{"id":2550,"date":"2018-06-13T00:28:11","date_gmt":"2018-06-13T00:28:11","guid":{"rendered":"https:\/\/www.inforsec.org\/wp\/?p=2550"},"modified":"2018-06-13T00:43:54","modified_gmt":"2018-06-13T00:43:54","slug":"deadline%ef%bc%9a%e4%b8%80%e4%b8%aa%e5%af%b9%e5%86%85%e6%a0%b8%e4%b8%addouble-fetch%e9%94%99%e8%af%af%e8%bf%9b%e8%a1%8c%e7%b2%be%e7%a1%ae%e6%a3%80%e6%b5%8b%e7%9a%84%e5%b7%a5%e5%85%b7","status":"publish","type":"post","link":"http:\/\/202.112.238.40\/wp\/?p=2550","title":{"rendered":"DEADLINE\uff1a\u4e00\u4e2a\u5bf9\u5185\u6838\u4e2ddouble-fetch\u9519\u8bef\u8fdb\u884c\u7cbe\u786e\u68c0\u6d4b\u7684\u5de5\u5177"},"content":{"rendered":"<p style=\"text-align: left;\"><strong>Precise and Scalable Detection of Double-Fetch Bugs in OS Kernels<\/strong><\/p>\n<p><strong>\u4f5c\u8005\uff1a\u502a\u8fdc\u4e1c \uff08\u6e05\u534e\u5927\u5b66\uff09<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u8bba\u6587\u53d1\u8868\u4e8e\u00a0<\/span>IEEE S&amp;P 2018\uff0c<span style=\"font-weight: 400;\">\u539f\u6587\u4f5c\u8005\uff1aMeng Xu, Chenxiong Qian, Kangjie Lu, Michael Backes, Taesoo Kim<\/span><\/p>\n<p><strong>\u6458\u8981<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u64cd\u4f5c\u7cfb\u7edf\u7684\u5185\u6838\u5728\u7cfb\u7edf\u8c03\u7528\u7684\u6267\u884c\u671f\u95f4\u53ef\u80fd\u591a\u6b21\u8bfb\u53d6\u540c\u4e00\u5757\u7528\u6237\u7a7a\u95f4\u7684\u5185\u5b58\uff0c\u82e5\u4e24\u6b21\u8bfb\u53d6\u4e4b\u95f4\u7528\u6237\u7a7a\u95f4\u4e2d\u7684\u6570\u636e\u53d1\u751f\u4e86\u53d8\u5316\uff0c\u5219\u53ef\u80fd\u5bfc\u81f4double-fetch\u8fd9\u79cdbug\u3002\u4e4b\u524d\u7684\u5f88\u591a\u5de5\u4f5c\u5c1d\u8bd5\u901a\u8fc7\u9759\u6001\u6216\u52a8\u6001\u7684\u65b9\u6cd5\u6765\u68c0\u6d4b\u8fd9\u79cdbug\uff0c\u7136\u800c\u7531\u4e8e\u5bf9double-fetch\u5b9a\u4e49\u4e0d\u6e05\u6670\uff0c\u8fd9\u4e9b\u5de5\u4f5c\u4f1a\u5bfc\u81f4\u5927\u91cf\u7684\u6f0f\u62a5\u548c\u8bef\u62a5\uff0c\u8fd8\u9700\u8981\u5f15\u5165\u5927\u91cf\u7684\u4eba\u5de5\u5206\u6790\u3002\u672c\u6587\u9996\u5148\u5bf9double-fetch\u8fdb\u884c\u4e86\u6b63\u5f0f\u548c\u7cbe\u786e\u7684\u5b9a\u4e49\uff0c\u5e76\u8bbe\u8ba1\u4e86\u9759\u6001\u5206\u6790\u5de5\u5177DEADLINE\u6765\u81ea\u52a8\u5316\u63a2\u6d4blinux kernal\u4e2d\u7684double-fetch\u9519\u8bef\u3002\u5de5\u5177\u53d1\u73b0\u4e86Linux\u7cfb\u7edf\u4e2d\u768423\u4e2a\u65b0bug\u548cfreeBSD\u76841\u4e2a\u65b0bug\u3002<\/span><\/p>\n<p><!--more--><\/p>\n<p><strong>\u80cc\u666f\u4ecb\u7ecd<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u5185\u6838\u662f\u64cd\u4f5c\u7cfb\u7edf\u7684\u91cd\u8981\u533a\u57df\uff0c\u4e00\u65e6\u53d1\u751fbug\u5c06\u9020\u6210\u5f88\u4e25\u91cd\u7684\u5371\u5bb3[1],[2]\u3002\u76ee\u524d\u6709\u5f88\u591a\u5de5\u4f5c\u9488\u5bf9\u5185\u6838\u4e2d\u7684bug\u8fdb\u884c\u63a2\u6d4b\u548c\u9632\u5fa1\uff0c\u4f46\u662f\u5927\u90e8\u5206\u5bf9\u4e8e\u903b\u8f91\u6f0f\u6d1e\u65e0\u80fd\u4e3a\u529b\u3002double-fetch\u5c31\u662f\u4e00\u7c7b\u91cd\u8981\u7684\u903b\u8f91\u6f0f\u6d1e\uff0c\u66fe\u7ecf\u6709\u653b\u51fb\u8005\u5229\u7528windows\u4e2d\u7684\u6b64\u7c7b\u6f0f\u6d1e\u6765\u8fdb\u884c\u63d0\u6743[3]\u3002double-fetch\u7684\u524d\u63d0\u662fmulti-reads\uff0c\u800c\u5185\u6838\u4e2d\u7531\u4e8e\u591a\u6b21\u8bfb\u53d6\u540c\u4e00\u5757\u7a7a\u95f4\u800c\u5bfc\u81f4double-reads\u7684\u60c5\u51b5\u666e\u904d\u5b58\u5728\u3002\u4f8b\u5982\uff0c\u5185\u6838\u9700\u8981\u4ece\u7528\u6237\u7a7a\u95f4\u8bfb\u53d6\u4e00\u5757\u6700\u5927\u957f\u5ea6\u4e3a4kb\u7684\u53d8\u957f\u6570\u636e\u65f6\uff0c\u53ef\u80fd\u4f1a\u9884\u5148\u5206\u914d\u4e00\u4e2a4kb\u7684\u7f13\u51b2\u533a\uff0c\u5e76\u4e00\u6b21\u6027\u4ece\u7528\u6237\u7a7a\u95f4\u8bfb\u53d64kb\u957f\u5ea6\u7684\u6570\u636e\u3002\u7136\u800c\uff0c\u5927\u591a\u6570\u60c5\u51b5\u4e0b\u6709\u6548\u6570\u636e\u7684\u957f\u5ea6\u53ea\u670964\u5b57\u8282\u6216\u662f\u66f4\u5c11\uff0c\u6b64\u65f6\u51fa\u4e8e\u4f18\u5316\u7684\u8003\u8651\uff0c\u5185\u6838\u4f1a\u5148\u4ece\u7528\u6237\u7a7a\u95f4\u8bfb\u53d6\u6570\u636e\u7684\u957f\u5ea6\u4fe1\u606f\uff0c\u4e4b\u540e\u518d\u5206\u914d\u7f13\u51b2\u533a\u5927\u5c0f\u5e76\u8bfb\u53d6\u6570\u636e\u3002<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u5bf9\u4e8eLinux\u7cfb\u7edf\u800c\u8a00\uff0c\u6b63\u5e38\u8fd0\u884c\u65