1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_LINUX_SECCOMP_H
3 #define _UAPI_LINUX_SECCOMP_H
5 #include <linux/compiler.h>
6 #include <linux/types.h>
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. */
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
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)
27 * All BPF programs must return a 32-bit value.
28 * The bottom 16-bits are for optional return data.
29 * The upper 16-bits are ordered from least permissive values to most,
30 * as a signed value (so 0x8000000 is negative).
32 * The ordering ensures that a min_t() over composed return values always
33 * selects the least permissive choice.
35 #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */
36 #define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
37 #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
38 #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
39 #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
40 #define SECCOMP_RET_USER_NOTIF 0x7fc00000U /* notifies userspace */
41 #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
42 #define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
43 #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
45 /* Masks for the return value sections. */
46 #define SECCOMP_RET_ACTION_FULL 0xffff0000U
47 #define SECCOMP_RET_ACTION 0x7fff0000U
48 #define SECCOMP_RET_DATA 0x0000ffffU
51 * struct seccomp_data - the format the BPF program executes over.
52 * @nr: the system call number
53 * @arch: indicates system call convention as an AUDIT_ARCH_* value
54 * as defined in <linux/audit.h>.
55 * @instruction_pointer: at the time of the system call.
56 * @args: up to 6 system call arguments always stored as 64-bit values
57 * regardless of the architecture.
62 __u64 instruction_pointer;
66 struct seccomp_notif_sizes {
68 __u16 seccomp_notif_resp;
72 struct seccomp_notif {
76 struct seccomp_data data;
80 * Valid flags for struct seccomp_notif_resp
82 * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution!
83 * If set by the process supervising the syscalls of another process the
84 * syscall will continue. This is problematic because of an inherent TOCTOU.
85 * An attacker can exploit the time while the supervised process is waiting on
86 * a response from the supervising process to rewrite syscall arguments which
87 * are passed as pointers of the intercepted syscall.
88 * It should be absolutely clear that this means that the seccomp notifier
89 * _cannot_ be used to implement a security policy! It should only ever be used
90 * in scenarios where a more privileged process supervises the syscalls of a
91 * lesser privileged process to get around kernel-enforced security
92 * restrictions when the privileged process deems this safe. In other words,
93 * in order to continue a syscall the supervising process should be sure that
94 * another security mechanism or the kernel itself will sufficiently block
95 * syscalls if arguments are rewritten to something unsafe.
97 * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF
98 * or SECCOMP_RET_TRACE. For SECCOMP_RET_USER_NOTIF filters acting on the
99 * same syscall, the most recently added filter takes precedence. This means
100 * that the new SECCOMP_RET_USER_NOTIF filter can override any
101 * SECCOMP_IOCTL_NOTIF_SEND from earlier filters, essentially allowing all
102 * such filtered syscalls to be executed by sending the response
103 * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_TRACE can equally
104 * be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE.
106 #define SECCOMP_USER_NOTIF_FLAG_CONTINUE (1UL << 0)
108 struct seccomp_notif_resp {
115 #define SECCOMP_IOC_MAGIC '!'
116 #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr)
117 #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type)
118 #define SECCOMP_IOW(nr, type) _IOW(SECCOMP_IOC_MAGIC, nr, type)
119 #define SECCOMP_IOWR(nr, type) _IOWR(SECCOMP_IOC_MAGIC, nr, type)
121 /* Flags for seccomp notification fd ioctl. */
122 #define SECCOMP_IOCTL_NOTIF_RECV SECCOMP_IOWR(0, struct seccomp_notif)
123 #define SECCOMP_IOCTL_NOTIF_SEND SECCOMP_IOWR(1, \
124 struct seccomp_notif_resp)
125 #define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOR(2, __u64)
126 #endif /* _UAPI_LINUX_SECCOMP_H */