seccomp.h (5989B) - Raw
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _LINUX_SECCOMP_H 3 #define _LINUX_SECCOMP_H 4 5 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 /* Received notifications wait in killable state (only respond to fatal signals) */ 27 #define SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV (1UL << 5) 28 29 /* 30 * All BPF programs must return a 32-bit value. 31 * The bottom 16-bits are for optional return data. 32 * The upper 16-bits are ordered from least permissive values to most, 33 * as a signed value (so 0x8000000 is negative). 34 * 35 * The ordering ensures that a min_t() over composed return values always 36 * selects the least permissive choice. 37 */ 38 #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */ 39 #define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */ 40 #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD 41 #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ 42 #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ 43 #define SECCOMP_RET_USER_NOTIF 0x7fc00000U /* notifies userspace */ 44 #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ 45 #define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */ 46 #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ 47 48 /* Masks for the return value sections. */ 49 #define SECCOMP_RET_ACTION_FULL 0xffff0000U 50 #define SECCOMP_RET_ACTION 0x7fff0000U 51 #define SECCOMP_RET_DATA 0x0000ffffU 52 53 /** 54 * struct seccomp_data - the format the BPF program executes over. 55 * @nr: the system call number 56 * @arch: indicates system call convention as an AUDIT_ARCH_* value 57 * as defined in <linux/audit.h>. 58 * @instruction_pointer: at the time of the system call. 59 * @args: up to 6 system call arguments always stored as 64-bit values 60 * regardless of the architecture. 61 */ 62 struct seccomp_data { 63 int nr; 64 __u32 arch; 65 __u64 instruction_pointer; 66 __u64 args[6]; 67 }; 68 69 struct seccomp_notif_sizes { 70 __u16 seccomp_notif; 71 __u16 seccomp_notif_resp; 72 __u16 seccomp_data; 73 }; 74 75 struct seccomp_notif { 76 __u64 id; 77 __u32 pid; 78 __u32 flags; 79 struct seccomp_data data; 80 }; 81 82 /* 83 * Valid flags for struct seccomp_notif_resp 84 * 85 * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution! 86 * If set by the process supervising the syscalls of another process the 87 * syscall will continue. This is problematic because of an inherent TOCTOU. 88 * An attacker can exploit the time while the supervised process is waiting on 89 * a response from the supervising process to rewrite syscall arguments which 90 * are passed as pointers of the intercepted syscall. 91 * It should be absolutely clear that this means that the seccomp notifier 92 * _cannot_ be used to implement a security policy! It should only ever be used 93 * in scenarios where a more privileged process supervises the syscalls of a 94 * lesser privileged process to get around kernel-enforced security 95 * restrictions when the privileged process deems this safe. In other words, 96 * in order to continue a syscall the supervising process should be sure that 97 * another security mechanism or the kernel itself will sufficiently block 98 * syscalls if arguments are rewritten to something unsafe. 99 * 100 * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF 101 * or SECCOMP_RET_TRACE. For SECCOMP_RET_USER_NOTIF filters acting on the 102 * same syscall, the most recently added filter takes precedence. This means 103 * that the new SECCOMP_RET_USER_NOTIF filter can override any 104 * SECCOMP_IOCTL_NOTIF_SEND from earlier filters, essentially allowing all 105 * such filtered syscalls to be executed by sending the response 106 * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_TRACE can equally 107 * be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE. 108 */ 109 #define SECCOMP_USER_NOTIF_FLAG_CONTINUE (1UL << 0) 110 111 struct seccomp_notif_resp { 112 __u64 id; 113 __s64 val; 114 __s32 error; 115 __u32 flags; 116 }; 117 118 #define SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP (1UL << 0) 119 120 /* valid flags for seccomp_notif_addfd */ 121 #define SECCOMP_ADDFD_FLAG_SETFD (1UL << 0) /* Specify remote fd */ 122 #define SECCOMP_ADDFD_FLAG_SEND (1UL << 1) /* Addfd and return it, atomically */ 123 124 /** 125 * struct seccomp_notif_addfd 126 * @id: The ID of the seccomp notification 127 * @flags: SECCOMP_ADDFD_FLAG_* 128 * @srcfd: The local fd number 129 * @newfd: Optional remote FD number if SETFD option is set, otherwise 0. 130 * @newfd_flags: The O_* flags the remote FD should have applied 131 */ 132 struct seccomp_notif_addfd { 133 __u64 id; 134 __u32 flags; 135 __u32 srcfd; 136 __u32 newfd; 137 __u32 newfd_flags; 138 }; 139 140 #define SECCOMP_IOC_MAGIC '!' 141 #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) 142 #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) 143 #define SECCOMP_IOW(nr, type) _IOW(SECCOMP_IOC_MAGIC, nr, type) 144 #define SECCOMP_IOWR(nr, type) _IOWR(SECCOMP_IOC_MAGIC, nr, type) 145 146 /* Flags for seccomp notification fd ioctl. */ 147 #define SECCOMP_IOCTL_NOTIF_RECV SECCOMP_IOWR(0, struct seccomp_notif) 148 #define SECCOMP_IOCTL_NOTIF_SEND SECCOMP_IOWR(1, \ 149 struct seccomp_notif_resp) 150 #define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOW(2, __u64) 151 /* On success, the return value is the remote process's added fd number */ 152 #define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOW(3, \ 153 struct seccomp_notif_addfd) 154 155 #define SECCOMP_IOCTL_NOTIF_SET_FLAGS SECCOMP_IOW(4, __u64) 156 157 #endif /* _LINUX_SECCOMP_H */