f6\u5185\u6838\u4e2d\u5b58\u5728\u4e0a\u5343\u4e2amulti-reads\u7684\u60c5\u51b5\uff0c\u4f46\u4e0d\u4e00\u5b9a\u90fd\u662fdouble-fetch\u800c\u4ea7\u751f\u9519\u8bef\u3002\u90a3\u5982\u4f55\u8fdb\u884c\u5408\u7406\u7684\u5224\u65ad\u5462\uff1f\u4e4b\u524d\u7684\u65b9\u6cd5\u4e3b\u8981\u662f\u5148\u901a\u8fc7\u5de5\u5177\u627e\u5230\u4ee3\u7801\u4e2d\u7684multi-reads\uff0c\u518d\u4eba\u5de5\u5ba1\u8ba1\u8fd9\u4e9b\u5b58\u5728\u95ee\u9898\u7684\u4ee3\u7801\u6765\u786e\u5b9adouble-fetch\uff0c\u56e0\u6b64\u9700\u8981\u5927\u91cf\u7684\u4eba\u529b\u548c\u7cbe\u529b\u6295\u5165[3][4]\u3002\u672c\u6587\u8bbe\u8ba1\u4e86\u4e00\u4e2a\u540d\u4e3aDEADLINE\u7684\u5de5\u5177\uff0c\u7528\u4e8e\u901a\u8fc7\u9759\u6001\u5206\u6790\u6765\u81ea\u52a8\u5316\u68c0\u6d4bdouble-fetch\u8fd9\u79cdbug\uff0c\u5e76\u5177\u6709\u5f88\u9ad8\u7684\u68c0\u6d4b\u7cbe\u5ea6\u548c\u8986\u76d6\u7387\u3002<\/span><\/p>\n<p><strong>\u5730\u5740\u7a7a\u95f4\u5212\u5206<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u5728\u73b0\u4ee3\u64cd\u4f5c\u7cfb\u7edf\u4e2d\uff0c\u865a\u62df\u5185\u5b58\u5206\u4e3a\u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u533a\u57df\u3002\u7528\u6237\u7a7a\u95f4\u533a\u57df\u5bf9\u4e8e\u7cfb\u7edf\u4e2d\u8fd0\u884c\u7684\u6bcf\u4e2a\u8fdb\u7a0b\u90fd\u662f\u5206\u5f00\u7684\uff0c\u56e0\u6b64\u6bcf\u4e00\u4e2a\u7a0b\u5e8f\u90fd\u53ef\u4ee5\u770b\u5230\u4e00\u5757\u81ea\u5df1\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u7a0b\u5e8f\u7684\u7528\u6237\u7a7a\u95f4\u5730\u5740\u53ef\u4ee5\u88ab\u8be5\u7a0b\u5e8f\u4e0b\u7684\u6240\u6709\u7ebf\u7a0b\u4ee5\u53ca\u7cfb\u7edf\u7684\u5185\u6838\u8fdb\u7a0b\u6240\u8bbf\u95ee\uff1b\u800c\u5185\u6838\u7a7a\u95f4\u533a\u57df\u662f\u53ea\u6709\u5185\u6838\u624d\u53ef\u4ee5\u8bbf\u95ee\u7684\u3002\u6b64\u5916\uff0c\u867d\u7136\u5185\u6838\u53ef\u4ee5\u8bbf\u95ee\u7528\u6237\u7a7a\u95f4\u5730\u5740\uff0c\u4f46\u662f\u51fa\u4e8e\u5b89\u5168\u6027\u548c\u9694\u79bb\u6027\u7684\u8003\u8651\uff0c\u5185\u6838\u4e0d\u4f1a\u76f4\u63a5\u8bfb\u53d6\u7528\u6237\u7a7a\u95f4\u5730\u5740\u6216\u8005\u76f4\u63a5\u89e3\u5f15\u7528\u7528\u6237\u5730\u5740\u7a7a\u95f4\u7684\u6307\u9488\uff0c\u800c\u662f\u91c7\u7528\u7cfb\u7edf\u5355\u72ec\u8bbe\u8ba1\u7684\u62f7\u8d1d\u51fd\u6570\u6765\u5c06\u6570\u636e\u4ece\u7528\u6237\u7a7a\u95f4\u62f7\u8d1d\u5230\u5185\u6838\u7a7a\u95f4\u4f7f\u7528\uff0c\u4f8b\u5982Linux\u4e2d\u7684copy_from_user\uff0cget_user\u548cFreeBSD\u4e2d\u7684copyin\uff0cfuword\u3002\u8fd9\u4e9b\u65b9\u6848\u4e0d\u4ec5\u4f1a\u8fdb\u884c\u6570\u636e\u4f20\u8f93\uff0c\u8fd8\u4e3b\u52a8\u9a8c\u8bc1\u7528\u6237\u7a7a\u95f4\u8bbf\u95ee\u7684\u6b63\u786e\u6027\uff0c\u5e76\u5904\u7406\u975e\u6cd5\u5730\u5740\u6216\u9875\u9762\u9519\u8bef\u7b49\u5f02\u5e38\u3002<\/span><\/p>\n<p><strong>multi-reads\u7684\u666e\u904d\u6027<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u51fa\u4e8e\u6027\u80fd\u7684\u8003\u8651\uff0c\u5185\u6838\u8fdb\u7a0b\u5728\u4ece\u7528\u6237\u5730\u5740\u7a7a\u95f4\u62f7\u8d1d\u6570\u636e\u65f6\uff0c\u4e00\u822c\u4e0d\u4f1a\u76f4\u63a5\u8fdb\u884c\u6570\u636e\u62f7\u8d1d\u3002\u66f4\u5e38\u89c1\u7684\u64cd\u4f5c\u662f\uff0c\u5148\u4ece\u7528\u6237\u7a7a\u95f4\u8bfb\u53d6\u9700\u8981\u62f7\u8d1d\u6570\u636e\u7684\u5927\u5c0f\uff08size\uff09\uff0c\u8fdb\u884c\u6821\u9a8c\u4e4b\u540e\uff0c\u518d\u4f7f\u7528\u8be5\u5927\u5c0f\u5206\u914d\u7279\u5b9a\u7684\u7f13\u51b2\u533a\u5927\u5c0f\uff0c\u5e76\u4ece\u7528\u6237\u7a7a\u95f4\u53bb\u62f7\u8d1dsize\u5927\u5c0f\u7684\u6570\u636e\uff0c\u56e0\u6b64\u4f1a\u53d1\u751f\u81f3\u5c11\u4e24\u6b21fetch\u64cd\u4f5c\u3002\u901a\u5e38\uff0c\u8fd9\u4e24\u79cdfetch\u64cd\u4f5c\u4f1a\u6709\u4e00\u5b9a\u7684\u5173\u8054\uff0c\u800csize\u53ea\u662f\u5176\u4e2d\u7684\u4e00\u79cd\u60c5\u51b5\u3002\u4f5c\u8005\u603b\u7ed3\uff0c\u4e24\u6b21fetch\u64cd\u4f5c\u7684\u6570\u636e\u901a\u5e38\u6709\u4ee5\u4e0b\u5173\u7cfb\uff1a<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4f9d\u8d56\u67e5\u627e\uff1a\u5bf9\u4e8e\u4e00\u6b21\u6570\u636e\u8bfb\u53d6\u8bf7\u6c42\uff0c\u53ef\u80fd\u6709\u591a\u4e2a\u5bf9\u5e94\u7684\u5904\u7406\u51fd\u6570\u3002\u5185\u6838\u5148\u4ece\u7528\u6237\u7a7a\u95f4\u62f7\u8d1d\u4e00\u4e9b\u7279\u5f81\u4fe1\u606f\uff0c\u5224\u65ad\u5373\u5c06\u8bfb\u53d6\u7684\u6570\u636