In the Linux kernel, the following vulnerability has been resolved:
net: qualcomm: rmnet: fix endpoint use-after-free in rmnet_dellink()
rmnet_dellink() removes the endpoint from the hash table with
hlist_del_init_rcu() and then immediately frees it with kfree(). However,
RCU readers on the receive path (rmnet_rx_handler ->
__rmnet_map_ingress_handler) may still hold a reference to the endpoint and
dereference ep->egress_dev after the memory has been freed. The endpoint is
a kmalloc-32 object, and the stale read at offset 8 corresponds to the
egress_dev pointer.
BUG: unable to handle page fault for address: ffffffffde942eef
Oops: 0002 [#1] SMP NOPTI
CPU: 1 UID: 0 PID: 137 Comm: poc_write Not tainted 7.0.0+ #4 PREEMPTLAZY
RIP: 0010:rmnet_vnd_rx_fixup (rmnet_vnd.c:27)
Call Trace:
<TASK>
__rmnet_map_ingress_handler (rmnet_handlers.c:48 rmnet_handlers.c:101)
rmnet_rx_handler (rmnet_handlers.c:129 rmnet_handlers.c:235)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6096)
__netif_receive_skb_one_core (net/core/dev.c:6208)
netif_receive_skb (net/core/dev.c:6467)
tun_get_user (drivers/net/tun.c:1955)
tun_chr_write_iter (drivers/net/tun.c:2003)
vfs_write (fs/read_write.c:688)
ksys_write (fs/read_write.c:740)
</TASK>
Add an rcu_head field to struct rmnet_endpoint and replace kfree() with
kfree_rcu() so the endpoint memory remains valid through the RCU grace
period. Also remove the rmnet_vnd_dellink() call and inline only the
nr_rmnet_devs decrement, since rmnet_vnd_dellink() would set
ep->egress_dev to NULL during the grace period, creating a data race
with lockless readers.
In the Linux kernel, the following vulnerability has been resolved:
xfs: fail recovery on a committed log item with no regions
If the first op of a transaction is a bare transaction header
(len == sizeof(struct xfs_trans_header)), xlog_recover_add_to_trans()
adds an item but no region, leaving it on r_itemq with ri_cnt == 0 and
ri_buf == NULL.
The header can be split across op records, so later ops may still add
regions; the item is only invalid if the transaction commits with none.
The runtime commit path never emits such a transaction, so this only
happens on a crafted log. It came from an AI-assisted code audit of the
recovery parser.
xlog_recover_reorder_trans() calls ITEM_TYPE() on the item, which reads
*(unsigned short *)item->ri_buf[0].iov_base and faults on the NULL
ri_buf. Reject it there, before the commit handlers that also read
ri_buf[0].
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:xlog_recover_reorder_trans (fs/xfs/xfs_log_recover.c:1836)
xlog_recover_commit_trans (fs/xfs/xfs_log_recover.c:2043)
xlog_recover_process_data (fs/xfs/xfs_log_recover.c:2501)
xlog_do_recovery_pass (fs/xfs/xfs_log_recover.c:3244)
xlog_recover (fs/xfs/xfs_log_recover.c:3493)
xfs_log_mount (fs/xfs/xfs_log.c:618)
xfs_mountfs (fs/xfs/xfs_mount.c:1034)
xfs_fs_fill_super (fs/xfs/xfs_super.c:1938)
vfs_get_tree (fs/super.c:1695)
path_mount (fs/namespace.c:4161)
__x64_sys_mount (fs/namespace.c:4367)
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix race between dump and ip_set_list resize
The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.
A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.
The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().
BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
Read of size 8 at addr ffff88800b5c4018 by task exploit/150
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
netlink_dump (net/netlink/af_netlink.c:2325)
netlink_recvmsg (net/netlink/af_netlink.c:1976)
sock_recvmsg (net/socket.c:1159)
__sys_recvfrom (net/socket.c:2315)
...
Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
Kernel panic - not syncing: Fatal exception
In the Linux kernel, the following vulnerability has been resolved:
gfs2: fix use-after-free in gfs2_qd_dealloc
gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),
accesses the superblock object sdp through qd->qd_sbd after freeing qd.
It does so to decrement sd_quota_count and wake up sd_kill_wait.
