╭─────────────╮ │scroll to top│ ╰─────────────╯ ╭ fuzzer.zig ───────────────────────────────────────────────────╮ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ╰───────────────────────────────────────────────────────────────╯
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╭ find file ─ ─ ─ ─ ─ ─ ─ ─ ─ ─╮ ╭────╮ ╭ clone ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╮ │ │ │http│ ssh │ │ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─╯ ╰────╯ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╯
.. build-web/ c/ compiler/ compiler_rt/ docs/ include/ init/ libc/ libcxx/ libcxxabi/ libtsan/ libunwind/ lldb/ std/ c.zig compiler_rt.zig ╭─────────────────────────────────╮ │fuzzer.zig │ ╰─────────────────────────────────╯ ubsan_rt.zig zig.h
2012 const len = @min( 2013 f.rngLessThan(u32, in_len - off) + 1, 2014 opts.limitSmall(rem_out.len), 2015 ); 2016 @memcpy(rem_out[0..len], in[off..][0..len]); 2017 rem_out = rem_out[len..]; 2018 }, 2019 } 2020 } 2021 2022 const copy = @min(rem_out.len, rem_copy.len); 2023 @memcpy(rem_out[0..copy], rem_copy[0..copy]); 2024 for (rem_out[copy..]) |*o| { 2025 o.* = @intCast(f.weightedValue(weights, weights_incl_sum)); 2026 } 2027 } 2028 2029 fn nextBytesInner(f: *Fuzzer, uid: Uid, out: []u8, weights: []const abi.Weight) void { 2030 so: switch (f.nextUntyped(uid, weights)) { 2031 .copy => |u| { 2032 if (u.bytes.len >= out.len) { 2033 @branchHint(.likely); 2034 @memcpy(out, u.bytes[0..out.len]); 2035 return; 2036 } 2037 2038 @memcpy(out[0..u.bytes.len], u.bytes); 2039 const weights_incl_sum = sumWeightsInclusive(weights); 2040 for (out[u.bytes.len..]) |*o| { 2041 o.* = @intCast(f.weightedValue(weights, weights_incl_sum)); 2042 } 2043 }, 2044 .mutate => |u| { 2045 if (u.bytes.len == 0) continue :so .fresh; 2046 f.mutateBytes(u.bytes, out, weights); 2047 }, 2048 .fresh => { 2049 const weights_incl_sum = sumWeightsInclusive(weights); 2050 for (out) |*o| { 2051 o.* = @intCast(f.weightedValue(weights, weights_incl_sum)); 2052 } 2053 }, 2054 } 2055 } 2056 2057 pub fn nextBytes(f: *Fuzzer, uid: Uid, out: []u8, weights: []const abi.Weight) void { 2058 const t = &f.tests[f.test_i]; 2059 f.req_values += 1; 2060 f.req_bytes +%= @truncate(out.len); // This function should panic since the 32-bit 2061 // data limit is exceeded, so wrapping is fine. 2062 if (@backingInt(t.corpus_pos) >= @backingInt(Input.Index.reserved_start)) { 2063 @branchHint(.unlikely); 2064 f.bytes_input.bytesWeightedWithHash(out, weights, undefined); 2065 if (t.corpus_pos == .bytes_fresh) { 2066 f.input_builder.checkSmithedLen(out.len); 2067 f.input_builder.addBytes(uid, out); 2068 } 2069 return; 2070 } 2071 2072 f.nextBytesInner(uid, out, weights); 2073 f.mmap_input.appendSlice(out); 2074 } 2075 2076 fn nextSliceInner( 2077 f: *Fuzzer, 2078 uid: Uid, 2079 buf: []u8, 2080 len_weights: []const abi.Weight, 2081 byte_weights: []const abi.Weight, 2082 ) u32 { 2083 so: switch (f.nextUntyped(uid, byte_weights)) { 2084 .copy => |u| { 2085 var len: u32 = @intCast(u.bytes.len); 