e\u7c7b\u578b\uff0c\u5e76\u67e5\u627e\u5e94\u8be5\u4f7f\u7528\u54ea\u4e2a\u5bf9\u5e94\u7684\u5904\u7406\u51fd\u6570\uff0c\u5224\u65ad\u4e4b\u540e\u8fdb\u884c\u7b2c\u4e8c\u6b21\u8bfb\u53d6\u3002\u793a\u4f8b\u5982\u56fe1\u6240\u793a\u3002<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u534f\u8bae\/\u7b7e\u540d\u6821\u9a8c\uff1a\u7b2c\u4e00\u6b21\u8bfb\u64cd\u4f5c\u5148\u8bfb\u53d6\u7279\u5b9a\u7684\u534f\u8bae\u7248\u672c\u53f7\u6216\u6d88\u606f\u7b7e\u540d\uff0c\u5185\u6838\u6821\u9a8c\u901a\u8fc7\u540e\u518d\u8fdb\u884c\u4e0b\u4e00\u6b21\u8bfb\u53d6\u3002\u793a\u4f8b\u5982\u56fe2\u6240\u793a\u3002<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4fe1\u606f\u731c\u6d4b\uff1a\u5982\u679c\u7f3a\u4e4f\u6570\u636e\u7684\u5177\u4f53\u4f4d\u7f6e\u4fe1\u606f\uff0c\u5185\u6838\u53ef\u80fd\u901a\u8fc7\u4f7f\u7528\u5faa\u73af\u6765\u591a\u6b21\u8bfb\u53d6\uff0c\u5c1d\u8bd5\u627e\u5230\u6709\u6548\u7684\u6570\u636e\u4f4d\u7f6e\uff0c\u7136\u540e\u518d\u4f7f\u7528\u4e00\u6b21\u8bfb\u53d6\u4ece\u7528\u6237\u7a7a\u95f4\u62f7\u8d1d\u5b8c\u6574\u6570\u636e\u3002\u793a\u4f8b\u5982\u56fe3\u6240\u793a\u3002<\/span><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image6.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2559 size-full\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image6.png\" alt=\"\" width=\"628\" height=\"474\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image6.png 628w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image6-300x226.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image6-199x150.png 199w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image6-150x113.png 150w\" sizes=\"auto, (max-width: 628px) 100vw, 628px\" \/><\/a><\/p>\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\">\u56fe1 \u4f9d\u8d56\u67e5\u627e<\/span><span style=\"font-weight: 400;\"><a href=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image4.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2557 size-full\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image4.png\" alt=\"\" width=\"615\" height=\"361\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image4.png 615w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image4-300x176.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image4-250x147.png 250w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image4-150x88.png 150w\" sizes=\"auto, (max-width: 615px) 100vw, 615px\" \/><\/a><\/span>\u56fe2 \u534f\u8bae\u6821\u9a8c<\/p>\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2558 size-full\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image5.png\" alt=\"\" width=\"624\" height=\"528\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image5.png 624w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image5-300x254.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image5-177x150.png 177w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image5-150x127.png 150w\" sizes=\"auto, (max-width: 624px) 100vw, 624px\" \/><\/span><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\">\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\">\u56fe3 \u4fe1\u606f\u731c\u6d4b<\/span><\/p>\n<p><strong>\u5f62\u5f0f\u5316\u5b9a\u4e49double-fetch<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u4e3a\u4e86\u4fbf\u4e8e\u540e\u7eed\u4f7f\u7528\u7a0b\u5e8f\u6765\u67e5\u627edouble-fetch\u9519\u8bef\uff0c\u8bba\u6587\u9996\u5148\u5bf9\u8fd9\u79cd\u9519\u8bef\u8fdb\u884c\u4e86\u5f62\u5f0f\u5316\u7684\u5b9a\u4e49\u3002\u4f5c\u8005\u8ba4\u4e3a\uff0cdouble-fetch\u7684\u786e\u8ba4\u8fc7\u7a0b\u5fc5\u987b\u7ecf\u8fc7\u4ee5\u4e0b\u7684\u56db\u4e2a\u6b65\u9aa4\uff1a<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u81f3\u5c11\u6709\u4e24\u6b21\u5bf9\u7528\u6237\u7a7a\u95f4\u7684\u8bfb\u64cd\u4f5c\uff0c\u5373double-fetch\u7684\u524d\u63d0\u662fmulti-reads\u3002\u8fd9\u4e00\u70b9\u53ef\u4ee5\u901a\u8fc7\u626b\u63cf\u4ee3\u7801\u4e2d\u7684copy_from_user()\u51fd\u6570\u6765\u786e\u5b9a\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4e24\u6b21\u8bfb\u53d6\u7684\u5185\u5bb9\u5fc5\u987b\u8981\u6709\u91cd\u53e0\u90e8\u5206\uff0c\u624d\u53ef\u80fd\u53d1\u751f\u9519\u8bef\u3002\u8fdb\u4e00\u6b65\u6765\u8bf4\uff0c\u8fd9\u4e2amulti-reads\u5fc5\u987b\u662f\u4e00\u4e2aoverlapped-fetch\