╭─────────────╮ │scroll to top│ ╰─────────────╯ ╭ serve_ssh_protocol.zig ───────────────────────────────────────╮ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ╰───────────────────────────────────────────────────────────────╯
🬐 🬠 🬞🬂🬏 🬟 🬑 🬟 🬑 ╭e773cb53..╮ e773cb53.. see-em: 🬋🬋🬋 🬋🬋🬋 🬋 🬋 │files │ commits refs discuss issues new login 🬐 🬠 🬐 🬠 🬑 🬟 🬰 ╰──────────╯ (613) user
╭────╮ ╭ clone ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╮ │http│ ssh │ │ ╰────╯ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╯
.. embed/ event/ test/ ui/ command.zig diff3.zig event.zig find.zig fork.zig lib.zig main.zig main_wasm.zig markdown.zig patch.zig progress.zig push.zig search.zig search_commit.zig search_thread.zig serve.zig serve_common.zig serve_http.zig serve_ssh.zig ╭─────────────────────────────────╮ │serve_ssh_protocol.zig │ ╰─────────────────────────────────╯ test.zig testnet.zig try.zig ui.zig web.zig
2135 try sendChannelMessage(conn, ch, if (success) SSH_MSG_CHANNEL_SUCCESS else SSH_MSG_CHANNEL_FAILURE); 2136 } 2137 2138 fn sendChannelMessage(conn: *Conn, ch: *Channel, msg_type: u8) !void { 2139 var packet: [5]u8 = undefined; 2140 packet[0] = msg_type; 2141 std.mem.writeInt(u32, packet[1..5], ch.remote_id, .big); 2142 try conn.writePacket(&.{&packet}); 2143 } 2144 2145 fn handleWindowAdjust(ch: *Channel, packet: []const u8) !void { 2146 // byte SSH_MSG_CHANNEL_WINDOW_ADJUST 2147 // uint32 recipient_channel 2148 // uint32 bytes_to_add 2149 var r = std.Io.Reader.fixed(packet[1..]); 2150 const recipient_channel = try r.takeInt(u32, .big); 2151 if (recipient_channel != ch.local_id) return error.UnknownChannel; 2152 const add = try r.takeInt(u32, .big); 2153 ch.remote_window +|= add; 2154 } 2155 2156 // charge a payload's bytes against the receive window without keeping them. 2157 // the caller credits the window back, choosing the budget that suits it. 2158 fn discardChannelData(ch: *Channel, packet: []const u8, extended: bool) !void { 2159 // byte SSH_MSG_CHANNEL_DATA/EXTENDED_DATA 2160 // uint32 recipient_channel 2161 // [if extended: uint32 type_code] 2162 // string data 2163 const payload = try parseChannelData(packet, extended, ch.local_id); 2164 const data_len: u32 = @intCast(payload.len); 2165 2166 if (data_len > ch.local_window) return error.WindowExceeded; 2167 ch.local_window -= data_len; 2168 } 2169 2170 pub fn parseChannelData(packet: []const u8, extended: bool, expected_channel: u32) ![]const u8 { 2171 if (packet.len < 1) return error.EmptyPacket; 2172 var r = std.Io.Reader.fixed(packet[1..]); 2173 const recipient_channel = try r.takeInt(u32, .big); 2174 if (recipient_channel != expected_channel) return error.UnknownChannel; 2175 if (extended) { 2176 const data_type = try r.takeInt(u32, .big); 2177 if (data_type != SSH_EXTENDED_DATA_STDERR) return error.UnsupportedExtendedData; 2178 } 2179 const data_len = try r.takeInt(u32, .big); 2180 // catches both data_len > remaining (would otherwise be a bounds-check 2181 // panic on the slice) and trailing junk after the declared payload. 2182 if (data_len != r.buffered().len) return error.InvalidChannelData; 2183 return r.buffered(); 2184 } 2185 2186 fn parseChannelId(packet: []const u8, expected_channel: u32) !void { 2187 var r = std.Io.Reader.fixed(packet[1..]); 2188 const recipient_channel = try r.takeInt(u32, .big); 2189 if (recipient_channel != expected_channel) return error.UnknownChannel; 2190 if (r.buffered().len != 0) return error.InvalidChannelMessage; 2191 } 2192 2193 /// send a CHANNEL_WINDOW_ADJUST if our receive window has dipped below half 2194 /// of `budget`, the credit we're willing to have outstanding. used both for 2195 /// the pre-session discard path and by SessionCtx after it consumes a 2196 /// CHANNEL_DATA payload. 