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std: Add libssp implementation for GNU/Windows targets

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Unlike glibc and musl, MinGW provides no libssp symbols leading to
countless compile errors if FORTIFY_SOURCE is defined.

Add a (incomplete) implementation of libssp written in Zig so that
linking succeeds.

Closes #6492
This commit is contained in:
LemonBoy 2020-10-02 16:48:18 +02:00 committed by Andrew Kelley
parent 2aff27d922
commit d44486b274
5 changed files with 276 additions and 53 deletions
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146
lib/std/special/c.zig
View File

@ -35,6 +35,10 @@ comptime {
@export(strncmp, .{ .name = "strncmp", .linkage = .Strong });
@export(strerror, .{ .name = "strerror", .linkage = .Strong });
@export(strlen, .{ .name = "strlen", .linkage = .Strong });
@export(strcpy, .{ .name = "strcpy", .linkage = .Strong });
@export(strncpy, .{ .name = "strncpy", .linkage = .Strong });
@export(strcat, .{ .name = "strcat", .linkage = .Strong });
@export(strncat, .{ .name = "strncat", .linkage = .Strong });
} else if (is_msvc) {
@export(_fltused, .{ .name = "_fltused", .linkage = .Strong });
}
@ -47,6 +51,90 @@ fn wasm_start() callconv(.C) void {
_ = main(0, undefined);
}
fn strcpy(dest: [*:0]u8, src: [*:0]const u8) callconv(.C) [*:0]u8 {
var i: usize = 0;
while (src[i] != 0) : (i += 1) {
dest[i] = src[i];
}
dest[i] = 0;
return dest;
}
test "strcpy" {
var s1: [9:0]u8 = undefined;
s1[0] = 0;
_ = strcpy(&s1, "foobarbaz");
std.testing.expectEqualSlices(u8, "foobarbaz", std.mem.spanZ(&s1));
}
fn strncpy(dest: [*:0]u8, src: [*:0]const u8, n: usize) callconv(.C) [*:0]u8 {
var i: usize = 0;
while (i < n and src[i] != 0) : (i += 1) {
dest[i] = src[i];
}
while (i < n) : (i += 1) {
dest[i] = 0;
}
return dest;
}
test "strncpy" {
var s1: [9:0]u8 = undefined;
s1[0] = 0;
_ = strncpy(&s1, "foobarbaz", 9);
std.testing.expectEqualSlices(u8, "foobarbaz", std.mem.spanZ(&s1));
}
fn strcat(dest: [*:0]u8, src: [*:0]const u8) callconv(.C) [*:0]u8 {
var dest_end: usize = 0;
while (dest[dest_end] != 0) : (dest_end += 1) {}
var i: usize = 0;
while (src[i] != 0) : (i += 1) {
dest[dest_end + i] = src[i];
}
dest[dest_end + i] = 0;
return dest;
}
test "strcat" {
var s1: [9:0]u8 = undefined;
s1[0] = 0;
_ = strcat(&s1, "foo");
_ = strcat(&s1, "bar");
_ = strcat(&s1, "baz");
std.testing.expectEqualSlices(u8, "foobarbaz", std.mem.spanZ(&s1));
}
fn strncat(dest: [*:0]u8, src: [*:0]const u8, avail: usize) callconv(.C) [*:0]u8 {
var dest_end: usize = 0;
while (dest[dest_end] != 0) : (dest_end += 1) {}
var i: usize = 0;
while (i < avail and src[i] != 0) : (i += 1) {
dest[dest_end + i] = src[i];
}
dest[dest_end + i] = 0;
return dest;
}
test "strncat" {
var s1: [9:0]u8 = undefined;
s1[0] = 0;
_ = strncat(&s1, "foo1111", 3);
_ = strncat(&s1, "bar1111", 3);
_ = strncat(&s1, "baz1111", 3);
std.testing.expectEqualSlices(u8, "foobarbaz", std.mem.spanZ(&s1));
}
fn strcmp(s1: [*:0]const u8, s2: [*:0]const u8) callconv(.C) c_int {
return std.cstr.cmp(s1, s2);
}
@ -92,7 +180,7 @@ pub fn panic(msg: []const u8, error_return_trace: ?*builtin.StackTrace) noreturn
while (true) {}
}
export fn memset(dest: ?[*]u8, c: u8, n: usize) ?[*]u8 {
export fn memset(dest: ?[*]u8, c: u8, n: usize) callconv(.C) ?[*]u8 {
@setRuntimeSafety(false);
var index: usize = 0;
@ -102,7 +190,13 @@ export fn memset(dest: ?[*]u8, c: u8, n: usize) ?[*]u8 {
return dest;
}
export fn memcpy(noalias dest: ?[*]u8, noalias src: ?[*]const u8, n: usize) ?[*]u8 {
export fn __memset(dest: ?[*]u8, c: u8, n: usize, dest_n: usize) callconv(.C) ?[*]u8 {
if (dest_n < n)
@panic("buffer overflow");
return memset(dest, c, n);
}
export fn memcpy(noalias dest: ?[*]u8, noalias src: ?[*]const u8, n: usize) callconv(.C) ?[*]u8 {
