{"id":157,"date":"2022-04-24T22:31:08","date_gmt":"2022-04-24T14:31:08","guid":{"rendered":"http:\/\/www.aqwu.net\/wp\/?p=157"},"modified":"2022-04-24T22:35:41","modified_gmt":"2022-04-24T14:35:41","slug":"2022-%e5%b9%b4%e7%bc%96%e5%86%99-linux-%e5%86%85%e6%a0%b8%e8%bf%9c%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/www.aqwu.net\/wp\/?p=157","title":{"rendered":"2022 \u5e74\u7f16\u5199 Linux \u5185\u6838\u8fdc\u7a0b"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u539f\u6587\u94fe\u63a5\uff1ahttps:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u5728\u8fd9\u7bc7\u535a\u5ba2\u4e2d\uff0c\u6211\u4eec\u7814\u7a76\u4e86 2022 \u5e74\u8fdc\u7a0b\u5229\u7528 Linux \u5185\u6838\u7684\u60c5\u51b5\uff0c\u91cd\u70b9\u4ecb\u7ecd\u4e86\u4e3b\u8981\u969c\u788d\u4ee5\u53ca\u4e0e\u672c\u5730\u5229\u7528\u7684\u5f02\u540c\u3002<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"overview\">\u6982\u8ff0<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728 Appgate \u5a01\u80c1\u54a8\u8be2\u670d\u52a1\uff0c\u6211\u4eec\u4e13\u6ce8\u4e8e\u653b\u51fb\u6027\u5b89\u5168\u7814\u7a76\uff0c\u4ee5\u8ddf\u4e0a\u4e0d\u65ad\u53d1\u5c55\u7684\u7f51\u7edc\u5b89\u5168\u5f62\u52bf\u3002\u6211\u4eec\u76f8\u4fe1\u4e86\u89e3\u8fdb\u653b\u6280\u672f\u548c\u8d8b\u52bf\u53ef\u4ee5\u63d0\u4f9b\u51fa\u8272\u7684\u9632\u5b88\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u8fd9\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u7684\u76ee\u6807\u662f\u901a\u8fc7\u6211\u4eec\u7684\u5a01\u80c1\u54a8\u8be2\u670d\u52a1\u56e2\u961f\u6700\u8fd1\u53d1\u73b0\u7684\u8fdc\u7a0b\u5806\u6808\u6ea2\u51fa (&nbsp;<a href=\"https:\/\/blog.immunityinc.com\/p\/a-remote-stack-overflow-in-the-linux-kernel\/\" target=\"_blank\" rel=\"noreferrer noopener\">CVE-2022-0435<\/a>&nbsp;)\u6765\u9610\u660e\u8fdc\u7a0b\u5185\u6838\u5229\u7528\u3002\u6211\u5728\u5904\u7406\u8fd9\u4e2a\u9519\u8bef\u65f6\u6ce8\u610f\u5230\uff0c\u4e0e\u6211\u4eec\u5728\u672c\u5730\u6743\u9650\u63d0\u5347 (LPE) \u7a7a\u95f4\u4e2d\u62e5\u6709\u7684\u5927\u91cf\u9ad8\u8d28\u91cf\u6587\u7ae0\u76f8\u6bd4\uff0c\u5185\u6838\u8fdc\u7a0b\u53ef\u7528\u7684\u4fe1\u606f\u76f8\u5f53\u7a00\u5c11\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u901a\u8fc7\u4ecb\u7ecd\u7f16\u5199\u8fd9\u4e2a\u8fdc\u7a0b\u5185\u6838\u6240\u6d89\u53ca\u7684\u5404\u4e2a\u6b65\u9aa4\uff0c\u6211\u5e0c\u671b\u65e2\u80fd\u63d0\u4f9b\u4e00\u4e9b\u5173\u4e8e\u8fdc\u7a0b Linux \u5185\u6838\u5229\u7528\u7684\u65b0\u89c1\u89e3\uff0c\u53c8\u80fd\u5f3a\u8c03\u4e0e\u672c\u5730\u5229\u7528\u7684\u5f02\u540c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"background\">\u80cc\u666f<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f5c\u4e3a\u80cc\u666f\uff0c\u5f53\u6211\u5728 12 \u6708\u52a0\u5165 Appgate \u5a01\u80c1\u54a8\u8be2\u670d\u52a1\u65f6\uff0c\u6211\u7684\u56e2\u961f\u8d1f\u8d23\u4eba\u5efa\u8bae\u6211\u4ece\u63a2\u7d22\u4e24\u4e2a\u5de7\u5999\u7684 Linux \u9519\u8bef\u5f00\u59cb\u3002\u4e24\u8005\u90fd\u6709\u73b0\u6709\u7684 LPE \u6982\u5ff5\u9a8c\u8bc1 (PoC)\uff0c\u4f46\u662f\u5176\u4e2d\u4e00\u4e2a\u662f\u5806\u6ea2\u51fa\uff0c\u5b83\u4e5f\u6070\u597d\u53ef\u4ee5\u8fdc\u7a0b\u8bbf\u95ee<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[0]<\/a>\uff0c\u5c3d\u7ba1\u6ca1\u6709\u8fdc\u7a0b PoC\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u7136\uff0c\u4f5c\u4e3a\u4e00\u540d\u65b0\u5458\u5de5\u5e76\u60f3\u7ed9\u4eba\u7559\u4e0b\u597d\u5370\u8c61\uff0c\u6211\u8c28\u614e\u884c\u4e8b\u5e76\u575a\u6301\u4f7f\u7528 LPE\u2026\u2026\u4e0d\uff0c\u6211\u5728\u5f00\u8c01\u7684\u73a9\u7b11\uff1f\u5f53\u7136\uff0c\u6211\u65e0\u6cd5\u6297\u62d2\u8fdc\u7a0b\u5185\u6838\u5229\u7528\u7684\u8bf1\u60d1\uff01<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8c08\u8bba\u8bd5\u70bc\uff08\u5c3d\u7ba1\u5b8c\u5168\u662f\u81ea\u5df1\u9020\u6210\u7684\uff09\uff0c\u4f46\u540e\u6765\u51fa\u73b0\u4e86\u4e00\u4e2a\u65b0\u6f0f\u6d1e\u548c\u5f88\u591a\u65ad\u70b9\uff0c\u6211\u5f88\u9ad8\u5174\u80fd\u591f\u5199\u8fd9\u7bc7\u6587\u7ae0\uff0c\u76ee\u7684\u662f\u5206\u4eab\u6211\u7684\u4e00\u4e9b\u5de5\u4f5c\u5e76\u4e3a\u4e00\u4e2a\u5f88\u68d2\u7684\u793e\u533a\u505a\u51fa\u8d21\u732e.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"setting-the-scene\">\u8bbe\u7f6e\u573a\u666f<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u597d\u4e86\uff0c\u5bd2\u6684\u5230\u6b64\u4e3a\u6b62\uff0c\u8ba9\u6211\u4eec\u6765\u4e86\u89e3\u4e00\u4e9b\u6280\u672f\u5427\uff01\u6b63\u5982\u6211\u4e4b\u524d\u63d0\u5230\u7684\uff0c\u6211\u4eec\u5c06\u7814\u7a76\u6211\u5728 CVE-2022-0435 \u4e0a\u7684\u5de5\u4f5c\uff0c\u56e0\u6b64\u6700\u597d\u4ecb\u7ecd\u4e00\u4e0b\u5b83\u5230\u5e95\u662f\u4ec0\u4e48\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">CVE-2022-0435 \u662f Linux \u5185\u6838\u7684\u900f\u660e\u8fdb\u7a0b\u95f4\u901a\u4fe1 (TIPC) \u7f51\u7edc\u6a21\u5757\u4e2d\u53ef\u8fdc\u7a0b\u89e6\u53d1\u7684\u5806\u6808\u6ea2\u51fa\u3002\u6211\u4eec\u57fa\u672c\u4e0a\u80fd\u591f\u5c06\u653b\u51fb\u8005\u63a7\u5236\u5927\u5c0f\u7684\u6709\u6548\u8f7d\u8377\u53d1\u9001\u5230\u76ee\u6807\uff0c\u5728\u90a3\u91cc\u5b83\u5c06\u88ab memcpy&#8217;d \u5230\u5185\u6838\u5806\u6808\u4e0a\u7684 272 \u5b57\u8282\u7f13\u51b2\u533a\u4e2d\u2014\u2014\u8fd9\u4e0d\u662f\u4e00\u4e2a\u7cdf\u7cd5\u7684\u539f\u8bed\uff0c\u5bf9\u5427\uff1f<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd8\u6709\u6bd4\u8fd9\u66f4\u591a\u7684\u7ec6\u5fae\u5dee\u522b\uff0c\u6211\u4eec\u5c06\u5f88\u5feb\u8ba8\u8bba\u6709\u6548\u8d1f\u8f7d\u9650\u5236\uff0c\u4f46\u8fd9\u662f\u5b83\u7684\u4e00\u822c\u8981\u70b9\u3002\u6709\u5173 TIPC \u7684\u66f4\u591a\u4fe1\u606f\u548c\u5bf9 bug \u7684\u66f4\u8be6\u7ec6\u4e86\u89e3\uff0c\u60a8\u53ef\u4ee5\u67e5\u770b\u6211\u7684\u4e0a\u4e00\u7bc7\u6587\u7ae0<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[1]<\/a>\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6211\u4eec\u53d1\u9001\u7684\u201c\u6709\u6548\u8d1f\u8f7d\u201d\u4f2a\u88c5\u6210\u57df\u8bb0\u5f55\uff0c\u5728 TIPC \u8282\u70b9\u4e4b\u95f4\u4f20\u8f93\u4ee5\u5171\u4eab\u7f51\u7edc\u62d3\u6251\u89c6\u56fe\u3002\u8fd9\u662f\u7ed3\u6784\u5b9a\u4e49\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#define MAX_MON_DOMAIN       64\n...