{"id":5920,"date":"2023-04-07T17:25:02","date_gmt":"2023-04-07T08:40:02","guid":{"rendered":"https:\/\/www.inforsec.org\/wp\/?p=5920"},"modified":"2023-04-07T17:25:02","modified_gmt":"2023-04-07T08:40:02","slug":"%e3%80%90sp-2022%e8%ae%ba%e6%96%87%e5%88%86%e4%ba%ab%e3%80%91%e4%bb%a5protocol%e4%b8%ba%e4%b8%ad%e5%bf%83%e7%9a%84uefi%e5%9b%ba%e4%bb%b6smm%e6%8f%90%e6%9d%83%e6%bc%8f%e6%b4%9e%e9%9d%99%e6%80%81","status":"publish","type":"post","link":"http:\/\/202.112.238.40\/wp\/?p=5920","title":{"rendered":"\u3010S&P 2022\u8bba\u6587\u5206\u4eab\u3011\u4ee5Protocol\u4e3a\u4e2d\u5fc3\u7684UEFI\u56fa\u4ef6SMM\u63d0\u6743\u6f0f\u6d1e\u9759\u6001\u68c0\u6d4b"},"content":{"rendered":"\n

\u524d\u8a00<\/strong><\/p>\n\n\n\n

\u672c\u6587\u6839\u636e\u82f1\u6587\u539f\u6587\u201cFinding SMM Privilege-Escalation Vulnerabilities in UEFI Firmware with Protocol-Centric Static Analysis.\u201d\u6574\u7406\u64b0\u5199\u3002\u539f\u6587\u53d1\u8868\u5728IEEE Symposium on Security and Privacy. 2022\u3002\u672c\u6587\u8f83\u539f\u6587\u6709\u6240\u5220\u51cf\uff0c\u8be6\u7ec6\u5185\u5bb9\u53ef\u53c2\u8003\u539f\u6587 \u3002\u539f\u6587\u4f5c\u8005\u4e3a\u5c39\u5609\u4f1f\u3001\u674e\u5b5f\u8c6a\u3001\u5434\u709c\u3001\u5b59\u4e39\u4e39\u3001\u5468\u5efa\u534e\u3001 \u970d\u73ae\u3001\u859b\u6676\u7075\u3002<\/p>\n\n\n\n

01\u4ecb\u7ecd<\/strong><\/p>\n\n\n\n

BIOS\uff08Basic Input\/Output System\uff09\uff0c\u5373\u57fa\u672c\u8f93\u5165\u8f93\u51fa\u7cfb\u7edf\uff0c\u8d1f\u8d23\u5728\u901a\u7535\u5f15\u5bfc\u9636\u6bb5\u8fdb\u884c\u786c\u4ef6\u521d\u59cb\u5316\uff0c\u5e76\u4e3a\u64cd\u4f5c\u7cfb\u7edf\u63d0\u4f9b\u8fd0\u884c\u65f6\u670d\u52a1\u3002\u800c\u968f\u7740\u4e91\u8ba1\u7b97\u3001\u7269\u8054\u7f51\u4e3a\u4ee3\u8868\u7684\u4e92\u8054\u7f51\u7684\u5feb\u901f\u53d1\u5c55\uff0c\u8fd0\u884c\u572816\u4f4d\u5bfb\u5740\u7684\u5b9e\u6a21\u5f0f\u7684BIOS\u5df2\u7ecf\u4e0d\u80fd\u6ee1\u8db3\u8ba1\u7b97\u673a\u7cfb\u7edf\u7684\u5feb\u901f\u53d1\u5c55\u3002\u56e0\u6b64\uff0c\u82f1\u7279\u5c14\u3001AMD\u7b49\u5382\u5546\u8054\u5408\u8bbe\u8ba1\u4e86UEFI (Unified Extensible Firmware Interface\uff09\u89c4\u8303\uff0c\u5373\u53ef\u6269\u5c55\u56fa\u4ef6\u63a5\u53e3\u89c4\u8303\u3002UEFI\u89c4\u8303\u5b9a\u4e49\u4e86\u4e00\u7cfb\u5217\u64cd\u4f5c\u7cfb\u7edf\u548c\u786c\u4ef6\u4ea4\u4e92\u6240\u9700\u7684\u6807\u51c6\u63a5\u53e3\u3002UEFI\u56fa\u4ef6\u63d0\u4f9b\u4e24\u7c7b\u670d\u52a1\uff0c\u4e00\u7c7b\u662f\u542f\u52a8\u5f15\u5bfc\u670d\u52a1\uff0c\u53e6\u4e00\u7c7b\u662f\u8fd0\u884c\u65f6\u670d\u52a1\u3002\u7cfb\u7edf\u52a0\u7535\u4ee5\u540e\uff0c\u9996\u5148\u6267\u884c\u7684\u662f\u542f\u52a8\u5f15\u5bfc\u670d\u52a1\uff0c\u5176\u8d1f\u8d23\u5728\u901a\u7535\u5f15\u5bfc\u9636\u6bb5\u8fd0\u884c\u786c\u4ef6\u4ee5\u53ca\u8fd0\u884c\u65f6\u670d\u52a1\u9a71\u52a8\u521d\u59cb\u5316\u5e76\u6821\u9a8c\u56fa\u4ef6\u7684\u5b8c\u6574\u6027\u3002\u800c\u8fd0\u884c\u65f6\u670d\u52a1\u5b9e\u73b0\u64cd\u4f5c\u7cfb\u7edf\u5bf9\u4e8e\u786c\u4ef6\u7684\u5b89\u5168\u8bbf\u95ee\u63a7\u5236\uff0c\u5176\u529f\u80fd\u4e3b\u8981\u5305\u542b\uff1a\u63d0\u4f9b\u5904\u7406\u5668\u8fc7\u70ed\u4fdd\u62a4\u7b49\u5b89\u5168\u9632\u62a4\u63aa\u65bd\u3001\u7535\u6e90\u7ba1\u7406\u3001SPI Flash\u7b49\u786c\u4ef6\u8d44\u6e90\u7684\u8bbf\u95ee\u63a7\u5236\u4ee5\u53ca\u5fae\u7801\u66f4\u65b0\u3002\u5e76\u4e14\uff0cUEFI\u56fa\u4ef6\u5b9a\u4e49\u4e86\u64cd\u4f5c\u7cfb\u7edf\u548c\u5e95\u5c42\u786c\u4ef6\u7684\u5b89\u5168\u8fb9\u754c\uff0c\u56e0\u6b64UEFI\u56fa\u4ef6\u662f\u6574\u4e2a\u8ba1\u7b97\u673a\u7cfb\u7edf\u7684\u4fe1\u4efb\u57fa\u3002<\/p>\n\n\n\n

