Commit b5222f86eec68088b9bd83ad2f648654242082ec | zig

author	Tom Read Cutting <readcuttingt@gmail.com> 2022-12-11 11:53:52+00:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-01-09 15:04:10-07:00
log	b5222f86eec68088b9bd83ad2f648654242082ec
tree	efeb5346647a475de4743a42b07316f2c16eb5bb
parent	7d0d99aac0c3e47ab4f82a43525a6f4a18334d43

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

...	@@ -1080,3 +1080,103 @@ test "isatty" {	...	@@ -1080,3 +1080,103 @@ test "isatty" {
1080	var file = try tmp.dir.createFile("foo", .{});	1080	var file = try tmp.dir.createFile("foo", .{});
1081	try expectEqual(os.isatty(file.handle), false);	1081	try expectEqual(os.isatty(file.handle), false);
1082	}	1082	}
		1083
		1084	test "read with empty buffer" {
		1085	if (native_os == .wasi) return error.SkipZigTest;
		1086
		1087	var tmp = tmpDir(.{});
		1088	defer tmp.cleanup();
		1089
		1090	var arena = ArenaAllocator.init(testing.allocator);
		1091	defer arena.deinit();
		1092	const allocator = arena.allocator();
		1093
		1094	// Get base abs path
		1095	const base_path = blk: {
		1096	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1097	break :blk try fs.realpathAlloc(allocator, relative_path);
		1098	};
		1099
		1100	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1101	var file = try fs.cwd().createFile(file_path, .{ .read = true });
		1102	defer file.close();
		1103
		1104	var bytes = try allocator.alloc(u8, 0);
		1105
		1106	_ = try os.read(file.handle, bytes);
		1107	}
		1108
		1109	test "pread with empty buffer" {
		1110	if (native_os == .wasi) return error.SkipZigTest;
		1111
		1112	var tmp = tmpDir(.{});
		1113	defer tmp.cleanup();
		1114
		1115	var arena = ArenaAllocator.init(testing.allocator);
		1116	defer arena.deinit();
		1117	const allocator = arena.allocator();
		1118
		1119	// Get base abs path
		1120	const base_path = blk: {
		1121	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1122	break :blk try fs.realpathAlloc(allocator, relative_path);
		1123	};
		1124
		1125	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1126	var file = try fs.cwd().createFile(file_path, .{ .read = true });
		1127	defer file.close();
		1128
		1129	var bytes = try allocator.alloc(u8, 0);
		1130
		1131	_ = try os.pread(file.handle, bytes, 0);
		1132	}
		1133
		1134	test "write with empty buffer" {
		1135	if (native_os == .wasi) return error.SkipZigTest;
		1136
		1137	var tmp = tmpDir(.{});
		1138	defer tmp.cleanup();
		1139
		1140	var arena = ArenaAllocator.init(testing.allocator);
		1141	defer arena.deinit();
		1142	const allocator = arena.allocator();
		1143
		1144	// Get base abs path
		1145	const base_path = blk: {
		1146	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1147	break :blk try fs.realpathAlloc(allocator, relative_path);
		1148	};
		1149
		1150	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1151	var file = try fs.cwd().createFile(file_path, .{});
		1152	defer file.close();
		1153
		1154	var bytes = try allocator.alloc(u8, 0);
		1155
		1156	_ = try os.write(file.handle, bytes);
		1157	}
		1158
		1159	test "pwrite with empty buffer" {
		1160	if (native_os == .wasi) return error.SkipZigTest;
		1161
		1162	var tmp = tmpDir(.{});
		1163	defer tmp.cleanup();
		1164
		1165	var arena = ArenaAllocator.init(testing.allocator);
		1166	defer arena.deinit();
		1167	const allocator = arena.allocator();
		1168
		1169	// Get base abs path
		1170	const base_path = blk: {
		1171	const relative_path = try fs.path.join(allocator, &[_][]const u8{ "zig-cache", "tmp", tmp.sub_path[0..] });
		1172	break :blk try fs.realpathAlloc(allocator, relative_path);
		1173	};
		1174
		1175	var file_path: []u8 = try fs.path.join(allocator, &[_][]const u8{ base_path, "some_file" });
		1176	var file = try fs.cwd().createFile(file_path, .{});
		1177	defer file.close();
		1178
		1179	var bytes = try allocator.alloc(u8, 0);
		1180
		1181	_ = try os.pwrite(file.handle, bytes, 0);
		1182	}

...	@@ -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	}