However, by the time the RCU callback runs, gfs2_put_super() may have
already freed sdp via free_sbd(). This can happen when
gfs2_quota_cleanup() is called during unmount: it disposes of quota
objects via call_rcu() and then waits on sd_kill_wait with a 60-second
timeout. If the timeout expires, or if gfs2_gl_hash_clear() triggers
additional qd_put() calls that schedule more RCU callbacks after the
wait completes, gfs2_put_super() will proceed to free the superblock
while RCU callbacks referencing it are still pending.
Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure
all pending RCU callbacks (including gfs2_qd_dealloc) have completed
before the superblock is freed.
In the Linux kernel, the following vulnerability has been resolved:
crypto: nx - fix nx_crypto_ctx_exit argument
nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...)
but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *.
Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx
call.
This fixes the following oops:
BUG: Unable to handle kernel data access at 0xc0403effffffffc8
Faulting instruction address: 0xc000000000396cb4
Oops: Kernel access of bad area, sig: 11 [#15]
Call Trace:
nx_crypto_ctx_shash_exit+0x24/0x60
crypto_shash_exit_tfm+0x28/0x40
crypto_destroy_tfm+0x98/0x140
crypto_exit_ahash_using_shash+0x20/0x40
crypto_destroy_tfm+0x98/0x140
hash_release+0x1c/0x30
alg_sock_destruct+0x38/0x60
__sk_destruct+0x48/0x2b0
af_alg_release+0x58/0xb0
__sock_release+0x68/0x150
sock_close+0x20/0x40
__fput+0x110/0x3a0
sys_close+0x48/0xa0
system_call_exception+0x140/0x2d0
system_call_common+0xf4/0x258
.. which came from hardlink(1) opportunistically using AF_ALG.
The same problem exists with nx_crypto_ctx_skcipher_exit getting a context
it wasn't expecting, but apparently nobody hit that for years.
In the Linux kernel, the following vulnerability has been resolved:
KVM: Replace guest-triggerable BUG_ON() in ioeventfd datamatch with get_unaligned()
Drop a BUG_ON() that has been reachable since it was first added, way back
in 2009, and instead use get_unaligned() to perform potentially-unaligned
accesses.
For a given store, KVM x86's emulator tracks the entire value in the
destination operand, x86_emulate_ctxt.dst. If the destination is memory,
and the target splits multiple pages and/or is emulated MMIO, then KVM
handles each fragment independently. E.g. on a page split starting at page
offset 0xffc, KVM writes 4 bytes to the first page, then the remaining
bytes to the second page, using ctxt->dst as the source for both (with
appropriate offsets).
If the destination splits a page *and* hits emulated MMIO on the second
page, then KVM will complete the write to the first page, then emulate the
MMIO access to the second page. If there is a datamatch-enabled ioeventfd
at offset 0 of the second page, then KVM will process the remainder of the
store as a potential ioeventfd signal.
Putting it all together, if the guest emits a store that splits a page
starting at page offset N, and the second page has a datamatch-enabled
ioeventfd at offset 0, then KVM will check for datamatch using
&dst.valptr[N] as the source. Due to dst (and thus dst.valptr) being
32-byte aligned, if N is not aligned to @len, the BUG_ON() fires.
E.g. with a 16-byte store at page offset 0xffc, to an ioeventfd of len 8,
all initial checks in ioeventfd_in_range() will succeed, and the BUG_ON()
fires due to @val being 4-byte aligned, but not 8-byte aligned.
------------[ cut here ]------------
kernel BUG at arch/x86/kvm/../../../virt/kvm/eventfd.c:783!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 0 UID: 1000 PID: 615 Comm: repro Not tainted 7.1.0-rc2-ff238429d1ea #365 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:ioeventfd_write+0x6c/0x70 [kvm]
Call Trace:
<TASK>
__kvm_io_bus_write+0x85/0xb0 [kvm]
kvm_io_bus_write+0x53/0x80 [kvm]
vcpu_mmio_write+0x66/0xf0 [kvm]
emulator_read_write_onepage+0x12a/0x540 [kvm]
emulator_read_write+0x109/0x2b0 [kvm]
x86_emulate_insn+0x4f8/0xfb0 [kvm]
x86_emulate_instruction+0x181/0x790 [kvm]
kvm_mmu_page_fault+0x313/0x630 [kvm]
vmx_handle_exit+0x18a/0x590 [kvm_intel]
kvm_arch_vcpu_ioctl_run+0xc81/0x1c90 [kvm]
kvm_vcpu_ioctl+0x2d5/0x970 [kvm]
__x64_sys_ioctl+0x8a/0xd0
do_syscall_64+0xb7/0x890
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f19c931a9bf
</TASK>
Modules linked in: kvm_intel kvm irqbypass
---[ end trace 0000000000000000 ]---
In a perfect world, the fix would be to simply delete the BUG_ON(), as KVM
x86 doesn't perform alignment checks on "normal" memory accesses at CPL0.