\u4e3a\u4e86\u63d0\u4f9b\u5bf9\u5916\u56f4\u786c\u4ef6\u7684\u5b89\u5168\u8bbf\u95ee\u63a7\u5236\uff0cUEFI\u56fa\u4ef6\u4e3a\u64cd\u4f5c\u7cfb\u7edf\u63d0\u4f9b\u4e86\u8bf8\u591a\u8fd0\u884c\u65f6\u670d\u52a1\uff0c\u4f8b\u5982\u7cfb\u7edf\u7535\u6e90\u7ba1\u7406\u670d\u52a1\u3001SPI\u95ea\u5b58\u8bfb\u5199\u670d\u52a1\u4ee5\u53ca\u786c\u4ef6\u9519\u8bef\u5904\u7406\u670d\u52a1\u3002\u5728Intel\u4ee5\u53caAMD\u8ba1\u7b97\u673a\u5e73\u53f0\u4e2d\uff0c\u8fd9\u4e9b\u8fd0\u884c\u65f6\u670d\u52a1\u7531\u7cfb\u7edf\u7ba1\u7406\u4e2d\u65ad (System Management Interrupt, SMI) \u5904\u7406\u7a0b\u5e8f\u63d0\u4f9b\u3002SMI\u5904\u7406\u7a0b\u5e8f\u5177\u6709\u5bf9\u7cfb\u7edf\u5e95\u5c42\u786c\u4ef6\u7684\u8bbf\u95ee\u63a7\u5236\u80fd\u529b\uff0c\u8fd9\u4e5f\u4f7f\u5f97SMI\u5904\u7406\u7a0b\u5e8f\u6210\u4e3a\u6076\u610f\u653b\u51fb\u8005\u7684\u91cd\u8981\u653b\u51fb\u76ee\u6807\u3002\u5e76\u4e14\uff0c\u6700\u8fd1\u7684\u7814\u7a76\u8868\u660e\uff0c\u5229\u7528\u5546\u7528UEFI\u56fa\u4ef6\u7684SMI\u5904\u7406\u7a0b\u5e8f\u4e2d\u5b58\u5728\u7684\u8fd0\u884c\u65f6\u670d\u52a1\u6f0f\u6d1e\uff0c\u653b\u51fb\u8005\u53ef\u4ee5\u5bf9\u8ba1\u7b97\u673a\u7cfb\u7edf\u7684\u5173\u952e\u5e95\u5c42\u786c\u4ef6\uff0c\u4f8b\u5982SPI Flash\u4ee5\u53ca\u7535\u6e90\u7ba1\u7406\u7b49\u5b9e\u65bd\u653b\u51fb\u3002<\/p>\n\n\n\n

\u4e3a\u4e86\u4fdd\u62a4UEFI\u56fa\u4ef6\u63d0\u4f9b\u7684\u8fd0\u884c\u65f6\u670d\u52a1\u7684\u5b89\u5168\u8fd0\u884c\uff0c\u5728\u57fa\u4e8eIntel\u548cAMD\u7684\u5e73\u53f0\u4e2d\uff0cUEFI\u56fa\u4ef6\u57fa\u4e8eCPU\u4ee5\u53ca\u5185\u5b58\u5b9e\u73b0\u4e86\u786c\u4ef6\u9694\u79bb\u673a\u5236\u4ee5\u5b9e\u73b0\u5bf9\u8fd0\u884c\u65f6\u670d\u52a1\u7684\u8bbf\u95ee\u63a7\u5236\u3002\u57fa\u4e8eCPU\uff0cIntel\u4ee5\u53caAMD\u5b9e\u73b0\u4e86\u540d\u4e3a\u7cfb\u7edf\u7ba1\u7406\u6a21\u5f0f\uff08System Management Mode\uff0cSMM\uff09\u7684CPU\u8fd0\u884c\u6a21\u5f0f\uff0cSMM\u6a21\u5f0f\u5177\u6709\u6bd4\u5185\u6838\u6a21\u5f0f\u66f4\u9ad8\u7684\u7279\u6743\u7ea7\u522b\uff0c\u662fCPU\u7684\u6700\u9ad8\u8fd0\u884c\u6743\u9650\uff0c\u8fd0\u884c\u5728\u5185\u6838\u6a21\u5f0f\u4e0b\u7684\u5185\u6838\u9a71\u52a8\u7a0b\u5e8f\u53ea\u80fd\u901a\u8fc7SMI\u4e2d\u65ad\u6765\u8bbf\u95ee\u8fd0\u884c\u5728SMM\u6a21\u5f0f\u4e0b\u7684UEFI\u56fa\u4ef6\u8fd0\u884c\u65f6\u670d\u52a1\u3002<\/p>\n\n\n\n

