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Kernel/aarch64: Flatten safe_{memset,strnlen,memcpy}()

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We want to detect if an access fault comes from within these operations,
so they cannot be calling out to the non-safe variants.
This commit is contained in:
Daniel Bertalan 2023-05-19 12:12:27 +02:00 • committed by Andreas Kling
parent ab279c850b
commit 0da2d2102a
1 changed files with 17 additions and 6 deletions
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23
Kernel/Arch/aarch64/SafeMem.cpp
View file

@ -9,23 +9,34 @@
namespace Kernel { namespace Kernel {
bool safe_memset(void* dest_ptr, int c, size_t n, void*&) bool safe_memset(void* dest_ptr, int c, size_t n, void*& fault_at)
{ {
// FIXME: Actually implement a safe memset. // FIXME: Actually implement a safe memset.
memset(dest_ptr, c, n); auto* dest = static_cast<u8*>(dest_ptr);
for (; n--;)
*dest++ = c;
fault_at = nullptr;
return true; return true;
} }
ssize_t safe_strnlen(char const* str, unsigned long max_n, void*&) ssize_t safe_strnlen(char const* str, unsigned long max_n, void*& fault_at)
{ {
// FIXME: Actually implement a safe strnlen. // FIXME: Actually implement a safe strnlen.
return strnlen(str, max_n); size_t len = 0;
for (; len < max_n && *str; str++)
len++;
fault_at = nullptr;
return len;
} }
bool safe_memcpy(void* dest_ptr, void const* src_ptr, unsigned long n, void*&) bool safe_memcpy(void* dest_ptr, void const* src_ptr, unsigned long n, void*& fault_at)
{ {
// FIXME: Actually implement a safe memcpy. // FIXME: Actually implement a safe memcpy.
memcpy(dest_ptr, src_ptr, n); auto* pd = static_cast<u8*>(dest_ptr);
auto const* ps = static_cast<u8 const*>(src_ptr);
for (; n--;)
*pd++ = *ps++;
fault_at = nullptr;
return true; return true;
} }