Merge pull request #6320 from ifreund/prctl

std: add prctl and securebits definitions for linux/C

lib/std/c.zig

@@ -340,3 +340,5 @@ pub extern "c" fn sync() void;
 pub extern "c" fn syncfs(fd: c_int) c_int;
 pub extern "c" fn fsync(fd: c_int) c_int;
 pub extern "c" fn fdatasync(fd: c_int) c_int;
+
+pub extern "c" fn prctl(option: c_int, ...) c_int;

lib/std/os.zig

@@ -5418,3 +5418,42 @@ pub fn fdatasync(fd: fd_t) SyncError!void {
         else => |err| return std.os.unexpectedErrno(err),
     }
 }
+
+pub const PrctlError = error{
+    /// Can only occur with PR_SET_SECCOMP/SECCOMP_MODE_FILTER or
+    /// PR_SET_MM/PR_SET_MM_EXE_FILE
+    AccessDenied,
+    /// Can only occur with PR_SET_MM/PR_SET_MM_EXE_FILE
+    InvalidFileDescriptor,
+    InvalidAddress,
+    /// Can only occur with PR_SET_SPECULATION_CTRL, PR_MPX_ENABLE_MANAGEMENT,
+    /// or PR_MPX_DISABLE_MANAGEMENT
+    UnsupportedFeature,
+    /// Can only occur wih PR_SET_FP_MODE
+    OperationNotSupported,
+    PermissionDenied,
+} || UnexpectedError;
+
+pub fn prctl(option: i32, args: anytype) PrctlError!u31 {
+    if (@typeInfo(@TypeOf(args)) != .Struct)
+        @compileError("Expected tuple or struct argument, found " ++ @typeName(@TypeOf(args)));
+    if (args.len > 4)
+        @compileError("prctl takes a maximum of 4 optional arguments");
+
+    var buf: [4]usize = undefined;
+    inline for (args) |arg, i| buf[i] = arg;
+
+    const rc = system.prctl(option, buf[0], buf[1], buf[2], buf[3]);
+    switch (errno(rc)) {
+        0 => return @intCast(u31, rc),
+        EACCES => return error.AccessDenied,
+        EBADF => return error.InvalidFileDescriptor,
+        EFAULT => return error.InvalidAddress,
+        EINVAL => unreachable,
+        ENODEV, ENXIO => return error.UnsupportedFeature,
+        EOPNOTSUPP => return error.OperationNotSupported,
+        EPERM, EBUSY => return error.PermissionDenied,
+        ERANGE => unreachable,
+        else => |err| return std.os.unexpectedErrno(err),
+    }
+}

lib/std/os/bits/linux.zig

@@ -25,6 +25,8 @@ pub usingnamespace switch (builtin.arch) {
 };
 
 pub usingnamespace @import("linux/netlink.zig");
+pub usingnamespace @import("linux/prctl.zig");
+pub usingnamespace @import("linux/securebits.zig");
 
 const is_mips = builtin.arch.isMIPS();
 