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4e24\u6b21\u8bfb\u53d6\u7684\u6570\u636e\u5fc5\u987b\u8981\u6709\u4e00\u5b9a\u7684\u5173\u8054\uff0c\u53ef\u4ee5\u662f\u6570\u636e\u4f9d\u8d56\u6216\u8005\u63a7\u5236\u4f9d\u8d56\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4e24\u6b21\u8bfb\u53d6\u7684\u91cd\u53e0\u90e8\u5206\u4e0d\u80fd\u88ab\u8bc1\u660e\u5728\u4e24\u6b21\u4e0d\u540c\u7684\u8bfb\u53d6\u4e2d\u4e00\u5b9a\u662f\u76f8\u540c\u7684\uff0c\u4e5f\u5c31\u662f\u8bf4\u7528\u6237\u7a7a\u95f4\u53ef\u80fd\u56e0\u4e3a\u6761\u4ef6\u7ade\u4e89\u800c\u5728\u4e24\u6b21\u8bfb\u53d6\u4e4b\u95f4\u6539\u53d8\u4e86\u8fd9\u4e2a\u533a\u57df\u7684\u503c\u3002<\/span><\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">\u8bba\u6587\u4e2d\u5bf9\u4e0a\u8ff0\u7684\u51e0\u4e2a\u5b9a\u4e49\u90fd\u8fdb\u884c\u4e86\u7b26\u53f7\u5316\u7684\u8868\u8ff0\u3002<\/span><\/p>\n<p><strong>\u7cfb\u7edf\u8bbe\u8ba1<\/strong><\/p>\n<p><strong>\u6982\u8ff0<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">DEADLINE\u4f7f\u7528\u7b26\u53f7\u6267\u884c\u6765\u5bf9\u5185\u6838\u4ee3\u7801\u8fdb\u884c\u9759\u6001\u7b26\u53f7\u68c0\u67e5\u4ee5\u786e\u5b9adouble-fetch\u9519\u8bef\u3002\u7b26\u53f7\u6267\u884c\u5728LLVM IR\u7684\u5c42\u6b21\u4e0a\u8fdb\u884c\uff0c\u524d\u4eba\u7684\u5de5\u4f5c\u4e5f\u8868\u660e\u4e86\u5728IR\u5c42\u9762\u8fdb\u884c\u7b26\u53f7\u6267\u884c\u76f8\u6bd4\u4e8e\u6e90\u7801\u6765\u8bf4\u6709\u8bf8\u591a\u7684\u597d\u5904[5][6]\u3002\u6574\u4e2a\u5de5\u5177\u7684\u8fd0\u884c\u6d41\u7a0b\u5982\u56fe4\u6240\u793a\u7684\u4f2a\u4ee3\u7801\u7b97\u6cd5\uff0c\u5373\u9996\u5148\u626b\u63cf\u5185\u6838\u6240\u6709\u7684\u4ee3\u7801\uff0c\u6536\u96c6\u6240\u6709\u7684multi-reads\u60c5\u51b5\uff0c\u5e76\u5bf9\u6bcf\u4e00\u7ec4\u6709\u5173\u8054\u7684multi-reads\u6267\u884c\u7b26\u53f7\u6267\u884c\u68c0\u67e5\uff0c\u5224\u65ad\u662f\u5426\u4f1a\u5bfc\u81f4double-fetch\u9519\u8bef\uff0c\u5982\u679c\u662f\uff0c\u5219\u5c06\u5176\u52a0\u5165\u8f93\u51fa\u96c6\u5408\u3002<\/span><\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2555 size-full\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image2.png\" alt=\"\" width=\"658\" height=\"392\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image2.png 658w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image2-300x179.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image2-250x150.png 250w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image2-150x89.png 150w\" sizes=\"auto, (max-width: 658px) 100vw, 658px\" \/><\/p>\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\">\u56fe4 \u8fd0\u884c\u6d41\u7a0b\u7b97\u6cd5<\/span><\/p>\n<p><strong>\u5bfb\u627emulti-reads<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u5982\u4f55\u627e\u5230\u5185\u6838\u4e2d\u6240\u6709\u7684multi-reads\u60c5\u51b5\u5462\uff1f\u4f5c\u8005\u9009\u53d6\u7684\u65b9\u5f0f\u662f\uff0c\u9996\u5148\u626b\u63cf\u5185\u6838\u4ee3\u7801\uff0c\u901a\u8fc7\u8bc6\u522b\u4ee3\u7801\u4e2d\u7684copy_from_user\u7b49\u8bfb\u53d6\u7528\u6237\u7a7a\u95f4\u6570\u636e\u7684\u51fd\u6570\u6765\u627e\u5230\u6240\u6709\u7684fetch\u64cd\u4f5c\uff0c\u5176\u6b21\u5bf9\u4e8e\u6bcf\u4e2afetch\u64cd\u4f5c\u6240\u5728\u7684\u51fd\u6570\uff0c\u8fdb\u884c\u51fd\u6570\u5185\u7684\u81ea\u5e95\u5411\u4e0a\u5206\u6790\uff0c\u4ee5\u627e\u5230\u4e00\u4e2afetch pair\u3002\u5982\u679c\u627e\u5230\u4e86\u4e00\u4e2afetch pair\uff0c\u5219\u8bf4\u660e\u627e\u5230\u4e86\u4e00\u4e2amulti-reads\u60c5\u51b5\uff0c\u5e76\u5c06\u5176\u7528\u4e00\u4e2a\u4e09\u5143\u7ec4&lt;F0,F1,Fn &gt;\u3002\u5728\u8fd9\u4e2a\u4e09\u5143\u7ec4\u4e2d\uff0cF0\u548cF1\u5206\u522b\u8868\u793a\u4e24\u6b21fetch\u6307\u4ee4\u7684\u4f4d\u7f6e\uff0cFn\u8868\u793a\u8fd9\u4e24\u6761\u6307\u4ee4\u6240\u5728\u7684\u51fd\u6570\u540d\u79f0\u3002\u51fd\u6570\u81ea\u5e95\u5411\u4e0a\u5206\u6790\u7684\u8fc7\u7a0b\u5982\u56fe5\u6240\u793a\uff0c\u4ecefetch\u64cd\u4f5c\u6240\u5728\u51fd\u6570\u7684\u5e95\u90e8\u5f00\u59cb\uff0c\u81ea\u5e95\u5411\u4e0a\u5206\u6790\u6307\u4ee4\uff0c\u5f53\u51fa\u73b0\u7b2c\u4e8c\u6b21fetch\u7684\u65f6\u5019\uff0c\u5c31\u53ef\u4ee5\u8ba4\u5b9a\u4e3a\u4e00\u4e2afetch pair\u5e76\u751f\u6210\u4e09\u5143\u7ec4\u3002\u5982\u679c\u5728\u5206\u6790\u7684\u8fc7\u7a0b\u4e2d\u9047\u5230\u4e86\u5e26\u6709fetch\u64cd\u4f5c\u7684\u51fd\u6570\uff0c\u5219\u4f1a\u5c06\u8fd9\u4e2a\u51fd\u6570\u4ee3\u7801\u5185\u8054\u8fdb\u6765\u8fdb\u884c\u5206\u6790\u3002<\/span><\/p>\n<p><a href=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image3.