1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _UAPI_LINUX_SECCOMP_H 3 #define _UAPI_LINUX_SECCOMP_H 4 5 #include <linux/compiler.h> 6 #include <linux/types.h> 7 8 9 /* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */ 10 #define SECCOMP_MODE_DISABLED 0 /* seccomp is not in use. */ 11 #define SECCOMP_MODE_STRICT 1 /* uses hard-coded filter. */ 12 #define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */ 13 14 /* Valid operations for seccomp syscall. */ 15 #define SECCOMP_SET_MODE_STRICT 0 16 #define SECCOMP_SET_MODE_FILTER 1 17 #define SECCOMP_GET_ACTION_AVAIL 2 18 #define SECCOMP_GET_NOTIF_SIZES 3 19 20 /* Valid flags for SECCOMP_SET_MODE_FILTER */ 21 #define SECCOMP_FILTER_FLAG_TSYNC (1UL << 0) 22 #define SECCOMP_FILTER_FLAG_LOG (1UL << 1) 23 #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2) 24 #define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3) 25 #define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4) 26 27 /* 28 * All BPF programs must return a 32-bit value. 29 * The bottom 16-bits are for optional return data. 30 * The upper 16-bits are ordered from least permissive values to most, 31 * as a signed value (so 0x8000000 is negative). 32 * 33 * The ordering ensures that a min_t() over composed return values always 34 * selects the least permissive choice. 35 */ 36 #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */ 37 #define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */ 38 #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD 39 #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ 40 #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ 41 #define SECCOMP_RET_USER_NOTIF 0x7fc00000U /* notifies userspace */ 42 #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ 43 #define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */ 44 #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ 45 46 /* Masks for the return value sections. */ 47 #define SECCOMP_RET_ACTION_FULL 0xffff0000U 48 #define SECCOMP_RET_ACTION 0x7fff0000U 49 #define SECCOMP_RET_DATA 0x0000ffffU 50 51 /** 52 * struct seccomp_data - the format the BPF program executes over. 53 * @nr: the system call number 54 * @arch: indicates system call convention as an AUDIT_ARCH_* value 55 * as defined in <linux/audit.h>. 56 * @instruction_pointer: at the time of the system call. 57 * @args: up to 6 system call arguments always stored as 64-bit values 58 * regardless of the architecture. 59 */ 60 struct seccomp_data { 61 int nr; 62 __u32 arch; 63 __u64 instruction_pointer; 64 __u64 args[6]; 65 }; 66 67 struct seccomp_notif_sizes { 68 __u16 seccomp_notif; 69 __u16 seccomp_notif_resp; 70 __u16 seccomp_data; 71 }; 72 73 struct seccomp_notif { 74 __u64 id; 75 __u32 pid; 76 __u32 flags; 77 struct seccomp_data data; 78 }; 79 80 /* 81 * Valid flags for struct seccomp_notif_resp 82 * 83 * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution! 84 * If set by the process supervising the syscalls of another process the 85 * syscall will continue. This is problematic because of an inherent TOCTOU. 86 * An attacker can exploit the time while the supervised process is waiting on 87 * a response from the supervising process to rewrite syscall arguments which 88 * are passed as pointers of the intercepted syscall. 89 * It should be absolutely clear that this means that the seccomp notifier 90 * _cannot_ be used to implement a security policy! It should only ever be used 91 * in scenarios where a more privileged process supervises the syscalls of a 92 * lesser privileged process to get around kernel-enforced security 93 * restrictions when the privileged process deems this safe. In other words, 94 * in order to continue a syscall the supervising process should be sure that 95 * another security mechanism or the kernel itself will sufficiently block 96 * syscalls if arguments are rewritten to something unsafe. 97 * 98 * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF 99 * or SECCOMP_RET_TRACE. For SECCOMP_RET_USER_NOTIF filters acting on the 100 * same syscall, the most recently added filter takes precedence. This means 101 * that the new SECCOMP_RET_USER_NOTIF filter can override any 102 * SECCOMP_IOCTL_NOTIF_SEND from earlier filters, essentially allowing all 103 * such filtered syscalls to be executed by sending the response 104 * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_TRACE can equally 105 * be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE. 106 */ 107 #define SECCOMP_USER_NOTIF_FLAG_CONTINUE (1UL << 0) 108 109 struct seccomp_notif_resp { 110 __u64 id; 111 __s64 val; 112 __s32 error; 113 __u32 flags; 114 }; 115 116 /* valid flags for seccomp_notif_addfd */ 117 #define SECCOMP_ADDFD_FLAG_SETFD (1UL << 0) /* Specify remote fd */ 118 #define SECCOMP_ADDFD_FLAG_SEND (1UL << 1) /* Addfd and return it, atomically */ 119 120 /** 121 * struct seccomp_notif_addfd 122 * @id: The ID of the seccomp notification 123 * @flags: SECCOMP_ADDFD_FLAG_* 124 * @srcfd: The local fd number 125 * @newfd: Optional remote FD number if SETFD option is set, otherwise 0. 126 * @newfd_flags: The O_* flags the remote FD should have applied 127 */ 128 struct seccomp_notif_addfd { 129 __u64 id; 130 __u32 flags; 131 __u32 srcfd; 132 __u32 newfd; 133 __u32 newfd_flags; 134 }; 135 136 #define SECCOMP_IOC_MAGIC '!' 137 #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) 138 #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) 139 #define SECCOMP_IOW(nr, type) _IOW(SECCOMP_IOC_MAGIC, nr, type) 140 #define SECCOMP_IOWR(nr, type) _IOWR(SECCOMP_IOC_MAGIC, nr, type) 141 142 /* Flags for seccomp notification fd ioctl. */ 143 #define SECCOMP_IOCTL_NOTIF_RECV SECCOMP_IOWR(0, struct seccomp_notif) 144 #define SECCOMP_IOCTL_NOTIF_SEND SECCOMP_IOWR(1, \ 145 struct seccomp_notif_resp) 146 #define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOW(2, __u64) 147 /* On success, the return value is the remote process's added fd number */ 148 #define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOW(3, \ 149 struct seccomp_notif_addfd) 150 151 #endif /* _UAPI_LINUX_SECCOMP_H */ 152