\u540c\u65f6\uff0cUEFI\u56fa\u4ef6\u5728\u7269\u7406\u5185\u5b58\u7a7a\u95f4\u4e2d\u4fdd\u7559\u4e86\u4e00\u4e2a\u540d\u4e3a\u7cfb\u7edf\u7ba1\u7406RAM (System Management Memory, SMRAM\uff09\u7684\u4e13\u7528\u5185\u5b58\u533a\u57df\uff0cSMRAM\u53ea\u80fd\u7531\u8fd0\u884c\u5728SMM\u6a21\u5f0f\u4e0b\u7684\u8fd0\u884c\u65f6\u670d\u52a1\u6240\u8bbf\u95ee\uff0c\u65e0\u6cd5\u7531\u5185\u6838\u6001\u7a0b\u5e8f\u8bbf\u95ee\u6216\u4fee\u6539\u3002<\/p>\n\n\n\n

\u867d\u7136\u8ba1\u7b97\u673a\u7cfb\u7edf\u90e8\u7f72\u4e86\u57fa\u4e8eCPU\u4ee5\u53ca\u7269\u7406\u5185\u5b58\u5b9e\u73b0\u7684\u5b89\u5168\u8bbf\u95ee\u63a7\u5236\uff0c\u4f46\u662f\u8fd0\u884c\u4e8eCPU\u6700\u9ad8\u6743\u9650\u4e0b\u7684\u8fd0\u884c\u65f6\u670d\u52a1\u7a0b\u5e8f\u4ecd\u7136\u66b4\u9732\u51fa\u4e25\u91cd\u7684\u653b\u51fb\u9762\u3002\u4f8b\u5982\uff0c\u7531\u4e8e\u4e0d\u5b8c\u5584\u7684\u8f93\u5165\u9a8c\u8bc1\u5bfc\u81f4\u7684\u5185\u6838\u6a21\u5f0f\u5230 SMM\u6a21\u5f0f\u7684\u6743\u9650\u63d0\u5347\u6f0f\u6d1e\u3002\u5728\u8fc7\u53bb\u7684\u51e0\u5e74\u91cc\uff0c\u4e00\u4e9bSMM\u6743\u9650\u63d0\u6f0f\u6d1e\u5df2\u7ecf\u88abUEFI\u56fa\u4ef6\u5b89\u5168\u7814\u7a76\u4eba\u5458\u76f8\u7ee7\u62ab\u9732\u3002\u653b\u51fb\u8005\u53ef\u4ee5\u5229\u7528\u9762\u5411\u8df3\u8f6c\u7684\u7f16\u7a0b(JOP\uff09\u7684\u65b9\u5f0f\u7ed5\u8fc7\u8fd0\u884c\u65f6\u670d\u52a1\u4e2d\u90e8\u7f72\u7684\u57fa\u4e8e\u8f6f\u4ef6\u7684\u7f13\u89e3\u673a\u5236\u3002\u4f8b\u5982 DEP\/NX\uff08\u6570\u636e\u4e0d\u53ef\u6267\u884c\uff09\u4ee5\u53caSMM_CODE_CHK\u7684\u4fdd\u62a4\u673a\u5236\u3002<\/p>\n\n\n\n

\u5176\u4e2d\uff0cSMM_CODE_CHK\u7528\u4e8e\u9632\u6b62SMRAM\u4e2d\u7684\u8fd0\u884c\u65f6\u670d\u52a1\u6267\u884cSMRAM\u4e4b\u5916\u7684\u4ee3\u7801\uff0cSMM_CODE_CHK\u7c7b\u4f3c\u4e8e\u5185\u6838\u6001\u9a71\u52a8\u7a0b\u5e8f\u7684\u7ba1\u7406\u6a21\u5f0f\u6267\u884c\u4fdd\u62a4(System Management Execution Protection, SMEP)\u3002\u5e76\u4e14\u7531\u4e8eUEFI\u56fa\u4ef6\u8fd0\u884c\u65f6\u670d\u52a1\u7684\u8fd0\u884c\u8d44\u6e90\u6709\u9650\uff0c\u76ee\u524d\u5546\u7528\u8ba1\u7b97\u673a\u7cfb\u7edf\u4e0a\u7684UEFI\u56fa\u4ef6\u5927\u591a\u6ca1\u6709\u90e8\u7f72\u8bf8\u5982DEP\/NX\u7b49\u7f13\u89e3\u673a\u5236\u3002\u56e0\u6b64\uff0c\u57fa\u4e8e\u76ee\u524dUEFI\u56fa\u4ef6\u8fd0\u884c\u65f6\u670d\u52a1\u9632\u62a4\u63aa\u65bd\u7f3a\u5931\u7684\u73b0\u72b6\uff0c\u82f1\u7279\u5c14\u63d0\u51fa\u4e86\u51e0\u79cd\u57fa\u4e8e\u786c\u4ef6\u7684\u7f13\u89e3\u673a\u5236\uff08\u4f8b\u5982\uff0cSMI Transfer Monitor, STM \uff09\u3002\u7136\u800c\uff0c\u6b63\u5982Intel 2020 \u5e74\u767d\u76ae\u4e66\u4e2d\u6240\u8ff0\uff0c\u201c\u5927\u591a\u6570\u5f53\u524d\u7684 BIOS \u4e0d\u652f\u6301 STM \u6216\u5176\u4ed6 SMM \u76d1\u89c6\u5668\u201d\uff0c\u56e0\u6b64\u603b\u7ed3\u5f53\u524dSMM\u63d0\u6743\u6f0f\u6d1e\u6210\u56e0\u7279\u5f81\u5e76\u4e14\u57fa\u4e8e\u6240\u63d0\u53d6\u7684\u6f0f\u6d1e\u6210\u56e0\u4ee5\u53ca\u4ee3\u7801\u7279\u5f81\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u81ea\u52a8\u5316\u7684SMM\u63d0\u6743\u6f0f\u6d1e\u9759\u6001\u68c0\u6d4b\u5de5\u5177\u662f\u5177\u6709\u8feb\u5207\u9700\u6c42\u548c\u4ef7\u503c\u7684\u3002<\/p>\n\n\n\n

