RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 13:48:12 +00:00
Code Issues Activity Actions

Kernel: Implement some basic stack pointer validation

Browse source 
VM regions can now be marked as stack regions, which is then validated
on syscall, and on page fault.

If a thread is caught with its stack pointer pointing into anything
that's *not* a Region with its stack bit set, we'll crash the whole
process with SIGSTKFLT.

Userspace must now allocate custom stacks by using mmap() with the new
MAP_STACK flag. This mechanism was first introduced in OpenBSD, and now
we have it too, yay! :^)
This commit is contained in:
Andreas Kling 2019-11-17 12:11:43 +01:00
parent 197ed1bb2a
commit 794758df3a
12 changed files with 101 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

8
Kernel/VM/Region.cpp
View file

@ -58,6 +58,7 @@ NonnullOwnPtr<Region> Region::clone()
ASSERT(is_user_accessible());
if (m_shared || (is_readable() && !is_writable())) {
ASSERT(!m_stack);
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): sharing %s (V%p)\n",
current->process().name().characters(),
@ -81,6 +82,13 @@ NonnullOwnPtr<Region> Region::clone()
remap();
auto clone_region = Region::create_user_accessible(m_range, m_vmobject->clone(), m_offset_in_vmo, m_name, m_access);
clone_region->ensure_cow_map();
if (m_stack) {
ASSERT(is_readable());
ASSERT(is_writable());
ASSERT(!is_shared());
ASSERT(vmobject().is_anonymous());
clone_region->set_stack(true);
}
return clone_region;
}