[PATCH v5 3/4] lib: efi_loader: efi_memory.c: add efi_realloc() for realloc memory

[Heinrich Schuchardt]

On 16.06.25 15:09, Ilias Apalodimas wrote:
> Hi Paul
> 
> [...]
> 
>> +/**
>> + * efi_realloc() - reallocate boot services data pool memory
>> + *
>> + * Reallocate memory from pool for a new size and copy the data from old one.
>> + *
>> + * @ptr:       pointer to old buffer
>> + * @size:      number of bytes to allocate
>> + * Return:     EFI status to indicate success or not
>> + */
>> +efi_status_t efi_realloc(void **ptr, size_t size)
>> +{
>> +       efi_status_t ret;
>> +       void *new_ptr;
>> +       struct efi_pool_allocation *alloc;
>> +       u64 num_pages = efi_size_in_pages(size +
>> +                                         sizeof(struct efi_pool_allocation));
>> +       size_t old_size;
>> +
>> +       if (!*ptr) {
>> +               *ptr = efi_alloc(size);
> 
> Shouldn't you check that *ptr != NULL before returning success here?

Hello Ilias,

Do you mean "check that ptr != NULL"?

Best regards

Heinrich

> 
>> +               return EFI_SUCCESS;
>> +       }
>> +
>> +       ret = efi_check_allocated((uintptr_t)*ptr, true);
>> +       if (ret != EFI_SUCCESS)
>> +               return ret;
>> +
>> +       alloc = container_of(*ptr, struct efi_pool_allocation, data);
>> +
>> +       /* Check that this memory was allocated by efi_allocate_pool() */
>> +       if (((uintptr_t)alloc & EFI_PAGE_MASK) ||
>> +           alloc->checksum != checksum(alloc)) {
>> +               printf("%s: illegal realloc 0x%p\n", __func__, *ptr);
>> +               return EFI_INVALID_PARAMETER;
>> +       }
>> +
>> +       /* Don't realloc. The actual size in pages is the same. */
>> +       if (alloc->num_pages == num_pages)
>> +               return EFI_SUCCESS;
>> +
>> +       old_size = alloc->num_pages * EFI_PAGE_SIZE -
>> +               sizeof(struct efi_pool_allocation);
>> +
>> +       new_ptr = efi_alloc(size);
>> +
>> +       /* copy old data to new alloced buffer */
>> +       memcpy(new_ptr, *ptr, min(size, old_size));
>> +
>> +       /* free the old buffer */
>> +       efi_free_pool(*ptr);
>> +
>> +       *ptr = new_ptr;
>> +
>> +       return EFI_SUCCESS;
>> +}
>> +
>>   /**
>>    * efi_free_pool() - free memory from pool
>>    *
>> --
>> 2.39.5
>>
> 
> Thanks
> /Ilias