{"id":5159,"date":"2022-04-01T19:04:31","date_gmt":"2022-04-01T10:19:31","guid":{"rendered":"https:\/\/www.inforsec.org\/wp\/?p=5159"},"modified":"2022-04-01T19:09:37","modified_gmt":"2022-04-01T10:24:37","slug":"xnu%e8%99%9a%e6%8b%9f%e5%86%85%e5%ad%98%e5%ae%89%e5%85%a8%e5%be%80%e4%ba%8b","status":"publish","type":"post","link":"http:\/\/202.112.238.40\/wp\/?p=5159","title":{"rendered":"XNU\u865a\u62df\u5185\u5b58\u5b89\u5168\u5f80\u4e8b"},"content":{"rendered":"\n

\u6587\/\u738b\u94c1\u78ca \u5317\u4eac\u5927\u5b66\u535a\u58eb<\/p>\n\n\n\n

1.\u5f15\u8a00<\/strong><\/p>\n\n\n\n

\u865a\u62df\u5185\u5b58 (Virtual Memory, VM) \u2f26\u7cfb\u7edf\u662f\u73b0\u4ee3\u64cd\u4f5c\u7cfb\u7edf\u57fa\u7840\u6838\u2f3c\u7ec4\u4ef6\uff0c\u4e0d\u4ec5\u8d1f\u8d23\u865a\u62df\u5730\u5740\u548c\u7269\u7406\u5185\u5b58\u7684\u6620\u5c04\u5173\u7cfb\uff0c\u7ba1\u7406\u8c03\u5ea6\u7269\u7406\u5185\u5b58\u7684\u4f7f\u2f64\uff0c\u4e3a\u7a0b\u5e8f\u5f00\u53d1\u63d0\u4f9b\u7edf\u2f00\u900f\u660e\u7684\u5730\u5740\u7a7a\u95f4\uff0c\u540c\u65f6\u4e5f\u8981\u4e3a\u4e0d\u540c\u6267\u2f8f\u73af\u5883\u63d0\u4f9b\u9694\u79bb\uff0c\u7ba1\u63a7\u7269\u7406\u9875\u2faf\u8bfb\u3001\u5199\u3001\u6267\u2f8f\u7b49\u6743\u9650\uff0c\u662f\u7cfb\u7edf\u5b89\u5168\u7684\u57fa\u2f6f\u3002\u7531\u4e8eVM\u2f26\u7cfb\u7edf\u9700\u8981\u540c\u65f6\u517c\u987e\u6027\u80fd\u3001\u6548\u7387\u3001\u900f\u660e\u6027\u548c\u5b89\u5168\u7b49\u2f6c\u6807\uff0c\u5bfc\u81f4VM\u2f26\u7cfb\u7edf\u5728\u5b9e\u73b0\u8fc7\u7a0b\u4e2d\u903b\u8f91\u2f24\u591a\u5f02\u5e38\u590d\u6742\uff0cVM\u2f26\u7cfb\u7edf\u4e2d\u7684\u5404\u79cd\u4f18\u5316\u7b56\u7565\u4e5f\u5c31\u6210\u4e86”\u903b\u8f91\u9519\u8bef”\u7c7b\u578b\u6f0f\u6d1e\u7684\u91cd\u707e\u533a\u3002<\/p>\n\n\n\n

\u672c\u2f42\u4ee5iOS\u3001macOS\u64cd\u4f5c\u7cfb\u7edf\u7684\u5185\u6838XNU\u4e3a\u4f8b\uff0c\u56de\u987e\u2f00\u4e9b\u4e0eXNU VM\u2f26\u7cfb\u7edf\u76f8\u5173\u7684\u5386\u53f2\u6f0f\u6d1e\uff1b\u901a\u8fc7\u5206\u6790\u8fd9\u4e9b\u6f0f\u6d1e\u7684\u6210\u56e0\uff0c\u68b3\u7406VM\u2f26\u7cfb\u7edf\u903b\u8f91\u6f0f\u6d1e\u7684\u8109\u7edc\uff0c\u5e0c\u671b\u80fd\u7ed9\u5176\u4ed6\u5b89\u5168\u7814\u7a76\u5e26\u6765\u2f00\u4e9b\u542f\u53d1\u3002<\/p>\n\n\n\n

2.\u672a\u9884\u671f\u7684\u7834\u574f<\/strong><\/p>\n\n\n\n

VM\u2f26\u7cfb\u7edf\u7684\u2f00\u4e2a\u7ecf\u5178\u529f\u80fd\u662fSwap\uff0c\u662f\u6307\u5728\u8c03\u5ea6\u7269\u7406\u9875\u2faf\u65f6\uff0cVM\u7cfb\u7edf\u53ef\u80fd\u4f1a\u5c06\u90e8\u5206\u7269\u7406\u9875\u2faf\u8f6c\u50a8\u2f84\u78c1\u76d8\u4ece\u2f7d\u83b7\u5f97\u2f9c\u591f\u7684\u7269\u7406\u7a7a\u95f4\uff1b\u5f53\u8fd9\u4e9b\u8f6c\u50a8\u7684\u7269\u7406\u9875\u2faf\u88ab\u771f\u6b63\u8bbf\u95ee\u65f6\uff0cVM\u2f26\u7cfb\u7edf\u518d\u4eceSwap\u2f42\u4ef6\u4e2d\u6062\u590d\u539f\u59cb\u7269\u7406\u9875\u2faf\u5185\u5bb9\u3002<\/p>\n\n\n\n

2017\u5e74\uff0cGoogle Project 0\u7814\u7a76\u5458Ian Beer\u4e0eJann Horn\u5728\u5934\u8111\u98ce\u66b4\u4e2d\uff0c\u60f3\u5230\u2f00\u4e2a\u95ee\u9898\uff0c\u8fd9\u4e2aSwap\u2f42\u4ef6\u80fd\u5426\u88ab\u7be1\u6539\u7834\u574f\uff1f\u4e0e\u5176\u767e\u601d\u4e0d\u89e3\uff0c\u4e0d\u5982\u7b80\u5355\u2f00\u8bd5\u3002macOS\u7cfb\u7edf\u4e0a\uff0cSwap\u2f42\u4ef6\u8def\u5f84\u662f\/private\/var\/vm\/swapfifile0\u3002Ian Beer\u7b80\u5355\u7c97\u66b4\u7684\u2f64\u968f\u673a\u6570\u636e\u8986\u76d6\u4e86\u8be5\u2f42\u4ef6\uff1a<\/p>\n\n\n\n

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

\u7ed3\u679c\u4e5f\u2f50\u8f83\u7c97\u66b4\uff0c\u5185\u6838\u76f4\u63a5\u5d29\u6e83\u4e86[1]\u3002\u8fd9\u610f\u5473\u7740macOS\u4e0a\u5728SIP[2] \u4fdd\u62a4\u673a\u5236\u5e76\u6ca1\u6709\u4fdd\u62a4\u8fd9\u4e2aSwap\u2f42\u4ef6\u3002\u5728\u5904\u7406\u88ab\u7834\u574f\u7684Swap\u2f42\u4ef6\u65f6\uff0c\u5185\u6838\u51fa\u73b0\u4e86\u5185\u5b58\u9519\u8bef\u3002\u2f24\u80c6\u601d\u8003\uff0c\u52c7\u4e8e\u5c1d\u8bd5\uff0c\u662f\u4e98\u53e4\u4e0d\u53d8\u7684\u9053\u7406\u3002<\/p>\n\n\n\n

