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Merge pull request #4270 from flysand7/heap-alloc-resize-fix

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Fix resize OOB when copying old data that's bigger than new data
This commit is contained in:
gingerBill
2024-09-19 12:57:18 +01:00
committed by GitHub
parent a7fe647c8c bec09d82df
commit 290561a39b
1 changed files with 12 additions and 10 deletions
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22
base/runtime/heap_allocator.odin
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@@ -20,25 +20,27 @@ heap_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
//
aligned_alloc :: proc(size, alignment: int, old_ptr: rawptr, old_size: int, zero_memory := true) -> ([]byte, Allocator_Error) {
// Not(flysand): We need to reserve enough space for alignment, which
// includes the user data itself, the space to store the pointer to
// allocation start, as well as the padding required to align both
// the user data and the pointer.
a := max(alignment, align_of(rawptr))
space := size + a - 1
space := a-1 + size_of(rawptr) + size
allocated_mem: rawptr
force_copy := old_ptr != nil && a > align_of(rawptr)
force_copy := old_ptr != nil && alignment > align_of(rawptr)
if !force_copy && old_ptr != nil {
if old_ptr != nil && !force_copy {
original_old_ptr := ([^]rawptr)(old_ptr)[-1]
allocated_mem = heap_resize(original_old_ptr, space+size_of(rawptr))
allocated_mem = heap_resize(original_old_ptr, space)
} else {
allocated_mem = heap_alloc(space+size_of(rawptr), zero_memory)
allocated_mem = heap_alloc(space, zero_memory)
}
aligned_mem := rawptr(([^]u8)(allocated_mem)[size_of(rawptr):])
ptr := uintptr(aligned_mem)
aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
diff := int(aligned_ptr - ptr)
if (size + diff) > space || allocated_mem == nil {
aligned_ptr := (ptr + uintptr(a)-1) & ~(uintptr(a)-1)
if allocated_mem == nil {
aligned_free(old_ptr)
aligned_free(allocated_mem)
return nil, .Out_Of_Memory
@@ -48,7 +50,7 @@ heap_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
([^]rawptr)(aligned_mem)[-1] = allocated_mem
if force_copy {
mem_copy_non_overlapping(aligned_mem, old_ptr, old_size)
mem_copy_non_overlapping(aligned_mem, old_ptr, min(old_size, size))
aligned_free(old_ptr)
}