authorgravatar for kcbanner@gmail.comCasey Banner <kcbanner@gmail.com> 2024-07-10 02:25:19-04:00
committergravatar for jacobly@ziglang.orgJacob Young <jacobly@ziglang.org> 2024-07-10 10:46:35-04:00
log95d9292a7a09ed883e65510ec054619747315c48
treeb335ce3241314861c08d8be1f8ccaa50766158d7
parent1f6b3d16644c8727323a1512d555236afbca7d7f

dwarf: use StackIterator.MemoryAccessor to check memory accesses instead of isValidMemory

4 files changed, 107 insertions(+), 57 deletions(-)

lib/std/debug.zig+3-3
......@@ -610,7 +610,7 @@ pub const StackIterator = struct {
610610 var iterator = init(first_address, null);
611611 iterator.unwind_state = .{
612612 .debug_info = debug_info,
613 .dwarf_context = try DW.UnwindContext.init(debug_info.allocator, context, &isValidMemory),
613 .dwarf_context = try DW.UnwindContext.init(debug_info.allocator, context),
614614 };
615615
616616 return iterator;
......@@ -793,7 +793,7 @@ pub const StackIterator = struct {
793793 // __unwind_info is a requirement for unwinding on Darwin. It may fall back to DWARF, but unwinding
794794 // via DWARF before attempting to use the compact unwind info will produce incorrect results.
795795 if (module.unwind_info) |unwind_info| {
796 if (DW.unwindFrameMachO(&unwind_state.dwarf_context, unwind_info, module.eh_frame, module.base_address)) |return_address| {
796 if (DW.unwindFrameMachO(&unwind_state.dwarf_context, &it.ma, unwind_info, module.eh_frame, module.base_address)) |return_address| {
797797 return return_address;
798798 } else |err| {
799799 if (err != error.RequiresDWARFUnwind) return err;
......@@ -804,7 +804,7 @@ pub const StackIterator = struct {
804804 }
805805
806806 if (try module.getDwarfInfoForAddress(unwind_state.debug_info.allocator, unwind_state.dwarf_context.pc)) |di| {
807 return di.unwindFrame(&unwind_state.dwarf_context, null);
807 return di.unwindFrame(&unwind_state.dwarf_context, &it.ma, null);
808808 } else return error.MissingDebugInfo;
809809 }
810810
lib/std/dwarf.zig+89-49
......@@ -475,8 +475,8 @@ const UnitHeader = struct {
475475 header_length: u4,
476476 unit_length: u64,
477477};
478fn readUnitHeader(fbr: *FixedBufferReader) !UnitHeader {
479 return switch (try fbr.readInt(u32)) {
478fn readUnitHeader(fbr: *FixedBufferReader, opt_ma: ?*debug.StackIterator.MemoryAccessor) !UnitHeader {
479 return switch (try if (opt_ma) |ma| fbr.readIntChecked(u32, ma) else fbr.readInt(u32)) {
480480 0...0xfffffff0 - 1 => |unit_length| .{
481481 .format = .@"32",
482482 .header_length = 4,
......@@ -486,7 +486,7 @@ fn readUnitHeader(fbr: *FixedBufferReader) !UnitHeader {
486486 0xffffffff => .{
487487 .format = .@"64",
488488 .header_length = 12,
489 .unit_length = try fbr.readInt(u64),
489 .unit_length = try if (opt_ma) |ma| fbr.readIntChecked(u64, ma) else fbr.readInt(u64),
490490 },
491491 };
492492}
......@@ -663,7 +663,7 @@ pub const DwarfInfo = struct {
663663 while (this_unit_offset < fbr.buf.len) {
664664 try fbr.seekTo(this_unit_offset);
665665
666 const unit_header = try readUnitHeader(&fbr);
666 const unit_header = try readUnitHeader(&fbr, null);
667667 if (unit_header.unit_length == 0) return;
668668 const next_offset = unit_header.header_length + unit_header.unit_length;
669669
......@@ -853,7 +853,7 @@ pub const DwarfInfo = struct {
853853 while (this_unit_offset < fbr.buf.len) {
854854 try fbr.seekTo(this_unit_offset);
855855
856 const unit_header = try readUnitHeader(&fbr);
856 const unit_header = try readUnitHeader(&fbr, null);
857857 if (unit_header.unit_length == 0) return;
858858 const next_offset = unit_header.header_length + unit_header.unit_length;
859859
......@@ -1200,7 +1200,7 @@ pub const DwarfInfo = struct {