2086 if (!weightsContain(len, len_weights)) { 2087 @branchHint(.unlikely); 2088 len = @intCast(f.weightedValue(len_weights, sumWeightsInclusive(len_weights))); 2089 } 2090 2091 if (u.bytes.len >= len) { 2092 @branchHint(.likely); 2093 @memcpy(buf[0..len], u.bytes[0..len]); 2094 return len; 2095 } 2096 2097 @memcpy(buf[0..u.bytes.len], u.bytes); 2098 const weights_incl_sum = sumWeightsInclusive(byte_weights); 2099 for (buf[u.bytes.len..len]) |*o| { 2100 o.* = @intCast(f.weightedValue(byte_weights, weights_incl_sum)); 2101 } 2102 return len; 2103 }, 2104 .mutate => |u| { 2105 if (u.bytes.len == 0) continue :so .fresh; 2106 const len: u32 = len: { 2107 const offseted: packed struct { 2108 is: u3, 2109 sub: bool, 2110 by: u3, 2111 } = @bitCast(f.rngInt(u7)); 2112 if (offseted.is != 0) { 2113 const len = if (offseted.sub) 2114 @as(u32, @intCast(u.bytes.len)) -| offseted.by 2115 else 2116 @min(u.bytes.len + offseted.by, @as(u32, @intCast(buf.len))); 2117 if (weightsContain(len, len_weights)) { 2118 break :len len; 2119 } 2120 } 2121 break :len @intCast(f.weightedValue( 2122 len_weights, 2123 sumWeightsInclusive(len_weights), 2124 )); 2125 }; 2126 f.mutateBytes(u.bytes, buf[0..len], byte_weights); 2127 return len; 2128 }, 2129 .fresh => { 2130 const len: u32 = @intCast(f.weightedValue( 2131 len_weights, 2132 sumWeightsInclusive(len_weights), 2133 )); 2134 const weights_incl_sum = sumWeightsInclusive(byte_weights); 2135 for (buf[0..len]) |*o| { 2136 o.* = @intCast(f.weightedValue(byte_weights, weights_incl_sum)); 2137 } 2138 return len; 2139 }, 2140 } 2141 } 2142 2143 pub fn nextSlice( 2144 f: *Fuzzer, 2145 uid: Uid, 2146 buf: []u8, 2147 len_weights: []const abi.Weight, 2148 byte_weights: []const abi.Weight, 2149 ) u32 { 2150 const t = &f.tests[f.test_i]; 2151 f.req_values += 1; 2152 if (@backingInt(t.corpus_pos) >= @backingInt(Input.Index.reserved_start)) { 2153 @branchHint(.unlikely); 2154 const n = f.bytes_input.sliceWeightedWithHash( 2155 buf, 2156 len_weights, 2157 byte_weights, 2158 undefined, 2159 ); 2160 if (t.corpus_pos == .bytes_fresh) { 2161 f.input_builder.checkSmithedLen(@as(usize, 4) + n); 2162 f.input_builder.addBytes(uid, buf[0..n]); 2163 } 2164 return n; 2165 } 2166 2167 const n = f.nextSliceInner(uid, buf, len_weights, byte_weights); 2168 f.mmap_input.appendLittleInt(u32, n); 2169 f.mmap_input.appendSlice(buf[0..n]); 2170 f.req_bytes += n; 2171 return n; 2172 } 2173 }; 2174 2175 export fn fuzzer_init(cache_dir_path: abi.Slice) void { 2176 exec = .init(cache_dir_path.toSlice()); 2177 } 2178 2179 export fn fuzzer_coverage() abi.Coverage { 2180 const coverage_id = exec.pc_digest; 2181 const header = @volatileCast(exec.seenPcsHeader()); 2182 2183 var seen_count: usize = 0; 2184 for (header.seenBits()) |chunk| { 2185 seen_count += @popCount(chunk); 2186 } 2187 2188 return .