3.\u672a\u9884\u671f\u7684\u5171\u4eab<\/strong><\/p>\n\n\n\n

\u5171\u4eab\u5185\u5b58 (Shared Memory) \u662f\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u5b9e\u73b0\u8fdb\u7a0b\u95f4\u901a\u4fe1\u7684\u91cd\u8981\u2f45\u5f0f\uff0c\u901a\u8fc7\u628a\u76f8\u540c\u7684\u7269\u7406\u9875\u2faf\u6620\u5c04\u5728\u4e0d\u540c\u6267\u2f8f\u4f53\u7684\u865a\u62df\u5730\u5740\u7a7a\u95f4\uff0c\u4f7f\u53cc\u2f45\u90fd\u80fd\u8bbf\u95ee\u540c\u6837\u7684\u7269\u7406\u9875\u2faf\uff0c\u4e0d\u4ec5\u80fd\u51cf\u5c11\u7269\u7406\u9875\u2faf\u7684\u4f7f\u2f64\uff0c\u4e5f\u80fd\u907f\u514d\u901a\u4fe1\u8fc7\u7a0b\u4e2d\u4f20\u8f93\u2f24\u5757\u6570\u636e\uff0c\u4ece\u2f7d\u63d0\u2fbc\u901a\u4fe1\u7684\u6548\u7387\u3002\u4e0d\u8fc7\uff0c\u5982\u679c\u591a\u2f45\u5bf9\u540c\u2f00\u5757\u5185\u5b58\u90fd\u5177\u6709\u5199\u6743\u9650\u65f6\uff0c\u7ef4\u62a4\u5185\u5b58\u2f00\u81f4\u6027\u53d8\u5f97\u5f88\u56f0\u96be\uff0c”\u7ade\u4e89\u5199”\u4e5f\u5bb9\u6613\u5f15\u53d1\u5f88\u591a\u5b89\u5168\u95ee\u9898\u3002<\/p>\n\n\n\n

\u5171\u4eab\u5185\u5b58\u7684\u53cc\u53d6 (Double Fetch) \u662f\u2f00\u7c7b\u2fae\u5e38\u5178\u578b\u7684\u5b89\u5168\u6f0f\u6d1e\u6210\u56e0\u3002\u4e0b\u8868\u5c55\u2f70\u4e86\u2f00\u4e2a\u7b80\u5355\u7684\u53cc\u53d6\u6f0f\u6d1e\uff1a\u7b2c\u2f00\u4e2a\u2f8f\u8c03\u2f64strlen\u8ba1\u7b97\u5171\u4eab\u5185\u5b58\u4e2d\u2f00\u4e2a\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff1b\u7b2c\u2f06\u2f8f\u6839\u636e\u8be5\u957f\u5ea6\u5206\u914d\u2f00\u4e2a\u672c\u5730\u5806\u5185\u5b58\uff1b\u7b2c\u4e09\u2f8f\u8c03\u7528strcpy\u628a\u5171\u4eab\u5185\u5b58\u4e2d\u7684\u5b57\u7b26\u4e32\u590d\u5236\u5230\u65b0\u5206\u914d\u7684\u672c\u5730\u5185\u5b58\u4e2d\u3002\u8fd9\u4e09\u2f8f\u4ee3\u7801\u7684\u95ee\u9898\u5728\u4e8e\uff0c\u56e0\u4e3aC string\u4ee5\\0\u4e3a\u622a\u2f4c\u7b26\uff0cstrlen\u626b\u63cf\u5b57\u7b26\u4e32\u65f6\u4ee5\u7b2c\u2f00\u6b21\u9047\u5230\u7684\\0\u8ba1\u7b97\u5f53\u524d\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff0c\u540c\u6837\uff0c strcpy \u590d\u5236\u5b57\u7b26\u4e32\u65f6\uff0c\u76f4\u5230\u9047\u5230\u7684\\0\u624d\u4f1a\u7ec8\u2f4c\u590d\u5236\u3002\u2f7d\u5171\u4eab\u5185\u5b58\u53e6\u2f00\u7aef\u63a7\u5236\u8005\uff0c\u53ef\u4ee5\u5728strlen\u548cstrcpy\u4e4b\u95f4\uff0c\u628a\u7b2c\u2f00\u4e2a\\0\u4fee\u6539\u4e3a\u2fae\u96f6\u5b57\u7b26\uff0c\u8fd9\u5bfc\u81f4strcpy\u4f1a\u590d\u5236\u8fc7\u591a\u5b57\u7b26\u5230 local_buffer \u4e2d\uff0c\u9020\u6210\u5806\u6ea2\u51fa\u3002<\/p>\n\n\n\n

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

\u968f\u7740\u7cfb\u7edf\u590d\u6742\u6027\u7684\u589e\u2fbc\u3001\u7cfb\u7edf\u901a\u4fe1\u5c42\u7ea7\u8d8a\u6765\u8d8a\u591a\uff0c\u5e95\u5c42\u5f00\u53d1\u8005\u4e0e\u5e94\u2f64\u5f00\u53d1\u8005\u9488\u5bf9\u6570\u636e\u4f20\u8f93\u548c\u4f7f\u2f64\u7684\u89c6\u2f93\u5f88\u96be\u7edf\u2f00\uff0c\u5bfc\u81f4\u5f88\u591a\u60c5\u51b5\u4e0b\u6570\u636e\u662f\u4ee5\u2fae\u9884\u671f\u7684\u5171\u4eab\u5185\u5b58\u5f62\u5f0f\u4f20\u9012\u7684\uff0c\u9020\u6210\u5f88\u591a\u5b89\u5168\u95ee\u9898\u3002\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u6765\u770b\u2f0f\u4e2a\u2fae\u9884\u671f\u5171\u4eab\u7684\u6848\u4f8b\u3002<\/p>\n\n\n\n

3.1 CVE-2017-7047\uff1axpc_data\u5171\u4eab\u5185\u5b58\u4f20\u8f93<\/strong><\/p>\n\n\n\n

XNU\u63d0\u4f9b\u4e86\u57fa\u4e8eMach Port\u548cMach Message\u7684\u7075\u6d3b\u901a\u4fe1\u673a\u5236\u3002\u5728MachMessage\u57fa\u7840\u4e0a\uff0c\u2f64\u6237\u6001\u8fdb\u2f00\u6b65\u5c01\u88c5\u4e86libxpc\u6846\u67b6\uff0c\u63d0\u4f9b\u4e86\u5b57\u5178\u3001\u961f\u5217\u3001\u5b57\u7b26\u4e32\u3001\u7eaf\u6570\u636e\u7b49\u5e38\u89c1\u6570\u636e\u7ed3\u6784\u7684\u5c01\u88c5\uff1b\u5728libxpc\u57fa\u7840\u4e0a\uff0c\u53c8\u5c01\u88c5\u4e86NSXPC\u6846\u67b6\uff0c\u91cd\u70b9\u2f40\u6301\u8fdc\u7a0b\u5bf9\u8c61\u548c\u2f45\u6cd5\u8c03\u2f64\u3002<\/p>\n\n\n\n

\"\"

