Commit d0eef26687ca2b4b206b70f001741314d4b8bae8 | zig

author	Tom Read Cutting <readcuttingt@gmail.com> 2022-12-11 11:53:52+00:00
committer	Andrew Kelley <andrew@ziglang.org> 2022-12-12 15:10:59-05:00
log	d0eef26687ca2b4b206b70f001741314d4b8bae8
tree	412effd210ef65092381783da7397e4376a7280a
parent	09cc6b4b9e76434d734ed131ed48ca849bf8a6ba

Add 0-length buffer checks to os.read & os.write

This helps prevent errors related to undefined pointers being passed
through to some OS apis when slices have 0 length.

Tests have also been added to catch these cases.

2 files changed, 104 insertions(+), 0 deletions(-)

lib
- std
  - os.zig
  - os
    test.zig

lib/std/os.zig+4

lib/std/os/test.zig+100

...	@@ -1068,3 +1068,103 @@ test "isatty" {	...	@@ -1068,3 +1068,103 @@ test "isatty" {
1068	var file = try tmp.dir.createFile("foo", .{});	1068	var file = try tmp.dir.createFile("foo", .{});
1069	try expectEqual(os.isatty(file.handle), false);	1069	try expectEqual(os.isatty(file.handle), false);
1070	}	1070	}
		1071
		1072	test "read with empty buffer" {
		1073	if (native_os == .wasi) return error.SkipZigTest;
		1074
		1075	var tmp = tmpDir(.{});
		1076	defer tmp.cleanup();
		1077
		1078	var arena = ArenaAllocator.init(testing.allocator);
		1079	defer arena.deinit();
		1080	const allocator = arena.allocator();
		1081
		1082	// Get base abs path
		1083	const base_path = blk: {
		1084	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1085	break :blk try fs.realpathAlloc(allocator, relative_path);
		1086	};
		1087
		1088	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1089	var file = try fs.cwd().createFile(file_path, .{ .read = true });
		1090	defer file.close();
		1091
		1092	var bytes = try allocator.alloc(u8, 0);
		1093
		1094	_ = try os.read(file.handle, bytes);
		1095	}
		1096
		1097	test "pread with empty buffer" {
		1098	if (native_os == .wasi) return error.SkipZigTest;
		1099
		1100	var tmp = tmpDir(.{});
		1101	defer tmp.cleanup();
		1102
		1103	var arena = ArenaAllocator.init(testing.allocator);
		1104	defer arena.deinit();
		1105	const allocator = arena.allocator();
		1106
		1107	// Get base abs path
		1108	const base_path = blk: {
		1109	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1110	break :blk try fs.realpathAlloc(allocator, relative_path);
		1111	};
		1112
		1113	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1114	var file = try fs.cwd().createFile(file_path, .{ .read = true });
		1115	defer file.close();
		1116
		1117	var bytes = try allocator.alloc(u8, 0);
		1118
		1119	_ = try os.pread(file.handle, bytes, 0);
		1120	}
		1121
		1122	test "write with empty buffer" {
		1123	if (native_os == .wasi) return error.SkipZigTest;
		1124
		1125	var tmp = tmpDir(.{});
		1126	defer tmp.cleanup();
		1127
		1128	var arena = ArenaAllocator.init(testing.allocator);
		1129	defer arena.deinit();
		1130	const allocator = arena.allocator();
		1131
		1132	// Get base abs path
		1133	const base_path = blk: {
		1134	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1135	break :blk try fs.realpathAlloc(allocator, relative_path);
		1136	};
		1137
		1138	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1139	var file = try fs.cwd().createFile(file_path, .{});
		1140	defer file.close();
		1141
		1142	var bytes = try allocator.alloc(u8, 0);
		1143
		1144	_ = try os.write(file.handle, bytes);
		1145	}
		1146
		1147	test "pwrite with empty buffer" {
		1148	if (native_os == .wasi) return error.SkipZigTest;
		1149
		1150	var tmp = tmpDir(.{});
		1151	defer tmp.cleanup();
		1152
		1153	var arena = ArenaAllocator.init(testing.allocator);
		1154	defer arena.deinit();
		1155	const allocator = arena.allocator();
		1156
		1157	// Get base abs path
		1158	const base_path = blk: {
		1159	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1160	break :blk try fs.realpathAlloc(allocator, relative_path);
		1161	};
		1162
		1163	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1164	var file = try fs.cwd().createFile(file_path, .{});
		1165	defer file.close();
		1166
		1167	var bytes = try allocator.alloc(u8, 0);
		1168
		1169	_ = try os.pwrite(file.handle, bytes, 0);
		1170	}