{ 2189 .id = coverage_id, 2190 .runs = header.n_runs, 2191 .unique = header.unique_runs, 2192 .seen = seen_count, 2193 }; 2194 } 2195 2196 export fn fuzzer_main( 2197 n_tests: u32, 2198 seed: u32, 2199 limit_kind: abi.LimitKind, 2200 amount_or_instance: u64, 2201 ) void { 2202 fuzzer = .init( 2203 n_tests, 2204 seed ^ amount_or_instance, // seed is otherwise the same for all instances 2205 if (limit_kind == .forever) @as(u32, @intCast(amount_or_instance)) else 0, 2206 if (limit_kind == .forever) null else amount_or_instance, 2207 ); 2208 defer fuzzer.deinit(); 2209 abi.runner_start_input_poller(); 2210 defer abi.runner_stop_input_poller(); 2211 2212 if (n_tests == 1) { 2213 // no swapping between fuzz tests 2214 runTest(0); 2215 } else { 2216 while (fuzzer.select()) |i| { 2217 runTest(i); 2218 } 2219 } 2220 } 2221 2222 export fn fuzzer_receive_input(test_i: u32, bytes_slice: abi.Slice) bool { 2223 const recv = &fuzzer.tests[test_i].received; 2224 if (recv.state.startWrite()) return true; 2225 defer recv.state.finishWrite(); 2226 2227 const bytes = bytes_slice.toSlice(); 2228 const len: u32 = @intCast(bytes.len); 2229 recv.inputs.ensureUnusedCapacity(gpa, 4 + bytes.len) catch @panic("OOM"); 2230 recv.inputs.appendSliceAssumeCapacity(@ptrCast(&len)); 2231 recv.inputs.appendSliceAssumeCapacity(bytes); 2232 2233 return false; 2234 } 2235 2236 fn runTest(i: u32) void { 2237 fuzzer.test_i = i; 2238 fuzzer.mmap_input.setTest(i); 2239 current_test_name = abi.runner_test_name(i).toSlice(); 2240 abi.runner_test_run(i); 2241 } 2242 2243 export fn fuzzer_set_test(test_one: abi.TestOne) void { 2244 fuzzer.test_one = test_one; 2245 } 2246 2247 export fn fuzzer_new_input(bytes: abi.Slice) void { 2248 if (bytes.len == 0) return; // An entry of length zero is always present 2249 if (fuzzer.tests[fuzzer.test_i].start_mut_corpus != math.maxInt(u32)) return; // Test ran previously 2250 fuzzer.newInputExternal(bytes.toSlice()); 2251 } 2252 2253 export fn fuzzer_start_test() void { 2254 fuzzer.ensureCorpusLoaded(); 2255 fuzzer.batch(); 2256 } 2257 2258 export fn fuzzer_int(uid: Uid, weights: abi.Weights) u64 { 2259 assert(uid.kind == .int); 2260 return fuzzer.nextInt(uid, weights.toSlice()); 2261 } 2262 2263 export fn fuzzer_eos(uid: Uid, weights: abi.Weights) bool { 2264 assert(uid.kind == .int); 2265 return fuzzer.nextEos(uid, weights.toSlice()); 2266 } 2267 2268 export fn fuzzer_bytes(uid: Uid, out: abi.MutSlice, weights: abi.Weights) void { 2269 assert(uid.kind == .bytes); 2270 return fuzzer.nextBytes(uid, out.toSlice(), weights.toSlice()); 2271 } 2272 2273 export fn fuzzer_slice( 2274 uid: Uid, 2275 buf: abi.MutSlice, 2276 len_weights: abi.Weights, 2277 byte_weights: abi.Weights, 2278 ) u32 { 2279 assert(uid.kind == .bytes); 2280 return fuzzer.nextSlice(uid, buf.toSlice(), len_weights.toSlice(), byte_weights.toSlice()); 2281 } 2282 2283 export fn fuzzer_unslide_address(addr: usize) usize { 2284 const si = std.debug.getSelfDebugInfo() catch @compileError("unsupported"); 2285 const slide = si.getModuleSlide(io, addr) catch |err| { 2286 // The LLVM backend seems to insert placeholder values of `1` in __sancov_pcs1 2287 if (addr == 1) return 1; 2288 panic("failed to find virtual address slide for address 0x{x}: {t}", .