\u9488\u5bf9\u5f53\u524dUEFI\u56fa\u4ef6\u6f0f\u6d1e\u7814\u7a76\u7f3a\u5931\u7684\u73b0\u72b6\uff0c\u672c\u6587\u5bf9 UEFI \u56fa\u4ef6\u4e2d\u5b58\u5728\u7684 SMM \u6743\u9650\u63d0\u5347\u6f0f\u6d1e\u8fdb\u884c\u4e86\u7cfb\u7edf\u7814\u7a76\u3002\u901a\u8fc7\u5206\u6790\uff0c\u672c\u6587\u53d1\u73b0\uff0c\u5c3d\u7ba1\u5728\u73b0\u4ee3CPU\u4e2d\u90e8\u7f72\u4e86\u8bf8\u5982\u6743\u9650\u63a7\u5236\u7b49\u786c\u4ef6\u9694\u79bb\u4ee5\u53caSMM_CODE_CHK\u7b49\u6f0f\u6d1e\u7f13\u89e3\u673a\u5236\uff0c\u7136\u800c\uff0c\u653b\u51fb\u8005\u4ecd\u53ef\u4ee5\u5229\u7528SMI\u5904\u7406\u7a0b\u5e8f\u5b58\u5728\u7684\u6f0f\u6d1e\u7ed5\u8fc7\u73b0\u6709\u7684\u6f0f\u6d1e\u9632\u62a4\u673a\u5236\uff0c\u8fdb\u800c\u5b9e\u73b0SMM\u63d0\u6743\u653b\u51fb\u3002\u5e76\u4e14\uff0c\u8fd0\u884c\u5728\u5904\u7406\u5668\u7684\u6700\u9ad8\u7279\u6743\u4e0b\u8fd0\u884c\u65f6\u670d\u52a1\u4ee5\u4f4e\u7279\u6743\u53ef\u63a7\u6570\u636e\u4f5c\u4e3a\u8f93\u5165\uff0c\u76ee\u524d\u7f3a\u4e4f\u76f8\u5e94\u4fdd\u62a4\u673a\u5236\u786e\u4fdd\u4f4e\u6743\u9650\u53ef\u63a7\u6570\u636e\u5df2\u7ecf\u8fc7\u5b8c\u5907\u7684\u6709\u6548\u6027\u9a8c\u8bc1\u3002\u5e76\u4e14\uff0c\u4ece\u8fd0\u884c\u4e8eCPU\u6700\u9ad8\u7279\u6743(ring -2\uff09\u4e0b\u7684SMI \u5904\u7406\u7a0b\u5e8f\u8fd0\u884c\u5728CPU\u6700\u9ad8\u7279\u6743(ring -2\uff09\u7ea7\u522b\u4e0b\uff0c\u56e0\u6b64\uff0c\u5bf9\u4e8eSMI\u5904\u7406\u7a0b\u5e8f\u6765\u8bf4\uff0c\u53ef\u4ee5\u88ab\u64cd\u4f5c\u7cfb\u7edf\u6743\u9650(ring 0\uff09\u7684\u5185\u6838\u6001\u7a0b\u5e8f\u8bbf\u95ee\u63a7\u5236\u7684\u6570\u636e\u88ab\u8ba4\u4e3a\u662f\u4e0d\u53d7\u4fe1\u4efb\u7684\u3002\u5982\u679cSMI\u5904\u7406\u7a0b\u5e8f\u4f7f\u7528\u4e86\u6ca1\u6709\u7ecf\u8fc7\u5b8c\u5584\u5b89\u5168\u6821\u9a8c\u7684\u4e0d\u53ef\u4fe1\u6570\u636e\uff0c\u5e76\u4e14\u4e0d\u53ef\u4fe1\u6570\u636e\u5f71\u54cd\u4e86SMI\u5904\u7406\u7a0b\u5e8f\u7684\u63a7\u5236\u6d41\u6216\u6570\u636e\u6d41\uff0c\u5219\u53ef\u80fd\u5f15\u5165\u8f93\u5165\u9a8c\u8bc1\u4e0d\u5f53\u5bfc\u81f4\u7684\u6f0f\u6d1e\uff0c\u6b64\u7c7b\u6f0f\u6d1e\u53ef\u80fd\u88ab\u7528\u6765\u52ab\u6301SMI \u5904\u7406\u7a0b\u5e8f\u7684\u63a7\u5236\u6d41\uff0c\u8fdb\u800c\u5b9e\u73b0\u6743\u9650\u63d0\u5347\u653b\u51fb\u3002<\/p>\n\n\n\n