@setRuntimeSafety(false);
var index: usize = 0;
@ -112,7 +206,7 @@ export fn memcpy(noalias dest: ?[*]u8, noalias src: ?[*]const u8, n: usize) ?[*]
return dest;
}
export fn memmove(dest: ?[*]u8, src: ?[*]const u8, n: usize) ?[*]u8 {
export fn memmove(dest: ?[*]u8, src: ?[*]const u8, n: usize) callconv(.C) ?[*]u8 {
@setRuntimeSafety(false);
if (@ptrToInt(dest) < @ptrToInt(src)) {
@ -131,7 +225,7 @@ export fn memmove(dest: ?[*]u8, src: ?[*]const u8, n: usize) ?[*]u8 {
return dest;
}
export fn memcmp(vl: ?[*]const u8, vr: ?[*]const u8, n: usize) isize {
export fn memcmp(vl: ?[*]const u8, vr: ?[*]const u8, n: usize) callconv(.C) isize {
@setRuntimeSafety(false);
var index: usize = 0;
@ -146,17 +240,17 @@ export fn memcmp(vl: ?[*]const u8, vr: ?[*]const u8, n: usize) isize {
}
test "test_memcmp" {
const base_arr = []u8{ 1, 1, 1 };
const arr1 = []u8{ 1, 1, 1 };
const arr2 = []u8{ 1, 0, 1 };
const arr3 = []u8{ 1, 2, 1 };
const base_arr = &[_]u8{ 1, 1, 1 };
const arr1 = &[_]u8{ 1, 1, 1 };
const arr2 = &[_]u8{ 1, 0, 1 };
const arr3 = &[_]u8{ 1, 2, 1 };
std.testing.expect(memcmp(base_arr[0..].ptr, arr1[0..].ptr, base_arr.len) == 0);
std.testing.expect(memcmp(base_arr[0..].ptr, arr2[0..].ptr, base_arr.len) > 0);
std.testing.expect(memcmp(base_arr[0..].ptr, arr3[0..].ptr, base_arr.len) < 0);
std.testing.expect(memcmp(base_arr[0..], arr1[0..], base_arr.len) == 0);
std.testing.expect(memcmp(base_arr[0..], arr2[0..], base_arr.len) > 0);
std.testing.expect(memcmp(base_arr[0..], arr3[0..], base_arr.len) < 0);
}
export fn bcmp(vl: [*]allowzero const u8, vr: [*]allowzero const u8, n: usize) isize {
export fn bcmp(vl: [*]allowzero const u8, vr: [*]allowzero const u8, n: usize) callconv(.C) isize {
@setRuntimeSafety(false);
var index: usize = 0;
@ -170,30 +264,21 @@ export fn bcmp(vl: [*]allowzero const u8, vr: [*]allowzero const u8, n: usize) i
}
test "test_bcmp" {
const base_arr = []u8{ 1, 1, 1 };
const arr1 = []u8{ 1, 1, 1 };
const arr2 = []u8{ 1, 0, 1 };
const arr3 = []u8{ 1, 2, 1 };
const base_arr = &[_]u8{ 1, 1, 1 };
const arr1 = &[_]u8{ 1, 1, 1 };
const arr2 = &[_]u8{ 1, 0, 1 };
const arr3 = &[_]u8{ 1, 2, 1 };
std.testing.expect(bcmp(base_arr[0..].ptr, arr1[0..].ptr, base_arr.len) == 0);
std.testing.expect(bcmp(base_arr[0..].ptr, arr2[0..].ptr, base_arr.len) != 0);
std.testing.expect(bcmp(base_arr[0..].ptr, arr3[0..].ptr, base_arr.len) != 0);
std.testing.expect(bcmp(base_arr[0..], arr1[0..], base_arr.len) == 0);
std.testing.expect(bcmp(base_arr[0..], arr2[0..], base_arr.len) != 0);
std.testing.expect(bcmp(base_arr[0..], arr3[0..], base_arr.len) != 0);
}
comptime {
if (builtin.mode != builtin.Mode.ReleaseFast and
builtin.mode != builtin.Mode.ReleaseSmall and
builtin.os.tag != .windows)
{
@export(__stack_chk_fail, .{ .name = "__stack_chk_fail" });
}
if (builtin.os.tag == .linux) {
@export(clone, .{ .name = "clone" });
}
}
fn __stack_chk_fail() callconv(.C) noreturn {
@panic("stack smashing detected");
}
// TODO we should be able to put this directly in std/linux/x86_64.zig but
// it causes a segfault in release mode. this is a workaround of calling it
@ -416,7 +501,6 @@ fn clone() callconv(.Naked) void {
\\ # move syscall number into r0
\\ li 0, 120
\\ sc
\\ # check for syscall error
\\ bns+ 1f # jump to label 1 if no summary overflow.
\\ #else
@ -424,10 +508,8 @@ fn clone() callconv(.Naked) void {
\\1:
\\ # compare sc result with 0
\\ cmpwi cr7, 3, 0
\\ # if not 0, jump to end
\\ bne cr7, 2f
\\ #else: we're the child
\\ #call funcptr: move arg (d) into r3
\\ mr 3, 31
@ -438,13 +520,11 @@ fn clone() callconv(.Naked) void {
\\ # mov SYS_exit into r0 (the exit param is already in r3)
\\ li 0, 1
\\ sc
\\2:
\\ # restore stack
\\ lwz 30, 0(1)
\\ lwz 31, 4(1)
\\ addi 1, 1, 16
\\ blr
);
},

