This enabled trivial ASLR bypass for non-dumpable programs by simply
opening /proc/PID/vm before exec'ing.
We now hold the target process's ptrace lock across the refresh/write
operations, and deny access if the process is non-dumpable. The lock
is necessary to prevent a TOCTOU race on Process::is_dumpable() while
the target is exec'ing.
Fixes#5270.
In preparation for marking BlockingResult [[nodiscard]], there are a few
places that perform infinite waits, which we never observe the result of
the wait. Instead of suppressing them, add an alternate function which
returns void when performing and infinite wait.
Now that we no longer need to support the signal trampolines being
user-accessible inside the kernel memory range, we can get rid of the
"kernel" and "user-accessible" flags on Region and simply use the
address of the region to determine whether it's kernel or user.
This also tightens the page table mapping code, since it can now set
user-accessibility based solely on the virtual address of a page.
The way we read/write directories is very inefficient, and this doesn't
solve any of that. It does however reduce memory usage of directory
entry vectors by 25% which has nice immediate benefits.
This patch adds Space, a class representing a process's address space.
- Each Process has a Space.
- The Space owns the PageDirectory and all Regions in the Process.
This allows us to reorganize sys$execve() so that it constructs and
populates a new Space fully before committing to it.
Previously, we would construct the new address space while still
running in the old one, and encountering an error meant we had to do
tedious and error-prone rollback.
Those problems are now gone, replaced by what's hopefully a set of much
smaller problems and missing cleanups. :^)
We were checking for size_t (unsigned) overflow but the current offset
is actually stored as off_t (signed). Fix this, and also fail with
EOVERFLOW correctly.
This patch adds sys$msyscall() which is loosely based on an OpenBSD
mechanism for preventing syscalls from non-blessed memory regions.
It works similarly to pledge and unveil, you can call it as many
times as you like, and when you're finished, you call it with a null
pointer and it will stop accepting new regions from then on.
If a syscall later happens and doesn't originate from one of the
previously blessed regions, the kernel will simply crash the process.
We had two ways of creating a new Ext2FS inode. Either they were empty,
or they started with some pre-allocated size.
In practice, the pre-sizing code path was only used for new directories
and it didn't actually improve anything as far as I can tell.
This patch simplifies inode creation by simply always allocating empty
inodes. Block allocation and block list generation now always happens
on the same code path.
The enumeration code is already enumerating all buses, recursively
enumerating bridges (which are buses) makes devices on bridges being
enumerated multiple times. Also, the PCI code was incorrectly mixing up
terminology; let's settle down on bus, device and function because ever
since PCIe came along "slots" isn't really a thing anymore.
This eliminates the window between calling Processor::current and
the member function where a thread could be moved to another
processor. This is generally not as big of a concern as with
Processor::current_thread, but also slightly more light weight.
Instead of letting each File subclass do range allocation in their
mmap() override, do it up front in sys$mmap().
This makes us honor alignment requests for file-backed memory mappings
and simplifies the code somwhat.
This was done with the help of several scripts, I dump them here to
easily find them later:
awk '/#ifdef/ { print "#cmakedefine01 "$2 }' AK/Debug.h.in
for debug_macro in $(awk '/#ifdef/ { print $2 }' AK/Debug.h.in)
do
find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/#ifdef '$debug_macro'/#if '$debug_macro'/' {} \;
done
# Remember to remove WRAPPER_GERNERATOR_DEBUG from the list.
awk '/#cmake/ { print "set("$2" ON)" }' AK/Debug.h.in
(mode & S_IFDIR) is not enough to check if "mode" is a directory,
we have to check all the bits in the S_IFMT mask.
Use the is_directory() helper to fix this bug.
Besides removing the monolithic DevFSDeviceInode::determine_name()
method, being able to determine a device's name inside the /dev
hierarchy outside of DevFS has its uses.
