void check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip)
{
u8 tag;
u8 *shadow_first, *shadow_last, *shadow;
void *untagged_addr;
if (unlikely(size == 0))
return;
tag = get_tag((const void *)addr);
/*
* Ignore accesses for pointers tagged with 0xff (native kernel
* pointer tag) to suppress false positives caused by kmap.
*
* Some kernel code was written to account for archs that don't keep
* high memory mapped all the time, but rather map and unmap particular
* pages when needed. Instead of storing a pointer to the kernel memory,
* this code saves the address of the page structure and offset within
* that page for later use. Those pages are then mapped and unmapped
* with kmap/kunmap when necessary and virt_to_page is used to get the
* virtual address of the page. For arm64 (that keeps the high memory
* mapped all the time), kmap is turned into a page_address call.
* The issue is that with use of the page_address + virt_to_page
* sequence the top byte value of the original pointer gets lost (gets
* set to KASAN_TAG_KERNEL (0xFF)).
*/
if (tag == KASAN_TAG_KERNEL)
return;
untagged_addr = reset_tag((const void *)addr);
if (unlikely(untagged_addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
kasan_report(addr, size, write, ret_ip);
return;
}
shadow_first = kasan_mem_to_shadow(untagged_addr);
shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1);
for (shadow = shadow_first; shadow <= shadow_last; shadow++) {
if (*shadow != tag) {
kasan_report(addr, size, write, ret_ip);
return;
}
}
}
static __always_inline void check_memory_region(unsigned long addr,
size_t size, bool write)
{
if (unlikely(size == 0))
return;
if (unlikely((void *)addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
kasan_report(addr, size, write, _RET_IP_);
return;
}
if (likely(!memory_is_poisoned(addr, size)))
return;
kasan_report(addr, size, write, _RET_IP_);
}
void __asan_report_store_n_noabort(unsigned long addr, size_t size)
{
kasan_report(addr, size, true, _RET_IP_);
}
void __asan_report_load_n_noabort(unsigned long addr, size_t size)
{
kasan_report(addr, size, false, _RET_IP_);
}