19
lib/std/special/compiler_rt.zig
View File

@ -284,11 +284,6 @@ comptime {
@export(@import("compiler_rt/stack_probe.zig").__chkstk, .{ .name = "__chkstk", .linkage = strong_linkage });
}
if (is_mingw) {
@export(__stack_chk_fail, .{ .name = "__stack_chk_fail", .linkage = strong_linkage });
@export(__stack_chk_guard, .{ .name = "__stack_chk_guard", .linkage = strong_linkage });
}
switch (builtin.arch) {
.i386 => {
@export(@import("compiler_rt/divti3.zig").__divti3, .{ .name = "__divti3", .linkage = linkage });
@ -311,9 +306,6 @@ comptime {
else => {},
}
} else {
if (std.Target.current.isGnuLibC() and builtin.link_libc) {
@export(__stack_chk_guard, .{ .name = "__stack_chk_guard", .linkage = linkage });
}
@export(@import("compiler_rt/divti3.zig").__divti3, .{ .name = "__divti3", .linkage = linkage });
@export(@import("compiler_rt/modti3.zig").__modti3, .{ .name = "__modti3", .linkage = linkage });
@export(@import("compiler_rt/multi3.zig").__multi3, .{ .name = "__multi3", .linkage = linkage });
@ -337,14 +329,3 @@ pub fn panic(msg: []const u8, error_return_trace: ?*builtin.StackTrace) noreturn
unreachable;
}
}
fn __stack_chk_fail() callconv(.C) noreturn {
@panic("stack smashing detected");
}
var __stack_chk_guard: usize = blk: {
var buf = [1]u8{0} ** @sizeOf(usize);
buf[@sizeOf(usize) - 1] = 255;
buf[@sizeOf(usize) - 2] = '\n';
break :blk @bitCast(usize, buf);
};

