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Kernel: Fix incorrect EFAULTs when syscall would write into COW pages.

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This commit is contained in:
Andreas Kling 2019-01-25 01:39:15 +01:00
parent a4a106a430
commit 11b73c38d8
4 changed files with 38 additions and 32 deletions
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26
Kernel/Process.cpp
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@ -1605,20 +1605,34 @@ bool Process::validate_read_from_kernel(LinearAddress laddr) const
bool Process::validate_read(const void* address, size_t size) const
{
if ((reinterpret_cast<dword>(address) & PAGE_MASK) != ((reinterpret_cast<dword>(address) + (size - 1)) & PAGE_MASK)) {
if (!MM.validate_user_read(*this, LinearAddress((dword)address).offset(size)))
if (isRing0())
return true;
ASSERT(size);
if (!size)
return false;
LinearAddress first_address((dword)address);
LinearAddress last_address = first_address.offset(size - 1);
if (first_address.page_base() != last_address.page_base()) {
if (!MM.validate_user_read(*this, last_address))
return false;
}
return MM.validate_user_read(*this, LinearAddress((dword)address));
return MM.validate_user_read(*this, first_address);
}
bool Process::validate_write(void* address, size_t size) const
{
if ((reinterpret_cast<dword>(address) & PAGE_MASK) != ((reinterpret_cast<dword>(address) + (size - 1)) & PAGE_MASK)) {
if (!MM.validate_user_write(*this, LinearAddress((dword)address).offset(size)))
if (isRing0())
return true;
ASSERT(size);
if (!size)
return false;
LinearAddress first_address((dword)address);
LinearAddress last_address = first_address.offset(size - 1);
if (first_address.page_base() != last_address.page_base()) {
if (!MM.validate_user_write(*this, last_address))
return false;
}
return MM.validate_user_write(*this, LinearAddress((dword)address));
return MM.validate_user_write(*this, last_address);
}
pid_t Process::sys$getsid(pid_t pid)