XNU\u901a\u4fe1\u67b6\u6784 <\/figcaption><\/figure><\/div>\n\n\n\n

2017\u5e74\uff0cIan Beer\u53d1\u73b0\uff0clibxpc\u5728\u4f20\u8f93xpc_data\u65f6\uff0c\u5982\u679c\u6570\u636e\u957f\u5ea6\u8d85\u8fc70x4000\uff0c\u4f1a\u8c03\u2f64 mach_make_memory_entry_64\u521b\u5efa\u865a\u62df\u5185\u5b58\u7684mach port\uff0c\u7136\u540e\u5c06mach port\u53d1\u9001\u51fa\u53bb\uff1b\u63a5\u6536\u2f45\u6536\u5230\u8fd9\u4e2amach port\u540e\uff0c\u8c03\u2f64mach_vm_map\u5c06port\u5bf9\u5e94\u7684\u865a\u62df\u5185\u5b58\u518d\u6620\u5c04\u5230\u672c\u5730\u3002\u5177\u4f53\u6d41\u7a0b\u5982\u4e0b\u56fe\u6240\u2f70\u3002<\/p>\n\n\n\n

\"\"

\u2f24\u5757xpc_data\u4f20\u9012 (\u53d1\u9001\u2f45\u4f7f\u2f64MAP_MEM_VM_COPY\u6807\u5fd7) <\/figcaption><\/figure><\/div>\n\n\n\n

\u4e3a\u907f\u514d\u5171\u4eab\u5185\u5b58\u7684\u9690\u60a3\uff0c\u53d1\u9001\u2f45\u8c03\u2f64 mach_make_memory_entry_64\u65f6\uff0c\u4f7f\u2f64\u4e86 MAP_MEM_VM_COPY\u6807\u5fd7\u3002\u7ed3\u5408XNU\u4e2d\u7684\u6ce8\u91ca\uff0c\u4e0d\u96be\u7406\u89e3\u4f7f\u2f64\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u521b\u5efamach port\u8fc7\u7a0b\u4e2d\uff0c\u4f1a\u521b\u5efa\u6570\u636e\u7684\u526f\u672c\u3002\u8fd9\u6837\u63a5\u6536\u2f45\u901a\u8fc7mach_vm_map\u518d\u6b21\u6620\u5c04\u540e\uff0c\u83b7\u5f97\u7684\u4e5f\u662f\u6570\u636e\u526f\u672c\u3002\u8fd9\u5176\u5b9e\u662f\u2f00\u79cd\u5c06xpc_data\u4ee5\u5199\u65f6\u590d\u5236(Copy-on-Write, COW)\u5f62\u5f0f\u4f20\u9012\u7684\u5b9e\u73b0\u2f45\u5f0f\uff0c\u907f\u514d\u4e86xpc_data\u7684\u5b8c\u5168\u5171\u4eab\u3002<\/p>\n\n\n\n

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

\u7136\u2f7d\uff0cIan Beer\u654f\u9510\u5730\u53d1\u73b0\uff0c\u8fd9\u79cdCOW\u4f9d\u8d56\u4e8e\u53d1\u9001\u2f45\u521b\u5efamach port\u65f6\u6307\u5b9aMAP_MEM_VM_COPY\u6807\u5fd7\u3002\u5bf9\u4e8e”\u6076\u610f”\u53d1\u9001\u2f45\uff0c\u5b8c\u5168\u53ef\u4ee5\u521b\u5efa\u2f00\u4e2a\u5168\u5171\u4eab\u5185\u5b58\u7684port\uff0c\u7136\u540e\u53d1\u9001\u7ed9\u63a5\u6536\u2f45\u3002\u8fd9\u6837\u901a\u8fc7mach_vm_map\u7b80\u5355\u6620\u5c04\u83b7\u5f97\u7684\u865a\u62df\u5730\u5740\uff0c\u4f1a\u548c\u53d1\u9001\u2f45\u5b8c\u5168\u5171\u4eab\u7269\u7406\u9875\u2faf\u3002\u8fd9\u6837\u2f00\u6765\uff0c\u63a5\u6536\u2f45\u4f7f\u2f64xpc_data\u65f6\u5c31\u53ef\u80fd\u5b58\u5728\u53cc\u53d6\u95ee\u9898\u3002<\/p>\n\n\n\n

Ian Beer\u7ee7\u7eed\u8ffd\u8e2a\u7cfb\u7edf\u4e2d\u5bf9xpc_data\u7684\u4e0d\u5b89\u5168\u4f7f\u2f64\u3002NSXPC\u662f\u5728libxpc\u57fa\u7840\u4e0a\uff0c\u5728\u8fdb\u7a0b\u95f4\u901a\u4fe1\u4e2d\u2f40\u6301\u8fdc\u7a0b\u5bf9\u8c61\u548c\u8fdc\u7a0b\u2f45\u6cd5\u8c03\u2f64\u3002\u5728\u5b9e\u73b0\u4e2d\uff0c\u8fd9\u4e9b\u8fdc\u7a0b\u5bf9\u8c61\u548c\u2f45\u6cd5\u8c03\u2f64\u7ecf\u5e8f\u5217\u5316\u540e\u7531xpc_data\u53d1\u9001\u3002Ian Beer\u5728\u8fd9\u4e2a\u53cd\u5e8f\u5217\u5316\u8fc7\u7a0b\u4e2d\uff0c\u628a\u2f00\u4e2a\u53cc\u53d6\u95ee\u9898\u8f6c\u6362\u6210\u4e86\u5806\u6ea2\u51fa\uff0c\u5b9e\u73b0\u4e86\u9488\u5bf9\u4efb\u610fNSXPC\u670d\u52a1\u7684\u539f\u578b\u653b\u51fb [4]\u3002<\/p>\n\n\n\n

Apple\u7684\u6f0f\u6d1e\u4fee\u590d\u2f45\u6848\u4e5f\u5f88\u6e05\u6670\u3002\u5728\u4f20\u8f93xpc_data\u8fc7\u7a0b\u4e2d\uff0c\u4e0d\u518d\u4fe1\u4efb\u53d1\u9001\u2f45\uff0c\u2f7d\u662f\u5728\u63a5\u6536\u2f45\u8c03\u2f64mach_vm_map\u65f6\uff0c\u5f3a\u5236\u5f00\u542fcopy\u9009\u9879\uff0c\u4e5f\u5c31\u662f\u4ee5COW\u5f62\u5f0f\u6620\u5c04\u3002\u8fd9\u6837\u53d1\u9001\u2f45\u5bf9 xpc_data \u7684\u4efb\u4f55\u4fee\u6539\u90fd\u4e0d\u4f1a\u4f20\u9012\u5230\u63a5\u6536\u2f45\uff0c\u907f\u514d\u4e86\u53cc\u53d6\u95ee\u9898\u3002<\/p>\n\n\n\n

\"\"

\u2f24\u5757xpc_data\u4f20\u9012 (\u63a5\u6536\u2f45\u5f3a\u5236mach_vm_map\u4f7f\u2f64copy\u9009\u9879) <\/figcaption><\/figure><\/div>\n\n\n\n

