motiejus/zig
1
Fork 0
Code Releases Activity

macho+elf: fix integer overflow in allocateAtom

Browse Source 
If there is a big atom available for re-use in the free list, and
it's the last atom in section, it's ideal capacity might span the
entire section in which case we do not want to calculate the actual
end VM addr of the symbol since it may overflow. Instead, we just take
the max capacity available as end VM addr estimate. In this case,
the max capacity equals `std.math.maxInt(u64)`.
This commit is contained in:
Jakub Konka
2022-01-22 08:47:04 +01:00
parent 062ddb693f
commit 406c85f9ba
2 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
src/link/Elf.zig
View File

@@ -2118,7 +2118,7 @@ fn allocateTextBlock(self: *Elf, block_list: *TextBlockList, text_block: *TextBl
const sym = self.local_symbols.items[big_block.local_sym_index];
const capacity = big_block.capacity(self.*);
const ideal_capacity = padToIdeal(capacity);
const ideal_capacity_end_vaddr = sym.st_value + ideal_capacity;
const ideal_capacity_end_vaddr = std.math.add(u64, sym.st_value, ideal_capacity) catch ideal_capacity;
const capacity_end_vaddr = sym.st_value + capacity;
const new_start_vaddr_unaligned = capacity_end_vaddr - new_block_ideal_capacity;
const new_start_vaddr = mem.alignBackwardGeneric(u64, new_start_vaddr_unaligned, alignment);

2
src/link/MachO.zig
View File

@@ -5064,7 +5064,7 @@ fn allocateAtom(self: *MachO, atom: *Atom, new_atom_size: u64, alignment: u64, m
const sym = self.locals.items[big_atom.local_sym_index];
const capacity = big_atom.capacity(self.*);
const ideal_capacity = if (needs_padding) padToIdeal(capacity) else capacity;
const ideal_capacity_end_vaddr = sym.n_value + ideal_capacity;
const ideal_capacity_end_vaddr = math.add(u64, sym.n_value, ideal_capacity) catch ideal_capacity;
const capacity_end_vaddr = sym.n_value + capacity;
const new_start_vaddr_unaligned = capacity_end_vaddr - new_atom_ideal_capacity;
const new_start_vaddr = mem.alignBackwardGeneric(u64, new_start_vaddr_unaligned, alignment);