\u6b64\u5916\uff0c\u672c\u6587\u8fd8\u57fa\u4e8eUEFI\u89c4\u8303\u5bf9SMI\u5904\u7406\u7a0b\u5e8f\u7684\u6267\u884c\u6a21\u578b\u8fdb\u884c\u4e86\u6df1\u5165\u5730\u603b\u7ed3\u548c\u5206\u6790\u3002\u5728\u6b64\u8fc7\u7a0b\u4e2d\uff0c\u672c\u6587\u53d1\u73b0\u9664\u4e86\u4e0a\u8ff0\u4e0d\u53ef\u4fe1\u6570\u636e\u5f15\u5165\u7684\u6f0f\u6d1e\uff0cSMI\u5904\u7406\u7a0b\u5e8f\u4e2d\u8fd8\u5b58\u5728\u4f7f\u7528UEFI\u56fa\u4ef6\u542f\u52a8\u9636\u6bb5\u5728\u975eSMRAM\u533a\u57df\u521b\u5efa\u548c\u521d\u59cb\u5316\u7684\u5bf9\u8c61\u7684\u60c5\u51b5\uff0c\u7531\u4e8e\u975eSMRAM\u533a\u57df\u7684\u5bf9\u8c61\u5185\u5bb9\u53ef\u4ee5\u88ab\u8fd0\u884c\u4e8e\u5185\u6838\u6001\u6743\u9650\u7684\u5185\u6838\u9a71\u52a8\u7a0b\u5e8f\u6240\u4fee\u6539\uff0c\u56e0\u6b64\uff0c\u5177\u6709\u5185\u6838\u6743\u9650\u7684\u653b\u51fb\u8005\u53ef\u4ee5\u901a\u8fc7\u63a7\u5236\u8fd9\u90e8\u5206\u6570\u636e\u5f71\u54cd\u76ee\u524dSMI\u5904\u7406\u7a0b\u5e8f\u7684\u6267\u884c\u72b6\u6001\uff0c\u8fdb\u800c\u5b9e\u73b0SMM\u63d0\u6743\u653b\u51fb\u3002\u672c\u6587\u5c06\u975eSMRAM\u533a\u57df\u521b\u5efa\u548c\u521d\u59cb\u5316\u7684\u5bf9\u8c61\u7684\u5f15\u7528\u79f0\u4e3a\u9003\u9038\u5f15\u7528(Escaped reference)\uff0c\u4e0d\u7b26\u5408\u5b89\u5168\u89c4\u8303\u7684\u9003\u9038\u5f15\u7528\u53ef\u80fd\u4f1a\u5728SMI\u5904\u7406\u7a0b\u5e8f\u4e2d\u5f15\u5165SMM\u63d0\u6743\u6f0f\u6d1e\u3002\u901a\u8fc7\u5bf9\u5546\u7528UEFI\u56fa\u4ef6\u7684\u9006\u5411\u5206\u6790\uff0c\u4ee5\u53ca\u5bf9SMI\u5904\u7406\u7a0b\u5e8f\u7684\u6267\u884c\u6a21\u578b\u7684\u6df1\u5165\u5206\u6790\uff0c\u57fa\u4e8e\u9003\u9038\u5f15\u5165\u7684\u521b\u5efa\u3001\u521d\u59cb\u5316\u4ee5\u53ca\u4f7f\u7528\u65b9\u5f0f\uff0c\u672c\u6587\u5206\u7c7b\u603b\u7ed3\u4e86\u4e24\u79cd\u7c7b\u578b\u7684\u9003\u9038\u5f15\u7528\uff0c\u9057\u7559\u5f15\u7528(Legacy Reference\uff09\u548c\u975e\u9884\u671f\u5f15\u7528(Unintential reference)\u3002\u6b64\u5916\uff0c\u901a\u8fc7\u5206\u7c7b\u603b\u7ed3\uff0c\u672c\u6587\u7ed9\u51fa\u4e86SMM\u63d0\u6743\u6f0f\u6d1e\u7684\u5b9a\u4e49\uff0c\u5e76\u4ee5\u8be5\u5b9a\u4e49\u4e3a\u57fa\u7840\uff0c\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u4e86\u7528\u4e8e\u68c0\u6d4b\u8fd0\u884c\u65f6\u670d\u52a1\u6f0f\u6d1e\u7684\u9759\u6001\u5206\u6790\u6846\u67b6\u3002<\/p>\n\n\n\n

\u7531\u4e8eUEFI\u56fa\u4ef6\u6620\u50cf\u662f\u53bb\u6389\u7b26\u53f7\u7684\u4e8c\u8fdb\u5236\u6587\u4ef6\uff0c\u5e76\u4e14UEFI\u56fa\u4ef6\u4e2d\u5b58\u5728\u5927\u91cf\u57fa\u4e8e\u56de\u8c03(Callback\uff09\u673a\u5236\u5b9e\u73b0\u7684\u8de8\u6587\u4ef6\u7684\u95f4\u63a5\u8c03\u7528\u3002\u5728\u56de\u8c03\u673a\u5236\u4e0b\uff0c\u4e00\u4e9b\u51fd\u6570\u5730\u5740\u88ab\u5b58\u50a8\u5230\u540d\u4e3aProtocol\u7684\u7ed3\u6784\u4f53\u5bf9\u8c61\u4e2d\uff0c\u800c\u6bcf\u4e00\u4e2a\u4e0d\u540c\u7684Protocol\u7ed3\u6784\u4f53\u5747\u7531\u4e00\u4e2a\u5168\u5c40\u552f\u4e00\u6807\u8bc6\u7b26(Globally Unique Identifiers, GUID\uff09\u6240\u6807\u8bc6\u3002\u5f53\u524d\u9759\u6001\u5206\u6790\u65e0\u6cd5\u51c6\u786e\u8bc6\u522b\u57fa\u4e8eProtocol-callback\u673a\u5236\u5b9e\u73b0\u7684\u8de8\u6587\u4ef6\u7684\u95f4\u63a5\u8c03\u7528\u7684\u76ee\u6807\u51fd\u6570\uff0c\u8fdb\u800c\u9020\u6210\u5927\u91cf\u6f0f\u62a5\u3002<\/p>\n\n\n\n