Sadly, C99 ruins all the fun; while the x86 architecture plays nice,
dereferencing an unaligned pointer directly is undefined behavior in C,
e.g. triggers splats when running with CONFIG_UBSAN_ALIGNMENT=y.
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level
When recovering hugepages in the shadow MMU, verify that the base gfn of
the shadow page is actually contained within the target memslot, *before*
querying the max mapping level given the shadow page's gfn. Failure to
pre-check the validity of the gfn can lead to an out-of-bounds access to
the slot's lpage_info (which typically manifests as a host #PF because the
lpage_info is vmalloc'd) if the guest creates a hugepage mapping (in its
PTEs) that extends "below" the bounds of a memslot.
When faulting in memory for a guest, and the size of the guest mapping is
greater than KVM's (current) max mapping, then KVM will create a "direct"
shadow page (direct in that there are no gPTEs to shadow, and so the target
gfn is a direct calculation given the base gfn of the shadow page). The
hugepage recovery flow looks for such direct shadow pages, as forcing 4KiB
mappings when dirty logging generates the guest > host mapping size case.
When the 4KiB restriction is lifted, then KVM can replace the shadow page
with a hugepage.
But if KVM originally used a smaller mapping than the guest because the
range of memory covered by the guest hugepage exceeds the bounds of a
memslot, then KVM will link a direct shadow page with a gfn that is outside
the bounds of the memslot being used to fault in memory. The rmap entry
added for the leaf mapping is correct and within bounds, but the gfn of the
leaf SPTE's parent shadow page will be out of bounds.
BUG: unable to handle page fault for address: ffffc90000806ffc
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 100000067 P4D 100000067 PUD 1002a7067 PMD 10612f067 PTE 0
Oops: Oops: 0000 [#1] SMP
CPU: 13 UID: 1000 PID: 757 Comm: mmu_stress_test Not tainted 7.1.0-rc1-48ce1e26eace-x86_pir_to_irr_comments-vm #341 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_mmu_max_mapping_level+0x79/0x2b0 [kvm]
Call Trace:
<TASK>
kvm_mmu_recover_huge_pages+0x21b/0x320 [kvm]
kvm_set_memslot+0x1ee/0x590 [kvm]
kvm_set_memory_region.part.0+0x3a1/0x4d0 [kvm]
kvm_vm_ioctl+0x9bf/0x15d0 [kvm]
__x64_sys_ioctl+0x8a/0xd0
do_syscall_64+0xb7/0xbb0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f21c0f1a9bf
</TASK>
Don't bother pre-checking the bounds of the potential hugepage, i.e. don't
check that e.g. sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level + 1) is also
within the memslot, as the checks performed by kvm_mmu_max_mapping_level()
are a superset of the basic bounds checks. I.e. pre-checking the full
range would be a dubious micro-optimization.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: reject oversized group bitmap descriptors
ocfs2_validate_gd_parent() only bounds bg_bits against the parent
allocator's chain geometry. A malicious descriptor can still claim a
bg_size/bg_bits pair that exceeds the bitmap bytes that physically fit in
the group descriptor block, so later bitmap scans and bit updates can run
past bg_bitmap.
Add a physical-cap check based on ocfs2_group_bitmap_size() for the parent
allocator type and reject descriptors whose bg_size or bg_bits exceed that
capacity. Keep the existing chain geometry check so both the on-disk
bitmap layout and the allocator metadata must agree before the descriptor
is used.
Validation reproduced this kernel report:
KASAN use-after-free in _find_next_bit+0x7f/0xc0
Read of size 8
Call trace:
dump_stack_lvl+0x66/0xa0 (?:?)
print_report+0xd0/0x630 (?:?)
_find_next_bit+0x7f/0xc0 (?:?)
srso_alias_return_thunk+0x5/0xfbef5 (?:?)