3.2 IOKit Out-of-line\u6570\u636e<\/strong><\/p>\n\n\n\n

IOKit\u662fXNU\u7684\u9a71\u52a8\u5f00\u53d1\u6846\u67b6\uff0c\u63d0\u4f9b\u4e86\u2f64\u6237\u6001\u7a0b\u5e8f\u3001\u5185\u6838\u3001\u8bbe\u5907\u4e4b\u95f4\u7684\u901a\u4fe1\u63a5\u53e3\u3002\u5176\u4e2d\uff0c\u2f64\u6237\u6001\u7a0b\u5e8f\u53ef\u4ee5\u901a\u8fc7 IOConnectCallMethod \u63a5\u53e3\u4e0e\u5185\u6838\u9a71\u52a8\u4f20\u9012\u6570\u636e\u3002\u5f53\u2f64\u6237\u6001\u4f20\u2f0a\u2f24\u5757\u6570\u636e\u65f6\uff08Out-of-line, OOL\uff09\uff0c\u7cfb\u7edf\u4f1a\u521b\u5efa IOMemoryDescriptor\uff0c\u5c06\u8be5\u6bb5\u6570\u636e\u6620\u5c04\u5230\u5185\u6838\u4f9b\u9a71\u52a8\u4f7f\u2f64\u3002\u7136\u2f7dXNU-3789.31.2\u7248\u672c\u4e4b\u524d\uff0cIOKit\u5f00\u53d1\u8005\u6ca1\u6709\u610f\u8bc6\u5230\uff0c\u8fd9\u6bb5\u6570\u636e\u5b9e\u9645\u662f\u4ee5\u5171\u4eab\u5185\u5b58\u5f62\u5f0f\u5b58\u5728\u7684\u3002IOKit\u6846\u67b6\u548c\u5177\u4f53\u9a71\u52a8\u5f00\u53d1\u8005\u4e4b\u95f4\u5e76\u6ca1\u6709\u6e05\u6670\u754c\u5b9aOOL\u6570\u636e\u7684\u5b58\u5728\u5f62\u6001\uff0c\u4ee5\u2f84\u4e8e\u5f88\u591a\u9a71\u52a8\u5b9e\u73b0\u4e2d\u90fd\u6709\u53cc\u53d6\u6f0f\u6d1e\u3002\u66f4\u591a\u6f0f\u6d1e\u7ec6\u8282\u53ef\u4ee5\u53c2\u8003Flanker\u7684blog [5]\u3002<\/p>\n\n\n\n

\"\"

OOL \u53cc\u53d6\u6f0f\u6d1e\u5b9e\u4f8b <\/figcaption><\/figure><\/div>\n\n\n\n

\u4f8b\u5982\uff0c\u5728macOS\u663e\u5361\u9a71\u52a8\u4e2d\uff0c IOAccelDisplayPipePostCSCGammaVID::init \u51fd\u6570\u5728\u5904\u7406OOL\u8f93\u2f0a\u65f6\uff0c\u4f1a\u6839\u636eOOL\u5185\u7684\u2f00\u4e2a\u6574\u6570\u8c03\u2f64 IOMalloc \u5206\u914d\u5185\u5b58\uff0c\u7136\u540e\u518d\u6b21\u8bfb\u53d6\u8be5\u6574\u6570\u2f64\u4e8e memcpy \u3002\u8fd9\u79cd\u5178\u578b\u7684\u53cc\u53d6\u6f0f\u6d1e\u9020\u6210\u6781\u5bb9\u6613\u5229\u2f64\u7684\u5806\u6ea2\u51fa[6]\u3002<\/p>\n\n\n\n

\u9274\u4e8e\u592a\u591a\u9a71\u52a8\u5f00\u53d1\u8005\u90fd\u6ca1\u6709\u610f\u8bc6\u5230OOL\u6570\u636e\u662f\u901a\u8fc7\u5171\u4eab\u5185\u5b58\u4f20\u9012\u7684\uff0c\u9010\u2f00\u7ea0\u6b63\u9a71\u52a8\u5f00\u53d1\u8005\u7684\u4ee3\u4ef7\u592a\u2f24\uff0cApple\u5728XNU-3789.31.2\u4e2d\uff0c\u76f4\u63a5\u5c06OOL\u6570\u636e\u4ee5COW\u5f62\u5f0f\u6620\u5c04\u3002\u76f8\u5e94\u7684\u8865\u4e01\u5982\u4e0b\u3002\u901a\u8fc7\u4f7f\u2f64 kIOMemoryMapCopyOnWrite \u6807\u5fd7\uff0c\u786e\u4fdd\u5185\u6838\u83b7\u5f97\u7684\u6570\u636e\u526f\u672c\u4e0d\u4f1a\u5b58\u5728\u53cc\u53d6\u95ee\u9898\u3002<\/p>\n\n\n\n

\"\"

OOL COW\u6620\u5c04\u8865\u4e01 <\/figcaption><\/figure><\/div>\n\n\n\n

3.3 Apple Neural Engine\u5171\u4eab\u5185\u5b58\u95ee\u9898<\/strong><\/p>\n\n\n\n

IOKit\u5904\u7406OOL\u65f6\u72af\u8fc7\u7684\u9519\u8bef\uff0c\u4e5f\u4f1a\u53cd\u5e94\u5728\u5355\u72ec\u7684\u9a71\u52a8\u4e2d\u3002\u9664\u4e86\u76f4\u63a5\u4f7f\u2f64OOL\u6570\u636e\uff0cIOKit\u9a71\u52a8\u4e5f\u53ef\u4ee5\u2f83\u2f8f\u6620\u5c04\u2f64\u6237\u6001\u5185\u5b58\u2f84\u5185\u6838\u4f7f\u2f64\u30022018\u5e74\uff0cApple\u63a8\u51fa\u4e86A12\u4eff\u2f63\u82af\u2f5a\uff0c\u642d\u8f7d\u4e86\u5f3a\u2f24\u7684\u795e\u7ecf\u2f79\u7edc\u5f15\u64ce\u3002\u76f8\u5e94\u5730\uff0ciOS\u5185\u6838\u4e2d\u4e5f\u589e\u52a0\u2f00\u4e2aH11ANEIn\u9a71\u52a8\uff0c\u2f64\u4e8e\u5904\u7406\u795e\u7ecf\u2f79\u7edc\u5f15\u64ce\u7684\u76f8\u5173\u8ba1\u7b97\u8bf7\u6c42\u3002H11ANEIn\u9700\u8981\u2f24\u91cf\u5f02\u6b65\u5904\u7406\uff0cIOKit\u6846\u67b6\u63d0\u4f9b\u7684OOL\u6570\u636e\u5e76\u4e0d\u9002\u5408\u5176\u8ba1\u7b97\u9700\u6c42\uff0c\u56e0\u6b64H11ANEIn\u76f4\u63a5\u6839\u636e\u2f64\u6237\u6001\u63d0\u4f9b\u7684\u5730\u5740\u521b\u5efa\u4e86 IOMemoryDescriptor \u3002<\/p>\n\n\n\n