\n\n\/* struct tipc_mon_domain: domain record to be transferred between peers\n * @len: actual size of domain record\n * @gen: current generation of sender's domain\n * @ack_gen: most recent generation of self's domain acked by peer\n * @member_cnt: number of domain member nodes described in this record\n * @up_map: bit map indicating which of the members the sender considers up\n * @members: identity of the domain members\n *\/\nstruct tipc_mon_domain {\n    u16 len;\n    u16 gen;\n    u16 ack_gen;\n    u16 member_cnt;\n    u64 up_map;\n    u32 members&#91;MAX_MON_DOMAIN];\n};\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f46\u662f\u5c71\u59c6\uff0c\u90a3\u4e2a\u7ed3\u6784\u663e\u7136\u662f 272 \u5b57\u8282\uff1f\u4f60\u7684\u5047\u8bbe\u662f\u6b63\u786e\u7684\uff01\u8fd9\u5c31\u662f\u6f0f\u6d1e\u6240\u5728\u3002\u5f53\u6a21\u5757\u63a5\u6536\u5230\u8fd9\u4e9b\u57df\u8bb0\u5f55\u65f6<code>tipc_mon_rcv()<\/code>\uff0c\u5b83\u4e0d\u4f1a\u68c0\u67e5<code>member_cnt &lt;= MAX_MON_DOMAIN<\/code>\uff1b\u8fd9\u5b9e\u8d28\u4e0a\u5141\u8bb8\u653b\u51fb\u8005\u63d0\u4ea4\u8fd9\u4e9b\u5f39\u6027\u5bf9\u8c61\uff0c\u5c31\u597d\u50cf\u6211\u4eec\u5df2\u7ecf\u63d0\u4ea4\u4e86<code>u32 members[member_cnt]<\/code>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u7a0d\u540e\uff0c\u5f53\u65b0\u7684\u57df\u8bb0\u5f55\u88ab\u7f13\u5b58\u65f6\uff0cTIPC \u5c06\u8fd9\u4e2a\u4efb\u610f\u5927\u5c0f\u7684\u57df\u8bb0\u5f55\u590d\u5236\u5230\u4e00\u4e2a\u9884\u8ba1\u6700\u591a 272 \u5b57\u8282\u7684\u5806\u6808\u7f13\u51b2\u533a\u4e2d\u2014\u2014\u8fd9\u5c31\u662f\u6211\u4eec\u7684\u5806\u6808\u6ea2\u51fa\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6709\u4e86\u8fd9\u4e9b\uff0c\u8ba9\u6211\u4eec\u6765\u8c08\u8c08\u6211\u4eec\u7684\u6709\u6548\u8f7d\u8377\u7684\u7ea6\u675f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><code>len<\/code>,&nbsp;<code>gen<\/code>,<code>ack_gen<\/code>\u548c<code>member_cnt<\/code>\u503c\u90fd\u53d7\u5230\u7ea6\u675f<\/li><li>\u4f46\u662f\uff0c<code>up_map<\/code>\u5e76\u4e14<code>members<\/code>\u53ef\u4ee5\u662f\u4efb\u610f\u7684<\/li><li>\u6709\u6548\u8f7d\u8377\u5927\u5c0f\u7531\u6211\u4eec\u7528\u6765\u53d1\u9001\u6709\u6548\u8f7d\u8377\u7684\u534f\u8bae\u7684\u6700\u5927\u4f20\u8f93\u5355\u5143 (MTU)\u5b9a\u4e49<code>len<\/code>\u5e76\u53d7\u5176\u7ea6\u675f\uff1b<code>member_cnt<\/code>\u867d\u7136\u6211\u4eec\u7a0d\u540e\u4f1a\u8c08\u5230\uff0c\u5982\u679c\u6211\u4eec\u60f3\u5c06\u6267\u884c\u5e72\u51c0\u5730\u4ea4\u8fd8\u7ed9\u5185\u6838\uff0c\u8fd9\u53ef\u80fd\u4f1a\u66f4\u77ed<\/li><li>\u5982\u679c\u6211\u4eec\u8fd8\u6ca1\u6709\u5f15\u8d77\u5185\u6838\u6050\u614c\uff0c\u6211\u4eec\u53ef\u4ee5\u591a\u6b21\u89e6\u53d1\u8fd9\u4e2a\u9519\u8bef<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"pwning-glossary\">Pwning \u8bcd\u6c47\u8868<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e3a\u4e86\u4f7f\u8fd9\u5835\u6587\u5b57\u5899\u66f4\u5bb9\u6613\u8bbf\u95ee\uff0c\u8fd9\u91cc\u6709\u4e00\u4e9b\u76f8\u5173\u6280\u672f\/\u7f13\u89e3\u63aa\u65bd\u4ee5\u53ca\u5e38\u7528\u672f\u8bed\u7684\u8d44\u6e90\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>LPE\uff1a\u672c\u5730\u6743\u9650\u5347\u7ea7\uff1a\u5229\u7528\u5177\u6709\u672c\u5730\u7528\u6237\u8bbf\u95ee\u6743\u9650\u7684\u76ee\u6807<\/li><li>RCE\uff1a\u8fdc\u7a0b\u4ee3\u7801\u6267\u884c\uff1a\u8fdc\u7a0b\u5229\u7528\u76ee\u6807<\/li><li>ROP\uff1a\u9762\u5411\u8fd4\u56de\u7684\u7f16\u7a0b\uff1b\u53c2\u89c1&nbsp;<a href=\"https:\/\/codearcana.com\/posts\/2013\/05\/28\/introduction-to-return-oriented-programming-rop.html\" target=\"_blank\" rel=\"noreferrer noopener\">Code Arcana \u7684 ROP \u7b80\u4ecb<\/a>(2013)<\/li><li><code>$RAX<\/code>\uff1a<code>x86_64<\/code>\u6613\u5931\u6027\u5bc4\u5b58\u5668\uff1b\u5e38\u7528\u4e8e\u5b58\u50a8\u8fd4\u56de\u503c<\/li><li><code>$RIP<\/code>\uff1a<code>x86_64<\/code>\u6307\u4ee4\u6307\u9488\u5bc4\u5b58\u5668\uff1b\u6307\u5411\u4e0b\u4e00\u6761\u8981\u6267\u884c\u7684\u6307\u4ee4\uff1b\u201c\u83b7\u5f97<code>$RIP<\/code>\u63a7\u5236\u201d = \u63a7\u5236\u6d41\u52ab\u6301<\/li><li><code>$RSP<\/code>\uff1a<code>x86_64<\/code>\u5806\u6808\u6307\u9488\uff1b\u6307\u5411\u5f53\u524d\u6808\u5e27\u7684\u9876\u90e8<\/li><li>\u5806\u6808\u7c89\u788e\uff1a\u7528\u4e8e\u5229\u7528\u5806\u6808\u7f13\u51b2\u533a\u6ea2\u51fa\u7684\u6280\u672f\u7684\u672f\u8bed\uff1b\u7531 Aleph One&nbsp;1998 \u5e74\u7684 Phrack \u6587\u7ae0<a href=\"http:\/\/phrack.org\/issues\/49\/14.html#article\" target=\"_blank\" rel=\"noreferrer noopener\">\u201cSmashing The Stack For Fun and Profit\u201d\u6c38\u5782\u4e0d\u673d<\/a><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"game-plan\">\u6bd4\u8d5b\u8ba1\u5212<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u597d\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u6709\u4e00\u4e2a\u975e\u5e38\u597d\u7684\u8fdc\u7a0b\u5806\u6808\u6ea2\u51fa\u539f\u8bed\uff0c\u4f46\u662f\u6211\u4eec\u4ece\u8fd9\u91cc\u5f00\u59cb\u5462\uff1f\u5728\u6211\u4eec\u60f3\u51fa\u4e00\u4e2a\u6e38\u620f\u8ba1\u5212\u4e4b\u524d\uff0c\u8ba9\u6211\u4eec\u8bc4\u4f30\u4e00\u4e0b\u6211\u4eec\u5f88\u53ef\u80fd\u5728\u76f8\u5bf9\u6700\u65b0\u7684\u5185\u6838\u4e0a\u9047\u5230\u7684\u76f8\u5173\u7f13\u89e3\u63aa\u65bd\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li><code>KASLR<\/code>: \u5185\u6838\u5730\u5740\u7a7a\u95f4\u5e03\u5c40\u968f\u673a\u5316\u5c06\u5728\u5f15\u5bfc\u65f6\u968f\u673a\u5316\u5185\u6838\u7684\u4f4d\u7f6e\uff0c\u8fd9\u4e5f\u8bb8\u4e0d\u8db3\u4e3a\u5947\u3002\u5bf9\u6211\u4eec\u6765\u8bf4\uff0c\u8fd9\u610f\u5473\u7740\u6bcf\u6b21\u7cfb\u7edf\u542f\u52a8\u65f6\u5185\u6838\u51fd\u6570\u7684\u5730\u5740\u90fd\u4f1a\u76f8\u5dee\u4e00\u4e2a\u4f2a\u968f\u673a\u504f\u79fb\u91cf\u3002\u6ce8\u610f\u5185\u6838\u7684\u987a\u5e8f\u6ca1\u6709\u6539\u53d8\uff0c\u53ea\u662f\u5185\u6838\u57fa\u5730\u5740&nbsp;<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[2]<\/a><\/li><li><code>CONFIG_STACKPROTECTOR<\/code>\uff1a\u4e5f\u79f0\u4e3a\u5806\u6808\u91d1\u4e1d\u96c0\uff0c\u6b64\u7f13\u89e3\u5728\u51fd\u6570\u5e8f\u8a00\u671f\u95f4\u5411\u5806\u6808\u6dfb\u52a0\u4e00\u4e2a\u4f2a\u968f\u673a\u503c\uff0c\u5e76\u68c0\u67e5\u5b83\u5728\u7ed3\u8bed\u4e2d\u662f\u5426\u5b8c\u597d\u65e0\u635f\u3002\u8fd9\u4e2a\u91d1\u4e1d\u96c0\u5c06\u4f4d\u4e8e\u7f13\u51b2\u533a\u548c\u8fd4\u56de\u5730\u5740\u4e4b\u95f4\uff0c\u8fd9\u610f\u5473\u7740\u4efb\u4f55\u6ea2\u51fa\u90fd\u4f1a\u9996\u5148\u7834\u574f\u8fd9\u4e2a\u91d1\u4e1d\u96c0\u503c\u3002\u5982\u679c\u5185\u6838\u53d1\u73b0\u91d1\u4e1d\u96c0\u53d1\u751f\u4e86\u53d8\u5316\uff0c\u5c31\u4f1a\u5bfc\u81f4\u5185\u6838\u6050\u614c\u3002\u6e38\u620f\u7ed3\u675f\uff01<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[3]<\/a><\/li><li><code>SMEP<\/code>&amp;&nbsp;<code>SMAP<\/code>\uff1aSupervisor