In the Linux kernel, the following vulnerability has been resolved:
x86/i8259: Mark legacy PIC interrupts with IRQ_LEVEL
Baoquan reported that after triggering a crash the subsequent crash-kernel
fails to boot about half of the time. It triggers a NULL pointer
dereference in the periodic tick code.
This happens because the legacy timer interrupt (IRQ0) is resent in
software which happens in soft interrupt (tasklet) context. In this context
get_irq_regs() returns NULL which leads to the NULL pointer dereference.
The reason for the resend is a spurious APIC interrupt on the IRQ0 vector
which is captured and leads to a resend when the legacy timer interrupt is
enabled. This is wrong because the legacy PIC interrupts are level
triggered and therefore should never be resent in software, but nothing
ever sets the IRQ_LEVEL flag on those interrupts, so the core code does not
know about their trigger type.
Ensure that IRQ_LEVEL is set when the legacy PCI interrupts are set up.
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener
A listening socket linked to a sockmap has its sk_prot overridden. It
points to one of the struct proto variants in tcp_bpf_prots. The variant
depends on the socket's family and which sockmap programs are attached.
A child socket cloned from a TCP listener initially inherits their sk_prot.
But before cloning is finished, we restore the child's proto to the
listener's original non-tcp_bpf_prots one. This happens in
tcp_create_openreq_child -> tcp_bpf_clone.
Today, in tcp_bpf_clone we detect if the child's proto should be restored
by checking only for the TCP_BPF_BASE proto variant. This is not
correct. The sk_prot of listening socket linked to a sockmap can point to
to any variant in tcp_bpf_prots.
If the listeners sk_prot happens to be not the TCP_BPF_BASE variant, then
the child socket unintentionally is left if the inherited sk_prot by
tcp_bpf_clone.
This leads to issues like infinite recursion on close [1], because the
child state is otherwise not set up for use with tcp_bpf_prot operations.
Adjust the check in tcp_bpf_clone to detect all of tcp_bpf_prots variants.
Note that it wouldn't be sufficient to check the socket state when
overriding the sk_prot in tcp_bpf_update_proto in order to always use the
TCP_BPF_BASE variant for listening sockets. Since commit
b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage")
it is possible for a socket to transition to TCP_LISTEN state while already
linked to a sockmap, e.g. connect() -> insert into map ->
connect(AF_UNSPEC) -> listen().
[1]: https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/
In the Linux kernel, the following vulnerability has been resolved:
scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress
If during iscsi_sw_tcp_session_create() iscsi_tcp_r2tpool_alloc() fails,
userspace could be accessing the host's ipaddress attr. If we then free the
session via iscsi_session_teardown() while userspace is still accessing the
session we will hit a use after free bug.
Set the tcp_sw_host->session after we have completed session creation and
can no longer fail.
In the Linux kernel, the following vulnerability has been resolved:
efi: fix potential NULL deref in efi_mem_reserve_persistent
When iterating on a linked list, a result of memremap is dereferenced
without checking it for NULL.
This patch adds a check that falls back on allocating a new page in
case memremap doesn't succeed.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
[ardb: return -ENOMEM instead of breaking out of the loop]
In the Linux kernel, the following vulnerability has been resolved:
mm/khugepaged: fix ->anon_vma race
If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires
it to be locked.
Page table traversal is allowed under any one of the mmap lock, the
anon_vma lock (if the VMA is associated with an anon_vma), and the
mapping lock (if the VMA is associated with a mapping); and so to be
able to remove page tables, we must hold all three of them.
retract_page_tables() bails out if an ->anon_vma is attached, but does
this check before holding the mmap lock (as the comment above the check
explains).
If we racily merged an existing ->anon_vma (shared with a child
process) from a neighboring VMA, subsequent rmap traversals on pages
belonging to the child will be able to see the page tables that we are
concurrently removing while assuming that nothing else can access them.
Repeat the ->anon_vma check once we hold the mmap lock to ensure that
there really is no concurrent page table access.
Hitting this bug causes a lockdep warning in collapse_and_free_pmd(),
in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)".
It can also lead to use-after-free access.
In the Linux kernel, the following vulnerability has been resolved:
kernel/irq/irqdomain.c: fix memory leak with using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
In the Linux kernel, the following vulnerability has been resolved:
mm: memcg: fix NULL pointer in mem_cgroup_track_foreign_dirty_slowpath()
As commit 18365225f044 ("hwpoison, memcg: forcibly uncharge LRU pages"),
hwpoison will forcibly uncharg a LRU hwpoisoned page, the folio_memcg
could be NULl, then, mem_cgroup_track_foreign_dirty_slowpath() could
occurs a NULL pointer dereference, let's do not record the foreign
writebacks for folio memcg is null in mem_cgroup_track_foreign_dirty() to
fix it.
In the Linux kernel, the following vulnerability has been resolved:
drm/i915: Fix potential bit_17 double-free
A userspace with multiple threads racing I915_GEM_SET_TILING to set the
tiling to I915_TILING_NONE could trigger a double free of the bit_17
bitmask. (Or conversely leak memory on the transition to tiled.) Move
allocation/free'ing of the bitmask within the section protected by the
obj lock.
[tursulin: Correct fixes tag and added cc stable.]
(cherry picked from commit 10e0cbaaf1104f449d695c80bcacf930dcd3c42e)