{ addr, err }); 2289 }; 2290 return addr - slide; 2291 } 2292 2293 /// Helps determine run uniqueness in the face of recursion. 2294 /// Currently not used by the fuzzer. 2295 export threadlocal var __sancov_lowest_stack: usize = 0; 2296 2297 export fn __sanitizer_cov_trace_pc_indir(callee: usize) void { 2298 // Not valuable because we already have pc tracing via 8bit counters. 2299 _ = callee; 2300 } 2301 export fn __sanitizer_cov_8bit_counters_init(start: usize, end: usize) void { 2302 // clang will emit a call to this function when compiling with code coverage instrumentation. 2303 // however, fuzzer_init() does not need this information since it directly reads from the 2304 // symbol table. 2305 _ = start; 2306 _ = end; 2307 } 2308 export fn __sanitizer_cov_pcs_init(start: usize, end: usize) void { 2309 // clang will emit a call to this function when compiling with code coverage instrumentation. 2310 // however, fuzzer_init() does not need this information since it directly reads from the 2311 // symbol table. 2312 _ = start; 2313 _ = end; 2314 } 2315 2316 /// Reusable and recoverable input. 2317 /// 2318 /// Has a 32-bit limit on the input length. This has the nice side effect that `u32` 2319 /// can be used in most placed in `fuzzer` with the last `@sizeOf(abi.MmapInputHeader)` 2320 /// values reserved. 2321 const MemoryMappedInput = struct { 2322 const Header = abi.MmapInputHeader; 2323 2324 len: u32, 2325 /// Directly accessing `memory` is unsafe, use either `inputSlice` or `writeSlice`. 2326 mmap: Io.File.MemoryMap, 2327 in_i: u32, 2328 2329 /// `file` becomes owned by the returned `MemoryMappedInput` 2330 pub fn init(file: Io.File, instance_id: u32, in_i: u32) MemoryMappedInput { 2331 var size = file.length(io) catch |e| 2332 panic("failed to get length of 'in{x}': {t}", .{ in_i, e }); 2333 if (size < std.heap.page_size_max) { 2334 size = std.heap.page_size_max; 2335 file.setLength(io, size) catch |e| 2336 panic("failed to resize 'in{x}': {t}", .{ in_i, e }); 2337 } 2338 const map = file.createMemoryMap(io, .{ .len = size }) catch |e| 2339 panic("failed to memmap input file 'in{x}': {t}", .{ in_i, e }); 2340 @as(*volatile Header, @ptrCast(map.memory)).* = .{ 2341 .pc_digest = mem.nativeToLittle(u64, exec.pc_digest), 2342 .instance_id = mem.nativeToLittle(u32, instance_id), 2343 .test_i = 0, 2344 .len = 0, 2345 }; 2346 return .{ 2347 .len = 0, 2348 .mmap = map, 2349 .in_i = in_i, 2350 }; 2351 } 2352 2353 pub fn deinit(l: *MemoryMappedInput) void { 2354 const f = l.mmap.file; 2355 l.mmap.write(io) catch |e| panic("failed to write memory map of 'in{x}': {t}", .{ l.in_i, e }); 2356 l.mmap.destroy(io); 2357 f.close(io); 2358 l.* = undefined; 2359 } 2360 2361 /// Modify the array so that it can hold at least `additional_count` **more** items. 2362 /// 2363 /// Invalidates element pointers if additional memory is needed. 