Mode Execution Prevention \u548c Supervisor Mode Access Prevention \u5206\u522b\u963b\u6b62\u6211\u4eec\u5728\u5185\u6838\u4e0a\u4e0b\u6587\/\u73af 0 \u4e2d\u8fd0\u884c\u65f6\u6267\u884c\u7528\u6237\u6a21\u5f0f\u4ee3\u7801\u548c\u53d6\u6d88\u5f15\u7528\u7528\u6237\u6a21\u5f0f\u6307\u9488\u3002&nbsp;<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[4]<\/a><\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u6211\u4eec\u7528\u8fdc\u7a0b\u5806\u6808\u6ea2\u51fa\u6210\u529f\u8986\u76d6\u8fd4\u56de\u5730\u5740\u5e76\u83b7\u5f97\u6267\u884c\u63a7\u5236\u6743\uff0c\u6211\u4eec\u8fd8\u9700\u8981\u8003\u8651\u6211\u4eec\u5c06\u52ab\u6301\u7684\u6267\u884c\u4e0a\u4e0b\u6587\u3002\u4e0e\u5927\u591a\u6570\u672c\u5730\u6f0f\u6d1e\u5229\u7528\u573a\u666f\u4e0d\u540c\uff0c\u6211\u4eec\u4e0d\u4f1a\u5728<strong>\u8fdb\u7a0b\u4e0a\u4e0b\u6587<\/strong>\u4e2d\u64cd\u4f5c\uff0c\u800c\u662f\u4f1a\u53d1\u73b0\u81ea\u5df1\u5904\u4e8e<strong>\u4e2d\u65ad\u4e0a\u4e0b\u6587\u4e2d<\/strong>\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u672c\u5730\u5229\u7528\u4e2d\uff0c\u6211\u4eec\u901a\u5e38\u4f1a\u901a\u8fc7\u7cfb\u7edf\u8c03\u7528\u5230\u8fbe\u5185\u6838\u4e2d\u6613\u53d7\u653b\u51fb\u7684\u4ee3\u7801\u8def\u5f84\uff0c\u5176\u4e2d\u7528\u6237\u6a21\u5f0f\u8fdb\u7a0b\u53ef\u4ee5\u8bf7\u6c42\u5185\u6838\u4ee3\u8868\u5b83\u6267\u884c\u7279\u6743\u64cd\u4f5c\uff08\u7a0d\u540e\u6211\u4eec\u5c06\u5bf9\u6b64\u8fdb\u884c\u66f4\u591a\u8ba8\u8bba\uff09\u3002Linux \u4e2d\u7684\u8fdb\u7a0b\u5728\u5185\u6838\u4e2d\u901a\u8fc7 \u8ddf\u8e2a<code>struct task_struct<\/code>\uff0c\u5b83\u9a7b\u7559\u5728\u5206\u914d\u7ed9\u6bcf\u4e2a\u8fdb\u7a0b\u7684\u5185\u6838\u5806\u6808\u4e0a\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u5185\u6838\u4ee3\u8868\u7528\u6237\u6a21\u5f0f\u8fdb\u7a0b\u5de5\u4f5c\u65f6\uff0c\u5b83\u5728\u8c03\u7528\u8fdb\u7a0b\u7684\u76f8\u5e94\u5185\u6838\u5806\u6808\u4e0a\u8fd0\u884c\uff0c\u5373\u5728\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u4e2d\u3002\u5f53\u6211\u4eec\u8fdc\u7a0b\u653b\u51fb\u76ee\u6807\u65f6\uff0c\u6ca1\u6709\u5173\u8054\u7684\u8fdb\u7a0b\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https:\/\/blog.immunityinc.com\/img\/linux_contexts.png\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"https:\/\/blog.immunityinc.com\/img\/linux_contexts.png\" alt=\"\"\/><\/a><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">\u76f8\u53cd\uff0c\u6211\u4eec\u5411\u76ee\u6807\u53d1\u9001\u4e00\u4e2a\u6570\u636e\u5305\uff0c\u7136\u540e\u7531\u7f51\u5361\u63a5\u6536\u3002\u7f51\u5361\u7136\u540e\u4ea7\u751f\u4e00\u4e2a\u4e2d\u65ad\u6765\u8868\u793a\u4e00\u4e2a\u6570\u636e\u5305\u5df2\u7ecf\u5230\u8fbe\u3002\u7136\u540e\u6267\u884c\u6d41\u7a0b\u5c06\u6682\u505c\uff0c\u76f8\u5e94\u7684\u4e2d\u65ad\u5904\u7406\u7a0b\u5e8f\u5c06\u8fd0\u884c\u3002\u5728\u6211\u4eec\u7684\u4f8b\u5b50\u4e2d\uff0c\u89e6\u53d1\u5806\u6808\u6ea2\u51fa\u7684\u7f51\u7edc\u5806\u6808\u5728\u6b64\u4e2d\u65ad\u4e0a\u4e0b\u6587\u4e2d\u8fd0\u884c\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ece\u5229\u7528\u4e0a\u4e0b\u6587\u6765\u770b\uff0c\u8fd9\u610f\u5473\u7740\u5f53\u6211\u4eec\u5728\u5185\u6838\u4e2d\u6267\u884c\u65f6\uff0c\u6ca1\u6709\u5173\u8054\u7684\u7528\u6237\u7a7a\u95f4\u4f9b\u6211\u4eec\u63d0\u5347\u6743\u9650\u548c\u6ce8\u5165\u6709\u6548\u8d1f\u8f7d\uff08\u4f8b\u5982\uff0c\u8fdc\u7a0b\u4fa6\u542c\u5668\uff09\u3002\u6b64\u5916\uff0c\u4e2d\u65ad\u4e0a\u4e0b\u6587\u6709\u5176\u81ea\u8eab\u7684\u4e00\u4e9b\u602a\u7656\uff0c\u4f8b\u5982\u6ca1\u6709\u4e0a\u4e0b\u6587\u5207\u6362\uff08\u56e0\u6b64\u6ca1\u6709\u7761\u7720\u3001\u8c03\u5ea6\u6216\u7528\u6237\u5185\u5b58\u8bbf\u95ee\uff09\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u54ce\u5440\uff0c\u4e8b\u60c5\u73b0\u5728\u5f00\u59cb\u770b\u8d77\u6765\u6709\u70b9\u590d\u6742\u4e86\u3002\u65e0\u8bba\u5982\u4f55\uff0c\u6211\u4eec\u62e5\u6709\u5236\u5b9a\u5229\u7528\u6b64\u8fdc\u7a0b\u5806\u6808\u6ea2\u51fa\u7684\u6e38\u620f\u8ba1\u5212\u6240\u9700\u7684\u6240\u6709\u4fe1\u606f\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li><strong>\u4fe1\u606f\u6cc4\u6f0f<\/strong>\uff1a\u9996\u5148\uff0c\u6211\u4eec\u9700\u8981\u6cc4\u6f0f\u5185\u6838\u5730\u5740\u4ee5\u7ed5\u8fc7 KASLR \u4ee5\u53ca\u5806\u6808\u91d1\u4e1d\u96c0\u4ee5\u7ed5\u8fc7 CONFIG_STACKPROTECTOR<\/li><li><strong>Shellcode \u6267\u884c<\/strong>\uff1a\u5728\u6211\u4eec\u63a7\u5236\u4e86\u8fd4\u56de\u5730\u5740\u4e4b\u540e\uff0c\u6211\u4eec\u5e0c\u671b\u5229\u7528\u6211\u4eec\u7684\u63a7\u5236\u6d41\u52ab\u6301\u539f\u8bed\u6765\u83b7\u5f97\u66f4\u7075\u6d3b\u7684\u4e1c\u897f\uff1bshellcode\u6267\u884c\u4f1a\u5f88\u597d<\/li><li><strong>\u8f6c\u5411\u8fdb\u7a0b\u4e0a\u4e0b\u6587<\/strong>\uff1a\u63a5\u4e0b\u6765\u6211\u4eec\u9700\u8981\u4ece\u4e2d\u65ad\u4e0a\u4e0b\u6587\u8f6c\u5411\u8fdb\u7a0b\u4e0a\u4e0b\u6587\uff0c\u6240\u4ee5\u6211\u4eec\u5b9e\u9645\u4e0a\u6709\u4e00\u4e2a\u7528\u6237\u7a7a\u95f4\u6765\u8fd0\u884c\u6211\u4eec\u7684\u6709\u6548\u8d1f\u8f7d<\/li><li><strong>Win<\/strong>\uff1a\u5207\u6362\u5230\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u540e\uff0c\u6211\u4eec\u53ea\u9700\u8981\u5c06\u6211\u4eec\u7684\u6709\u6548\u8d1f\u8f7d\u6ce8\u5165\u6839\u8fdb\u7a0b\uff0c\u77a7\uff01<\/li><\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"information-leak\">\u4fe1\u606f\u6cc4\u9732<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><code>dmesg<\/code>?&nbsp;\u7cfb\u7edf\u8c03\u7528\u4e2d\u672a\u521d\u59cb\u5316\u7684\u5806\u6808\u53d8\u91cf\uff1f<code>msg_msg<\/code>\u6076\u4f5c\u5267\uff1f\u5f88\u957f\u4e00\u6bb5\u65f6\u95f4\u4ee5\u6765\uff0c\u666e\u904d\u7684\u5171\u8bc6\u662f KASLR \u66f4\u4ee4\u4eba\u8ba8\u538c\uff0c\u800c\u4e0d\u662f\u4e25\u91cd\u7f13\u89e3\u672c\u5730\u5229\u7528<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[5]<\/a>\u3002\u7136\u800c\uff0c\u8fdc\u7a0b\u5f00\u53d1\u7684\u52a8\u6001\u53d8\u5316\u5f88\u5927\uff1b\u653b\u51fb\u9762\u5927\u5927\u51cf\u5c11\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u7a81\u7136\u95f4\uff0c\u8868\u9762\u7f29\u5c0f\u5230\u6211\u4eec\u53ef\u4ee5\u8fdc\u7a0b\u8bbf\u95ee\u7684\u7f51\u7edc\u5806\u6808\u90e8\u5206\u3002\u5373\u4f7f\u6211\u4eec\u53d1\u73b0\u4e86\u4e00\u4e2a\u9519\u8bef\uff0c\u6211\u4eec\u4e5f\u9700\u8981\u80fd\u591f\u901a\u8fc7\u7f51\u7edc\u5c06\u6cc4\u6f0f\u8fd4\u56de\u7ed9\u6211\u4eec\u3002\u5f53\u6211\u4eec\u8003\u8651\u5806\u6808\u91d1\u4e1d\u96c0\u65f6\uff0c\u8fd9\u5c24\u5176\u56f0\u96be\uff0c\u56e0\u4e3a\u6211\u4eec\u5c06\u8303\u56f4\u8fdb\u4e00\u6b65\u9650\u5236\u4e3a\u7f51\u7edc\u5806\u6808\u4e2d\u7684\u5806\u6808\u6cc4\u6f0f\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e5f\u8bb8\u4e0d\u8db3\u4e3a\u5947\u7684\u662f\uff0c\u8fdc\u7a0b