\u4e0d\u5e78\u7684\u662f\uff0cH11ANEIn\u5f00\u53d1\u8005\u663e\u7136\u4e0d\u6e05\u695aIOKit\u7684\u5386\u53f2\u65e7\u8d26\uff0c\u5728\u521b\u5efaIOMemoryDescriptor\u65f6\uff0c\u4ec5\u4f7f\u2f64\u4e86 kIODirectionOutIn\u53c2\u6570\uff0c\u4e5f\u5c31\u662f\u201c\u8bfb\u5199\u201d\u6743\u9650\u3002H11ANEIn\u5728\u4f7f\u2f64\u8fd9\u6bb5\u6570\u636e\u65f6\u66f4\u52a0\u8086\u610f\uff0c\u76f4\u63a5\u628a\u2f00\u4e2aPort\u6307\u9488\u4fdd\u5b58\u5728\u8fd9\u6bb5\u5185\u5b58\u3002\u56e0\u4e3a\u8fd9\u6bb5\u5185\u5b58\u88ab\u5185\u6838\u548c\u2f64\u6237\u6001\u5171\u4eab\uff0c\u2f64\u6237\u6001\u4e0d\u4ec5\u53ef\u4ee5\u76f4\u63a5\u83b7\u53d6\u8fd9\u4e2aPort\u6307\u9488\u9020\u6210\u5185\u6838\u5730\u5740\u7a7a\u95f4\u7684\u4fe1\u606f\u6cc4\u6f0f\uff0c\u4e5f\u80fd\u76f4\u63a5\u4efb\u610f\u66ff\u6362\u8fd9\u4e2aPort\u6307\u9488\uff0c\u901a\u8fc7\u4f2a\u9020Port\u6307\u9488\u83b7\u53d6\u5185\u6838\u63a7\u5236\u6743[7]\u3002\u8fd9\u4e2a\u6f0f\u6d1e\u2f83iOS 12\u7248\u672c\u5f15\u2f0a\uff0c\u76f4\u5230iOS 13.6\u624d\u88ab\u4fee\u590d\uff1b\u4e0a\u2f42IOKit\u6846\u67b6\u5904\u7406OOL\u6570\u636e\u7684\u95ee\u9898\u9690\u85cf\u7684\u66f4\u4e45\uff0c\u8fd9\u4e9b\u4e5f\u5370\u8bc1\u4e86\u2fae\u9884\u671f\u5171\u4eab\u95ee\u9898\u7684\u9690\u853d\u6027\u3002<\/p>\n\n\n\n

4.\u590d\u6742\u7684COW<\/strong><\/p>\n\n\n\n

\u5bf9\u4e8e\u2fae\u9884\u671f\u5171\u4eab\u7c7b\u578b\u7684\u95ee\u9898\uff0c\u2f00\u4e2a\u76f4\u63a5\u7684\u4fee\u590d\u2f45\u6848\u5c31\u662f\u4ee5\u5199\u65f6\u590d\u5236(Copy-on-Write, COW)\u5206\u4eab\u6570\u636e\u3002COW\u662fVM\u2f26\u7cfb\u7edf\u7684\u2f00\u4e2a\u7ecf\u5178\u4f18\u5316\u7b56\u7565\uff0c\u5176\u6838\u2f3c\u601d\u60f3\u662f\u540c\u2f00\u4e2a\u7269\u7406\u9875\u2faf\u53ef\u4ee5\u540c\u65f6\u6620\u5c04\u5728\u4e0d\u540c\u8fdb\u7a0b\u7684\u865a\u62df\u5730\u5740\u7a7a\u95f4\u5185\uff0c\u4efb\u610f\u2f00\u2f45\u8bd5\u56fe\u4fee\u6539\u7269\u7406\u9875\u2faf\u5185\u5bb9\u65f6\uff0c\u7cfb\u7edf\u4f1a\u4e3a\u5176\u5206\u914d\u2f00\u4e2a\u539f\u7269\u7406\u9875\u2faf\u7684\u526f\u672c\u9875\u2faf\uff0c\u8fd9\u6837\u5199\u64cd\u4f5c\u6700\u7ec8\u4f5c\u2f64\u5728\u526f\u672c\u9875\u2faf\uff0c\u2f7d\u4e0d\u4f1a\u5f71\u54cd\u539f\u59cb\u9875\u2faf\uff0c\u4ece\u2f7d\u8fd9\u4e2a\u5199\u64cd\u4f5c\u4e5f\u4e0d\u4f1a\u88ab\u53e6\u2f00\u2f45\u6240\u611f\u77e5\u3002COW\u539f\u7406\u7b80\u5355\u2f7d\u5b9e\u73b0\u590d\u6742\u3002\u5f88\u591a\u64cd\u4f5c\u7cfb\u7edf\u5728COW\u7684\u5b9e\u73b0\u4e0a\u51fa\u73b0\u8fc7\u95ee\u9898\uff0c\u4f8b\u59822016\u5e74Linux\u7cfb\u7edf\u4e2d\u7684\u810f\u2f5c (Dirty COW) \u6f0f\u6d1e\u3002\u4e0b\u2faf\u6211\u4eec\u770b\u2f0f\u4e2aXNU\u4e2dCOW\u76f8\u5173\u7684\u5b89\u5168\u95ee\u9898\u3002<\/p>\n\n\n\n

\"\"

COW\u2f70\u610f\u56fe <\/figcaption><\/figure><\/div>\n\n\n\n

4.1 \u65e2\u5171\u4eab\u53c8COW (CVE-2017-2456)<\/strong><\/p>\n\n\n\n

COW\u901a\u5e38\u628a\u2f00\u4e2a\u7269\u7406\u9875\u2faf\u4ee5read-only\u6743\u9650\u6620\u5c04\u5230\u4e24\u4e2a\u865a\u62df\u5730\u5740\uff0c\u7136\u540e\u4efb\u610f\u2f00\u4e2a\u865a\u62df\u5730\u5740\u53d1\u2f63\u5199\u64cd\u4f5c\u7684\u65f6\u5019\uff0c\u7cfb\u7edf\u4f1a\u6355\u83b7\u9875\u2faf\u5199\u5f02\u5e38\uff0c\u5728\u5f02\u5e38\u5904\u7406\u8fc7\u7a0b\u4e2d\u590d\u5236\u65b0\u7684\u7269\u7406\u9875\u2faf\u5e76\u66f4\u65b0\u6620\u5c04\u5173\u7cfb\u3002\u5982\u679c\u865a\u62df\u5730\u5740VA\u548c\u865a\u62df\u5730\u5740VB\u662fCOW\u5173\u7cfb\uff0c\u2f7d\u865a\u62df\u5730\u5740VA\u548c\u865a\u62df\u5730\u5740VC\u662f\u5b8c\u5168\u5171\u4eab\u5173\u7cfb\uff0c\u5373\u540c\u2f00\u4e2a\u7269\u7406\u9875\u2faf\u88ab\u6620\u5c04\u5230\u4e09\u4e2a\uff08\u751a\u2f84\u66f4\u591a\uff09\u865a\u62df\u5730\u5740\u65f6\uff0c\u7cfb\u7edf\u5982\u4f55\u5904\u7406\u901a\u8fc7\u865a\u62df\u5730\u5740VC\u53d1\u2f63\u7684\u5199\u64cd\u4f5c\u5462\uff1f\u8fd9\u5e76\u4e0d\u662f\u2f00\u4e2a\u5bb9\u6613\u56de\u7b54\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n

\"\"

COW\u548c\u5b8c\u5168\u5171\u4eab\u540c\u65f6\u5b58\u5728 <\/figcaption><\/figure><\/div>\n\n\n\n