...	@@ -660,6 +660,7 @@ pub const ReadError = error{	...	@@ -660,6 +660,7 @@ pub const ReadError = error{
660	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.	660	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.
661	/// The corresponding POSIX limit is `math.maxInt(isize)`.	661	/// The corresponding POSIX limit is `math.maxInt(isize)`.
662	pub fn read(fd: fd_t, buf: []u8) ReadError!usize {	662	pub fn read(fd: fd_t, buf: []u8) ReadError!usize {
		663	if (buf.len == 0) return 0;
663	if (builtin.os.tag == .windows) {	664	if (builtin.os.tag == .windows) {
664	return windows.ReadFile(fd, buf, null, std.io.default_mode);	665	return windows.ReadFile(fd, buf, null, std.io.default_mode);
665	}	666	}
...	@@ -787,6 +788,7 @@ pub const PReadError = ReadError \|\| error{Unseekable};	...	@@ -787,6 +788,7 @@ pub const PReadError = ReadError \|\| error{Unseekable};
787	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.	788	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.
788	/// The corresponding POSIX limit is `math.maxInt(isize)`.	789	/// The corresponding POSIX limit is `math.maxInt(isize)`.
789	pub fn pread(fd: fd_t, buf: []u8, offset: u64) PReadError!usize {	790	pub fn pread(fd: fd_t, buf: []u8, offset: u64) PReadError!usize {
		791	if (buf.len == 0) return 0;
790	if (builtin.os.tag == .windows) {	792	if (builtin.os.tag == .windows) {
791	return windows.ReadFile(fd, buf, offset, std.io.default_mode);	793	return windows.ReadFile(fd, buf, offset, std.io.default_mode);
792	}	794	}
...	@@ -1045,6 +1047,7 @@ pub const WriteError = error{	...	@@ -1045,6 +1047,7 @@ pub const WriteError = error{
1045	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.	1047	/// The limit on Darwin is `0x7fffffff`, trying to read more than that returns EINVAL.
1046	/// The corresponding POSIX limit is `math.maxInt(isize)`.	1048	/// The corresponding POSIX limit is `math.maxInt(isize)`.
1047	pub fn write(fd: fd_t, bytes: []const u8) WriteError!usize {	1049	pub fn write(fd: fd_t, bytes: []const u8) WriteError!usize {
		1050	if (bytes.len == 0) return 0;
1048	if (builtin.os.tag == .windows) {	1051	if (builtin.os.tag == .windows) {
1049	return windows.WriteFile(fd, bytes, null, std.io.default_mode);	1052	return windows.WriteFile(fd, bytes, null, std.io.default_mode);
1050	}	1053	}
...	@@ -1197,6 +1200,7 @@ pub const PWriteError = WriteError \|\| error{Unseekable};	...	@@ -1197,6 +1200,7 @@ pub const PWriteError = WriteError \|\| error{Unseekable};
1197	/// The limit on Darwin is `0x7fffffff`, trying to write more than that returns EINVAL.	1200	/// The limit on Darwin is `0x7fffffff`, trying to write more than that returns EINVAL.
1198	/// The corresponding POSIX limit is `math.maxInt(isize)`.	1201	/// The corresponding POSIX limit is `math.maxInt(isize)`.
1199	pub fn pwrite(fd: fd_t, bytes: []const u8, offset: u64) PWriteError!usize {	1202	pub fn pwrite(fd: fd_t, bytes: []const u8, offset: u64) PWriteError!usize {
		1203	if (bytes.len == 0) return 0;
1200	if (builtin.os.tag == .windows) {	1204	if (builtin.os.tag == .windows) {
1201	return windows.WriteFile(fd, bytes, offset, std.io.default_mode);	1205	return windows.WriteFile(fd, bytes, offset, std.io.default_mode);
1202	}	1206	}