141
lib/std/special/ssp.zig Normal file
View File

@ -0,0 +1,141 @@
// 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.
//
// Small Zig reimplementation of gcc's libssp.
//
// This library implements most of the builtins required by the stack smashing
// protection as implemented by gcc&clang.
const std = @import("std");
const builtin = std.builtin;
// Missing exports:
// - __gets_chk
// - __mempcpy_chk
// - __snprintf_chk
// - __sprintf_chk
// - __stpcpy_chk
// - __vsnprintf_chk
// - __vsprintf_chk
extern fn strncpy(dest: [*:0]u8, src: [*:0]const u8, n: usize) callconv(.C) [*:0]u8;
extern fn memset(dest: ?[*]u8, c: u8, n: usize) callconv(.C) ?[*]u8;
extern fn memcpy(noalias dest: ?[*]u8, noalias src: ?[*]const u8, n: usize) callconv(.C) ?[*]u8;
extern fn memmove(dest: ?[*]u8, src: ?[*]const u8, n: usize) callconv(.C) ?[*]u8;
// Avoid dragging in the runtime safety mechanisms into this .o file.
pub fn panic(msg: []const u8, error_return_trace: ?*builtin.StackTrace) noreturn {
@setCold(true);
if (@hasDecl(std.os, "abort"))
std.os.abort();
while (true) {}
}
export fn __stack_chk_fail() callconv(.C) noreturn {
@panic("stack smashing detected");
}
export fn __chk_fail() callconv(.C) noreturn {
@panic("buffer overflow detected");
}
// Emitted when targeting some architectures (eg. i386)
// XXX: This symbol should be hidden
export fn __stack_chk_fail_local() callconv(.C) noreturn {
__stack_chk_fail();
}
// XXX: Initialize the canary with random data
export var __stack_chk_guard: usize = blk: {
var buf = [1]u8{0} ** @sizeOf(usize);
buf[@sizeOf(usize) - 1] = 255;
buf[@sizeOf(usize) - 2] = '\n';
break :blk @bitCast(usize, buf);
};
export fn __strcpy_chk(dest: [*:0]u8, src: [*:0]const u8, dest_n: usize) callconv(.C) [*:0]u8 {
@setRuntimeSafety(false);
var i: usize = 0;
while (i < dest_n and src[i] != 0) : (i += 1) {
dest[i] = src[i];
}
if (i == dest_n) __chk_fail();
dest[i] = 0;
return dest;
}
export fn __strncpy_chk(dest: [*:0]u8, src: [*:0]const u8, n: usize, dest_n: usize) callconv(.C) [*:0]u8 {
if (dest_n < n) __chk_fail();
return strncpy(dest, src, n);
}
export fn __strcat_chk(dest: [*:0]u8, src: [*:0]const u8, dest_n: usize) callconv(.C) [*:0]u8 {
@setRuntimeSafety(false);
var avail = dest_n;
var dest_end: usize = 0;
while (avail > 0 and dest[dest_end] != 0) : (dest_end += 1) {
avail -= 1;
}
if (avail < 1) __chk_fail();
var i: usize = 0;
while (avail > 0 and src[i] != 0) : (i += 1) {
dest[dest_end + i] = src[i];
avail -= 1;
}
if (avail < 1) __chk_fail();
dest[dest_end + i] = 0;
return dest;
}
export fn __strncat_chk(dest: [*:0]u8, src: [*:0]const u8, n: usize, dest_n: usize) callconv(.C) [*:0]u8 {
@setRuntimeSafety(false);
var avail = dest_n;
var dest_end: usize = 0;
while (avail > 0 and dest[dest_end] != 0) : (dest_end += 1) {
avail -= 1;
}
if (avail < 1) __chk_fail();
var i: usize = 0;
while (avail > 0 and i < n and src[i] != 0) : (i += 1) {
dest[dest_end + i] = src[i];
avail -= 1;
}
if (avail < 1) __chk_fail();
dest[dest_end + i] = 0;
return dest;
}
export fn __memcpy_chk(noalias dest: ?[*]u8, noalias src: ?[*]const u8, n: usize, dest_n: usize) callconv(.C) ?[*]u8 {
if (dest_n < n) __chk_fail();
return memcpy(dest, src, n);
}
export fn __memmove_chk(dest: ?[*]u8, src: ?[*]const u8, n: usize, dest_n: usize) callconv(.C) ?[*]u8 {
if (dest_n < n) __chk_fail();
return memmove(dest, src, n);
}
export fn __memset_chk(dest: ?[*]u8, c: u8, n: usize, dest_n: usize) callconv(.C) ?[*]u8 {
if (dest_n < n) __chk_fail();
return memset(dest, c, n);
}