__virt_addr_valid+0x188/0x2f0 (?:?)
kasan_report+0xe4/0x120 (?:?)
ocfs2_find_max_contig_free_bits+0x35/0x70 (fs/ocfs2/suballoc.c:1375)
ocfs2_block_group_set_bits+0x472/0x4b0 (fs/ocfs2/suballoc.c:1457)
ocfs2_cluster_group_search+0x16b/0x440 (fs/ocfs2/suballoc.c:86)
ocfs2_bg_discontig_fix_result+0x1ef/0x230 (fs/ocfs2/suballoc.c:1786)
ocfs2_search_chain+0x8f8/0x10a0 (fs/ocfs2/suballoc.c:1886)
get_page_from_freelist+0x70e/0x2370 (?:?)
lock_release+0xc6/0x290 (?:?)
do_raw_spin_unlock+0x9a/0x100 (?:?)
kasan_unpoison+0x27/0x60 (?:?)
__bfs+0x147/0x240 (?:?)
get_page_from_freelist+0x83d/0x2370 (?:?)
ocfs2_claim_suballoc_bits+0x38c/0xe70 (fs/ocfs2/suballoc.c:96)
sched_domains_numa_masks_clear+0x70/0xd0 (?:?)
check_irq_usage+0xe8/0xb70 (?:?)
__ocfs2_claim_clusters+0x18d/0x4c0 (fs/ocfs2/suballoc.c:2497)
check_path+0x24/0x50 (?:?)
rcu_is_watching+0x20/0x50 (?:?)
check_prev_add+0xfd/0xd00 (?:?)
ocfs2_add_clusters_in_btree+0x17d/0x810 (fs/ocfs2/suballoc.c:?)
__folio_batch_add_and_move+0x1f5/0x3d0 (?:?)
ocfs2_add_inode_data+0xd9/0x120 (fs/ocfs2/suballoc.c:?)
filemap_add_folio+0x105/0x1f0 (?:?)
ocfs2_write_begin_nolock+0x29f7/0x2f80 (fs/ocfs2/suballoc.c:3043)
ocfs2_read_inode_block+0xb5/0x110 (fs/ocfs2/suballoc.c:?)
down_write+0xf5/0x180 (?:?)
ocfs2_write_begin+0x180/0x240 (fs/ocfs2/suballoc.c:?)
__mark_inode_dirty+0x758/0x9a0 (?:?)
inode_to_bdi+0x41/0x90 (?:?)
balance_dirty_pages_ratelimited_flags+0xf8/0x1d0 (?:?)
generic_perform_write+0x252/0x440 (?:?)
mnt_put_write_access_file+0x16/0x70 (?:?)
file_update_time_flags+0xe4/0x200 (?:?)
ocfs2_file_write_iter+0x80a/0x1320 (fs/ocfs2/suballoc.c:?)
lock_acquire+0x184/0x2f0 (?:?)
ksys_write+0xd2/0x170 (?:?)
apparmor_file_permission+0xf5/0x310 (?:?)
read_zero+0x8d/0x140 (?:?)
lock_is_held_type+0x8f/0x100 (?:?)
In the Linux kernel, the following vulnerability has been resolved:
rpmsg: char: Fix use-after-free on probe error path
rpmsg_chrdev_probe() stores the newly allocated eptdev in the default
endpoint's priv pointer before calling rpmsg_chrdev_eptdev_add(). If
rpmsg_chrdev_eptdev_add() then fails, its error path frees eptdev while
the default endpoint may still dispatch callbacks with the stale priv
pointer.
Avoid publishing eptdev through the default endpoint until
rpmsg_chrdev_eptdev_add() succeeds. Messages received before the priv
pointer is published should be ignored by rpmsg_ept_cb(). Flow-control
updates can hit rpmsg_ept_flow_cb() in the same window, so make both
callbacks return success when priv is NULL.
In the Linux kernel, the following vulnerability has been resolved:
irqchip/imgpdc: Fix resource leak, add missing chained handler cleanup on remove
The driver allocates domain generic chips using
irq_alloc_domain_generic_chips() during probe and sets up chained
handlers using irq_set_chained_handler_and_data(). However, on driver
removal, the generic chips are not freed and the chained handlers are
not removed.
The generic chips remain on the global gc_list and may later be accessed by
generic interrupt chip suspend, resume, or shutdown callbacks after the
driver has been removed, potentially resulting in a use-after-free and
kernel crash.
The chained handlers that were installed in probe for peripheral and
syswake interrupts are also left dangling, which can lead to spurious
interrupts accessing freed memory.
Fix these issues by:
- Setting IRQ_DOMAIN_FLAG_DESTROY_GC flag in domain->flags, so the
core code automatically removes generic chips when irq_domain_remove()
is called
- Clearing all chained handlers with NULL in pdc_intc_remove()