diff --git a/Kernel/MemoryManager.cpp b/Kernel/MemoryManager.cpp index 0751dab286..d2a176ba69 100644 --- a/Kernel/MemoryManager.cpp +++ b/Kernel/MemoryManager.cpp @@ -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).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).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::clone() diff --git a/Kernel/MemoryManager.h b/Kernel/MemoryManager.h index 9b01df68d2..35ffbbc3f0 100644 --- a/Kernel/MemoryManager.h +++ b/Kernel/MemoryManager.h @@ -246,6 +246,7 @@ private: void remove_identity_mapping(PageDirectory&, LinearAddress, size_t); static Region* region_from_laddr(Process&, LinearAddress); + static const Region* region_from_laddr(const Process&, LinearAddress); bool copy_on_write(Region&, unsigned page_index_in_region); bool page_in_from_inode(Region&, unsigned page_index_in_region); diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp index 515cc8aa1e..69801b9896 100644 --- a/Kernel/Process.cpp +++ b/Kernel/Process.cpp @@ -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(address) & PAGE_MASK) != ((reinterpret_cast(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(address) & PAGE_MASK) != ((reinterpret_cast(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) diff --git a/Terminal/main.cpp b/Terminal/main.cpp index 1670e20458..6242246cf2 100644 --- a/Terminal/main.cpp +++ b/Terminal/main.cpp @@ -90,7 +90,7 @@ int main(int, char**) } if (FD_ISSET(ptm_fd, &rfds)) { - byte buffer[1024]; + byte buffer[4096]; ssize_t nread = read(ptm_fd, buffer, sizeof(buffer)); if (nread < 0) { dbgprintf("Terminal read error: %s\n", strerror(errno));