/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ #ifndef _LINUX_SECCOMP_H #define _LINUX_SECCOMP_H #include <linux/types.h> /* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */ #define SECCOMP_MODE_DISABLED 0 /* seccomp is not in use. */ #define SECCOMP_MODE_STRICT 1 /* uses hard-coded filter. */ #define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */ /* Valid operations for seccomp syscall. */ #define SECCOMP_SET_MODE_STRICT 0 #define SECCOMP_SET_MODE_FILTER 1 #define SECCOMP_GET_ACTION_AVAIL 2 #define SECCOMP_GET_NOTIF_SIZES 3 /* Valid flags for SECCOMP_SET_MODE_FILTER */ #define SECCOMP_FILTER_FLAG_TSYNC (1UL << 0) #define SECCOMP_FILTER_FLAG_LOG (1UL << 1) #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2) #define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3) #define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4) /* * All BPF programs must return a 32-bit value. * The bottom 16-bits are for optional return data. * The upper 16-bits are ordered from least permissive values to most, * as a signed value (so 0x8000000 is negative). * * The ordering ensures that a min_t() over composed return values always * selects the least permissive choice. */ #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */ #define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */ #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ #define SECCOMP_RET_USER_NOTIF 0x7fc00000U /* notifies userspace */ #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ #define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */ #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ /* Masks for the return value sections. */ #define SECCOMP_RET_ACTION_FULL 0xffff0000U #define SECCOMP_RET_ACTION 0x7fff0000U #define SECCOMP_RET_DATA 0x0000ffffU /** * struct seccomp_data - the format the BPF program executes over. * @nr: the system call number * @arch: indicates system call convention as an AUDIT_ARCH_* value * as defined in <linux/audit.h>. * @instruction_pointer: at the time of the system call. * @args: up to 6 system call arguments always stored as 64-bit values * regardless of the architecture. */ struct seccomp_data { int nr; __u32 arch; __u64 instruction_pointer; __u64 args[6]; }; struct seccomp_notif_sizes { __u16 seccomp_notif; __u16 seccomp_notif_resp; __u16 seccomp_data; }; struct seccomp_notif { __u64 id; __u32 pid; __u32 flags; struct seccomp_data data; }; /* * Valid flags for struct seccomp_notif_resp * * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution! * If set by the process supervising the syscalls of another process the * syscall will continue. This is problematic because of an inherent TOCTOU. * An attacker can exploit the time while the supervised process is waiting on * a response from the supervising process to rewrite syscall arguments which * are passed as pointers of the intercepted syscall. * It should be absolutely clear that this means that the seccomp notifier * _cannot_ be used to implement a security policy! It should only ever be used * in scenarios where a more privileged process supervises the syscalls of a * lesser privileged process to get around kernel-enforced security * restrictions when the privileged process deems this safe. In other words, * in order to continue a syscall the supervising process should be sure that * another security mechanism or the kernel itself will sufficiently block * syscalls if arguments are rewritten to something unsafe. * * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF * or SECCOMP_RET_TRACE. For SECCOMP_RET_USER_NOTIF filters acting on the * same syscall, the most recently added filter takes precedence. This means * that the new SECCOMP_RET_USER_NOTIF filter can override any * SECCOMP_IOCTL_NOTIF_SEND from earlier filters, essentially allowing all * such filtered syscalls to be executed by sending the response * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_TRACE can equally * be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE. */ #define SECCOMP_USER_NOTIF_FLAG_CONTINUE (1UL << 0) struct seccomp_notif_resp { __u64 id; __s64 val; __s32 error; __u32 flags; }; /* valid flags for seccomp_notif_addfd */ #define SECCOMP_ADDFD_FLAG_SETFD (1UL << 0) /* Specify remote fd */ /** * struct seccomp_notif_addfd * @id: The ID of the seccomp notification * @flags: SECCOMP_ADDFD_FLAG_* * @srcfd: The local fd number * @newfd: Optional remote FD number if SETFD option is set, otherwise 0. * @newfd_flags: The O_* flags the remote FD should have applied */ struct seccomp_notif_addfd { __u64 id; __u32 flags; __u32 srcfd; __u32 newfd; __u32 newfd_flags; }; #define SECCOMP_IOC_MAGIC '!' #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) #define SECCOMP_IOW(nr, type) _IOW(SECCOMP_IOC_MAGIC, nr, type) #define SECCOMP_IOWR(nr, type) _IOWR(SECCOMP_IOC_MAGIC, nr, type) /* Flags for seccomp notification fd ioctl. */ #define SECCOMP_IOCTL_NOTIF_RECV SECCOMP_IOWR(0, struct seccomp_notif) #define SECCOMP_IOCTL_NOTIF_SEND SECCOMP_IOWR(1, \ struct seccomp_notif_resp) #define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOW(2, __u64) /* On success, the return value is the remote process's added fd number */ #define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOW(3, \ struct seccomp_notif_addfd) #endif /* _LINUX_SECCOMP_H */