12001200 var fbr: FixedBufferReader = .{ .buf = di.section(.debug_line).?, .endian = di.endian };
12011201 try fbr.seekTo(line_info_offset);
12021202
1203 const unit_header = try readUnitHeader(&fbr);
1203 const unit_header = try readUnitHeader(&fbr, null);
12041204 if (unit_header.unit_length == 0) return missingDwarf();
12051205 const next_offset = unit_header.header_length + unit_header.unit_length;
12061206
......@@ -1532,7 +1532,7 @@ pub const DwarfInfo = struct {
15321532 if (di.section(frame_section)) |section_data| {
15331533 var fbr: FixedBufferReader = .{ .buf = section_data, .endian = di.endian };
15341534 while (fbr.pos < fbr.buf.len) {
1535 const entry_header = try EntryHeader.read(&fbr, frame_section);
1535 const entry_header = try EntryHeader.read(&fbr, null, frame_section);
15361536 switch (entry_header.type) {
15371537 .cie => {
15381538 const cie = try CommonInformationEntry.parse(
......@@ -1580,7 +1580,7 @@ pub const DwarfInfo = struct {
15801580 ///
15811581 /// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
15821582 /// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
1583 pub fn unwindFrame(di: *const DwarfInfo, context: *UnwindContext, explicit_fde_offset: ?usize) !usize {
1583 pub fn unwindFrame(di: *const DwarfInfo, context: *UnwindContext, ma: *debug.StackIterator.MemoryAccessor, explicit_fde_offset: ?usize) !usize {
15841584 if (!comptime abi.supportsUnwinding(builtin.target)) return error.UnsupportedCpuArchitecture;
15851585 if (context.pc == 0) return 0;
15861586
......@@ -1599,14 +1599,14 @@ pub const DwarfInfo = struct {
15991599 .endian = di.endian,
16001600 };
16011601
1602 const fde_entry_header = try EntryHeader.read(&fbr, dwarf_section);
1602 const fde_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
16031603 if (fde_entry_header.type != .fde) return error.MissingFDE;
16041604
16051605 const cie_offset = fde_entry_header.type.fde;
16061606 try fbr.seekTo(cie_offset);
16071607
16081608 fbr.endian = native_endian;
1609 const cie_entry_header = try EntryHeader.read(&fbr, dwarf_section);
1609 const cie_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
16101610 if (cie_entry_header.type != .cie) return badDwarf();
16111611
16121612 cie = try CommonInformationEntry.parse(
......@@ -1631,7 +1631,7 @@ pub const DwarfInfo = struct {
16311631 } else if (di.eh_frame_hdr) |header| {
16321632 const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
16331633 try header.findEntry(
1634 context.isValidMemory,
1634 ma,
16351635 eh_frame_len,
16361636 @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
16371637 context.pc,
......@@ -1656,7 +1656,7 @@ pub const DwarfInfo = struct {
16561656
16571657 var expression_context: expressions.ExpressionContext = .{
16581658 .format = cie.format,
1659 .isValidMemory = context.isValidMemory,
1659 .memory_accessor = ma,
16601660 .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
16611661 .thread_context = context.thread_context,
16621662 .reg_context = context.reg_context,
......@@ -1691,7 +1691,7 @@ pub const DwarfInfo = struct {
16911691 else => return error.InvalidCFARule,
16921692 };
16931693
1694 if (!context.isValidMemory(context.cfa.?)) return error.InvalidCFA;
1694 if (ma.load(usize, context.cfa.?) == null) return error.InvalidCFA;
16951695 expression_context.cfa = context.cfa;
16961696
16971697 // Buffering the modifications is done because copying the thread context is not portable,
......@@ -1730,6 +1730,7 @@ pub const DwarfInfo = struct {
17301730 try column.resolveValue(
17311731 context,
17321732 expression_context,
1733 ma,
17331734 src,
17341735 );
17351736 }
......@@ -1788,7 +1789,13 @@ const macho = std.macho;
17881789/// Unwind a frame using MachO compact unwind info (from __unwind_info).