2197 fn maybeRefillRecvWindow(conn: *Conn, ch: *Channel, budget: u32) !void { 2198 if (ch.local_window >= budget / 2) return; 2199 const add = budget - ch.local_window; 2200 ch.local_window += add; 2201 var packet: [9]u8 = undefined; 2202 packet[0] = SSH_MSG_CHANNEL_WINDOW_ADJUST; 2203 std.mem.writeInt(u32, packet[1..5], ch.remote_id, .big); 2204 std.mem.writeInt(u32, packet[5..9], add, .big); 2205 try conn.writePacket(&.{&packet}); 2206 } 2207 2208 pub fn writeU32(buf: *std.ArrayList(u8), allocator: std.mem.Allocator, value: u32) !void { 2209 var bytes: [4]u8 = undefined; 2210 std.mem.writeInt(u32, &bytes, value, .big); 2211 try buf.appendSlice(allocator, &bytes); 2212 } 2213 2214 test "pty dimensions have bounded axes, preserving normal and zero sizes" { 2215 for ([_]struct { width: u32, height: u32, expected: PtySize }{ 2216 .{ .width = 80, .height = 24, .expected = .{ .width_cells = 80, .height_cells = 24 } }, 2217 .{ .width = 0, .height = 0, .expected = .{ .width_cells = 0, .height_cells = 0 } }, 2218 .{ .width = 0xffffffff, .height = 0xffffffff, .expected = .{ .width_cells = 512, .height_cells = 128 } }, 2219 }) |case| { 2220 var bytes: [8]u8 = undefined; 2221 std.mem.writeInt(u32, bytes[0..4], case.width, .big); 2222 std.mem.writeInt(u32, bytes[4..8], case.height, .big); 2223 var reader = std.Io.Reader.fixed(&bytes); 2224 try std.testing.expectEqual(case.expected, try takePtySize(&reader)); 2225 } 2226 } 2227 2228 test "channel close before shell or exec is acknowledged" { 2229 const io = std.testing.io; 2230 const allocator = std.testing.allocator; 2231 const key = [_]u8{0x5a} ** 64; 2232 var encoded: [256]u8 = undefined; 2233 var encoded_writer = std.Io.Writer.fixed(&encoded); 2234 var sender = Cipher.init(&key, 0); 2235 var open: std.ArrayList(u8) = .empty; 2236 defer open.deinit(allocator); 2237 try open.append(allocator, SSH_MSG_CHANNEL_OPEN); 2238 try writeStringField(&open, allocator, "session"); 2239 try writeU32(&open, allocator, 7); 2240 try writeU32(&open, allocator, 32768); 2241 try writeU32(&open, allocator, 32768); 2242 try sender.writePacket(io, &encoded_writer, &.{open.items}); 2243 try sender.writePacket(io, &encoded_writer, &.{&.{ SSH_MSG_CHANNEL_CLOSE, 0, 0, 0, 0 }}); 2244 var reader = std.Io.Reader.fixed(encoded_writer.buffered()); 2245 var output: [256]u8 = undefined; 2246 var writer = std.Io.Writer.fixed(&output); 2247 var idle = IdleState{}; 2248 var conn = Conn{ 2249 .io = io, 2250 .allocator = allocator, 2251 .reader = &reader, 2252 .writer = &writer, 2253 .cs_cipher = Cipher.init(&key, 0), 2254 .sc_cipher = Cipher.init(&key, 0), 2255 .rekey = undefined, 2256 .idle = &idle, 2257 }; 2258 const Handler = struct { 2259 pub fn handleSession(_: *@This(), _: *SessionCtx, _: Request) !void { 2260 return error.UnexpectedSession; 2261 } 2262 }; 2263 var handler = Handler{}; 2264 try runChannelLayer(&conn, &([_]u8{0} ** fingerprint_len), &handler); 2265 var output_reader = std.Io.Reader.fixed(writer.buffered()); 2266 var receiver = Cipher.init(&key, 0); 2267 const confirmation = try receiver.readPacket(allocator, &output_reader); 2268 defer allocator.free(confirmation); 2269 try std.testing.expectEqual(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, confirmation[0]); 2270 const close = try receiver.readPacket(allocator, &output_reader); 2271 defer allocator.free(close); 2272 try std.testing.expectEqualSlices(u8, &.{ SSH_MSG_CHANNEL_CLOSE, 0, 0, 0, 7 }, close); 2273 try std.testing.expectEqual(0, output_reader.buffered().len); 2274 } 2275