\u5e26\u7740\u8fd9\u4e2a\u7591\u8651\uff0cLokihardt\u505a\u4e86\u2f00\u4e2a\u6d4b\u8bd5 [2]\u3002\u4ed6\u521b\u5efa\u4e86\u2f00\u4e2aMemory entryport\u540e\uff0c\u901a\u8fc7\u5b8c\u5168\u5171\u4eab\u7684\u5f62\u5f0f\u628a\u8fd9\u4e2a\u5185\u5b58\u9875\u2faf\u6620\u5c04\u5728\u4e24\u4e2a\u4e0d\u540c\u7684\u865a\u62df\u5730\u5740VA\u548cVC\u3002\u7136\u540e\u5c06VA\u901a\u8fc7\u590d\u6742\u6d88\u606f Mach Message\u53d1\u9001\u5230\u53e6\u2f00\u4e2a\u8fdb\u7a0b\u3002\u6839\u636eMachMessage\u7684\u4f20\u9012\u89c4\u5219\uff0c\u6d88\u606f\u63a5\u6536\u2f45\u4f1a\u4ee5COW\u7684\u5f62\u5f0f\u6620\u5c04VA\u5bf9\u5e94\u7684\u7269\u7406\u5185\u5b58\u2f84\u865a\u62df\u5730\u5740VB\u3002\u4f46\u662f\uff0cLokihardt\u53d1\u73b0\u6b64\u65f6\u5728\u53d1\u9001\u2f45\u4fee\u6539VC\u5185\u5bb9\uff0c\u5e76\u4e0d\u4f1a\u89e6\u53d1\u7cfb\u7edf\u7684COW\u8bed\u610f\uff1b\u6362\u2f7d\u2f94\u4e4b\uff0c\u901a\u8fc7VC\u7684\u6240\u6709\u5199\uff0c\u5728VB\u7aef\u5168\u90e8\u53ef\u89c1\u3002Lokihardt\u57fa\u4e8e\u8fd9\u4e2a\u601d\u8def\uff0c\u5728libxpc\u53cd\u5e8f\u5217\u8fc7\u7a0b\u4e2d\u53d1\u73b0\u4e86\u5185\u5b58\u53cc\u95ee\u9898\uff0c\u5229\u2f64\u53cc\u53d6\u5f15\u53d1\u7684\u5185\u5b58\u6ea2\u51fa\uff0c\u5b9e\u73b0\u4e86\u5bf9\u4efb\u610flibxpc\u670d\u52a1\u7684\u653b\u51fb (CVE-2017-2456)\u3002\u5728\u4fee\u590d\u8fd9\u4e2a\u6f0f\u6d1e\u65f6\uff0cXNU\u4e25\u683c\u68c0\u67e5\u4e86\u7269\u7406\u9875\u2faf\u662f\u5426\u591a\u91cd\u6620\u5c04\uff0c\u786e\u4fddCOW\u7684\u2f00\u81f4\u6027\u3002<\/p>\n\n\n\n

\"\"

CVE-2017-2456\u7684\u4fee\u590d <\/figcaption><\/figure><\/div>\n\n\n\n

4.2 \u9690\u853d\u7684\u5199\u64cd\u4f5c<\/strong><\/p>\n\n\n\n

COW\u5b9e\u73b0\u7684\u2f00\u4e2a\u5173\u952e\u70b9\u5728\u4e8e\uff1a\u6355\u83b7\u5199\u64cd\u4f5c\u3002\u8fd9\u4e2a\u95ee\u9898\u4f3c\u4e4e\u5f88\u7b80\u5355\uff0c\u5c06\u7269\u7406\u5730\u5740\u4ee5\u53ea\u8bfb\u6743\u9650\u6620\u5c04\uff0c\u5199\u64cd\u4f5c\u2f83\u7136\u5c31\u4f1a\u89e6\u53d1\u5f02\u5e38\u3002\u4f46\u662f\u5982\u679c\u5199\u64cd\u4f5c\u5e76\u4e0d\u662f\u901a\u8fc7\u865a\u62df\u5730\u5740\u6765\u5b9e\u73b0\uff0cCOW\u5c31\u53ef\u80fd\u51fa\u73b0\u95ee\u9898\u3002<\/p>\n\n\n\n

iOS\u8bbe\u5907\u4e0a\u914d\u5907\u4e86\u4e13\u95e8\u7684\u534f\u5904\u7406\u5668\u2f40\u6301\u5feb\u901f\u56fe\u50cf\u7f29\u653e\u3001\u2f8a\u5f69\u8f6c\u6362\u7b49\u64cd\u4f5c\u3002\u5185\u6838\u4e2d\u901a\u8fc7\u2f00\u4e2a\u540d\u4e3aAppleM2Scaler\u7684\u9a71\u52a8\u534f\u8c03\u2f64\u6237\u6001\u548c\u534f\u5904\u7406\u5668\u7684\u901a\u4fe1\u3002\u5bf9\u4e8e\u56fe\u50cf\u7f29\u653e\uff0c\u672c\u8d28\u4e0a\u662f\u2f64\u6237\u6001\u6307\u5b9a\u2f00\u4e2a\u2f6c\u6807\u5185\u5b58\u533a\u57df\u548c\u2f00\u4e2a\u6e90\u5185\u5b58\u533a\u57df\uff0cAppleM2Scaler\u901a\u77e5\u534f\u5904\u7406\u5668\u901a\u8fc7DMA\u2f45\u5f0f\u76f4\u63a5\u4ece\u6e90\u5185\u5b58\u533a\u57df\u8bfb\u53d6\u6570\u636e\u5904\u7406\u540e\u5199\u2f0a\u2f6c\u6807\u533a\u57df\u3002\u7136\u2f7d\uff0cAppleM2Scaler\u5ffd\u7565\u4e86\u2f64\u6237\u6001\u5185\u5b58\u7684\u8bfb\u5199\u5c5e\u6027\u3002\u8fd9\u5bfc\u81f4\u2f64\u6237\u6001\u5e94\u2f64\u53ef\u4ee5\u901a\u8fc7AppleM2Scaler\u9a71\u52a8\u4fee\u6539\u4efb\u610f\u53ea\u8bfb\u5185\u5b58\u3002<\/p>\n\n\n\n

\u8fd9\u4e2a\u6f0f\u6d1e\u2f50Linux\u4e0a\u7684\u810f\u2f5c\u6f0f\u6d1e\u8fd8\u8981\u4e25\u91cd\u30022018\u5e74\uff0c\u9648\u826f\u5229\u2f64\u8be5\u6f0f\u6d1e [8]\uff0c\u5728\u5e94\u2f64\u7a0b\u5e8f\u5185\u5b58\u7a7a\u95f4\u5185\u4fee\u6539\u4e86\u2f00\u5757\u53ea\u8bfb\u5185\u5b58\uff1b\u8fd9\u5757\u53ea\u8bfb\u5185\u5b58\u672c\u6765\u4ec5\u5185\u6838\u53ef\u5199\uff0c\u5185\u6838\u5728\u4f7f\u2f64\u8fd9\u4e9b\u6570\u636e\u65f6\u4e0d\u518d\u8fdb\u2f8f\u9a8c\u8bc1\uff1b\u9648\u826f\u5229\u2f64AppleM2Scaler\u7be1\u6539\u8fd9\u6bb5\u53ea\u8bfb\u5185\u5b58\u540e\u89e6\u53d1\u5185\u6838\u5176\u4ed6\u6f0f\u6d1e\uff0c\u5b9e\u73b0iOS\u7684\u8d8a\u72f1\u3002<\/p>\n\n\n\n