17891790/// If the compact encoding can't encode a way to unwind a frame, it will
17901791/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
1791pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_frame: ?[]const u8, module_base_address: usize) !usize {
1792pub fn unwindFrameMachO(
1793 context: *UnwindContext,
1794 ma: *debug.StackIterator.MemoryAccessor,
1795 unwind_info: []const u8,
1796 eh_frame: ?[]const u8,
1797 module_base_address: usize,
1798) !usize {
17921799 const header = mem.bytesAsValue(
17931800 macho.unwind_info_section_header,
17941801 unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
......@@ -1950,7 +1957,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
19501957 const new_sp = fp + 2 * @sizeOf(usize);
19511958
19521959 // Verify the stack range we're about to read register values from
1953 if (!context.isValidMemory(new_sp) or !context.isValidMemory(fp - frame_offset + max_reg * @sizeOf(usize))) return error.InvalidUnwindInfo;
1960 if (ma.load(usize, new_sp) == null or ma.load(usize, fp - frame_offset + max_reg * @sizeOf(usize)) == null) return error.InvalidUnwindInfo;
19541961
19551962 const ip_ptr = fp + @sizeOf(usize);
19561963 const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
......@@ -1981,7 +1988,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
19811988 module_base_address +
19821989 entry.function_offset +
19831990 encoding.value.x86_64.frameless.stack.indirect.sub_offset;
1984 if (!context.isValidMemory(sub_offset_addr)) return error.InvalidUnwindInfo;
1991 if (ma.load(usize, sub_offset_addr) == null) return error.InvalidUnwindInfo;
19851992
19861993 // `sub_offset_addr` points to the offset of the literal within the instruction
19871994 const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
......@@ -2023,7 +2030,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
20232030 }
20242031
20252032 var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
2026 if (!context.isValidMemory(reg_addr)) return error.InvalidUnwindInfo;
2033 if (ma.load(usize, reg_addr) == null) return error.InvalidUnwindInfo;
20272034 for (0..reg_count) |i| {
20282035 const reg_number = try compactUnwindToDwarfRegNumber(registers[i]);
20292036 (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
......@@ -2035,7 +2042,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
20352042
20362043 const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
20372044 const new_sp = ip_ptr + @sizeOf(usize);
2038 if (!context.isValidMemory(new_sp)) return error.InvalidUnwindInfo;
2045 if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
20392046
20402047 (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
20412048 (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
......@@ -2043,7 +2050,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
20432050 break :blk new_ip;
20442051 },
20452052 .DWARF => {
2046 return unwindFrameMachODwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
2053 return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
20472054 },
20482055 },
20492056 .aarch64 => switch (encoding.mode.arm64) {
......@@ -2052,12 +2059,12 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
20522059 const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
20532060 const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
20542061 const new_ip = (try abi.regValueNative(usize, context.thread_context, 30, reg_context)).*;
2055 if (!context.isValidMemory(new_sp)) return error.InvalidUnwindInfo;
2062 if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
20562063 (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
20572064 break :blk new_ip;
20582065 },
20592066 .DWARF => {
2060 return unwindFrameMachODwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
2067 return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
20612068 },
20622069 .FRAME => blk: {