\u9488\u5bf9\u8fd9\u6837\u7684\u95ee\u9898\uff0c\u63d0\u51fa\u4e86\u4ee5Protocol\u4e3a\u4e2d\u5fc3\u7684UEFI\u56fa\u4ef6\u63d0\u6743\u6f0f\u6d1e\u9759\u6001\u5206\u6790\u65b9\u6cd5\u6765\u68c0\u6d4bUEFI\u56fa\u4ef6\u4e2d\u5b58\u5728\u7684SMM\u63d0\u6743\u6f0f\u6d1e\u3002\u57fa\u4e8e\u6240\u63d0\u51fa\u7684\u65b9\u6cd5\u672c\u6587\u5b9e\u73b0\u4e86\u540d\u4e3aSPENDER\u7684\u9759\u6001\u5206\u6790\u6846\u67b6\uff0c\u5176\u7528\u4e8e\u9ad8\u6548\u3001\u51c6\u786e\u5730\u53d1\u73b0UEFI\u56fa\u4ef6\u4e2d\u9690\u85cf\u7684SMM\u6743\u9650\u63d0\u5347\u6f0f\u6d1e\u3002SPENDER \u5728\u5bf91148\u4e2a\u65e0\u7b26\u53f7\u5546\u7528UEFI\u56fa\u4ef6\u955c\u50cf\u7684\u9759\u6001\u5206\u6790\u8fc7\u7a0b\u4e2d\uff0c\u603b\u5171\u53d1\u73b0\u4e8636 \u4e2a\u6f0f\u6d1e\uff08\u5305\u62ec\u4e24\u4e2a\u5148\u524d\u5df2\u77e5\u7684 1-day \u6f0f\u6d1e\u548c 34 \u4e2a\u672a\u77e5\u7684 0-day \u6f0f\u6d1e\uff09\uff0c\u5728\u68c0\u6d4b\u8fc7\u7a0b\u4e2d\uff0cSPENDER\u7684\u8bef\u62a5\u7387\u4e3a 10%\uff0cSPENDER\u5206\u6790\u4e00\u4e2a SMI \u5904\u7406\u7a0b\u5e8f\u7684\u5e73\u5747\u65f6\u95f4\u4e3a12.46\u79d2\u3002<\/p>\n\n\n\n

02\u80cc\u666f<\/strong><\/p>\n\n\n\n

1. UEFI\u56fa\u4ef6\u4e0eSMM\u9a71\u52a8<\/strong><\/p>\n\n\n\n

UEFI\u56fa\u4ef6\u4e3b\u8981\u5305\u542b\u4e94\u4e2a\u6a21\u5757\uff1a\u5b89\u5168(Security, SEC\uff09\u6a21\u5757\u3001EFI\u9884\u521d\u59cb\u5316(Pre-EFI Initialization, PEI\uff09\u6a21\u5757\u3001\u9a71\u52a8\u7a0b\u5e8f\u6267\u884c\u73af\u5883(Driver Execution Environment, DXE\uff09\u6a21\u5757\u3001\u7cfb\u7edf\u7ba1\u7406(System Management Mode, SMM\uff09\u6a21\u5757\u548c\u5f15\u5bfc\u8bbe\u5907\u9009\u62e9(Boot Device Selection, BDS\uff09\u6a21\u5757\u3002\u5176\u4e2d\uff0cSMM\u6a21\u5757\u7531\u4e00\u7cfb\u5217SMM\u9a71\u52a8\u7a0b\u5e8f\u7ec4\u6210\uff0cSMM\u9a71\u52a8\u7a0b\u5e8f\u4e2d\u5305\u542b\u4e00\u7cfb\u5217SMI\u5904\u7406\u7a0b\u5e8f\uff0c\u6b63\u5982\u524d\u6587\u6240\u8ff0\uff0cSMI\u5904\u7406\u7a0b\u5e8f\u4e3a\u4e0a\u5c42\u64cd\u4f5c\u7cfb\u7edf\u63d0\u4f9b\u8bb8\u591a\u8fd0\u884c\u65f6\u670d\u52a1\uff0c\u4ee5\u5b9e\u73b0\u5bf9\u6574\u4e2a\u8ba1\u7b97\u673a\u7cfb\u7edf\u81f3\u5173\u91cd\u8981\u7684\u5916\u56f4\u786c\u4ef6\u7684\u5b89\u5168\u8bbf\u95ee\u63a7\u5236\u3002<\/p>\n\n\n\n

2.SMM\u9a71\u52a8\u6267\u884c\u6a21\u578b<\/strong><\/p>\n\n\n\n

\u56fe 1\u63cf\u8ff0\u4e86SMM\u9a71\u52a8\u7684\u6267\u884c\u6a21\u578b\uff0cSMM\u9a71\u52a8\u7684\u6574\u4e2a\u751f\u547d\u5468\u671f\u4e3b\u8981\u5206\u6210\u4e24\u4e2a\u9636\u6bb5\uff1a\u542f\u52a8\u9636\u6bb5\u00a0(Boot Phase) \u548c\u8fd0\u884c\u65f6\u9636\u6bb5 (Runtime Phase)\u3002\u00a0<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u56fe 1 SMM\u9a71\u52a8\u6267\u884c\u6a21\u578b<\/strong><\/p>\n\n\n\n

