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macho: fix overlapping segments in file offset

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This commit is contained in:
Jakub Konka
2022-09-16 12:31:02 +02:00
parent 66942cbc1a
commit 275abf7c57
1 changed files with 42 additions and 33 deletions
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75
src/link/MachO.zig
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@@ -1137,11 +1137,10 @@ pub fn allocateSpecialSymbols(self: *MachO) !void {
const global = self.getGlobal(name) orelse continue;
if (global.file != null) continue;
const sym = self.getSymbolPtr(global);
const seg_id = switch (self.mode) {
.incremental => self.sections.items(.segment_index)[self.text_section_index.?],
.one_shot => self.text_segment_cmd_index.?,
const seg = switch (self.mode) {
.incremental => self.getSegment(self.text_section_index.?),
.one_shot => self.segments.items[self.text_segment_cmd_index.?],
};
const seg = self.segments.items[seg_id];
sym.n_sect = 1;
sym.n_value = seg.vmaddr;
@@ -2239,7 +2238,6 @@ pub fn writeMainLC(self: *MachO, ncmds: *u32, lc_writer: anytype) !void {
if (self.base.options.output_mode != .Exe) return;
const seg_id = switch (self.mode) {
.incremental => self.header_segment_cmd_index.?,
// .incremental => self.sections.items(.segment_index)[self.text_section_index.?],
.one_shot => self.text_segment_cmd_index.?,
};
const seg = self.segments.items[seg_id];
@@ -3713,9 +3711,9 @@ fn allocateSection(self: *MachO, segname: []const u8, sectname: []const u8, opts
return section_id;
}
fn moveSectionInVirtualMemory(self: *MachO, sect_id: u32, needed_size: u64) !void {
fn moveSectionInVirtualMemory(self: *MachO, sect_id: u8, needed_size: u64) !void {
const header = &self.sections.items(.header)[sect_id];
const segment = &self.segments.items[self.sections.items(.segment_index)[sect_id]];
const segment = self.getSegmentPtr(sect_id);
const increased_size = padToIdeal(needed_size);
const old_aligned_end = segment.vmaddr + segment.vmsize;
const new_aligned_end = segment.vmaddr + mem.alignForwardGeneric(u64, increased_size, self.page_size);
@@ -3728,9 +3726,9 @@ fn moveSectionInVirtualMemory(self: *MachO, sect_id: u32, needed_size: u64) !voi
// TODO: enforce order by increasing VM addresses in self.sections container.
for (self.sections.items(.header)[sect_id + 1 ..]) |*next_header, next_sect_id| {
const index = sect_id + 1 + next_sect_id;
const index = @intCast(u8, sect_id + 1 + next_sect_id);
const maybe_last_atom = &self.sections.items(.last_atom)[index];
const next_segment = &self.segments.items[self.sections.items(.segment_index)[index]];
const next_segment = self.getSegmentPtr(index);
next_header.addr += diff;
next_segment.vmaddr += diff;
@@ -3753,7 +3751,7 @@ fn allocateAtom(self: *MachO, atom: *Atom, new_atom_size: u64, alignment: u64) !
defer tracy.end();
const sect_id = atom.getSymbol(self).n_sect - 1;
const segment = &self.segments.items[self.sections.items(.segment_index)[sect_id]];
const segment = self.getSegmentPtr(sect_id);
const header = &self.sections.items(.header)[sect_id];
const free_list = &self.sections.items(.free_list)[sect_id];
const maybe_last_atom = &self.sections.items(.last_atom)[sect_id];
@@ -4017,7 +4015,7 @@ fn writeSegmentHeaders(self: *MachO, ncmds: *u32, writer: anytype) !void {
}
fn writeLinkeditSegmentData(self: *MachO, ncmds: *u32, lc_writer: anytype) !void {
const seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const seg = self.getLinkeditSegmentPtr();
seg.filesize = 0;
seg.vmsize = 0;
@@ -4061,15 +4059,14 @@ fn writeDyldInfoData(self: *MachO, ncmds: *u32, lc_writer: anytype) !void {
const slice = self.sections.slice();
for (slice.items(.last_atom)) |last_atom, sect_id| {
var atom = last_atom orelse continue;
const segment_index = slice.items(.segment_index)[sect_id];
const header = slice.items(.header)[sect_id];
const segment_index = slice.items(.segment_index)[sect_id];
const seg = self.getSegment(@intCast(u8, sect_id));
if (mem.eql(u8, header.segName(), "__TEXT")) continue; // __TEXT is non-writable
log.debug("dyld info for {s},{s}", .{ header.segName(), header.sectName() });
const seg = self.segments.items[segment_index];
while (true) {
log.debug(" ATOM(%{d}, '{s}')", .{ atom.sym_index, atom.getName(self) });
const sym = atom.getSymbol(self);
@@ -4193,7 +4190,7 @@ fn writeDyldInfoData(self: *MachO, ncmds: *u32, lc_writer: anytype) !void {
try trie.finalize(gpa);
}
const link_seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const link_seg = self.getLinkeditSegmentPtr();
const rebase_off = mem.alignForwardGeneric(u64, link_seg.fileoff, @alignOf(u64));
assert(rebase_off == link_seg.fileoff);