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2556 size-full\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image3.png\" alt=\"\" width=\"817\" height=\"456\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3.png 817w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3-300x167.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3-768x429.png 768w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3-250x140.png 250w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3-360x200.png 360w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image3-150x84.png 150w\" sizes=\"auto, (max-width: 817px) 100vw, 817px\" \/><\/a><\/p>\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\">\u56fe5 \u81ea\u5e95\u5411\u4e0a\u5206\u6790\u8fc7\u7a0b<\/span><\/p>\n<p><strong>\u4ecemulti-reads\u5230double-fetch<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u4e4b\u524d\u7684\u4e00\u4e9b\u8bba\u6587\u4e2d\u7684\u5de5\u5177\u4e3b\u8981\u6b62\u6b65\u4e8e\u627e\u5230\u5185\u6838\u4e2d\u7684multi-reads\u60c5\u51b5\uff0c\u4e4b\u540e\u91c7\u7528\u4eba\u5de5\u5206\u6790\u6765\u4ece\u4e2d\u786e\u5b9adouble-fetch\u7684bug\uff0c\u9700\u8981\u8017\u8d39\u5927\u91cf\u7684\u4eba\u529b\u3002\u672c\u6587\u8bbe\u8ba1\u7684\u5de5\u5177\u5728\u53d1\u73b0multi-reads\u4e4b\u540e\uff0c\u5c06\u7ee7\u7eed\u4f7f\u7528\u7b26\u53f7\u6267\u884c\u6765\u8fdb\u884c\u9759\u6001\u5206\u6790\uff0c\u4ee5\u53d1\u73b0\u771f\u6b63\u53ef\u80fd\u5bfc\u81f4double-fetch\u9519\u8bef\u7684\u4ee3\u7801\u3002<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u4e0e\u5e38\u89c4\u7684\u7b26\u53f7\u6267\u884c\u4e0d\u540c\u5728\u4e8e\uff0c\u4f20\u7edf\u7684\u7b26\u53f7\u6267\u884c\u5728\u5904\u7406\u5185\u5b58\u8bfb\u5199\u65f6\uff0c\u82e5\u4e24\u6b21\u8bfb\u53d6\u540c\u4e00\u4f4d\u7f6e\u7684\u64cd\u4f5c\u4e4b\u95f4\u6ca1\u6709\u5185\u5b58\u7684\u5199\u64cd\u4f5c\uff0c\u5219\u5047\u8bbe\u4ece\u540c\u4e00\u4f4d\u7f6e\u8bfb\u53d6\u7684\u503c\u90fd\u662f\u4e00\u6837\u7684[5][7][8]\u3002\u4f46\u8fd9\u4e2a\u6a21\u578b\u5728\u5f53\u524d\u7684\u73af\u5883\u4e2d\u663e\u7136\u662f\u4e0d\u9002\u7528\u7684\uff0c\u5426\u5219\u5c31\u627e\u4e0d\u5230double-fetch\u9519\u8bef\u4e86\u3002\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0cDEADLINE\u91c7\u53d6\u7684\u65b9\u6cd5\u662f\u5bf9\u6bcf\u4e00\u6b21\u7684\u5185\u5b58\u8bfb\u53d6\u8fdb\u884c\u7f16\u53f7\uff0c\u4ee5\u8868\u793a\u4e24\u6b21\u8bfb\u53d6\u7684\u5185\u5bb9\u53ef\u4ee5\u4e0d\u540c\u3002<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u6700\u540e\uff0c\u4f7f\u7528\u7b26\u53f7\u6267\u884c\u6784\u5efa\u7ea6\u675f\u4e4b\u540e\u5bf9\u7ea6\u675f\u8fdb\u884c\u6c42\u89e3\uff0c\u770b\u662f\u5426\u6ee1\u8db3\u5f62\u5f0f\u5316\u5b9a\u4e49\u4e2d\u63d0\u51fa\u7684\u56db\u4e2a\u6761\u4ef6\uff0c\u4ece\u800c\u6c42\u89e3\u662f\u5426\u5b58\u5728double-fetch\u3002<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u4f5c\u8005\u7ed9\u51fa\u4e86\u4e00\u4e2a\u5b8c\u6574\u7684\u6848\u4f8b\u5206\u6790\uff0c\u5982\u56fe6\u6240\u793a\u3002\u6574\u4e2a\u7b26\u53f7\u5206\u6790\u7684\u8fc7\u7a0b\uff0c\u9996\u5148\u5bf9\u51fd\u6570\u53c2\u6570\u548c\u5168\u5c40\u53d8\u91cf\u8fdb\u884c\u7b26\u53f7\u5316\uff0c\u4f5c\u4e3a\u6839SR\uff08symbolic representation\uff09\uff0c\u4e4b\u540e\u5bf9\u6307\u4ee4\u8fdb\u884c\u7b26\u53f7\u5316\u8868\u8ff0\u3002\u7b26\u53f7\u5316\u7684\u8fc7\u7a0b\u4e2d\uff0c\u5bf9\u4e8e\u4e00\u6b21fetch\u64cd\u4f5c\uff0c\u4f7f\u7528\u4e00\u4e2a{A,S}\u5bf9\u6765\u8868\u793a\u672c\u6b21\u64cd\u4f5c\u7684\u5c5e\u6027\uff0c\u5176\u4e2dA\u8868\u793a\u8bfb\u53d6\u6570\u636e\u7684\u5730\u5740\uff0cS\u8868\u8ff0\u6570\u636e\u7684\u5927\u5c0f\u3002\u9047\u5230\u4e0efetch\u6570\u636e\u76f8\u5173\u7684\u5206\u652f\u5224\u65ad\uff0c\u5219\u5c06\u5176\u8f6c\u5316\u4e3aassert\u65ad\u8a00\u4f5c\u4e3a\u6761\u4ef6\u7ea6\u675f\u4e4b\u4e00\u3002\u4e24\u6b21fetch\u4e4b\u540e\uff0c\u4f7f\u7528\u524d\u8ff0\u5bf9double-fetch\u7684\u5f62\u5f0f\u5316\u5b9a\u4e49\u6765\u8bbe\u7f6e\u7ea6\u675f\u5e76\u6c42\u89e3\uff1a\u5373\u5148\u5224\u65ad\u4e24\u6b21\u6240\u8bfb\u53d6\u7684\u6570\u636e\u662f\u5426\u6709\u91cd\u53e0\uff0c\u518d\u5224\u65ad\u662f\u5426\u53ef\u4ee5\u8bc1\u660e\u4e24\u6b21\u8bfb\u53d6\u7684\u6570\u636e\u91cd\u53e0\u90e8\u5206\u662f\u76f8\u7b49\u7684\u3002\u5728\u8fd9\u4e2a\u6848\u4f8b\u4e2d\uff0c\u7531\u4e8e\u4e24\u6b21\u8bfb\u53d6\u5206\u522b\u88ab\u6807\u8bc6\u4e3aU0\u548cU1\uff0c\u4e14\u6ca1\u6709\u7ea6\u675f\u8bc1\u660e\u4e24\u8005\u662f\u76f8\u7b49\u7684\uff0c\u6545\u7ea6\u675f\u6c42\u89e3\u5931\u8d25\uff0cDEADLINE\u7ed9\u51fa\u7ed3\u679c\uff0c\u5373\u6b64\u5904\u5b58\u5728double-fetch\u9519\u8bef\u3002<\/span><\/p>\n<p><a