lib/std/os/bits/linux/prctl.zig

@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2015-2020 Zig Contributors
+// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
+// The MIT license requires this copyright notice to be included in all copies
+// and substantial portions of the software.
+
+pub const PR_SET_PDEATHSIG = 1;
+pub const PR_GET_PDEATHSIG = 2;
+
+pub const PR_GET_DUMPABLE = 3;
+pub const PR_SET_DUMPABLE = 4;
+
+pub const PR_GET_UNALIGN = 5;
+pub const PR_SET_UNALIGN = 6;
+pub const PR_UNALIGN_NOPRINT = 1;
+pub const PR_UNALIGN_SIGBUS = 2;
+
+pub const PR_GET_KEEPCAPS = 7;
+pub const PR_SET_KEEPCAPS = 8;
+
+pub const PR_GET_FPEMU = 9;
+pub const PR_SET_FPEMU = 10;
+pub const PR_FPEMU_NOPRINT = 1;
+pub const PR_FPEMU_SIGFPE = 2;
+
+pub const PR_GET_FPEXC = 11;
+pub const PR_SET_FPEXC = 12;
+pub const PR_FP_EXC_SW_ENABLE = 0x80;
+pub const PR_FP_EXC_DIV = 0x010000;
+pub const PR_FP_EXC_OVF = 0x020000;
+pub const PR_FP_EXC_UND = 0x040000;
+pub const PR_FP_EXC_RES = 0x080000;
+pub const PR_FP_EXC_INV = 0x100000;
+pub const PR_FP_EXC_DISABLED = 0;
+pub const PR_FP_EXC_NONRECOV = 1;
+pub const PR_FP_EXC_ASYNC = 2;
+pub const PR_FP_EXC_PRECISE = 3;
+
+pub const PR_GET_TIMING = 13;
+pub const PR_SET_TIMING = 14;
+pub const PR_TIMING_STATISTICAL = 0;
+pub const PR_TIMING_TIMESTAMP = 1;
+
+pub const PR_SET_NAME = 15;
+pub const PR_GET_NAME = 16;
+
+pub const PR_GET_ENDIAN = 19;
+pub const PR_SET_ENDIAN = 20;
+pub const PR_ENDIAN_BIG = 0;
+pub const PR_ENDIAN_LITTLE = 1;
+pub const PR_ENDIAN_PPC_LITTLE = 2;
+
+pub const PR_GET_SECCOMP = 21;
+pub const PR_SET_SECCOMP = 22;
+
+pub const PR_CAPBSET_READ = 23;
+pub const PR_CAPBSET_DROP = 24;
+
+pub const PR_GET_TSC = 25;
+pub const PR_SET_TSC = 26;
+pub const PR_TSC_ENABLE = 1;
+pub const PR_TSC_SIGSEGV = 2;
+
+pub const PR_GET_SECUREBITS = 27;
+pub const PR_SET_SECUREBITS = 28;
+
+pub const PR_SET_TIMERSLACK = 29;
+pub const PR_GET_TIMERSLACK = 30;
+
+pub const PR_TASK_PERF_EVENTS_DISABLE = 31;
+pub const PR_TASK_PERF_EVENTS_ENABLE = 32;
+
+pub const PR_MCE_KILL = 33;
+pub const PR_MCE_KILL_CLEAR = 0;
+pub const PR_MCE_KILL_SET = 1;
+
+pub const PR_MCE_KILL_LATE = 0;
+pub const PR_MCE_KILL_EARLY = 1;
+pub const PR_MCE_KILL_DEFAULT = 2;
+
+pub const PR_MCE_KILL_GET = 34;
+
+pub const PR_SET_MM = 35;
+pub const PR_SET_MM_START_CODE = 1;
+pub const PR_SET_MM_END_CODE = 2;
+pub const PR_SET_MM_START_DATA = 3;
+pub const PR_SET_MM_END_DATA = 4;
+pub const PR_SET_MM_START_STACK = 5;
+pub const PR_SET_MM_START_BRK = 6;
+pub const PR_SET_MM_BRK = 7;
+pub const PR_SET_MM_ARG_START = 8;
+pub const PR_SET_MM_ARG_END = 9;
+pub const PR_SET_MM_ENV_START = 10;
+pub const PR_SET_MM_ENV_END = 11;
+pub const PR_SET_MM_AUXV = 12;
+pub const PR_SET_MM_EXE_FILE = 13;
+pub const PR_SET_MM_MAP = 14;
+pub const PR_SET_MM_MAP_SIZE = 15;
+
+pub const prctl_mm_map = extern struct {
+    start_code: u64,
+    end_code: u64,
+    start_data: u64,
+    end_data: u64,
+    start_brk: u64,
+    brk: u64,
+    start_stack: u64,
+    arg_start: u64,
+    arg_end: u64,
+    env_start: u64,
+    env_end: u64,
+    auxv: *u64,
+    auxv_size: u32,
+    exe_fd: u32,
+};
+
+pub const PR_SET_PTRACER = 0x59616d61;
+pub const PR_SET_PTRACER_ANY = std.math.maxInt(c_ulong);
+
+pub const PR_SET_CHILD_SUBREAPER = 36;
+pub const PR_GET_CHILD_SUBREAPER = 37;
+
+pub const PR_SET_NO_NEW_PRIVS = 38;
+pub const PR_GET_NO_NEW_PRIVS = 39;
+
+pub const PR_GET_TID_ADDRESS = 40;
+
+pub const PR_SET_THP_DISABLE = 41;
+pub const PR_GET_THP_DISABLE = 42;
+
+pub const PR_MPX_ENABLE_MANAGEMENT = 43;
+pub const PR_MPX_DISABLE_MANAGEMENT = 44;
+
+pub const PR_SET_FP_MODE = 45;
+pub const PR_GET_FP_MODE = 46;
+pub const PR_FP_MODE_FR = 1 << 0;
+pub const PR_FP_MODE_FRE = 1 << 1;
+
+pub const PR_CAP_AMBIENT = 47;
+pub const PR_CAP_AMBIENT_IS_SET = 1;
+pub const PR_CAP_AMBIENT_RAISE = 2;
+pub const PR_CAP_AMBIENT_LOWER = 3;
+pub const PR_CAP_AMBIENT_CLEAR_ALL = 4;
+
+pub const PR_SVE_SET_VL = 50;
+pub const PR_SVE_SET_VL_ONEXEC = 1 << 18;
+pub const PR_SVE_GET_VL = 51;
+pub const PR_SVE_VL_LEN_MASK = 0xffff;
+pub const PR_SVE_VL_INHERIT = 1 << 17;
+
+pub const PR_GET_SPECULATION_CTRL = 52;
+pub const PR_SET_SPECULATION_CTRL = 53;
+pub const PR_SPEC_STORE_BYPASS = 0;
+pub const PR_SPEC_NOT_AFFECTED = 0;
+pub const PR_SPEC_PRCTL = 1 << 0;
+pub const PR_SPEC_ENABLE = 1 << 1;
+pub const PR_SPEC_DISABLE = 1 << 2;
+pub const PR_SPEC_FORCE_DISABLE = 1 << 3;