17
src/Compilation.zig
View File

@ -84,6 +84,9 @@ libcxxabi_static_lib: ?CRTFile = null,
/// Populated when we build the libunwind static library. A Job to build this is placed in the queue
/// and resolved before calling linker.flush().
libunwind_static_lib: ?CRTFile = null,
/// Populated when we build the libssp static library. A Job to build this is placed in the queue
/// and resolved before calling linker.flush().
libssp_static_lib: ?CRTFile = null,
/// Populated when we build the libc static library. A Job to build this is placed in the queue
/// and resolved before calling linker.flush().
libc_static_lib: ?CRTFile = null,
@ -160,6 +163,7 @@ const Job = union(enum) {
libunwind: void,
libcxx: void,
libcxxabi: void,
libssp: void,
/// needed when producing a dynamic library or executable
libcompiler_rt: void,
/// needed when not linking libc and using LLVM for code generation because it generates
@ -927,6 +931,10 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
(comp.getTarget().isWasm() and comp.bin_file.options.output_mode != .Obj);
if (needs_compiler_rt_and_c and build_options.is_stage1) {
try comp.work_queue.writeItem(.{ .libcompiler_rt = {} });
// MinGW provides no libssp, use our own implementation.
if (comp.getTarget().isMinGW()) {
try comp.work_queue.writeItem(.{ .libssp = {} });
}
if (!comp.bin_file.options.link_libc) {
try comp.work_queue.writeItem(.{ .zig_libc = {} });
}
@ -978,6 +986,9 @@ pub fn destroy(self: *Compilation) void {
if (self.compiler_rt_static_lib) |*crt_file| {
crt_file.deinit(gpa);
}
if (self.libssp_static_lib) |*crt_file| {
crt_file.deinit(gpa);
}
if (self.libc_static_lib) |*crt_file| {
crt_file.deinit(gpa);
}
@ -1329,6 +1340,12 @@ pub fn performAllTheWork(self: *Compilation) error{ TimerUnsupported, OutOfMemor
fatal("unable to build compiler_rt: {}", .{@errorName(err)});
};
},
.libssp => {
self.buildStaticLibFromZig("ssp.zig", &self.libssp_static_lib) catch |err| {
// TODO Expose this as a normal compile error rather than crashing here.
fatal("unable to build libssp: {}", .{@errorName(err)});
};
},
.zig_libc => {
self.buildStaticLibFromZig("c.zig", &self.libc_static_lib) catch |err| {
// TODO Expose this as a normal compile error rather than crashing here.

6
src/link/Coff.zig
View File

@ -1117,11 +1117,15 @@ fn linkWithLLD(self: *Coff, comp: *Compilation) !void {
try argv.append(comp.libunwind_static_lib.?.full_object_path);
}
// compiler-rt and libc
// compiler-rt, libc and libssp
if (is_exe_or_dyn_lib and !self.base.options.is_compiler_rt_or_libc) {
if (!self.base.options.link_libc) {
try argv.append(comp.libc_static_lib.?.full_object_path);
}
// MinGW doesn't provide libssp symbols
if (target.abi.isGnu()) {
try argv.append(comp.libssp_static_lib.?.full_object_path);
}
// MSVC compiler_rt is missing some stuff, so we build it unconditionally but
// and rely on weak linkage to allow MSVC compiler_rt functions to override ours.
try argv.append(comp.compiler_rt_static_lib.?.full_object_path);