href=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2554 size-large\" src=\"https:\/\/www.inforsec.org\/wp\/wp-content\/uploads\/2018\/06\/image1-1024x573.png\" alt=\"\" width=\"800\" height=\"448\" srcset=\"http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1-1024x573.png 1024w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1-300x168.png 300w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1-768x430.png 768w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1-250x140.png 250w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1-150x84.png 150w, http:\/\/202.112.238.40\/wp\/wp-content\/uploads\/2018\/06\/image1.png 1165w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><\/p>\n<p style=\"text-align: center;\"><span style=\"font-weight: 400;\">\u56fe6 \u7b26\u53f7\u5206\u6790\u5b9e\u4f8b<\/span><\/p>\n<p><strong>\u5b9e\u73b0<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u4f5c\u8005\u91c7\u7528LLVM\u5bf9\u5185\u6838\u8fdb\u884c\u7f16\u8bd1\u4e3aIR\uff0c\u518d\u5c06IR\u8f6c\u6362\u4e3aSR\u8fdb\u884c\u7b26\u53f7\u6267\u884c\u5e76\u6784\u5efa\u7ea6\u675f\uff0c\u6700\u540e\u4f7f\u7528Z3\u8fdb\u884c\u7ea6\u675f\u6c42\u89e3\u3002\u5728\u5b9e\u73b0\u7ae0\u8282\uff0c\u4f5c\u8005\u8c08\u5230\u4e86\u4e24\u4e2a\u6280\u5de7\uff1a<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u6700\u5927\u5316\u4ee3\u7801\u8986\u76d6\u7387\u3002\u4e3a\u4e86\u6700\u5927\u5316\u80fd\u6d4b\u8bd5\u5230\u7684\u4ee3\u7801\u8986\u76d6\u7387\uff0c\u4f5c\u8005\u5c1d\u8bd5\u5bf9\u4ee3\u7801\u4e2d\u7684\u5b8f\u5b9a\u4e49\u8fdb\u884c\u5c3d\u53ef\u80fd\u7684\u5c55\u5f00\u7f16\u8bd1\u3002<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4f7f\u7528LLVM\u8fdb\u884c\u7f16\u8bd1\u3002\u4f7f\u7528LLVVM\u7f16\u8bd1\u4e3b\u8981\u662f\u4e3a\u4e86\u65b9\u4fbf\u4f7f\u7528IR\u8fdb\u884c\u540e\u7eed\u7684CFG\u6784\u5efa\u548c\u7b26\u53f7\u5206\u6790\u3002\u7531\u4e8eLinux Kernal\u5bf9LLVM\u7f16\u8bd1\u5341\u5206\u4e0d\u53cb\u597d\uff0c\u4f5c\u8005\u91c7\u53d6\u7684\u7b56\u7565\u662f\u9996\u5148\u4f7f\u7528GCC\u5bf9\u5185\u6838\u4ee3\u7801\u8fdb\u884c\u7f16\u8bd1\uff0c\u5e76\u5c06\u7f16\u8bd1\u65e5\u5fd7\u8bb0\u5f55\u4e0b\u6765\uff0c\u7528\u4e8eLLVM\u7684\u7f16\u8bd1\u3002\u4f46\u662f\u4ecd\u7136\u5b58\u5728\u5c11\u6570\u7684\u6587\u4ef6\u65e0\u6cd5\u901a\u8fc7\u7f16\u8bd1\u3002<\/span><\/li>\n<\/ul>\n<p><strong>\u53d1\u73b0<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">DEADLINE\u5728Linux\u548cfreeBSD\u4e2d\u5206\u522b\u53d1\u73b0\u4e861104\u5904\u548c101\u5904multi-reads\u7684\u60c5\u51b5\u3002\u8fd9\u6837\u7684\u7ed3\u679c\u4e0d\u4ec5\u80fd\u8bf4\u660emulti-reads\u7684\u60c5\u51b5\u5728kernal\u4e2d\u5341\u5206\u666e\u904d\uff0c\u66f4\u91cd\u8981\u7684\u662f\uff0c\u8fd9\u6837\u7684\u5de5\u4f5c\u91cf\u5982\u679c\u8fdb\u884c\u4eba\u5de5\u9a8c\u8bc1\u9700\u8981\u8017\u8d39\u5927\u91cf\u7684\u7cbe\u529b\uff0c\u8fd9\u4e5f\u518d\u6b21\u4f53\u73b0\u4e86\u81ea\u52a8\u5316\u4ece\u5176\u4e2d\u5bfb\u627e\u5904double-fetch\u7684\u91cd\u8981\u6027\u3002<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u6700\u540e\uff0c\u4f5c\u8005\u5728Linux\u548cfreeBSD\u4e2d\u5206\u522b\u53d1\u73b0\u4e8623\u4e2a\u548c1\u4e2a\u65b0\u7684double-fetch bud\u3002\u8fd9\u4e9bbug\u4e2d\u7684\u4e00\u4e9b\u5df2\u7ecf\u4e0e\u5f00\u53d1\u8005\u8fdb\u884c\u6c9f\u901a\u5e76\u4fee\u8865\uff0c\u4f46\u662f\u4ecd\u7136\u6709\u4e24\u4e2a\u88ab\u5f00\u53d1\u8005\u6807\u6ce8\u4e3a\u201cwon&#8217;t