lib/std/os/bits/linux/securebits.zig

@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2015-2020 Zig Contributors
+// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
+// The MIT license requires this copyright notice to be included in all copies
+// and substantial portions of the software.
+
+fn issecure_mask(comptime x: comptime_int) comptime_int {
+    return 1 << x;
+}
+
+pub const SECUREBITS_DEFAULT = 0x00000000;
+
+pub const SECURE_NOROOT = 0;
+pub const SECURE_NOROOT_LOCKED = 1;
+
+pub const SECBIT_NOROOT = issecure_mask(SECURE_NOROOT);
+pub const SECBIT_NOROOT_LOCKED = issecure_mask(SECURE_NOROOT_LOCKED);
+
+pub const SECURE_NO_SETUID_FIXUP = 2;
+pub const SECURE_NO_SETUID_FIXUP_LOCKED = 3;
+
+pub const SECBIT_NO_SETUID_FIXUP = issecure_mask(SECURE_NO_SETUID_FIXUP);
+pub const SECBIT_NO_SETUID_FIXUP_LOCKED = issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED);
+
+pub const SECURE_KEEP_CAPS = 4;
+pub const SECURE_KEEP_CAPS_LOCKED = 5;
+
+pub const SECBIT_KEEP_CAPS = issecure_mask(SECURE_KEEP_CAPS);
+pub const SECBIT_KEEP_CAPS_LOCKED = issecure_mask(SECURE_KEEP_CAPS_LOCKED);
+
+pub const SECURE_NO_CAP_AMBIENT_RAISE = 6;
+pub const SECURE_NO_CAP_AMBIENT_RAISE_LOCKED = 7;
+
+pub const SECBIT_NO_CAP_AMBIENT_RAISE = issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE);
+pub const SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED = issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED);
+
+pub const SECURE_ALL_BITS = issecure_mask(SECURE_NOROOT) |
+    issecure_mask(SECURE_NO_SETUID_FIXUP) |
+    issecure_mask(SECURE_KEEP_CAPS) |
+    issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE);
+pub const SECURE_ALL_LOCKS = SECURE_ALL_BITS << 1;

lib/std/os/linux.zig

@@ -1259,6 +1259,10 @@ pub fn fdatasync(fd: fd_t) usize {
     return syscall1(.fdatasync, @bitCast(usize, @as(isize, fd)));
 }
 
+pub fn prctl(option: i32, arg2: usize, arg3: usize, arg4: usize, arg5: usize) usize {
+    return syscall5(.prctl, @bitCast(usize, @as(isize, option)), arg2, arg3, arg4, arg5);
+}
+
 test "" {
     if (builtin.os.tag == .linux) {
         _ = @import("linux/test.zig");