l \u542f\u52a8\u9636\u6bb5\uff1a\u5728\u542f\u52a8\u9636\u6bb5\uff0c\u5982\u56fe 1(a\uff09\u6240\u793a\uff0cUEFI\u56fa\u4ef6\u5229\u7528DXE\u6a21\u5757\u7684\u521d\u59cb\u5316\u51fd\u6570 (Initialization function) \u6267\u884c\u4e09\u4e2a\u521d\u59cb\u5316\u64cd\u4f5c\u3002\u9996\u5148\uff0cDXE\u6a21\u5757\u5206\u914d\u548c\u521d\u59cb\u5316\u6570\u636e\u5bf9\u8c61\uff08\u672c\u6587\u79f0\u4e3aBoot-only\u5bf9\u8c61\uff09\uff0c\u5728\u672c\u6587\u4e2d\uff0c\u6211\u4eec\u5c06 Boot-only\u5bf9\u8c61\u6240\u5728\u7684\u5185\u5b58\u533a\u57df\uff0c\u79f0\u4e3aDXE-DATA \u533a\u57df(\u2460)\uff0cDXE-DATA\u533a\u57df\u4f4d\u4e8eSMRAM \u4e4b\u5916\u3002\u5176\u6b21\uff0cDXE\u6a21\u5757\u5229\u7528Boot-only\u6570\u636e\u5bf9\u8c61\u8c03\u7528SMM\u6a21\u5757\u4e2d\u7684\u521d\u59cb\u5316\u51fd\u6570\uff0c\u8be5\u521d\u59cb\u5316\u51fd\u6570\u4f1a\u5c06\u6240\u6709SMM\u9a71\u52a8\u52a0\u8f7d\u5230SMRAM\u4e2d\u5e76\u6267\u884c\u5df2\u52a0\u8f7dSMM\u9a71\u52a8\u7684\u521d\u59cb\u5316\u51fd\u6570\uff08\u2461\uff09\u3002\u6700\u540e\uff0cDXE \u6a21\u5757\u4f1a\u5c06SMRAM\u9501\u5b9a\uff0c\u81f3\u6b64\uff0cSMRAM\u65e0\u6cd5\u88ab\u8fd0\u884c\u4e8e\u5185\u6838\u6743\u9650\u7684\u5185\u6838\u9a71\u52a8\u4ee3\u7801\u6240\u8bbf\u95ee\uff08\u2462\uff09\u3002<\/p>\n\n\n\n

l \u8fd0\u884c\u9636\u6bb5\uff1a\u5728\u8fd0\u884c\u65f6\u9636\u6bb5\uff0c\u5982\u56fe 1(b\uff09\u6240\u793a\uff0c\u8fd0\u884c\u4e8e\u5185\u6838\u6743\u9650\u7684\u5185\u6838\u9a71\u52a8\u4ee3\u7801\u901a\u8fc7\u5982\u4e0b\u4e09\u4e2a\u6b65\u9aa4\u4e0eSMI\u5904\u7406\u7a0b\u5e8f\u8fdb\u884c\u4ea4\u4e92\u3002\u9996\u5148(\u6b65\u9aa41)\uff0c\u5185\u6838\u9a71\u52a8\u4ee3\u7801\u5728CommBuffer \u4e2d\u586b\u5145SMI\u5904\u7406\u7a0b\u5e8f\u6267\u884c\u6240\u9700\u7684\u4e0a\u4e0b\u6587\u4fe1\u606f\uff0c\u4f8b\u5982SMI\u5904\u7406\u7a0b\u5e8f\u5e8f\u53f7\u4ee5\u53ca\u6240\u9700\u8f93\u5165\u6570\u636e\u7b49\u3002CommBuffer\u662f\u4e00\u4e2a\u5206\u914d\u5728DXE-DATA\u533a\u57df\u7684\u7f13\u51b2\u533a\uff0c\u5185\u6838\u6743\u9650\u4e0b\u7684\u9a71\u52a8\u7a0b\u5e8f\u5229\u7528\u8be5\u7f13\u51b2\u533a\u5b58\u50a8SMI\u5904\u7406\u7a0b\u5e8f\u6267\u884c\u7684\u4e0a\u4e0b\u6587\u4fe1\u606f\uff0c\u5e76\u4e3aSMI\u5904\u7406\u7a0b\u5e8f\u63d0\u4f9b\u8f93\u5165\u3002SMI\u5904\u7406\u7a0b\u5e8f\u5229\u7528\u8be5\u7f13\u51b2\u533a\u4e3a\u8fd0\u884c\u5728\u5185\u6838\u6743\u9650\u4e0b\u7684\u7a0b\u5e8f\u8fd4\u56de\u4e2d\u65ad\u8bf7\u6c42\u7ed3\u679c\u3002\u4e4b\u540e(\u6b65\u9aa4\u4e8c\uff09\uff0c\u8fd0\u884c\u5728\u5185\u6838\u6743\u9650\u4e0b\u7684\u9a71\u52a8\u7a0b\u5e8f \u89e6\u53d1SMI\u4e2d\u65ad\uff0c\u5f53CPU\u63a5\u6536\u5230SMI \u4e2d\u65ad\u65f6\uff0cCPU\u4f1a\u5c06\u81ea\u8eab\u6743\u9650\u63d0\u5347\u5230SMM\u6743 \u9650\uff0c\u5e76\u8c03\u7528\u5b58\u50a8\u5728SMRAM\u4e2d\u7684\u540d\u4e3a SMM dispatcher\u7684\u51fd\u6570\u3002SMM dispatcher\u51fd\u6570\u4f1a\u6839\u636eCommBuffer\u4e2d\u4fdd\u5b58\u7684SMI handler\u5e8f\u53f7\uff0c\u8c03\u7528\u76f8\u5e94\u7684SMI handler\uff0c\u4ee5\u54cd\u5e94\u5185\u6838\u6743\u9650\u4e0b\u5185\u6838\u9a71\u52a8\u7a0b\u5e8f\u7684\u76f8\u5e94\u8bf7\u6c42\u3002<\/p>\n\n\n\n

