u6ee1\u8db3\u4ee5\u4e0b\u6761\u4ef6\u4e4b\u4e00<\/strong>\u65f6\uff0csetresuid\u88ab\u6267\u884c\uff1a
    \u2460\u5f53\u524d\u8fdb\u7a0b\u7684euid\u662froot\uff08AID_ROOT\uff09
    \u2461\u4e09\u4e2a\u53c2\u6570ruid\u3001euid\u3001suid\u4e2d\u7684\u6bcf\u4e00\u4e2a\uff0c\u90fd\u548c\u5f53\u524d\u8fdb\u7a0b\u7684\u67d0\u4e2aUID\u503c \u76f8\u7b49<\/p>\n

    \u4f8b\u5982\uff1a<\/p>\n

      \n
    • \n

      \u5982\u679c\u5f53\u524d\u8fdb\u7a0b\u7684RUID=100,EUID=0,SUID=300
      \u5219setresuid(200,300,100)\u53ef\u4ee5\u6267\u884c\uff0c\u56e0\u4e3a\u539f\u6765\u7684euid=0<\/p>\n<\/li>\n

    • \n

      \u5982\u679c\u5f53\u524d\u8fdb\u7a0b\u7684RUID=100,EUID=300,SUID=200
      \u5219setresuid(200,300,100)\u53ef\u4ee5\u6267\u884c\uff0c\u56e0\u4e3a\u8fd9\u4e09\u4e2a\u53c2\u6570\u90fd\u662f\u5f53\u524dUID\u4e2d\u7684\u67d0\u4e00\u4e2a\uff1b
      \u4f46setresuid(100,200,400)\u4e0d\u80fd\u6267\u884c\uff0c\u56e0\u4e3a400\u4e0d\u7b49\u4e8e\u5f53\u524dUID\u4e2d\u7684\u4efb\u610f\u4e00\u4e2a\u3002<\/p>\n<\/li>\n<\/ul>\n

      \u4e09\u3001getuid\u3001geteuid\u51fd\u6570<\/h2>\n

      getuid\u8fd4\u56de\u5f53\u524d\u8fdb\u7a0b\u7684RUID<\/strong>
      geteuid\u8fd4\u56de\u5f53\u524d\u8fdb\u7a0b\u7684EUID<\/strong><\/p>\n

      \u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\u7c73\u4e91\uff01\u66f4\u591a\u5173\u4e8e\u6587\u7ae0\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

