1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef SANDBOX_LINUX_SERVICES_YAMA_H_ 6 #define SANDBOX_LINUX_SERVICES_YAMA_H_ 7 8 #include "base/basictypes.h" 9 #include "base/process/process_handle.h" 10 #include "sandbox/sandbox_export.h" 11 12 namespace sandbox { 13 14 // Yama is a LSM kernel module which can restrict ptrace(). 15 // This class provides ways to detect if Yama is present and enabled 16 // and to restrict which processes can ptrace the current process. 17 class SANDBOX_EXPORT Yama { 18 public: 19 // This enum should be used to set or check a bitmask. 20 // A value of 0 would indicate that the status is not known. 21 enum GlobalStatus { 22 STATUS_KNOWN = 1 << 0, 23 STATUS_PRESENT = 1 << 1, 24 STATUS_ENFORCING = 1 << 2, 25 // STATUS_STRICT_ENFORCING corresponds to either mode 2 or mode 3 of Yama. 26 // Ptrace could be entirely denied, or restricted to CAP_SYS_PTRACE 27 // and PTRACE_TRACEME. 28 STATUS_STRICT_ENFORCING = 1 << 3 29 }; 30 31 // Restrict who can ptrace() the current process to its ancestors. 32 // If this succeeds, then Yama is available on this kernel. 33 // However, Yama may not be enforcing at this time. 34 static bool RestrictPtracersToAncestors(); 35 36 // Disable Yama restrictions for the current process. 37 // This will fail if Yama is not available on this kernel. 38 // This is meant for testing only. If you need this, implement 39 // a per-pid authorization instead. 40 static bool DisableYamaRestrictions(); 41 42 // Checks if Yama is currently in enforcing mode for the machine (not the 43 // current process). This requires access to the filesystem and will use 44 // /proc/sys/kernel/yama/ptrace_scope. 45 static int GetStatus(); 46 47 // Helper for checking for STATUS_PRESENT in GetStatus(). 48 static bool IsPresent(); 49 // Helper for checkking for STATUS_ENFORCING in GetStatus(). 50 static bool IsEnforcing(); 51 52 private: 53 DISALLOW_IMPLICIT_CONSTRUCTORS(Yama); 54 }; 55 56 } // namespace sandbox 57 58 #endif // SANDBOX_LINUX_SERVICES_YAMA_H_ 59