2364 pub fn ensureUnusedCapacity(l: *MemoryMappedInput, additional_count: usize) void { 2365 return l.ensureSize(@sizeOf(Header) + l.len + additional_count); 2366 } 2367 2368 fn ensureSize(l: *MemoryMappedInput, min_capacity: usize) void { 2369 if (l.mmap.memory.len < min_capacity) { 2370 @branchHint(.unlikely); 2371 2372 const max_capacity = 1 << 32; // The size of the header is not added 2373 // in order to keep the capacity page aligned and to allow those values to 2374 // reserved for other places. 2375 if (min_capacity > max_capacity) @panic("too much smith data requested"); 2376 2377 const new_capacity = @min(growCapacity(min_capacity), max_capacity); 2378 l.mmap.file.setLength(io, new_capacity) catch |e| 2379 panic("failed to resize 'in{x}': {t}", .{ l.in_i, e }); 2380 l.mmap.setLength(io, new_capacity) catch |se| switch (se) { 2381 error.OperationUnsupported => { 2382 const f = l.mmap.file; 2383 l.mmap.destroy(io); 2384 l.mmap = f.createMemoryMap(io, .{ .len = new_capacity }) catch |e| 2385 panic("failed to memory map 'in{x}': {t}", .{ l.in_i, e }); 2386 }, 2387 else => panic("failed to resize memory map of 'in{x}': {t}", .{ l.in_i, se }), 2388 }; 2389 } 2390 } 2391 2392 // Only writing has side effects, so volatile is not needed 2393 pub fn inputSlice(l: *MemoryMappedInput) []const u8 { 2394 return l.mmap.memory[@sizeOf(Header)..][0..l.len]; 2395 } 2396 2397 // Writing has side effectsd, so volatile is necessary 2398 pub fn writeSlice(l: *MemoryMappedInput) []volatile u8 { 2399 return l.mmap.memory; 2400 } 2401 2402 fn writeLen(l: *MemoryMappedInput) void { 2403 l.writeSlice()[@offsetOf(Header, "len")..][0..4].* = 2404 @bitCast(mem.nativeToLittle(u32, l.len)); 2405 } 2406 2407 pub fn setTest(l: *MemoryMappedInput, i: u32) void { 2408 l.writeSlice()[@offsetOf(Header, "test_i")..][0..4].* = 2409 @bitCast(mem.nativeToLittle(u32, i)); 2410 } 2411 2412 /// Invalidates all element pointers. 2413 pub fn clearRetainingCapacity(l: *MemoryMappedInput) void { 2414 l.len = 0; 2415 l.writeLen(); 2416 } 2417 2418 /// Append the slice of items to the list. 2419 /// 2420 /// Invalidates item pointers if more space is required. 2421 pub fn appendSlice(l: *MemoryMappedInput, items: []const u8) void { 2422 l.ensureUnusedCapacity(items.len); 2423 @memcpy(l.writeSlice()[@sizeOf(Header) + l.len ..][0..items.len], items); 2424 l.len += @as(u32, @intCast(items.len)); 2425 l.writeLen(); 2426 } 2427 2428 /// Append the little-endian integer to the list. 2429 /// 2430 /// Invalidates item pointers if more space is required. 2431 pub fn appendLittleInt(l: *MemoryMappedInput, T: type, x: T) void { 2432 l.ensureUnusedCapacity(@sizeOf(T)); 2433 l.writeSlice()[@sizeOf(Header) + l.len ..][0..@sizeOf(T)].* = 2434 @bitCast(mem.nativeToLittle(T, x)); 2435 l.len += @sizeOf(T); 2436 l.writeLen(); 2437 } 2438 2439 /// Called when memory growth is necessary. Returns a capacity larger than 2440 /// minimum that grows super-linearly. 2441 fn growCapacity(minimum: usize) usize { 2442 return mem.alignForward( 2443 usize, 2444 minimum +| (minimum / 2 + std.heap.page_size_max), 2445 std.heap.page_size_max, 2446 ); 2447 } 2448 }; 2449