KASLR \u6cc4\u6f0f\u7684\u53ef\u7528\u8d44\u6e90\uff0c\u66f4\u4e0d\u7528\u8bf4\u91d1\u4e1d\u96c0\u6cc4\u6f0f\uff0c\u76f8\u5f53\u7a00\u5c11\u3002\u6700\u8fd1\u4e00\u4e2a\u503c\u5f97\u6ce8\u610f\u7684\u4f8b\u5b50\u662f<a href=\"https:\/\/arxiv.org\/pdf\/1906.10478.pdf\" target=\"_blank\" rel=\"noreferrer noopener\">\u201c\u4ece IP ID \u5230\u8bbe\u5907 ID \u548c KASLR \u7ed5\u8fc7\u201d<\/a>&nbsp;(CVE-2019-10639)\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u597d\u50cf\u627e\u5230\u4e00\u4e2a\u5185\u6838\u5730\u5740\u52a0\u4e0a\u91d1\u4e1d\u96c0\u6cc4\u6f0f\u5e76\u5c06\u5176\u8fd4\u56de\u7ed9\u6211\u4eec\u8fd8\u4e0d\u591f\u56f0\u96be\uff0c\u6211\u4eec\u8fd8\u9700\u8981\u4e00\u79cd\u65b9\u6cd5\u6765\u8bc6\u522b\u76ee\u6807\u4e0a\u8fd0\u884c\u7684\u5185\u6838\u7248\u672c\u3002\u6ca1\u6709\u8fd9\u4e2a\uff0c\u6211\u4eec\u5c31\u65e0\u6cd5\u771f\u6b63\u5904\u7406<code>KASLR<\/code>\u6cc4\u6f0f\u95ee\u9898\uff0c\u56e0\u4e3a\u5185\u6838\u7b26\u53f7\u7684\u504f\u79fb\u91cf\u56e0\u56fe\u50cf\u800c\u5f02\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5bf9\u4e8e\u8fd9\u7bc7\u6587\u7ae0\u7684\u8303\u56f4\uff0c\u6211\u4eec\u5c06\u5047\u8bbe\u76ee\u6807\u4e0a\u6ca1\u6709<code>KASLR<\/code>+&nbsp;<code>CONFIG_STACKPROTECTOR<\/code>\uff0c\u6216\u8005\u5b58\u5728\u5177\u6709\u53ef\u7528\u8fdc\u7a0b\u6cc4\u6f0f\u7684\u5185\u6838\u7248\u672c\u3002\u6bcb\u5eb8\u7f6e\u7591\uff0c\u5728\u6211\u4eec\u7684\u56db\u5206\u6bd4\u8d5b\u8ba1\u5212\u4e2d\uff0c\u7b2c\u4e00\u662f\u6700\u96be\u514b\u670d\u7684\u969c\u788d\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"shellcode-execution\">Shellcode \u6267\u884c<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u73b0\u5728\u662f\u65f6\u5019\u9677\u5165\u56f0\u5883\u4e86\uff01\u4f7f\u7528<code>KASLR<\/code>&amp;<code>CONFIG_STACKPROTECTOR<\/code>\u5e73\u65b9\uff0c\u6211\u4eec\u80fd\u591f\u89e6\u53d1\u6211\u4eec\u7684\u8fdc\u7a0b\u5806\u6808\u6ea2\u51fa\u5e76\u8986\u76d6\u8fd4\u56de\u5730\u5740\u800c\u4e0d\u4f1a\u5bfc\u81f4\u5185\u6838\u6050\u614c\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u6211\u4eec\u67e5\u770b\u6613\u53d7\u653b\u51fb\u51fd\u6570\u7684\u6c47\u7f16\u7ed3\u5c3e\uff0c\u5728\u8fd4\u56de\u5730\u5740\u4e4b\u524d\u8fd8\u4f1a\u4ece\u5806\u6808\u4e2d\u5f39\u51fa\u51e0\u4e2a\u5bc4\u5b58\u5668\uff0c\u8fd9\u610f\u5473\u7740\u6211\u4eec\u4e5f\u53ef\u4ee5\u5b8c\u5168\u63a7\u5236\u8fd9\u4e9b\u503c\u3002\u8fd9\u662f\u4e00\u4e2a<code>x86_64<\/code>\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>tipc_mon_rcv:\n    ...\n    &lt;+191&gt;:   pop    rbx\n    &lt;+192&gt;:   pop    r12\n    &lt;+194&gt;:   pop    r13\n    &lt;+196&gt;:   pop    r14\n    &lt;+198&gt;:   pop    r15\n    &lt;+200&gt;:   pop    rbp\n    &lt;+201&gt;:   ret    \n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u73b0\u5728\u6211\u4eec\u80fd\u591f\u52ab\u6301\u63a7\u5236\u6d41\uff0c\u6211\u4eec\u60f3\u7528\u5b83\u505a\u4ec0\u4e48\uff1f\u73b0\u5728\uff0c\u8ba9\u6211\u4eec\u4e13\u6ce8\u4e8e\u6211\u4eec\u4e0d\u80fd\u505a\u7684\u4e8b\u60c5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u7531\u4e8e\u6211\u4eec\u5728\u4e2d\u65ad\u4e0a\u4e0b\u6587\u4e2d\u5e76\u4e14\u6211\u4eec\u662f\u8fdc\u7a0b\u653b\u51fb\u8005\uff0c\u56e0\u6b64\u6ca1\u6709\u6211\u4eec\u53ef\u4ee5\u8df3\u8f6c\u5230\u7684\u7528\u6237\u6a21\u5f0f \u200b\u200bshellcode\uff1b\u4e0d\u662f\u8fd9\u6837<code>SMEP<\/code>&amp;<code>SMAP<\/code>\u65e0\u8bba\u5982\u4f55\u4f1a\u8ba9\u6211\u4eec\u73b0\u5728\u89e6\u6478\u7528\u6237\u6a21\u5f0f\u3002<\/li><li><code>NX Stack<\/code>\uff1a\u5728\u73b0\u4ee3 CPU \u4e2d\uff0c\u5185\u5b58\u7ba1\u7406\u5355\u5143 (MMU) \u63d0\u4f9b\u4e86\u5404\u79cd\u529f\u80fd\u3002\u4e0e\u6211\u4eec\u76f8\u5173\u7684\u662f\u201cNX \u4f4d\u201d\uff08\u4e0d\u53ef\u6267\u884c\u4f4d\uff09\u7684\u5b58\u5728\uff0c\u5b83\u5141\u8bb8 CPU \u5c06\u5185\u5b58\u9875\u6807\u8bb0\u4e3a\u4e0d\u53ef\u6267\u884c\u3002\u5bf9\u6211\u4eec\u6765\u8bf4\u4e0d\u5e78\u7684\u662f\uff0c\u5185\u6838\u4f7f\u7528\u6b64\u529f\u80fd\u4f7f\u6211\u4eec\u7684\u5185\u6838\u5806\u6808\u4e0d\u53ef\u6267\u884c\u3002<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u610f\u5473\u7740\u6211\u4eec\u4e0d\u80fd\u53ea\u5728\u6211\u4eec\u7684\u5806\u6808\u6709\u6548\u8d1f\u8f7d\u4e2d\u5305\u542b\u4e00\u4e9b shellcode \u5e76\u8df3\u8f6c\u5230\u90a3\u4e2a\uff0c\u9664\u975e\u6211\u4eec\u80fd\u591f\u8c03\u7528\u4e00\u4e2a\u540d\u4e3a<code>set_memory_x()<\/code>?&nbsp;\u591a\u4e8f\u4e86\u4e00\u79cd\u79f0\u4e3a\u9762\u5411\u8fd4\u56de\u7f16\u7a0b (ROP) \u7684\u5229\u7528\u6280\u672f\uff0c\u6211\u4eec\u53ef\u4ee5\u505a\u5230\u8fd9\u4e00\u70b9\u3002\u901a\u8fc7\u5bf9\u6307\u4ee4\u6307\u9488\u7684\u63a7\u5236\uff0c\u6211\u4eec\u53ef\u4ee5\u8c03\u7528\u5176\u4ed6\u5408\u6cd5\u5185\u6838\u4ee3\u7801\u7247\u6bb5\uff0c\u5c06\u5b83\u4eec\u94fe\u63a5\u5728\u4e00\u8d77\u4ee5\u8fdb\u884c\u6211\u4eec\u7684\u7ade\u6807\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u56e0\u6b64\uff0c\u8fd9\u91cc\u7684\u76ee\u6807\u662f\u521b\u5efa\u4e00\u4e2a\u57fa\u672c\u4e0a\u6267\u884c\u4ee5\u4e0b\u4f2a\u4ee3\u7801\u7684 ROP \u94fe\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>call set_memory_x($RSP &amp; ~0xfff, 1)\njmp $RSP<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u51fd\u6570\u7b7e\u540d\u662f<code>set_memory_x(unsigned long addr, int numpages)<\/code>\uff0c\u5176\u4e2d<code>addr<\/code>\u5fc5\u987b\u662f\u9875\u9762\u5bf9\u9f50\u7684\u5730\u5740\u3002\u56e0\u6b64\uff0c\u4e3a\u4e86\u627e\u5230\u6211\u4eec\u7684\u5806\u6808\u6709\u6548\u8d1f\u8f7d\u6240\u5728\u7684\u9875\u9762\uff0c\u6211\u4eec\u5c06\u9875\u9762\u63a9\u7801\u5e94\u7528\u4e8e<code>$RSP<\/code>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f7f\u7528\u65f6\u9ae6\u53c2\u6570\u7684\u539f\u56e0<code>set_memory_x()<\/code>\u662f\u5b83\u5fc5\u987b\u91c7\u7528\u9875\u9762\u5bf9\u9f50\u6307\u9488\uff0c\u7136\u540e\u5c06\u9875\u9762\u6570\u8bbe\u7f6e\u4e3a\u53ef\u6267\u884c\u6587\u4ef6\u3002\u4e3a\u4e86\u83b7\u53d6\u6211\u4eec\u5f53\u524d\u6240\u5728\u9875\u9762\u7684\u8d77\u59cb\u5730\u5740\uff0c\u6211\u4eec\u5e94\u7528\u4e86\u9875\u9762\u63a9\u7801\uff08<code>~0xfff<\/code>\u5bf9\u4e8e 4k \u9875\u9762\uff09\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u901a\u8fc7\u5229\u7528\u6211\u4eec\u53ef\u4ee5\u63a7\u5236\u7684\u5bc4\u5b58\u5668\u548c<code>ropper<\/code>\u6316\u6398\u4ee3\u8868\u6027\u5185\u6838\u6620\u50cf\u4e2d\u7684\u5c0f\u5de5\u5177\u4e4b\u7c7b\u7684\u5de5\u5177\uff0c\u6211\u4eec\u53ef\u4ee5\u83b7\u5f97\u4e00\u4e2a\u53ef\u6267\u884c\u5806\u6808\uff0c\u6211\u4eec\u53ef\u4ee5\u8df3\u8f6c\u5230\u6267\u884c\u3002\u8ba9\u6211\u4eec\u82b1\u70b9\u65f6\u95f4\u60f3\u8c61\u4e00\u4e0b\u6211\u4eec\u7684<code>struct tipc_mon_receive<\/code>\u6709\u6548\u8f7d\u8377\u662f\u4ec0\u4e48\u6837\u7684\uff1a<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https:\/\/blog.immunityinc.com\/img\/payload1.png\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"https:\/\/blog.immunityinc.com\/img\/payload1.png\" alt=\"\"\/><\/a><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">\u60ca\u4eba\u7684\uff01\u73b0\u5728\u6211\u4eec\u6709\u4e86\u4e00\u4e2a\u53ef\u6267\u884c\u5806\u6808\uff0c\u6211\u4eec\u6709\u4e86\u66f4\u591a\u7684\u7075\u6d3b\u6027\uff0c\u56e0\u4e3a\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u5728\u6211\u4eec\u7684\u6709\u6548\u8d1f\u8f7d\u4e2d\u5305\u542b shellcode\uff0c\u8fd9\u5c06\u7531\u5185\u6838\u8fd0\u884c\u3002\u6211\u4eec\u73b0\u5728\u6709\u7a7a\u95f4\u4e13\u6ce8\u4e8e\u8f6c\u5411\u6d41\u7a0b\u4e0a\u4e0b\u6587\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"cleanup\">\u6e05\u7406<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8ba9\u6211\u4eec\u4e0d\u8981\u8d85\u8d8a\u81ea\u5df1\uff01\u5f53\u7136\uff0c\u6211\u4eec\u6709 shellcode \u6267\u884c\uff0c\u4f46\u662f\u5982\u679c\u6211\u4eec\u4e00\u4ea4\u56de\u6267\u884c\uff0c\u5185\u6838\u5c31\u5d29\u6e83\u4e86\uff0c\u90a3\u4e48\u5f39\u51fa\u4e00\u4e2a root \u6709\u6548\u8f7d\u8377\u6709\u4ec0\u4e48\u7528\u5462\uff1f<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u6211\u4eec\u7ee7\u7eed\u4e4b\u524d\uff0c\u6211\u4eec\u9700\u8981\u786e\u4fdd\u5728\u89e6\u53d1\u5806\u6808\u6ea2\u51fa\u540e\u6211\u4eec\u53ef\u4ee5\u5e72\u51c0\u5730\u5c06\u6267\u884c\u4ea4\u8fd8\u7ed9\u5185\u6838\u3002\u8fd9\u4e0d\u4ec5\u5bf9\u786e\u5b9a\u6f0f\u6d1e\u5229\u7528\u7684\u53ef\u884c\u6027\u5f88\u91cd\u8981\uff0c\u800c\u4e14\u8fd8\u53ef\u80fd\u5bf9\u6709\u6548\u8d1f\u8f7d\u65bd\u52a0\u989d\u5916\u7684\u9650\u5236\u2014\u2014\u6211\u4eec\u8d8a\u65e9\u77e5\u9053\u8fd9\u4e9b\u8d8a\u597d\uff01<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e3a\u4e86\u5728\u6211\u4eec\u5229\u7528\u6f0f\u6d1e\u540e\u5c06\u6267\u884c\u8fd4\u56de\u5185\u6838\u5e76\u8ba9\u4e8b\u60c5\u518d\u6b21\u987a\u5229\u8fd0\u884c\uff0c\u6211\u4eec\u9700\u8981\u5728\u52ab\u6301\u4e00\u5207\u4e4b\u524d\u4e86\u89e3\u6267\u884c\u72b6\u6001\u3002\u6211\u4eec\u8981\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u5206\u6790\u5806\u6808\u524d\/\u540e\u6ea2\u51fa\uff1b\u6211\u4eec\u6b63\u5728\u7834\u574f\u54ea\u4e2a\u51fd\u6570\u7684\u5806\u6808\u5e27\uff1f<\/li><li>\u786e\u5b9a\u6211\u4eec\u53ef\u4ee5\u8fd4\u56de\u7684\u6700\u8fd1\u7684\u672a\u7834\u574f\u5806\u6808\u5e27\u662f\u4ec0\u4e48<\/li><li>\u786e\u5b9a\u6211\u4eec\u8df3\u8fc7\u8fd4\u56de\u7684\u51fd\u6570\u4e2d\u662f\u5426\u91ca\u653e\u4e86\u4efb\u4f55\u9501\u3002\u5982\u679c\u662f\u8fd9\u6837\uff0c\u6211\u4eec\u9700\u8981\u81ea\u5df1\u91ca\u653e\u8fd9\u4e9b<\/li><li><code>$RSP<\/code>\u5728\u6211\u4eec\u9009\u62e9\u4e00\u4e2a\u8fd4\u56de\u5730\u5740\u540e\uff0c\u786e\u4fdd<code>$RBP<\/code>\u548c\u4efb\u4f55\u5176\u4ed6\u5fc5\u9700\u7684\u5bc4\u5b58\u5668\u90fd\u662f\u6b63\u786e\u7684<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u6211\u4eec\u770b\u4e00\u4e0b\u6613\u53d7\u653b\u51fb\u7684\u51fd\u6570\u4e2d\u7684\u56de\u6eaf\uff0c\u6211\u4eec\u53ef\u4ee5\u5f00\u59cb\u56de\u7b54\u4ee5\u4e0b\u4e00\u4e9b\u95ee\u9898\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&#91;#1] 0xffffffffc072dd4c \u2192 tipc_mon_rcv(net=&lt;optimised out&gt;, data=0xffff88810dba7176, dlen=&lt;optimised out&gt;, addr=&lt;optimised out&gt;, state=0xffff88810035848a, bearer_id=&lt;optimised out&gt;)\n&#91;#2] 0xffffffffc07274e6 \u2192 tipc_link_proto_rcv(l=0xffff888100358400, skb=0xffff888102036c00, xmitq=0xffffc900000e4cc8)\n&#91;#3] 0xffffffffc0727f4e \u2192 tipc_link_rcv(l=0xffff888100358400, skb=0xffff888102036c00, xmitq=0xffffc900000e4cc8)\n&#91;#4] 0xffffffffc07388a1 \u2192 tipc_rcv(net=0xffffffff830e5640 &lt;init_net&gt;, skb=&lt;optimised out&gt;, b=&lt;optimised out&gt;)\n&#91;#5] 0xffffffffc071ffe9 \u2192 tipc_l2_rcv_msg(skb=0xffff888102036c00, dev=&lt;optimised out&gt;, pt=&lt;optimised out&gt;, orig_dev=&lt;optimised out&gt;)\n&#91;#6] 0xffffffff819f3b67 \u2192 __netif_receive_skb_list_ptype(orig_dev=0xffff888102062000, pt_prev=0xffff88810bc3da80, head=0xffffc900000e4d68)\n&#91;#7] 0xffffffff819f3b67 \u2192 __netif_receive_skb_list_ptype(orig_dev=0xffff888102062000, pt_prev=0xffff88810bc3da80, head=0xffffc900000e4d68)\n&#91;#8] 0xffffffff819f3b67 \u2192 __netif_receive_skb_list_core(head=0xffff888102062a60, pfmemalloc=&lt;optimised out&gt;)\n&#91;#9] 0xffffffff819f3d4e \u2192 __netif_receive_skb_list(head=0xffff888102062a60)\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u8003\u8651\u4e86\u6211\u4eec\u7684 ROP \u94fe\u3001shellcode \u548c\u6e05\u7406\u4ee3\u7801\u7684\u4e00\u822c\u5927\u5c0f\u8981\u6c42\u5e76\u5c06\u5b83\u4eec\u4e0e\u6211\u4eec\u7684\u56de\u6eaf\u4e2d\u7684\u5806\u6808\u5e27\u7684\u5927\u5c0f\u8fdb\u884c\u6bd4\u8f83\u4e4b\u540e\uff0c\u6211\u4eec\u81f3\u5c11\u77e5\u9053\u6211\u4eec\u5c06\u8981\u4f7f\u7528 clobber<code>#2<\/code>\u548c<code>#3<\/code>&amp;&nbsp;<code>#4<\/code>\u3002\u8fd9\u610f\u5473\u7740\u6211\u4eec\u5b9e\u9645\u4e0a\u5e0c\u671b\u5c06\u6267\u884c\u6743\u79fb\u4ea4\u7ed9<code>#5<\/code>\u4ee5\u540e\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f46\u662f\uff0c\u5728\u7834\u574f<code>#2<\/code>&amp;\u671f\u95f4<code>#4<\/code>\uff0c\u6211\u4eec\u5b9e\u9645\u4e0a\u91ca\u653e\u4e86 TIPC \u5bf9\u8c61\u4e0a\u7684\u4e00\u4e9b\u91cd\u8981\u9501\uff0c\u56e0\u6b64\u6211\u4eec\u9700\u8981\u81ea\u5df1\u91ca\u653e\u8fd9\u4e9b\u9501\u3002\u7531\u4e8e TIPC \u662f\u4e00\u4e2a<strong>\u53ef\u52a0\u8f7d\u7684\u6a21\u5757<\/strong>\uff0c\u6211\u4eec\u7684<code>KASLR<\/code>\u6cc4\u6f0f\u5728\u8fd9\u91cc\u5bf9\u6211\u4eec\u6ca1\u6709\u5e2e\u52a9\uff0c\u6240\u4ee5\u8981\u91ca\u653e\u8fd9\u4e9b\u9501\uff0c\u6211\u4eec\u9700\u8981\u4ece\u5806\u6808\u4e2d\u83b7\u53d6\u4e00\u4e2a TIPC \u5730\u5740\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u7ed9\u6211\u4eec\u7559\u4e0b\u4e86<code>#5<\/code>\u4f5c\u4e3a\u6211\u4eec\u6700\u65b0\u7684\u8fd4\u56de\u70b9\uff0c\u4f5c\u4e3a\u5e26\u6709 