fix\u201d\uff0c\u5173\u4e8e\u8fd9\u4e00\u70b9\u7684\u5177\u4f53\u539f\u56e0\u5c06\u5728\u540e\u9762\u7684\u201c\u5c40\u9650\u6027\u201d\u7ae0\u8282\u8fdb\u884c\u5c55\u5f00\u3002<\/span><\/p>\n<p><strong>\u7f13\u89e3\u63aa\u65bd<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u4f5c\u8005\u901a\u8fc7\u4e0e\u5f00\u53d1\u8005\u4ea4\u6d41bug\u4fee\u590d\u7684\u8fc7\u7a0b\uff0c\u603b\u7ed3\u4e86\u4e00\u4e9b\u5173\u4e8edouble-fetch\u7684\u7f13\u89e3\u63aa\u65bd\uff1a<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u91cd\u5199\uff1a\u5bf9\u4e8e\u7b2c\u4e8c\u6b21fetch\u7684\u6570\u636e\u4e2d\u91cd\u53e0\u90e8\u5206\uff0c\u4f7f\u7528\u7b2c\u4e00\u6b21fetch\u65f6\u8bfb\u53d6\u7684\u6570\u636e\u5bf9\u5176\u8fdb\u884c\u8986\u76d6\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u68c0\u6d4b\u5230\u53d8\u5316\u5219\u4e2d\u6b62\uff1a\u5982\u679c\u68c0\u6d4b\u5230\u4e24\u6b21fetch\u6570\u636e\u4e0d\u4e00\u81f4\uff0c\u5219\u4e2d\u6b62\u63a5\u4e0b\u6765\u7684\u64cd\u4f5c\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u589e\u91cf\u8bfb\u53d6\uff1a\u7b2c\u4e8c\u6b21fetch\u65f6\uff0c\u5c06\u8df3\u8fc7\u7b2c\u4e00\u6b21fetch\u8fc7\u7684\u6570\u636e\uff0c\u4ee5\u907f\u514d\u8bfb\u53d6\u91cd\u590d\u6570\u636e\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u91cd\u6784\u4e3asingal-fetch\uff1a\u5982\u679c\u662f\u63a7\u5236\u4f9d\u8d56\uff0c\u5219\u53ef\u4ee5\u4e00\u6b21fetch\u6240\u6709\u7684\u6570\u636e\u3002<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">\u5f53\u7136\u4e0a\u8ff0\u7684\u63aa\u65bd\u5e76\u4e0d\u80fd\u4fee\u8865\u6240\u6709\u7684bug\uff0c\u9488\u5bf9\u4e00\u4e9b\u590d\u6742\u7684\u60c5\u51b5\u8fd8\u5f97\u5355\u72ec\u8fdb\u884c\u5904\u7406\u3002<\/span><\/p>\n<p><strong>\u5c40\u9650\u6027<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u4f5c\u8005\u4ece\u4ee5\u4e0b\u51e0\u4e2a\u65b9\u9762\u8ba8\u8bba\u4e86DEADLINE\u7684\u4e00\u4e9b\u5c40\u9650\u6027\uff1a<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u4ee3\u7801\u8986\u76d6\u7387\uff1a\u4f5c\u8005\u4f7f\u7528LLVM\u5bf9\u5185\u6838\u8fdb\u884c\u7f16\u8bd1\uff0c\u4f46\u5bf9\u4e8e\u6ca1\u6709\u7f16\u8bd1\u6210\u529f\u7684\u6587\u4ef6\u548c\u6ca1\u6709\u5c55\u5f00\u7684\u5b8f\u4ee3\u7801\uff0c\u5c06\u4e0d\u4f1a\u88ab\u6d4b\u8bd5\u8986\u76d6\uff1b<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u5173\u4e8e\u8def\u5f84\u6784\u5efa\u7684\u9650\u5236\uff0c\u6709\u51e0\u79cd\u60c5\u51b5\uff1a\u4e00\u662f\u5728\u51fd\u6570\u5185\u6784\u5efa\u8def\u5f84\u65f6\uff0c\u9650\u5236\u4e86\u6700\u5927\u7684\u8def\u5f84\u6570\uff084096\uff09\uff0c\u5982\u679c\u4e24\u6b21\u8bfb\u53d6\u8de8\u8d8a\u4e86\u8fd9\u4e2a\u8def\u5f84\u957f\u5ea6\u9650\u5236\uff0c\u5219\u65e0\u6cd5\u8fdb\u884c\u5206\u6790\uff1b\u4e8c\u662f\u5faa\u73af\u5c55\u5f00\u65f6\u4ec5\u5c55\u5f00\u4e00\u91cd\u5faa\u73af\uff0c\u80cc\u540e\u7684\u5047\u8bbe\u662f\u5faa\u73af\u4e2d\u7684\u63d0\u53d6\u901a\u5e38\u662f\u589e\u91cf\u8fdb\u884c\u7684\uff0c\u4f46\u8fd9\u4e2a\u5047\u8bbe\u4e0d\u4e00\u5b9a\u6210\u7acb\uff0c\u53ef\u80fd\u51fa\u73b0\u8de8\u5faa\u73af\u5bfc\u81f4\u7684double-fetch\uff1b\u5982\u679c\u5faa\u73af\u4e2d\u6709\u5206\u652f\uff0c\u4ec5\u4f1a\u5904\u7406\u4e00\u91cd\u5faa\u73af\u4e2d\u7684\u5206\u652f\u8def\u5f84\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e5f\u662f\u6709\u8def\u5f84\u9057\u6f0f\u7684\u3002<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">\u7b26\u53f7\u68c0\u67e5\u53ef\u80fd\u5b58\u5728\u7684\u95ee\u9898\uff1a\u4e00\u662f\u5de5\u5177\u9009\u62e9\u5ffd\u7565\u4e86\u5185\u8054\u51fd\u6570\uff0c\u5047\u8bbe\u5176\u5bf9\u7b26\u53f7\u6267\u884c\u6ca1\u6709\u5f71\u54cd\uff0c\u4e14\u5185\u6838\u5e93\u51fd\u6570\u662f\u624b\u5de5\u7f16\u5199\u5e93\u51fd\u6570\u7684\u7b26\u53f7\u89c4\u5219\uff0c\u53ef\u80fd\u4e0d\u51c6\u786e\uff1b\u4e8c\u662f\u5bf9\u4e8e\u6307\u9488\u89e3\u5f15\u7528\u91c7\u53d6\u7684\u7b56\u7565\u662f\u201c\u4efb\u4f55\u4e0d\u80fd\u786e\u5b9a\u5bf9\u8c61\u7684\u6307\u9488\u201d\u90fd\u89c6\u4e3a\u65b0\u7684\u5730\u5740\uff0c\u53ef\u80fd\u5b58\u5728\u8bef\u5dee\uff1b\u4e09\u662f\u5c06\u7ea6\u675f\u68c0\u67e5\u9650\u5236\u5728\u5c01\u95ed\u51fd\u6570\u5185\uff0c\u4f46\u662f\u4e24\u6b21\u8bfb\u53d6\u7684\u503c\u53ef\u80fd\u90fd\u88ab\u4f20\u51fa\u51fd\u6570\uff0c\u5e76\u5728\u51fd\u6570\u5916\u8fdb\u884c\u68c0\u67e5\uff0c\u8fd9\u79cd\u60c5\u51b5\u5c31\u4f1a\u51fa\u73b0\u8bef\u62a5\u3002<\/span><\/li>\n<\/ul>\n<p><strong>\u603b\u7ed3<\/strong><\/p>\n<p><span style=\"font-weight: 