20632070 const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
......@@ -2069,7 +2076,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
20692076 @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
20702077 const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
20712078
2072 if (!context.isValidMemory(new_sp) or !context.isValidMemory(min_reg_addr)) return error.InvalidUnwindInfo;
2079 if (ma.load(usize, new_sp) == null or ma.load(usize, min_reg_addr) == null) return error.InvalidUnwindInfo;
20732080
20742081 var reg_addr = fp - @sizeOf(usize);
20752082 inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
......@@ -2114,7 +2121,7 @@ pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_fra
21142121 return new_ip;
21152122}
21162123
2117fn unwindFrameMachODwarf(context: *UnwindContext, eh_frame: []const u8, fde_offset: usize) !usize {
2124fn unwindFrameMachODwarf(context: *UnwindContext, ma: *debug.StackIterator.MemoryAccessor, eh_frame: []const u8, fde_offset: usize) !usize {
21182125 var di = DwarfInfo{
21192126 .endian = native_endian,
21202127 .is_macho = true,
......@@ -2126,7 +2133,7 @@ fn unwindFrameMachODwarf(context: *UnwindContext, eh_frame: []const u8, fde_offs
21262133 .owned = false,
21272134 };
21282135
2129 return di.unwindFrame(context, fde_offset);
2136 return di.unwindFrame(context, ma, fde_offset);
21302137}
21312138
21322139pub const UnwindContext = struct {
......@@ -2135,12 +2142,21 @@ pub const UnwindContext = struct {
21352142 pc: usize,
21362143 thread_context: *debug.ThreadContext,
21372144 reg_context: abi.RegisterContext,
2138 isValidMemory: *const fn (address: usize) bool,
21392145 vm: call_frame.VirtualMachine,
21402146 stack_machine: expressions.StackMachine(.{ .call_frame_context = true }),
21412147
2142 pub fn init(allocator: mem.Allocator, thread_context: *const debug.ThreadContext, isValidMemory: *const fn (address: usize) bool) !UnwindContext {
2143 const pc = abi.stripInstructionPtrAuthCode((try abi.regValueNative(usize, thread_context, abi.ipRegNum(), null)).*);
2148 pub fn init(
2149 allocator: mem.Allocator,
2150 thread_context: *const debug.ThreadContext,
2151 ) !UnwindContext {
2152 const pc = abi.stripInstructionPtrAuthCode(
2153 (try abi.regValueNative(
2154 usize,
2155 thread_context,
2156 abi.ipRegNum(),
2157 null,
2158 )).*,
2159 );
21442160
21452161 const context_copy = try allocator.create(debug.ThreadContext);
21462162 debug.copyContext(thread_context, context_copy);
......@@ -2151,7 +2167,6 @@ pub const UnwindContext = struct {
21512167 .pc = pc,
21522168 .thread_context = context_copy,
21532169 .reg_context = undefined,
2154 .isValidMemory = isValidMemory,
21552170 .vm = .{},
21562171 .stack_machine = .{},
21572172 };
......@@ -2297,25 +2312,26 @@ pub const ExceptionFrameHeader = struct {
22972312
22982313 fn isValidPtr(
22992314 self: ExceptionFrameHeader,
2315 comptime T: type,
23002316 ptr: usize,
2301 isValidMemory: *const fn (address: usize) bool,
2317 ma: *debug.StackIterator.MemoryAccessor,
23022318 eh_frame_len: ?usize,
23032319 ) bool {
23042320 if (eh_frame_len) |len| {
2305 return ptr >= self.eh_frame_ptr and ptr < self.eh_frame_ptr + len;
2321 return ptr >= self.eh_frame_ptr and ptr <= self.eh_frame_ptr + len - @sizeOf(T);
23062322 } else {
2307 return isValidMemory(ptr);
2323 return ma.load(T, ptr) != null;
23082324 }
23092325 }
23102326
23112327 /// Find an entry by binary searching the eh_frame_hdr section.
23122328 ///
23132329 /// Since the length of the eh_frame section (`eh_frame_len`) may not be known by the caller,
2314 /// `isValidMemory` will be called before accessing any memory referenced by
2315 /// the header entries. If `eh_frame_len` is provided, then these checks can be skipped.
2330 /// MemoryAccessor will be used to verify readability of the header entries.
2331 /// If `eh_frame_len` is provided, then these checks can be skipped.