      linux uid\u7684\u4f5c\u7528\u662f\u4ec0\u4e48 \u5b66\u4e60\u6587\u7ae0\u8981\u52aa\u529b\uff0c\u4f46\u662f\u4e0d\u8981\u6025\uff01\u4eca\u5929\u7684\u8fd9\u7bc7\u6587\u7ae0\u300alinux uid\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\u300b\u5c06\u4f1a\u4ecb\u7ecd\u5230\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u60f3\u6df1\u5165\u5b66\u4e60\u6587\u7ae0\uff0c\u53ef\u4ee5\u5173\u6ce8\u6211\uff01\u6211\u4f1a\u6301\u7eed\u66f4\u65b0\u76f8\u5173\u6587\u7ae0\u7684\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u90fd\u80fd\u6709\u6240\u5e2e\u52a9\uff01 linux uid\u7684\u4f5c\u7528\u662f\u6807\u8bc6\u4e00\u4e2a\u7528\u6237\uff0c\u6bcf\u4e2a\u7528\u6237\u6709\u4e00\u4e2aUID\uff1blinux\u4e2d\u6709\u4e09\u4e2aUID\u6807\u8bc6\u5206\u522b\u662f\uff1a1\u3001RUID\uff0cReal UID\uff0c\u5b9e\u9645\u7528\u6237ID\uff1b2\u3001EUID\uff0cEffective UID\uff0c\u6709\u6548\u7528\u6237ID\uff1b3\u3001SUID\uff0cSaved Set-user-ID\uff0c\u4fdd\u5b58\u7684\u8bbe\u7f6e\u7528\u6237ID\u3002 \u4e00\u3001Linux \u4e2d\u7684UID 1.1 \u6bcf\u4e2a\u8fdb\u7a0b\u7684\u4e09\u4e2aUID\u503c \u6bcf\u4e2a\u7528\u6237\u6709\u4e00\u4e2aUID\u3002 \u5185\u6838\u4e3a\u6bcf\u4e2a\u8fdb\u7a0b\u7ef4\u62a43\u4e2aUID\u6807\u8bc6\u3002\u8fd9\u4e09\u4e2aUID\u6807\u8bc6\u5206\u522b\u662fRUID(Real UID\uff0c\u5b9e\u9645\u7528\u6237ID)\u3001EUID(Effective UID\uff0c\u6709\u6548\u7528\u6237ID)\u3001SUID(Saved Set-user-ID\uff0c\u4fdd\u5b58\u7684\u8bbe\u7f6e\u7528\u6237ID)\u3002 RUID\uff1a\u6211\u4eec\u5f53\u524d\u4ee5\u54ea\u4e2a\u7528\u6237\u767b\u5f55\uff0c\u6211\u4eec\u8fd0\u884c\u7a0b\u5e8f\u4ea7\u751f\u8fdb\u7a0b\u7684RUID\u5c31\u662f\u8fd9\u4e2a\u7528\u6237\u7684UID\u3002 EUID\uff1a\u6307\u5f53\u524d\u8fdb\u7a0b\u5b9e\u9645\u4ee5\u54ea\u4e2aUID\u6765\u8fd0\u884c\u3002\u4e00\u822c\u60c5\u51b5\u4e0bEUID\u7b49\u4e8eRUID\uff1b\u4f46\u5982\u679c\u8fdb\u7a0b\u5bf9\u5e94\u7684\u53ef\u6267\u884c\u6587\u4ef6\u5177\u6709SUID\u6743\u9650\uff08\u4e5f\u5c31\u662frws\u7684s\uff09\uff0c\u90a3\u4e48\u8fdb\u7a0b\u7684EUID\u662f\u53ef\u6267\u884c\u6587\u4ef6\u7684\u6240\u6709\u8005\u7684UID\u3002 SUID\uff1aEUID\u7684\u4e00\u4e2a\u526f\u672c\uff0c\u4e0eSUID\u6743\u9650\u6709\u5173\u3002 1.2 \u4e8c\u8fdb\u5236\u6587\u4ef6\u7684SUID\u6743\u9650 \u4ee5passwd\u8fd9\u4e2a\u53ef\u6267\u884c\u6587\u4ef6\u4e3a\u4f8b\u3002 password\u6587\u4ef6\u7684\u6743\u9650\u4e3a\uff1a-rwsr-xr-x passwd\u7684\u6240\u6709\u8005\u662froot\uff0c\u4f46\u662f\u5176\u4ed6\u7528\u6237\u5bf9\u4e8epasswd\u4e5f\u6709\u6267\u884c\u6743\u9650\uff0c\u5e76\u4e14passwd\u81ea\u8eab\u5177\u6709SUID\u6743\u9650\uff08rws\u7684s\uff09\u3002 \u90a3\u4e48\uff0c\u5f53\u975eroot\u7528\u6237\u6267\u884cpasswd\u8fd9\u4e2a\u53ef\u6267\u884c\u6587\u4ef6\u7684\u65f6\u5019\uff0c\u4ea7\u751f\u7684\u8fdb\u7a0b\u7684EUID\uff0c\u5c31\u662froot\u7528\u6237\u7684UID\u3002\u6362\u8a00\u4e4b\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u4ea7\u751f\u7684\u8fdb\u7a0b\uff0c\u5b9e\u9645\u4ee5root\u7528\u6237\u7684ID\u6765\u8fd0\u884c\u4e8c\u8fdb\u5236\u6587\u4ef6\u3002 \u9700\u8981\u8bf4\u660e\u7684\u662f\uff0cSUID\u6743\u9650\u5177\u6709\u65f6\u6548\u6027\uff1a\u4ec5\u5728\u6267\u884c\u8be5\u6587\u4ef6\u7684\u8fc7\u7a0b\u4e2d\u6709\u6548\u3002 \u4e8c\u3001setuid\u3001setresuid\u51fd\u6570 2.1 setuid\u51fd\u6570 \u51fd\u6570\u539f\u578b\uff1aint setuid(uid_t uid); \u5728Linux\u4e2d\uff0c setuid(uid)\u51fd\u6570\u7684\u6267\u884c\u6b65\u9aa4\u4e3a: \uff081\uff09\u5982\u679c\u7531Root\u6743\u9650\u8fdb\u7a0b\uff08EUID\u4e3a0\u7684\u8fdb\u7a0b\uff09\u8c03\u7528\uff0c\u5219\u5c06\u8fdb\u7a0b\u7684RUID\uff0cEUID\u548cSUID\u90fd\u8bbe\u7f6e\u4e3auid\uff0c\u8fd4\u56de0 \uff082\uff09\u5982\u679c\u7531\u666e\u901a\u6743\u9650\u8fdb\u7a0b\u8c03\u7528\uff0c\u4e14uid\u7b49\u4e8eRUID\u6216uid\u7b49\u4e8eSUID\uff0c\u5219\u5c06\u8fdb\u7a0b\u7684EUID\u8bbe\u7f6e\u4e3auid\uff0c\u8fd4\u56de0 \uff083\uff09\u5982\u679c\u7531\u666e\u901a\u6743\u9650\u8fdb\u7a0b\u8c03\u7528\uff0c\u4e14uid\u4e0d\u7b49\u4e8eRUID\u6216SUID\uff0c\u5219\u8bbe\u7f6eerrno\u4e3aEPERM\uff0c\u5e76\u8fd4\u56de-1\uff08\u8868\u793a\u6267\u884c\u5931\u8d25\uff09 \u4e0a\u6587\u4e2d\uff0c\u6267\u884cpassword\u7684\u8fdb\u7a0b\uff0cEUID\u662fpassword\u7684\u6240\u6709\u8005\u7684UID\uff0c\u4e5f\u5c31\u662froot\u7528\u6237\u7684UID\uff0c\u4e5f\u5c31\u662f0\u3002\u6240\u4ee5\uff0c\u5c5e\u4e8e\u60c5\u51b5\uff081\uff09\u3002 su\u6587\u4ef6\u540c\u6837\u662f-rwsr-xr-x\u6743\u9650\u3002\u6240\u4ee5\uff0c\u5b89\u5353\u4e2d\uff0c\u666e\u901a\u8fdb\u7a0b\u901a\u8fc7Runtime.getRuntime().exec(\u201csu\u201d)\uff0c\u53d1\u8d77\u4e00\u4e2ashell\u8fdb\u7a0b\uff0c\u53bb\u6267\u884csu\u7684\u65f6\u5019\uff0c\u540c\u6837\u5c5e\u4e8e\u60c5\u51b5\uff081\uff09\u3002 2.2 setresuid\u51fd\u6570 \u51fd\u6570\u539f\u578b\uff1aint setresuid(uid_t ruid, uid_t euid, uid_t suid); 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