400;\">\u9996\u5148\uff0c\u672c\u6587\u5bf9\u5185\u6838\u4e2d\u5b58\u5728\u7684double-fetch\u9519\u8bef\u8fdb\u884c\u4e86\u7cbe\u786e\u548c\u5f62\u5f0f\u5316\u7684\u5b9a\u4e49\uff0c\u4ece\u5f62\u5f0f\u5316\u89d2\u5ea6\u660e\u786e\u533a\u5206\u4e86multi-reads\u548cdouble-fetch\u7684\u533a\u522b\u3002\u63a5\u7740\uff0c\u4f5c\u8005\u5f00\u53d1\u4e86\u68c0\u6d4b\u5de5\u5177DEADLINE\uff0c\u53ef\u4ee5\u901a\u8fc7\u7b26\u53f7\u6267\u884c\u7684\u9759\u6001\u5206\u6790\u65b9\u6cd5\u5bf9\u5185\u6838\u4ee3\u7801\u4e2d\u7684double-fetch\u9519\u8bef\u8fdb\u884c\u81ea\u52a8\u5316\u68c0\u6d4b\uff0c\u5e76\u5728Linux Kernal\u548cfreeBSD\u4e2d\u5206\u522b\u53d1\u73b0\u4e8623\u4e2a\u548c1\u4e2a\u65b0\u7684bug\u3002\u6700\u540e\uff0c\u6587\u7ae0\u8fdb\u4e00\u6b65\u8ba8\u8bba\u4e86double-fetch\u7684\u5371\u5bb3\u3001\u7f13\u89e3\u63aa\u65bd\u4ee5\u53caDEADLINE\u7684\u4e00\u4e9b\u5c40\u9650\u6027\u3002<\/span><\/p>\n<p><b>\u53c2\u8003\u6587\u732e<\/b><\/p>\n<p><span style=\"font-weight: 400;\">[1]<\/span> <span style=\"font-weight: 400;\">N. Wilfahrt, \u201cDirty COW (CVE-2016-5195) is a privilege escalation vulnerability in the Linux Kernel,\u201d 2016, <\/span><a href=\"https:\/\/dirtycow.ninja\/\"><span style=\"font-weight: 400;\">https:\/\/dirtycow.ninja\/<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[2]<\/span> <span style=\"font-weight: 400;\">S. Khandelwal, \u201c11-Year Old Linux Kernel Local Privilege Escalation Flaw Discovered,\u201d 2017, http:\/\/thehackernews.com\/2017\/02\/linux-kernel- local-root.html.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[3]<\/span> <span style=\"font-weight: 400;\">G. C. Mateusz Jurczyk, \u201cBochspwn: Identifying 0-days via System-wide Memory Access Pattern Analysis,\u201d in Black Hat USA Briefings (Black Hat USA), Las Vegas, NV, Aug. 2013.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[4]<\/span> <span style=\"font-weight: 400;\">P. Wang, J. Krinke, K. Lu, G. Li, and S. Dodier-Lazaro, \u201cHow Double- Fetch Situations Turn into Double-Fetch Vulnerabilities: A Study of Double Fetches in the Linux Kernel,\u201d in Proceedings of the 26th USENIX Security Symposium (Security), Vancouver, BC, Canada, Aug. 2017.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[5]<\/span> <span style=\"font-weight: 400;\">C. Cadar, D. Dunbar, and D. Engler, \u201cKLEE: Unassisted and Automatic Generation of High-Coverage Tests for Complex Systems Programs,\u201d in Proceedings of the 8th USENIX Symposium on Operating Systems Design and Implementation (OSDI), San Diego, CA, Dec. 2008.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[6]<\/span> <span style=\"font-weight: 400;\">P. Godefroid, M. Y. Levin, and D. Molnar, \u201cAutomated Whitebox Fuzz Testing,\u201d in Proceedings of the 15th Annual Network and Distributed System Security Symposium (NDSS), San Diego, CA, Feb. 2008.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[7]<\/span> <span style=\"font-weight: 400;\">J. McCarthy and J. Painter, \u201cCorrectness of a compiler for arithmetic expressions,\u201d Mathematical Aspects of Computer Science, vol. 1, 1967.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">[8]<\/span> <span style=\"font-weight: 400;\">L. de Moura and N. Bjorner, \u201cGeneralized, Efficient Array Decision Procedures,\u201d Microsoft Research, Tech. Rep., Sep. 2009.<\/span><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Precise and Scalable Detection of Double-Fetch Bug&#8230; <a class=\"continue-reading-link\" href=\"http:\/\/202.112.238.40\/wp\/?p=2550\"> Continue reading <span class=\"meta-nav\">&rarr; <\/span><\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-2550","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\/2550","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\/13"}],"replies":[{"embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2550"}],"version-history":[{"count":7,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts\/2550\/revisions"}],"predecessor-version":[{"id":2563,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=\/wp\/v2\/posts\/2550\/revisions\/2563"}],"wp:attachment":[{"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2550"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/202.112.238.40\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}