RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-28 19:55:10 +00:00
Code Issues Activity Actions

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

Browse source
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
Download patch file Download diff file Expand all files Collapse all files

41
Kernel/MemoryManager.cpp
View file

@ -208,7 +208,18 @@ Region* MemoryManager::region_from_laddr(Process& process, LinearAddress laddr)
if (region->contains(laddr))
return region.ptr();
}
kprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), laddr.get(), process.page_directory().cr3());
dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), laddr.get(), process.page_directory().cr3());
return nullptr;
}
const Region* MemoryManager::region_from_laddr(const Process& process, LinearAddress laddr)
{
// FIXME: Use a binary search tree (maybe red/black?) or some other more appropriate data structure!
for (auto& region : process.m_regions) {
if (region->contains(laddr))
return region.ptr();
}
dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), laddr.get(), process.page_directory().cr3());
return nullptr;
}
@ -515,34 +526,14 @@ bool MemoryManager::map_region(Process& process, Region& region)
bool MemoryManager::validate_user_read(const Process& process, LinearAddress laddr) const
{
dword pageDirectoryIndex = (laddr.get() >> 22) & 0x3ff;
dword pageTableIndex = (laddr.get() >> 12) & 0x3ff;
auto pde = PageDirectoryEntry(&const_cast<Process&>(process).page_directory().entries()[pageDirectoryIndex]);
if (!pde.is_present())
return false;
auto pte = PageTableEntry(&pde.pageTableBase()[pageTableIndex]);
if (!pte.is_present())
return false;
if (process.isRing3() && !pte.is_user_allowed())
return false;
return true;
auto* region = region_from_laddr(process, laddr);
return region && region->is_readable();
}
bool MemoryManager::validate_user_write(const Process& process, LinearAddress laddr) const
{
dword pageDirectoryIndex = (laddr.get() >> 22) & 0x3ff;
dword pageTableIndex = (laddr.get() >> 12) & 0x3ff;
auto pde = PageDirectoryEntry(&const_cast<Process&>(process).page_directory().entries()[pageDirectoryIndex]);
if (!pde.is_present())
return false;
auto pte = PageTableEntry(&pde.pageTableBase()[pageTableIndex]);
if (!pte.is_present())
return false;
if (process.isRing3() && !pte.is_user_allowed())
return false;
if (!pte.is_writable())
return false;
return true;
auto* region = region_from_laddr(process, laddr);
return region && region->is_writable();
}
RetainPtr<Region> Region::clone()