23162332 pub fn findEntry(
23172333 self: ExceptionFrameHeader,
2318 isValidMemory: *const fn (address: usize) bool,
2334 ma: *debug.StackIterator.MemoryAccessor,
23192335 eh_frame_len: ?usize,
23202336 eh_frame_hdr_ptr: usize,
23212337 pc: usize,
......@@ -2364,14 +2380,9 @@ pub const ExceptionFrameHeader = struct {
23642380 .data_rel_base = eh_frame_hdr_ptr,
23652381 }) orelse return badDwarf()) orelse return badDwarf();
23662382
2367 // Verify the length fields of the FDE header are readable
2368 if (!self.isValidPtr(fde_ptr, isValidMemory, eh_frame_len) or fde_ptr < self.eh_frame_ptr) return badDwarf();
2369
2370 var fde_entry_header_len: usize = 4;
2371 if (!self.isValidPtr(fde_ptr + 3, isValidMemory, eh_frame_len)) return badDwarf();
2372 if (self.isValidPtr(fde_ptr + 11, isValidMemory, eh_frame_len)) fde_entry_header_len = 12;
2383 if (fde_ptr < self.eh_frame_ptr) return badDwarf();
23732384
2374 // Even if eh_frame_len is not specified, all ranges accssed are checked by isValidPtr
2385 // Even if eh_frame_len is not specified, all ranges accssed are checked via MemoryAccessor
23752386 const eh_frame = @as([*]const u8, @ptrFromInt(self.eh_frame_ptr))[0 .. eh_frame_len orelse math.maxInt(u32)];
23762387
23772388 const fde_offset = fde_ptr - self.eh_frame_ptr;
......@@ -2381,15 +2392,15 @@ pub const ExceptionFrameHeader = struct {
23812392 .endian = native_endian,
23822393 };
23832394
2384 const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, .eh_frame);
2385 if (!self.isValidPtr(@intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), isValidMemory, eh_frame_len)) return badDwarf();
2395 const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
2396 if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
23862397 if (fde_entry_header.type != .fde) return badDwarf();
23872398
23882399 // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
23892400 const cie_offset = fde_entry_header.type.fde;
23902401 try eh_frame_fbr.seekTo(cie_offset);
2391 const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, .eh_frame);
2392 if (!self.isValidPtr(@intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), isValidMemory, eh_frame_len)) return badDwarf();
2402 const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
2403 if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
23932404 if (cie_entry_header.type != .cie) return badDwarf();
23942405
23952406 cie.* = try CommonInformationEntry.parse(
......@@ -2434,11 +2445,15 @@ pub const EntryHeader = struct {
24342445
24352446 /// Reads a header for either an FDE or a CIE, then advances the fbr to the position after the trailing structure.
24362447 /// `fbr` must be a FixedBufferReader backed by either the .eh_frame or .debug_frame sections.
2437 pub fn read(fbr: *FixedBufferReader, dwarf_section: DwarfSection) !EntryHeader {
2448 pub fn read(
2449 fbr: *FixedBufferReader,
2450 opt_ma: ?*debug.StackIterator.MemoryAccessor,
2451 dwarf_section: DwarfSection,
2452 ) !EntryHeader {
24382453 assert(dwarf_section == .eh_frame or dwarf_section == .debug_frame);
24392454
24402455 const length_offset = fbr.pos;
2441 const unit_header = try readUnitHeader(fbr);
2456 const unit_header = try readUnitHeader(fbr, opt_ma);
24422457 const unit_length = math.cast(usize, unit_header.unit_length) orelse return badDwarf();
24432458 if (unit_length == 0) return .{
24442459 .length_offset = length_offset,
......@@ -2450,7 +2465,10 @@ pub const EntryHeader = struct {
24502465 const end_offset = start_offset + unit_length;
24512466 defer fbr.pos = end_offset;
24522467
2453 const id = try fbr.readAddress(unit_header.format);
2468 const id = try if (opt_ma) |ma|
2469 fbr.readAddressChecked(unit_header.format, ma)
2470 else
2471 fbr.readAddress(unit_header.format);
24542472 const entry_bytes = fbr.buf[fbr.pos..end_offset];
24552473 const cie_id: u64 = switch (dwarf_section) {
24562474 .eh_frame => CommonInformationEntry.eh_id,
......@@ -2732,7 +2750,7 @@ pub const FixedBufferReader = struct {
27322750 pos: usize = 0,
27332751 endian: std.builtin.Endian,
27342752
2735 pub const Error = error{ EndOfBuffer, Overflow };
2753 pub const Error = error{ EndOfBuffer, Overflow, InvalidBuffer };