 \uff08\u672c\u6587\u53ea\u9009\u53d6\u539f\u6587\u4e2d\u90e8\u5206\u7ae0\u8282\uff0c\u66f4\u591a\u7cbe\u5f69\u5185\u5bb9\u656c\u8bf7\u671f\u5f85\u540e\u7eed\u51fa\u7248\u7684\u300a\u7f51\u7edc\u5b89\u5168\u7814\u7a76\u8fdb\u5c55\u300b\uff09<\/em><\/p>\n\n\n\n

\u4f5c\u8005\u7b80\u4ecb<\/strong><\/p>\n\n\n\n

\u5c39\u5609\u4f1f\uff0c\u4e2d\u56fd\u79d1\u5b66\u9662\u4fe1\u606f\u5de5\u7a0b\u7814\u7a76\u6240\u5728\u8bfb\u535a\u58eb\u751f\u3002\u4e3b\u8981\u7814\u7a76\u9886\u57df\u4e3a\u8ba1\u7b97\u673a\u53ef\u4fe1\u57fa\u7684\u653b\u9632\u6280\u672f\u3002\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u4e86UEFI\u6f0f\u6d1e\u81ea\u52a8\u5316\u68c0\u6d4b\u5de5\u5177\uff0c\u8be5\u5de5\u4f5c\u5df2\u7ecf\u53d1\u8868\u4e8eS&P 2022\uff08CCF A\uff09\u3002\u8fc4\u4eca\u4e3a\u6b62\uff0c\u5171\u6316\u6398UEFI\u96f6\u65e5\u6f0f\u6d1e146\u4e2a\uff0c\u83b7\u5f97CVE\u7f16\u53f768\u4e2a\uff0c\u6d89\u53caMicrosoft\uff0cIntel\uff0cAMD\uff0cLenovo\uff0cHP\uff0cDell, Insyde\u4ee5\u53caASUS\u7b49\u5382\u5546\uff1b\u5229\u7528\u6240\u6316\u6398\u5230\u7684\u96f6\u65e5\u6f0f\u6d1e\u83b7\u5f97Google\uff0cIntel\uff0cLenovo\uff0cHP\uff0cDell\uff0cInsyde\u4ee5\u53caASUS\u7b49\u5382\u5546\u516c\u5f00\u81f4\u8c22\u3002\u83b7\u5f97Intel\u9ad8\u5371\u5386\u53f2\u6f0f\u6d1e\u79ef\u5206\u7b2c\u4e00\u3001Intel\u5168\u7403\u5b89\u5168\u540d\u4eba\u699c\u7b2c\u4e8c\u3001Dell\u5b89\u5168\u7814\u7a76\u4eba\u5458\u540d\u4eba\u5802\u5168\u7403\u6392\u540d\u7b2c\u4e00\u7684\u6210\u7ee9\uff1b\u5165\u9009ASUS\u5168\u7403\u5b89\u5168\u7814\u7a76\u4eba\u5458\u540d\u4eba\u5802\u3001\u5fae\u8f6f2022\u7b2c\u4e09\u5b63\u5ea6LeaderBorad\u3002\u5229\u7528\u6316\u6398\u5230\u7684UEFI\u56fa\u4ef6\u96f6\u65e5\u6f0f\u6d1e\uff0c\u53c2\u52a02019\u5e74\u5929\u5e9c\u676f\u539f\u521b\u6f0f\u6d1e\u6f14\u793a\u590d\u73b0\u8d5b\uff0c\u6210\u529f\u6f14\u793a\u590d\u73b0\uff1b\u6316\u6398\u534e\u4e3a\u9cb2\u9e4f\u670d\u52a1\u5668\u6f0f\u6d1e\uff0c\u83b7\u5f97\u534e\u4e3a\u9cb2\u9e4f2021\u5e74\u5ea6\u516c\u5f00\u81f4\u8c22\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

BIOS\uff08Basic Input\/Output System\uff09\uff0c\u5373\u57fa\u672c\u8f93\u5165\u8f93\u51fa\u7cfb\u7edf\uff0c\u8d1f\u8d23\u5728\u901a\u7535\u5f15\u5bfc\u9636\u6bb5\u8fdb\u884c\u786c\u4ef6\u521d\u59cb\u5316\uff0c\u5e76\u4e3a\u64cd\u4f5c\u7cfb\u7edf\u63d0\u4f9b\u8fd0\u884c\u65f6\u670d\u52a1\u3002\u800c\u968f\u7740\u4e91\u8ba1\u7b97\u3001\u7269\u8054\u7f51\u4e3a\u4ee3\u8868\u7684\u4e92\u8054\u7f51\u7684\u5feb\u901f\u53d1\u5c55\uff0c\u8fd0\u884c\u572816\u4f4d\u5bfb\u5740\u7684\u5b9e\u6a21\u5f0f\u7684BIOS\u5df2\u7ecf\u4e0d\u80fd\u6ee1\u8db3\u8ba1\u7b97\u673a\u7cfb\u7edf\u7684\u5feb\u901f\u53d1\u5c55\u3002 Continue reading → <\/span><\/a><\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-5920","post","type-post","status-publish","format-standard","hentry","category-research"],"_links":{"self":[{"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5920","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5920"}],"version-history":[{"count":1,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5920\/revisions"}],"predecessor-version":[{"id":5922,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts\/5920\/revisions\/5922"}],"wp:attachment":[{"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5920"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5920"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5920"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}