const rebase_size = try bind.rebaseInfoSize(rebase_pointers.items);
@@ -4275,11 +4272,7 @@ fn populateLazyBindOffsetsInStubHelper(self: *MachO, buffer: []const u8) !void {
{
var stub_atom = last_atom;
var laptr_atom = self.sections.items(.last_atom)[self.la_symbol_ptr_section_index.?].?;
const base_addr = blk: {
const seg_id = self.sections.items(.segment_index)[self.la_symbol_ptr_section_index.?];
const seg = self.segments.items[seg_id];
break :blk seg.vmaddr;
};
const base_addr = self.getSegment(self.la_symbol_ptr_section_index.?).vmaddr;
while (true) {
const laptr_off = blk: {
@@ -4461,7 +4454,7 @@ fn writeSymtab(self: *MachO, lc: *macho.symtab_command) !SymtabCtx {
const nimports = @intCast(u32, imports.items.len);
const nsyms = nlocals + nexports + nimports;
const seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const seg = self.getLinkeditSegmentPtr();
const offset = mem.alignForwardGeneric(
u64,
seg.fileoff + seg.filesize,
@@ -4492,7 +4485,7 @@ fn writeSymtab(self: *MachO, lc: *macho.symtab_command) !SymtabCtx {
}
fn writeStrtab(self: *MachO, lc: *macho.symtab_command) !void {
const seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const seg = self.getLinkeditSegmentPtr();
const offset = mem.alignForwardGeneric(u64, seg.fileoff + seg.filesize, @alignOf(u64));
const needed_size = self.strtab.buffer.items.len;
seg.filesize = offset + needed_size - seg.fileoff;
@@ -4520,7 +4513,7 @@ fn writeDysymtab(self: *MachO, ctx: SymtabCtx, lc: *macho.dysymtab_command) !voi
const iextdefsym = ctx.nlocalsym;
const iundefsym = iextdefsym + ctx.nextdefsym;
const seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const seg = self.getLinkeditSegmentPtr();
const offset = mem.alignForwardGeneric(u64, seg.fileoff + seg.filesize, @alignOf(u64));
const needed_size = nindirectsyms * @sizeOf(u32);
seg.filesize = offset + needed_size - seg.fileoff;
@@ -4592,7 +4585,7 @@ fn writeCodeSignaturePadding(
ncmds: *u32,
lc_writer: anytype,
) !u32 {
const seg = &self.segments.items[self.linkedit_segment_cmd_index.?];
const seg = self.getLinkeditSegmentPtr();
// Code signature data has to be 16-bytes aligned for Apple tools to recognize the file
// https://github.com/opensource-apple/cctools/blob/fdb4825f303fd5c0751be524babd32958181b3ed/libstuff/checkout.c#L271
const offset = mem.alignForwardGeneric(u64, seg.fileoff + seg.filesize, 16);
@@ -4616,8 +4609,7 @@ fn writeCodeSignaturePadding(
}
fn writeCodeSignature(self: *MachO, code_sig: *CodeSignature, offset: u32) !void {
const seg_id = self.sections.items(.segment_index)[self.text_section_index.?];
const seg = self.segments.items[seg_id];
const seg = self.getSegment(self.text_section_index.?);
var buffer = std.ArrayList(u8).init(self.base.allocator);
defer buffer.deinit();
@@ -4696,11 +4688,12 @@ fn detectAllocCollision(self: *MachO, start: u64, size: u64) ?u64 {
const end = start + padToIdeal(size);
for (self.sections.items(.header)) |header| {
const tight_size = header.size;
for (self.sections.items(.segment_index)) |segment_index| {
const segment = self.segments.items[segment_index];
const tight_size = segment.filesize;
const increased_size = padToIdeal(tight_size);
const test_end = header.offset + increased_size;
if (end > header.offset and start < test_end) {
const test_end = segment.fileoff + increased_size;
if (end > segment.fileoff and start < test_end) {
return test_end;
}
}
@@ -4712,9 +4705,10 @@ fn allocatedSize(self: *MachO, start: u64) u64 {
if (start == 0)
return 0;
var min_pos: u64 = std.math.maxInt(u64);
for (self.sections.items(.header)) |header| {
if (header.offset <= start) continue;
if (header.offset < min_pos) min_pos = header.offset;
for (self.sections.items(.segment_index)) |segment_index| {
const segment = self.segments.items[segment_index];
if (segment.fileoff <= start) continue;
if (segment.fileoff < min_pos) min_pos = segment.fileoff;
}
return min_pos - start;
}
@@ -4752,6 +4746,21 @@ fn getSegmentByName(self: MachO, segname: []const u8) ?u8 {
} else return null;
}
pub fn getSegment(self: MachO, sect_id: u8) macho.segment_command_64 {
const index = self.sections.items(.segment_index)[sect_id];
return self.segments.items[index];
}
pub fn getSegmentPtr(self: *MachO, sect_id: u8) *macho.segment_command_64 {
const index = self.sections.items(.segment_index)[sect_id];
return &self.segments.items[index];
}
pub fn getLinkeditSegmentPtr(self: *MachO) *macho.segment_command_64 {
const index = self.linkedit_segment_cmd_index.?;
return &self.segments.items[index];
}
pub fn getSectionByName(self: MachO, segname: []const u8, sectname: []const u8) ?u8 {
// TODO investigate caching with a hashmap
for (self.sections.items(.header)) |header, i| {