27362754
27372755 fn seekTo(fbr: *FixedBufferReader, pos: u64) Error!void {
27382756 if (pos > fbr.buf.len) return error.EndOfBuffer;
......@@ -2761,6 +2779,17 @@ pub const FixedBufferReader = struct {
27612779 return mem.readInt(T, fbr.buf[fbr.pos..][0..size], fbr.endian);
27622780 }
27632781
2782 fn readIntChecked(
2783 fbr: *FixedBufferReader,
2784 comptime T: type,
2785 ma: *debug.StackIterator.MemoryAccessor,
2786 ) Error!T {
2787 if (ma.load(T, @intFromPtr(fbr.buf[fbr.pos..].ptr)) == null)
2788 return error.InvalidBuffer;
2789
2790 return readInt(fbr, T);
2791 }
2792
27642793 fn readUleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
27652794 return std.leb.readUleb128(T, fbr);
27662795 }
......@@ -2776,6 +2805,17 @@ pub const FixedBufferReader = struct {
27762805 };
27772806 }
27782807
2808 fn readAddressChecked(
2809 fbr: *FixedBufferReader,
2810 format: Format,
2811 ma: *debug.StackIterator.MemoryAccessor,
2812 ) Error!u64 {
2813 return switch (format) {
2814 .@"32" => try fbr.readIntChecked(u32, ma),
2815 .@"64" => try fbr.readIntChecked(u64, ma),
2816 };
2817 }
2818
27792819 fn readBytes(fbr: *FixedBufferReader, len: usize) Error![]const u8 {
27802820 if (fbr.buf.len - fbr.pos < len) return error.EndOfBuffer;
27812821 defer fbr.pos += len;
lib/std/dwarf/call_frame.zig+3-2
......@@ -365,6 +365,7 @@ pub const VirtualMachine = struct {
365365 self: Column,
366366 context: *dwarf.UnwindContext,
367367 expression_context: dwarf.expressions.ExpressionContext,
368 ma: *debug.StackIterator.MemoryAccessor,
368369 out: []u8,
369370 ) !void {
370371 switch (self.rule) {
......@@ -385,7 +386,7 @@ pub const VirtualMachine = struct {
385386 .offset => |offset| {
386387 if (context.cfa) |cfa| {
387388 const addr = try applyOffset(cfa, offset);
388 if (expression_context.isValidMemory) |isValidMemory| if (!isValidMemory(addr)) return error.InvalidAddress;
389 if (ma.load(usize, addr) == null) return error.InvalidAddress;
389390 const ptr: *const usize = @ptrFromInt(addr);
390391 mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
391392 } else return error.InvalidCFA;
......@@ -408,7 +409,7 @@ pub const VirtualMachine = struct {
408409 break :blk v.generic;
409410 } else return error.NoExpressionValue;
410411
411 if (!context.isValidMemory(addr)) return error.InvalidExpressionAddress;
412 if (ma.load(usize, addr) == null) return error.InvalidExpressionAddress;
412413 const ptr: *usize = @ptrFromInt(addr);
413414 mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
414415 },
lib/std/dwarf/expressions.zig+12-3
......@@ -15,8 +15,8 @@ pub const ExpressionContext = struct {
1515 /// The dwarf format of the section this expression is in
1616 format: dwarf.Format = .@"32",
1717
18 /// If specified, any addresses will pass through this function before being accessed
19 isValidMemory: ?*const fn (address: usize) bool = null,
18 /// If specified, any addresses will pass through before being accessed
19 memory_accessor: ?*std.debug.StackIterator.MemoryAccessor = null,
2020
2121 /// The compilation unit this expression relates to, if any
2222 compile_unit: ?*const dwarf.CompileUnit = null,
......@@ -460,7 +460,6 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
460460 // This code will need to be updated to handle any architectures that utilize this.
461461 _ = addr_space_identifier;
462462
463 if (context.isValidMemory) |isValidMemory| if (!isValidMemory(addr)) return error.InvalidExpression;
464463 const size = switch (opcode) {
465464 OP.deref,
466465 OP.xderef,
......@@ -474,6 +473,16 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
474473 else => unreachable,
475474 };
476475
476 if (context.memory_accessor) |memory_accessor| {
477 if (!switch (size) {
478 1 => memory_accessor.load(u8, addr) != null,
479 2 => memory_accessor.load(u16, addr) != null,
480 4 => memory_accessor.load(u32, addr) != null,
481 8 => memory_accessor.load(u64, addr) != null,
482 else => return error.InvalidExpression,
483 }) return error.InvalidExpression;
484 }
485
477486 const value: addr_type = std.math.cast(addr_type, @as(u64, switch (size) {
478487 1 => @as(*const u8, @ptrFromInt(addr)).*,
479488 2 => @as(*const u16, @ptrFromInt(addr)).*,