TIPC \u5f15\u7528\u7684\u6700\u540e\u4e00\u4e2a\u5806\u6808\u5e27\u3002\u7136\u540e\u6211\u4eec\u53ef\u4ee5\u5206\u6790\u8fd9\u4e2a\u548c\u540e\u7eed\u51fd\u6570\u6765\u68c0\u67e5\u4ed6\u4eec\u671f\u671b\u7684\u5bc4\u5b58\u5668\u503c\u3002\u6211\u4eec\u73b0\u5728\u4e5f\u77e5\u9053\u6211\u4eec\u9700\u8981\u8c03\u6574\u7684\u6570\u91cf<code>$RSP<\/code>\u3002<code>$RBP<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6536\u96c6\u5230\u4e0a\u8ff0\u8981\u6c42\u540e\uff0c\u6211\u4eec\u73b0\u5728\u77e5\u9053\u4e86\u5bf9\u6211\u4eec\u7684\u6709\u6548\u8d1f\u8f7d\u5927\u5c0f\u7684\u9650\u5236\uff0c\u4ee5\u4fbf\u5b89\u5168\u5730\u4ea4\u56de\u6267\u884c\uff0c\u6211\u4eec\u53ef\u4ee5\u76f8\u5e94\u5730\u8ba1\u5212\u4e0b\u4e00\u4e2a\u9636\u6bb5\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd8\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff0c\u6211\u4eec\u53ef\u4ee5\u591a\u6b21\u629b\u51fa\u8fd9\u4e2a\u6f0f\u6d1e\u3002\u867d\u7136 ROP \u94fe\u5728\u7b2c\u4e00\u6b21\u629b\u51fa\u65f6\u53ef\u80fd\u4f1a\u5360\u7528\u5408\u7406\u7684\u7a7a\u95f4\u90e8\u5206\uff0c\u4f46\u7531\u4e8e\u5806\u6808\u662f\u786e\u5b9a\u6027\u7684\uff0c\u6211\u4eec\u53ea\u9700\u4f7f\u5176\u53ef\u6267\u884c\u4e00\u6b21\u3002\u968f\u540e\u7684 throws \u53ef\u4ee5\u76f4\u63a5\u8df3\u8f6c\u5230<code>$RSP<\/code>\uff0c\u4e3a\u6211\u4eec\u7684 shellcode \u63d0\u4f9b\u66f4\u591a\u7a7a\u95f4\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"pivot-to-process-context\">\u67a2\u8f74\u5904\u7406\u4e0a\u4e0b\u6587<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u597d\u5427\uff0c\u6211\u4eec\u5728\u54ea\u91cc\uff1f\u6211\u4eec\u5df2\u7ecf\u6709\u4e86\u4e00\u4e2a\u53ef\u6267\u884c\u5806\u6808\uff0c\u662f\u65f6\u5019\u7f16\u5199\u4e00\u4e9b shellcode \u4e86\u3002\u9664\u4e86\u6211\u4eec\u4e0a\u9762\u63d0\u5230\u7684\u5f3a\u5236\u6e05\u7406\u4e4b\u5916\uff0c\u6211\u4eec\u8fd8\u60f3\u627e\u5230\u4e00\u79cd\u65b9\u6cd5\u6765\u8f6c\u79fb\u5230\u8fdb\u7a0b\u4e0a\u4e0b\u6587\uff0c\u6240\u4ee5\u6211\u4eec\u5b9e\u9645\u4e0a\u6709\u4e00\u4e2a\u7528\u6237\u7a7a\u95f4\u6765 pwn\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u201c\u6211\u4eec\u5c06\u5982\u4f55\u8f6c\u5411\u6d41\u7a0b\u73af\u5883\uff1f\u201d&nbsp;\u6211\u542c\u5230\u4f60\u95ee\u3002\u597d\u5427\uff0c\u7b54\u6848\u662f\uff1a\u7cfb\u7edf\u8c03\u7528\u6302\u94a9\u3002\u65e9\u4e9b\u65f6\u5019\uff0c\u6211\u4eec\u7b80\u5355\u5730\u8c08\u5230\u4e86\u7cfb\u7edf\u8c03\u7528\u4fc3\u8fdb\u4e86\u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u4e4b\u95f4\u7684\u4ea4\u4e92\u8fd9\u4e00\u4e8b\u5b9e\uff0c\u6240\u4ee5\u5728\u54ea\u91cc\u66f4\u597d\u5730\u4e3a\u81ea\u5df1\u627e\u5230\u4e00\u4e2a\u8fdb\u7a0b\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"syscall-primer\">\u7cfb\u7edf\u8c03\u7528\u5165\u95e8<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8ba9\u6211\u4eec\u4ed4\u7ec6\u770b\u770b\u5728 Linux \u4e2d\u7cfb\u7edf\u8c03\u7528\u662f\u5982\u4f55\u5904\u7406\u7684\uff0c\u4ee5\u53ca\u6211\u4eec\u5982\u4f55\u80fd\u591f\u5229\u7528\u5b83\u6765\u53d1\u6325\u6211\u4eec\u7684\u4f18\u52bf\u3002\u5bf9\u4e8e\u4e0d\u719f\u6089\u7684\u4eba\u6765\u8bf4\uff0c\u7cfb\u7edf\u8c03\u7528\u662f\u7528\u6237\u8fdb\u7a0b\u548c\u5185\u6838\u4e4b\u95f4\u7684\u57fa\u672c\u63a5\u53e3\u3002\u5982\u679c\u7528\u6237\u8fdb\u7a0b\u9700\u8981\u5185\u6838\u4ee3\u8868\u5b83\u505a\u67d0\u4e8b\uff0c\u5b83\u53ef\u4ee5\u901a\u8fc7\u7cfb\u7edf\u8c03\u7528\u8be2\u95ee\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6211\u4eec\u4ecb\u7ecd\u4e86\u4e2d\u65ad\u7684\u6982\u5ff5\uff0c\u4f8b\u5982\u5f53\u4f60\u7684\u7f51\u5361\u63a5\u6536\u5230\u4e00\u4e2a\u6570\u636e\u5305\u65f6\uff0c\u5b83\u4f1a\u4ea7\u751f\u4e00\u4e2a\u786c\u4ef6\u4e2d\u65ad\u3002\u7cfb\u7edf\u8c03\u7528\u4e5f\u662f\u4e2d\u65ad\u3002\u5b83\u4eec\u662f\u53ef\u4ee5\u7531\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u751f\u6210\u7684\u7279\u5b9a\u8f6f\u4ef6\u4e2d\u65ad\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>x86_64<\/code>\u8fd9\u53ef\u4ee5\u901a\u8fc7<code>syscall<\/code>\u6307\u4ee4\u5b8c\u6210\uff0c\u6839\u636e\u624b\u518c\uff1a<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>\u201cSYSCALL \u8c03\u7528\u7279\u6743\u7ea7\u522b 0 \u7684 OS \u7cfb\u7edf\u8c03\u7528\u5904\u7406\u7a0b\u5e8f\u3002\u5b83\u901a\u8fc7\u4ece IA32_LSTAR MSR \u52a0\u8f7d RIP \u6765\u5b9e\u73b0\uff08\u5728\u5c06 SYSCALL \u4e4b\u540e\u7684\u6307\u4ee4\u5730\u5740\u4fdd\u5b58\u5230 RCX \u4e4b\u540e\uff09\u3002\uff08WRMSR \u6307\u4ee4\u786e\u4fdd IA32_LSTAR MSR \u59cb\u7ec8\u5305\u542b\u89c4\u8303\u5730\u5740\u3002\uff09\u201d\u2014\u2014\u82f1\u7279\u5c14\u6307\u4ee4\u96c6\u53c2\u8003<\/p><\/blockquote>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https:\/\/blog.immunityinc.com\/img\/syscall.png\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"https:\/\/blog.immunityinc.com\/img\/syscall.png\" alt=\"\"\/><\/a><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">\u603b\u7ed3\u4e00\u4e0b\u8fc7\u7a0b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5c06\u53c2\u6570\u653e\u5165\u5bc4\u5b58\u5668\uff0c\u7cfb\u7edf\u8c03\u7528\u53f7\u653e\u5165<code>$RAX<\/code>\u5e76\u6267\u884c<code>syscall<\/code>\u6307\u4ee4<\/li><li>\u5185\u6838\u5728 IDT \u4e2d\u627e\u5230\u7cfb\u7edf\u8c03\u7528\u4e2d\u65ad\u7684\u4e2d\u65ad\u5904\u7406\u7a0b\u5e8f\uff0c<code>entry_SYSCALL_64()<\/code>\u5728\u6211\u4eec\u7684\u793a\u4f8b\u4e2d<\/li><li>\u6b64\u65f6\uff0c\u7528\u6237\u6a21\u5f0f\u5bc4\u5b58\u5668\u88ab\u4fdd\u5b58\u5230\u5806\u6808\u4e2d\uff0c\u5b9a\u4e49\u4e3a<code>struct