\u8fd9\u4e2a\u6f0f\u6d1e\u8fd8\u6709\u5f88\u591a\u5176\u4ed6\u5229\u2f64\u2f45\u5f0f\u3002iOS\u8bbe\u5907\u4e0a\u52a8\u6001\u94fe\u63a5\u5e93\u90fd\u88ab\u63d0\u524d\u94fe\u63a5\u4fdd\u5b58\u5728\u2f00\u4e2ashared cache\u2f42\u4ef6\u4e2d\u3002\u8fd9\u4e2ashared cache\u5728\u8bbe\u5907\u542f\u52a8\u4e4b\u521d\uff0c\u88ab\u52a0\u8f7d\u6620\u5c04\u5230\u5185\u5b58\u4e2d\u3002\u968f\u540e\u6240\u6709\u542f\u52a8\u7684\u8fdb\u7a0b\uff0c\u90fd\u4f1a\u5171\u4eab\u8fd9\u4e2ashared cache\u5185\u5b58\u3002\u5f53\u7136\u5bf9\u4e8e\u5176\u4e2d\u7684\u4ee3\u7801\u9875\u2faf\uff0c\u5e94\u2f64\u7a0b\u5e8f\u4ec5\u5177\u6709\u8bfb+\u6267\u2f8f\u7684\u6743\u9650\u3002AppleM2Scaler\u8fd9\u4e2a\u6f0f\u6d1e\u53ef\u4ee5\u76f4\u63a5\u7be1\u6539shared cache\u4ee3\u7801\u9875\u2faf\uff0c\u9020\u6210\u5728\u2fbc\u6743\u9650\u8fdb\u7a0b\u4e2d\u7684\u4efb\u610f\u4ee3\u7801\u6267\u2f8f\u3002\u503c\u5f97\u2f00\u63d0\u7684\u662f\uff0ciOS\u8bbe\u5907\u4e0a\u5f00\u542f\u4e86\u5f3a\u5236\u4ee3\u7801\u7b7e\u540d\u673a\u5236\u3002\u4fee\u6539\u4ee3\u7801\u9875\u2faf\u540e\uff0c\u5fc5\u987b\u907f\u514d\u7cfb\u7edf\u5bf9\u9875\u2faf\u518d\u6b21\u8fdb\u2f8f\u7b7e\u540d\u9a8c\u8bc1\u3002\u8fd9\u9700\u8981\u901a\u8fc7\u5176\u4ed6\u2f00\u4e9b\u6280\u5de7\u963b\u2f4c\u88ab\u4fee\u6539\u7684\u9875\u2faf\u89e6\u53d1page fault\u3002<\/p>\n\n\n\n

\u9664\u4e86DMA\uff0c\u7cfb\u7edf\u8fd8\u53ef\u80fd\u6709\u5176\u4ed6\u201c\u9690\u853d\u5199\u201d\u64cd\u4f5c\u3002Jann Horn\u9488\u5bf9\u2f42\u4ef6\u6620\u5c04\u5185\u5b58\u505a\u4e86\u2f00\u4e9b\u7814\u7a76 [9,10]\uff0c\u53d1\u73b0\u4e86\u2f00\u4e9b\u653b\u51fb\u8def\u5f84\u3002\u4f8b\u5982\uff0c\u628a\u2f42\u4ef6\u6620\u5c04\u5230\u5185\u5b58\u540e\uff0c\u4ee5COW\u5f62\u5f0f\u5206\u4eab\u7ed9\u53e6\u2f00\u4e2a\u8fdb\u7a0b\uff0c\u6b64\u65f6\u2f42\u4ef6\u5185\u5bb9\u7f13\u5b58\u5728\u7269\u7406\u5185\u5b58\u9875\u2faf\u3002\u5f53\u7cfb\u7edf\u5185\u5b58\u5403\u7d27\u65f6\uff0c\u2f42\u4ef6\u5185\u5b58\u9875\u2faf\u4f1a\u88ab\u4ea4\u6362\u51fa\u53bb\uff1b\u4f46\u662fJann Horn\u53d1\u73b0\uff0c\u5f53\u8fd9\u4e9b\u5185\u5b58\u9875\u2faf\u518d\u6b21\u88ab\u8bbf\u95ee\u65f6\uff0c\u7cfb\u7edf\u4f1a\u4ece\u78c1\u76d8\u4e2d\u91cd\u65b0\u8bfb\u53d6\u2f42\u4ef6\u6062\u590d\u9875\u2faf\u5185\u5bb9\u3002\u8fd9\u5c31\u9020\u6210\u4e86\u2f00\u4e2a\u653b\u51fb\u7a97\u53e3\u3002\u5982\u679c\u2f42\u4ef6\u6765\u6e90\u4e8e\u653b\u51fb\u8005\u2f83\u2f30\u52a0\u8f7d\u7684\u2f42\u4ef6\u7cfb\u7edf\u955c\u50cf\uff0c\u653b\u51fb\u8005\u53ef\u4ee5\u76f4\u63a5\u4fee\u6539(pwrite) \u8fd9\u4e2a\u2f42\u4ef6\u7cfb\u7edf\u955c\u50cf\u4ece\u2f7d\u4fee\u6539\u76f8\u5e94\u2f42\u4ef6\u5185\u5bb9\u3002\u8fd9\u6837\u4ece\u2f42\u4ef6\u4e2d\u518d\u6b21\u6062\u590d\u7269\u7406\u9875\u2faf\u5185\u5bb9\u65f6\uff0c\u7269\u7406\u9875\u2faf\u5185\u5bb9\u4e0d\u518d\u4e0e\u4e4b\u524d\u9875\u2faf\u5185\u5bb9\u2f00\u81f4\uff0c\u7834\u574fCOW\u7684\u8bed\u610f\u3002<\/p>\n\n\n\n

4.3 \u5371\u9669\u7684\u9501<\/strong><\/p>\n\n\n\n

2018\u5e74\uff0cIan Beer \u53d1\u73b0XNU\u5728\u5904\u7406COW\u6620\u5c04\u65f6\uff0c\u6709\u8fd9\u6837\u2f00\u4e2a\u4f18\u5316\u7b56\u7565\uff1a\u5f53\u2f00\u4e2a\u8fdb\u7a0b\u901a\u8fc7mach message\u628a\u2f00\u4e2a\u865a\u62df\u5730\u5740VA\u5bf9\u5e94\u7684\u5185\u5b58\u4ee5COW\u5f62\u5f0f\u53d1\u9001\u51fa\u53bb\uff0c\u5e76\u4e14\u5728mach message\u4e2d\u6307\u660e\u6d88\u606f\u53d1\u9001\u540e\u5c31\u5728\u672c\u5730\u91ca\u653e\u865a\u62df\u5730\u5740VA\u65f6\uff0cXNU\u4f1a\u5ffd\u7565COW\u2f7d\u76f4\u63a5\u628a VA\u5bf9\u5e94\u7684\u5185\u5b58\u9879\u79fb\u5230\u63a5\u6536\u2f45\uff0c\u7701\u6389\u4e86\u5c06\u5185\u5b58\u53d8\u4e3aCOW\u6240\u9700\u7684\u9875\u2faf\u6743\u9650\u4fee\u6539\u7684\u8fc7\u7a0b\u3002<\/p>\n\n\n\n

