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| 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 | +/* 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 /* _UAPI_LINUX_SECCOMP_H */ |
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