pt_regs<\/code><\/li><li>\u4f20\u5165\u7684\u7cfb\u7edf\u8c03\u7528\u53f7<code>$RAX<\/code>\u7528\u4f5c<code>sys_call_table<\/code>\u67e5\u627e\u6b63\u786e\u5904\u7406\u7a0b\u5e8f\u7684\u7d22\u5f15<\/li><li>\u8fd0\u884c\u6b63\u786e\u7684\u7cfb\u7edf\u8c03\u7528\u5904\u7406\u7a0b\u5e8f\uff0c\u6211\u4eec\u4ece\u5806\u6808\u4e2d\u83b7\u53d6\u5e76\u6062\u590d\u7528\u6237\u6a21\u5f0f\u5bc4\u5b58\u5668\uff0c\u5e76\u5c06\u7ed3\u679c\u901a\u8fc7<code>$RAX<\/code><\/li><\/ol>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"syscall-hooking\">\u7cfb\u7edf\u8c03\u7528\u6302\u94a9<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u6062\u590d\u8425\u4e1a\uff01\u5c31\u50cf\u6211\u63d0\u5230\u7684\uff0c\u6211\u4eec\u5230\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u7684\u8def\u5f84\u662f\u901a\u8fc7\u4f7f\u7528\u4e00\u79cd\u901a\u7528\u6280\u672f\u5b9e\u73b0\u7684\uff1a\u7cfb\u7edf\u8c03\u7528\u6302\u94a9\u3002\u8ba1\u5212\u662f<code>sys_call_table<\/code>\u7528\u6211\u4eec\u81ea\u5df1\u7684\u4ee3\u7801\u8986\u76d6\u5176\u4e2d\u7684\u4e00\u4e2a\u51fd\u6570\u6307\u9488\uff0c\u56e0\u6b64\u4e0b\u6b21\u8fd0\u884c\u8be5\u7cfb\u7edf\u8c03\u7528\u65f6\uff0c\u5b83\u4f1a\u8fd0\u884c\u6211\u4eec\u7684\u4ee3\u7801\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u9664\u4e86\uff0c\u4e0e\u4e00\u4e9b\u66f4\u5178\u578b\u7684\u7528\u4f8b\u4e0d\u540c\uff0c\u6211\u4eec\u5c06\u4f7f\u7528\u6211\u4eec\u7684\u94a9\u5b50\u5c06\u7528\u6237\u6a21\u5f0f\u6709\u6548\u8d1f\u8f7d\u6ce8\u5165\u5230\u8c03\u7528\u6211\u4eec\u94a9\u5b50\u7cfb\u7edf\u8c03\u7528\u7684\u4e0d\u5e78\u8fdb\u7a0b\u4e2d\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u5f88\u597d\uff0c\u56e0\u4e3a\u4f5c\u4e3a\u8fdc\u7a0b\u653b\u51fb\u8005\uff0c\u6211\u4eec\u5bf9\u76ee\u6807\u4e0a\u8fd0\u884c\u7684\u8fdb\u7a0b\u6ca1\u6709\u592a\u5927\u5f71\u54cd\uff0c\u4f46\u6211\u4eec\u53ef\u4ee5\u81ea\u4fe1\u5730\u5047\u8bbe\u67d0\u4e9b\u7cfb\u7edf\u8c03\u7528\u5c06\u88ab\u5b9a\u671f\u8c03\u7528\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5c31\u8fd9\u6837\uff0c\u6211\u4eec\u8d62\u4e86\uff01\u597d\u5427\uff0c\u597d\u5427\uff0c\u6ca1\u90a3\u4e48<em>\u5bb9\u6613<\/em>\u3002\u6211\u4eec\u8fd8\u6709\u66f4\u591a\u7684\u969c\u788d\u9700\u8981\u8de8\u8d8a\u3002\u9996\u5148\uff0c\u4e3a\u4e86\u6302\u94a9\u6211\u4eec\u9009\u62e9\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u6211\u4eec\u9700\u8981\u5728\u6211\u4eec\u7684 shellcode \u4e2d\u505a\u51e0\u4ef6\u4e8b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u6211\u4eec\u9700\u8981<code>kmalloc<\/code>\u4e00\u4e9b\u5185\u5b58\u624d\u80fd\u8ba9\u6211\u4eec\u7684\u94a9\u5b50\u548c\u7528\u6237\u6a21\u5f0f\u6709\u6548\u8d1f\u8f7d\u5b58\u6d3b\uff1b\u7136\u540e\u6211\u4eec\u9700\u8981<code>set_memory_x()<\/code>\u6211\u4eec\u7684\u94a9\u5b50<\/li><li><code>set_memory_w()<\/code>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u9700\u8981<code>sys_call_table<\/code>\u7981\u7528\u5199\u4fdd\u62a4\u4f4d<code>$CR0<\/code><\/li><li>\u73b0\u5728\u6211\u4eec\u53ef\u4ee5\u8986\u76d6<code>sys_call_table<\/code><\/li><\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"hooked\">\u4e0a\u94a9\u4e86\uff01<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f88\u8fd1\uff01\u73b0\u5728\u5269\u4e0b\u7684\u5c31\u662f\u7f16\u5199\u6211\u4eec\u771f\u6b63\u7684\u94a9\u5b50\uff0c\u77a7\u3002\u8fd9\u91cc\u7684\u76ee\u7684\u662f\u4f7f\u7528\u6211\u4eec\u7684\u7528\u6237\u6a21\u5f0f\u6709\u6548\u8d1f\u8f7d\u6ce8\u5165\u8fdb\u7a0b\uff0c\u7136\u540e\u5c06\u63a7\u5236\u6743\u4f20\u9012\u56de\u539f\u59cb\u7cfb\u7edf\u8c03\u7528\u5904\u7406\u7a0b\u5e8f\uff0c\u5c31\u50cf\u4ec0\u4e48\u90fd\u6ca1\u53d1\u751f\u4e00\u6837\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u7cfb\u7edf\u8c03\u7528\u6302\u94a9\u7684\u597d\u5904\u5728\u4e8e\uff0c\u7cfb\u7edf\u8c03\u7528\u5904\u7406\u7a0b\u5e8f\u88ab\u4f20\u9012\u4e86\u4e00\u4e2a\u6307\u5411<code>struct pt_regs<\/code>\uff08\u4e0a\u9762\u7684\u6b65\u9aa4 3\uff09\u7684\u6307\u9488\uff0c\u8fd9\u4f7f\u6211\u4eec\u53ef\u4ee5\u8bbf\u95ee\u7528\u6237\u7a7a\u95f4\u5bc4\u5b58\u5668\u3002\u8fd9\u610f\u5473\u7740\u6211\u4eec\u53ef\u4ee5\u5b8c\u5168\u8986\u76d6\u6307\u4ee4\u6307\u9488\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6211\u4eec\u8fd8\u53ef\u4ee5\u8bbf\u95ee<code>current<\/code>&nbsp;<code>task_struct<\/code>\uff0c\u8fd9\u610f\u5473\u7740\u6211\u4eec\u4e0d\u5fc5\u6ee1\u8db3\u4e8e\u66f4\u5c11\uff1b\u6211\u4eec\u53ef\u4ee5\u68c0\u67e5<code>uid<\/code>\u5f53\u524d\u8fdb\u7a0b\u4ee5\u786e\u4fdd\u6211\u4eec\u53ea\u6ce8\u5165\u5230\u6839\u8fdb\u7a0b\u4e2d\u3002\u6ca1\u6709 unpriv&#8217;d shell\uff0c\u975e\u5e38\u611f\u8c22\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u603b\u7684\u6765\u8bf4\uff0c\u6211\u4eec\u7684\u94a9\u5b50\u770b\u8d77\u6765\u50cf\u8fd9\u6837\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><code>getuid()<\/code>\u786e\u4fdd\u6211\u4eec\u6b63\u5728\u6302\u94a9\u6839\u8fdb\u7a0b\u8c03\u7528\uff1b\u5982\u679c\u4e0d\u662f\u6839\u5219\u5ffd\u7565<\/li><li><code>mmap()<\/code>\u548c\u6211\u4eec\u6709\u6548\u8f7d\u8377\u7684\u7528\u6237\u7a7a\u95f4\u4e2d\u7684\u53ef\u6267\u884c\u533a\u57df<\/li><li><code>copy_to_user()<\/code>\u6211\u4eec\u7684\u7528\u6237\u7a7a\u95f4\u6709\u6548\u8f7d\u8377<\/li><li>\u8c03\u6574<code>struct pt_regs<\/code>\u4ee5<code>pt_regs-&gt;ip<\/code>\u6307\u5411\u6211\u4eec\u7684\u7528\u6237\u7a7a\u95f4\u6709\u6548\u8d1f\u8f7d<\/li><li>\u6210\u529f\u7684\u6e05\u7406\u94a9\u5b50<\/li><li>\u5c06\u6267\u884c\u8fd4\u56de\u5230\u539f\u59cb\u5904\u7406\u7a0b\u5e8f<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"winning\">\u83b7\u80dc<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u73b0\u5728\u4e00\u5207\u90fd\u53d6\u51b3\u4e8e\u6211\u4eec\u7684\u60f3\u8c61\u3002\u6211\u4eec\u6709\u4e00\u4e2a\u5728\u6839\u8fdb\u7a0b\u4e2d\u8fd0\u884c\u7684\u4efb\u610f\u7528\u6237\u7a7a\u95f4\u6709\u6548\u8d1f\u8f7d\uff0c\u9690\u85cf\u5728\u6211\u4eec\u81ea\u5df1\u7684\u5c0f\u533a\u57df\u4e2d<code>mmap()<\/code>\u3002\u53ea\u8bb0\u5f97\u6e05\u7406\u5e76\u8fd4\u56de\u6267\u884c\uff01<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u6211\u4eec\u7684\u793a\u4f8b\u4e2d\uff0c\u7528\u6237\u6001\u6709\u6548\u8d1f\u8f7d\u53ef\u80fd\u7c7b\u4f3c\u4e8e\u4ee5\u4e0b\u4f2a\u4ee3\u7801\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>fork()\nif (parent)\n    repair_registers() \/\/ E.g. RBP, RSP\n    jmp_old_ip()       \/\/ hand back execution to original instruction ptr\nelse \n    CANVAS_callback()  \/\/ establish connection with the CANVAS server<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"mitigations\">\u7f13\u89e3\u63aa\u65bd<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u6211\u4eec\u7ed3\u675f\u4e4b\u524d\uff0c\u5982\u679c\u6211\u4e0d\u6d89\u53ca\u9488\u5bf9 CVE-2022-0435 \u7b49\u6f0f\u6d1e\u7684\u73b0\u6709\u7f13\u89e3\u63aa\u65bd\uff0c\u90a3\u6211\u5c31\u5931\u804c\u4e86\u3002\u6240\u4ee5\uff0c\u8fd9\u91cc\u6709\u4e00\u4e2a\u76f8\u5173\u7f13\u89e3\u63aa\u65bd\u7684\u5c0f\u8bcd\u6c47\u8868\uff0c\u5305\u62ec\u6211\u4eec\u5df2\u7ecf\u63d0\u5230\u7684\u4e00\u4e9b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><code>KASLR<\/code>&amp;<code>CONFIG_STACKPROTECTOR<\/code>\u5728\u73b0\u4ee3\u7cfb\u7edf\u4e0a\u9ed8\u8ba4\u542f\u7528\uff0c\u5e76\u4e14\u8003\u8651\u5230\u6709\u9650\u7684\u8868\u9762\uff0c\u90fd\u5bf9\u8fdc\u7a0b\u653b\u51fb\u8005\u65bd\u52a0\u4e86\u4e25\u683c\u7684\u4fe1\u606f\u6cc4\u6f0f\u8981\u6c42<\/li><li><code>CONFIG_FORTIFY_SRC<\/code>\uff1a\u81ea 