\u7136\u2f7d\uff0c\u8fd9\u4e2a\u4f18\u5316\u7b56\u7565\u5b9e\u73b0\u7684\u8fc7\u7a0b\u4e2d\u5b58\u5728\u6761\u4ef6\u7ade\u4e89 [11]\uff0c\u5bfc\u81f4\u2f00\u4e2a\u8fdb\u7a0b\u53ef\u4ee5\u540c\u65f6\u628aVA\u53d1\u9001\u7ed9\u53e6\u2f00\u4e2a\u8fdb\u7a0b\u548c\u2f83\u2f9d\u3002\u8fd9\u6837\u53e6\u5916\u2f00\u4e2a\u8fdb\u7a0b\u548c\u2f83\u2f9d\u8fdb\u7a0b\u90fd\u4f5c\u4e3a\u8fd9\u4e2aVA\u7684\u63a5\u6536\u2f45\uff0c\u90fd\u4f1a\u83b7\u53d6\u8fd9\u4e2aVA\u5bf9\u5e94\u5185\u5b58\u7684\u8bbf\u95ee\u6743\u9650\uff1b\u2f7d\u6839\u636e\u4f18\u5316\u7b56\u7565\uff0c\u8fd9\u4e24\u6b21\u63a5\u53d7\u90fd\u4e0d\u4f1a\u6fc0\u6d3bCOW\u590d\u5236\u3002Ian Beer\u5229\u2f64\u8fd9\u4e2a\u7279\u6027\uff0c\u5728A12\u673a\u578b\u4e0a\u91cd\u73b0\u4e86\u4e0a\u2f42Lokihardt\u9488\u5bf9libxpc\u53cd\u5e8f\u5217\u5316\u7684\u53cc\u53d6\u6f0f\u6d1e\u653b\u51fb\u3002<\/p>\n\n\n\n

Ian Beer\u57282018\u5e7412\u2f49\u62a5\u544a\u4e86\u8fd9\u4e2a\u95ee\u9898\uff0cApple\u57282019\u5e74\u521d\u5bf9\u8be5\u95ee\u9898\u505a\u4e86\u2f00\u6b21\u4fee\u590d\u3002\u5dee\u4e0d\u591a\u65f6\u9694\u2f00\u5e74\u540e\uff0c2019\u5e7410\u2f49Ian Beer\u518d\u6b21\u5206\u6790\u8fd9\u4e2a\u6f0f\u6d1e\u65f6\uff0c\u53d1\u73b0\u7531\u4e8e\u6761\u4ef6\u7ade\u4e89\u7684\u590d\u6742\u6027\uff0cApple\u7684\u8fd9\u6b21\u4fee\u590d\u5e76\u4e0d\u5b8c\u6574\u3002Ian Beer\u518d\u6b21\u63d0\u4ea4\u4e86PoC\u3002\u6839\u636eIan Beer \u7684\u62a5\u544a\uff0cApple\u57282020\u5e74\u521d\u518d\u6b21\u5bf9\u6f0f\u6d1e\u4fee\u590d\u3002<\/p>\n\n\n\n

5.\u7ed3\u8bed<\/strong><\/p>\n\n\n\n

\u672c\u2f42\u56de\u987e\u4e86XNU\u5728VM\u7ba1\u7406\u5c42\u2faf\u7684\u2f00\u4e9b\u5386\u53f2\u6f0f\u6d1e\uff0c\u5c24\u5176\u662f\u56f4\u7ed5COW\u5b9e\u73b0\u7684\u5404\u4e2a\u73af\u8282\uff0c\u5206\u6790\u4e86\u5404\u79cd\u7684\u6f0f\u6d1e\u6210\u56e0\u3002\u5c3d\u7ba1\u8fd9\u4e9b\u6f0f\u6d1e\u5df2\u7ecf\u4fee\u590d\uff0c\u5176\u5b9e\u8fd8\u6709\u5f88\u591a\u5f00\u653e\u6027\u95ee\u9898\u662f\u672c\u2f42\u6ca1\u6709\u89e3\u7b54\u7684\u3002\u4f8b\u5982\uff0cApple\u9488\u5bf9\u8fd9\u4e9b\u6f0f\u6d1e\u7684\u4fee\u590d\u662f\u5426\u5b8c\u5907\uff1f\u6709\u6ca1\u6709\u5176\u4ed6\u9014\u5f84\u7ed5\u8fc7\u8fd9\u4e9b\u4fee\u590d\uff1f\u968f\u7740\u7cfb\u7edf\u529f\u80fd\u7684\u4e0d\u65ad\u53d8\u5316\uff0c\u4f1a\u4e0d\u4f1a\u518d\u6b21\u5f15\u2f0a\u672a\u9884\u671f\u7684\u5171\u4eab\uff1f\u9664\u4e86\u2f42\u4ef6\u6620\u5c04\u5185\u5b58\u548cDMA\uff0c\u7cfb\u7edf\u4e2d\u662f\u5426\u8fd8\u5b58\u5728\u9690\u853d\u7684\u5199\u64cd\u4f5c\u7ed5\u8fc7COW\uff1f\u73b0\u6709\u7684COW\u5b9e\u73b0\u662f\u4e0d\u662f\u8fd8\u6709\u6f0f\u6d1e\uff1f\u5e0c\u671b\u8fd9\u4e9b\u95ee\u9898\u80fd\u5f15\u53d1\u2f24\u5bb6\u7684\u601d\u8003\uff0c\u6fc0\u53d1\u2f24\u5bb6\u7075\u611f\u53bb\u5bfb\u627e\u65b0\u7684\u5b89\u5168\u95ee\u9898\u3002<\/p>\n\n\n\n

\u53c2\u8003\u6587\u732e<\/strong><\/p>\n\n\n\n

1. MacOS uses an insecure swap file. https:\/\/bugs.chromium.org\/p\/project-zero\/issues\/detail?id=1131, 2017.
<\/p>\n\n\n\n

2.  About System Integrity Protection on your Mac.<\/p>\n\n\n\n

3.  macOS\/IOS: mach_msg doesn’t copy memory in a certain case.<\/p>\n\n\n\n

https:\/\/bugs.chromium.org\/p\/project-zero\/issues\/detail?d=1083. 2017.<\/p>\n\n\n\n

4. Many iOS\/MacOS sandbox escapes due to unexpected shared memory-backed xpc_data object. https:\/\/bugs.chromium.org\/p\/project-zero\/issues\/detail?id=1247. 2017.<\/p>\n\n\n\n

5. Racing for everyone: descriptor describes TOCTOU in Apple\u2019s core.<\/p>\n\n\n\n

6. Pwning the macOS Sierra Kernel Inside the Safari Sandbox.<\/p>\n\n\n\n

7. Don\u2019t place a port in shared memory. https:\/\/blog.pangu.io\/?p=221 .<\/p>\n\n\n\n

8. KeenLab iOS Jailbreak Internals. https:\/\/i.blackhat.com\/us-18\/Wed-August-8\/us-18-Chen-KeenLab-iOS-Jailbreak-Internals.pdf<\/p>\n\n\n\n

9. XNU: copy-on-write behavior bypass via partial-page truncation of file.<\/p>\n\n\n\n

https:\/\/ bugs.chromium.org\/p\/project-zero\/issues\/detail?id=1725. 2018.<\/p>\n\n\n\n

10. XNU: copy-on-write behavior bypass via mount of user-owned filesystem image. https:\/\/bugs.chromium.org\/p\/project-zero\/issues\/detail?id=1726.2018.<\/p>\n\n\n\n

11. XNU vm_map_copy optimization which requires atomicity isn’t atomic.<\/p>\n\n\n\n

https:\/\/ bugs.chromium.org\/p\/project-zero\/issues\/detail?id=1728. 2018.<\/p>\n\n\n\n

\u5173\u4e8e\u4f5c\u8005<\/strong><\/p>\n\n\n\n

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