2021 \u5e74\u590f\u5b63<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[6]<\/a>\u8d77\uff0c\u5411 Linux \u5185\u6838\u6dfb\u52a0\u4e86\u4e25\u683c<code>memcpy()<\/code>\u7684\u8fb9\u754c\u68c0\u67e5\u3002\u672c\u8d28\u4e0a\uff0c\u5f53\u6211\u4eec\u77e5\u9053<a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\">[7]<\/a><code>fortify_panic()<\/code>\u65f6\uff0c\u5982\u679c\u6211\u4eec\u5c1d\u8bd5\u8fd9\u6837\u505a\uff0c\u8fd9\u79cd\u7f13\u89e3\u5c06\u89e6\u53d1<code>memcpy(dst, src, size)<\/code><code>size &gt; sizeof(dst\/src)<\/code><a href=\"https:\/\/blog.immunityinc.com\/p\/writing-a-linux-kernel-remote-in-2022\/#refs\"><\/a><\/li><li><code>CONFIG_FG_KASLR<\/code>\uff1a\u6b63\u5982\u6211\u4eec\u6240\u63d0\u5230\u7684<code>KASLR<\/code>\uff0c\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff0c\u51fd\u6570\u7c92\u5ea6 KASLR \u901a\u8fc7\u5728\u6bcf\u4e2a\u51fd\u6570\u7ea7\u522b\u968f\u673a\u5316\u5185\u6838\u7684\u4f4d\u7f6e\uff0c\u800c\u4e0d\u662f\u5355\u4e2a KASLR \u5e7b\u706f\u7247\uff0c\u66f4\u8fdb\u4e00\u6b65<\/li><li>\u6709\u51e0\u79cd\u67b6\u6784\/\u7f16\u8bd1\u5668\u7279\u5b9a\u7684\u5b9e\u73b0\u65e8\u5728\u901a\u8fc7\u4fdd\u62a4\u524d\u5411\u8fb9\u7f18\uff08\u60f3\u60f3\u51fd\u6570\u6307\u9488\uff09\u548c\/\u6216\u540e\u5411\u8fb9\u7f18\uff08\u60f3\u60f3\u8fd4\u56de\u5730\u5740\uff09\u6765\u63d0\u4f9b<strong>\u63a7\u5236\u6d41\u5b8c\u6574\u6027\uff08CFI \uff09\u3002<\/strong>\u8fd9\u4e9b\u65e8\u5728\u51cf\u8f7b\u63a7\u5236\u6d41\u52ab\u6301\u6280\u672f\uff0c\u4f8b\u5982\u6211\u4eec\u5728\u672c\u6587\u4e2d\u770b\u5230\u7684 ROP \u6280\u672f\u3002<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u5173\u4e8e\u7f13\u89e3\u95ee\u9898\uff0c\u6211\u8877\u5fc3\u63a8\u8350<a href=\"https:\/\/twitter.com\/a13xp0p0v\" target=\"_blank\" rel=\"noreferrer noopener\">@a13xp0p0v<\/a>\u7684<a href=\"https:\/\/github.com\/a13xp0p0v\/linux-kernel-defence-map\" target=\"_blank\" rel=\"noreferrer noopener\">Linux Kernel Defense Map<\/a>\u9879\u76ee\uff0c\u4ee5\u63ed\u5f00 Linux \u5185\u6838\u5b89\u5168\u72b6\u6001\u7684\u795e\u79d8\u9762\u7eb1\uff0c\u8fd9\u662f\u4e00\u79cd\u7b80\u6d01\u7684\u56fe\u5f62\u683c\u5f0f\uff01<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"conclusion\">\u7ed3\u8bba<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u56e0\u6b64\uff0c\u6211\u4eec\u6709\u5b83\uff01\u4f7f\u7528\u6700\u8fd1\u7684\u6f0f\u6d1e\u7f16\u5199\u5185\u6838\u8fdc\u7a0b\u7684\u6545\u969c\u3002\u5e0c\u671b\u8fd9\u7bc7\u6587\u7ae0\u63d0\u4f9b\u4e86\u4e00\u4e9b\u5173\u4e8e\u5185\u6838\u5229\u7528\u7684\u89c1\u89e3\uff0c\u5e76\u5f3a\u8c03\u4e86\u4e0e\u672c\u5730\u5229\u7528\u7684\u4e00\u4e9b\u5dee\u5f02\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u80fd\u591f\u5206\u4eab\u6211\u5728 Apppgate Threat Advisory Services \u6240\u505a\u7684\u4e00\u4e9b\u4ee4\u4eba\u96be\u4ee5\u7f6e\u4fe1\u7684\u5de5\u4f5c\u771f\u662f\u592a\u597d\u4e86\u3002\u5982\u679c\u6709\u4eba\u6709\u4efb\u4f55\u95ee\u9898\u3001\u5efa\u8bae\u6216\u66f4\u6b63\uff0c\u8bf7\u901a\u8fc7<a href=\"mailto:samuel.page@appgate.com\">samuel.page@appgate.com<\/a>\u4e0e\u6211\u8054\u7cfb\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8c22\u8c22\u9605\u8bfb\uff01<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"creds\">\u4fe1\u7528<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u6211\u60f3\u5411\u6211\u7684\u56e2\u961f\u8d1f\u8d23\u4eba\u963f\u5c14\u5f17\u96f7\u591a\u00b7\u4f69\u7d22\u5229\uff08&nbsp;<a href=\"https:\/\/twitter.com\/__rev\" target=\"_blank\" rel=\"noreferrer noopener\">Alfredo Pesoli<\/a>&nbsp;\uff09\u5927\u58f0\u75be\u547c\uff0c\u611f\u8c22\u4ed6\u4eec\u4e00\u8def\u4e0a\u7684\u9f13\u52b1\u3001\u652f\u6301\u548c\u5e2e\u52a9\u3002\u591a\u4e8f\u4e86\u4ed6\u548c\u56e2\u961f\uff0c\u6211\u624d\u80fd\u5199\u51fa\u50cf\u8fd9\u6837\u5f88\u9177\u7684\u4e1c\u897f\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6211\u8fd8\u60f3\u53c2\u8003 Dan Rosenberg \u7684 2011 \u5e74\u6f14\u8bb2<a rel=\"noreferrer noopener\" href=\"https:\/\/doc.lagout.org\/security\/2011_remote_kernel_exploit.pdf\" target=\"_blank\">\u201c\u8fdc\u7a0b\u5185\u6838\u5229\u7528\u5256\u6790\u201d<\/a>\uff0c\u4f5c\u4e3a\u5f00\u59cb\u8fdc\u7a0b\u5229\u7528\u8def\u5f84\u7684\u91cd\u8981\u5e2e\u52a9\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd8\u53ef\u4ee5\u53c2\u7167\uff1ahttps:\/\/blog.immunityinc.com\/p\/a-remote-stack-overflow-in-the-linux-kernel\/<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"refs\">\u53c2\u8003\u6587\u732e<\/h2>\n\n\n\n<ol class=\"wp-block-list\" start=\"0\"><li><a href=\"https:\/\/www.sentinelone.com\/labs\/tipc-remote-linux-kernel-heap-overflow-allows-arbitrary-code-execution\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.sentinelone.com\/labs\/tipc-remote-linux-kernel-heap-overflow-allows-arbitrary-code-execution\/<\/a><\/li><li><a href=\"https:\/\/blog.immunityinc.com\/p\/a-remote-stack-overflow-in-the-linux-kernel\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/blog.immunityinc.com\/p\/a-remote-stack-overflow-in-the-linux-kernel\/<\/a><\/li><li><a href=\"https:\/\/lwn.net\/Articles\/569635\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/lwn.net\/Articles\/569635\/<\/a><\/li><li><a href=\"https:\/\/cateee.net\/lkddb\/web-lkddb\/STACKPROTECTOR.html\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/cateee.net\/lkddb\/web-lkddb\/STACKPROTECTOR.html<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Supervisor_Mode_Access_Prevention\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/en.wikipedia.org\/wiki\/Supervisor_Mode_Access_Prevention<\/a><\/li><li><a href=\"https:\/\/forums.grsecurity.net\/viewtopic.php?f=7&amp;t=3367\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/forums.grsecurity.net\/viewtopic.php?f=7&amp;t=3367<\/a><\/li><li><a href=\"https:\/\/lwn.net\/Articles\/864521\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/lwn.net\/Articles\/864521\/<\/a><\/li><li><a href=\"https:\/\/github.com\/torvalds\/linux\/blob\/master\/include\/linux\/fortify-string.h#L212\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/github.com\/torvalds\/linux\/blob\/master\/include\/linux\/fortify-string.h#L212<\/a><\/li><\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\u539f\u6587\u94fe\u63a5\uff1ahttps:\/\/blog.immunityinc.com\/p\/writing-a-linux-ker [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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