| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: discard the rest of the packet on a stale-cookie error
When an association is in COOKIE-ECHOED state and the peer sends a
bundled [ERROR(Stale Cookie)][DATA] packet from one of its non-primary
addresses, processing the ERROR chunk takes the non-fatal stale-cookie
retry path sctp_sf_do_5_2_6_stale(), which queues
SCTP_CMD_DEL_NON_PRIMARY while keeping the association alive.
sctp_cmd_del_non_primary() removes every non-primary transport -
including the very transport this packet arrived on, which is still
referenced by the receive lookup and shared by all chunks of the
packet via chunk->transport.
sctp_assoc_rm_peer() does redirect asoc->peer.last_data_from away from
the removed transport, but right afterwards the bundled DATA chunk
makes sctp_assoc_bh_rcv() re-register
asoc->peer.last_data_from = chunk->transport unconditionally, undoing
the redirection with the just-removed transport.
Once the packet is done, the receive reference is dropped and the
transport is RCU-freed, while the surviving association keeps the
dangling last_data_from. A later FWD-TSN (or the delayed SACK timer)
makes sctp_gen_sack() dereference it (->param_flags and friends), and
sctp_make_sack()/sctp_outq_select_transport() may write to the freed
object and link it into the live transport list. This is a
use-after-free triggerable by any malicious SCTP peer (or a local
unprivileged user acting as one) with no capabilities required:
BUG: KASAN: slab-use-after-free in sctp_do_sm+0x498a/0x5660
Read of size 4 at addr ffff88800e1e356c by task poc/115
Call Trace: sctp_do_sm <- sctp_assoc_bh_rcv <- sctp_inq_push <-
sctp_rcv <- ip_protocol_deliver_rcu <- ip_rcv
Allocated: sctp_transport_new <- sctp_assoc_add_peer <-
sctp_process_init (INIT-ACK processing)
Freed: kfree <- sctp_transport_destroy_rcu <- rcu_core
(call_rcu queued by sctp_transport_put at end of sctp_rcv)
The buggy address is located 364 bytes inside of freed 1024-byte
region [ffff88800e1e3400, ffff88800e1e3800), cache kmalloc-1k
Note that commit 03a9d10ecf71 ("sctp: drop a chunk if its transport
was removed") only covers the window between the receive lookup and
the chunk processing (e.g. an ASCONF DEL-IP racing the socket backlog);
here the transport is removed *while* the packet is being processed,
by an earlier chunk of the same packet, so the drop in sctp_inq_push()
does not reach this path. Verified with the bundled [ERROR(Stale
Cookie)][DATA] + FWD-TSN reproducer: the KASAN report above still
fires with that commit applied, and is gone with this patch on top.
Fix it by discarding the rest of the packet on this path, as suggested
by Xin. After the stale-cookie ERROR has sent the association back to
COOKIE-WAIT and removed the non-primary transports, the remaining
chunks of the packet can only run against the restarted handshake
while referencing the removed arrival transport through
chunk->transport: besides the last_data_from registration above,
sctp_cmd_setup_t2() and the sctp_make_*() reply builders would also
copy that pointer into association-lifetime state that
sctp_assoc_rm_peer() has already sanitized. Let the peer retransmit
them, in line with what sctp_inq_push() does for chunks whose
transport was removed before processing. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: do not let ipv6_find_hdr() return an offset past the packet end
ipv6_find_hdr() walks the extension header chain, skipping each header by
the length that header itself declares. ipv6_optlen() returns up to 2048,
and the skip is never checked against skb->len, so the offset stored in
*offset can point past the end of the packet.
openvswitch installs that offset as the transport header, and
update_ipv6_checksum() then reads and writes the transport checksum field
out of bounds:
BUG: KASAN: slab-use-after-free in inet_proto_csum_replace16+0x445/0x470
Read of size 2 at addr ffff88810b754b06 by task ovs_ipv6_oob/629
CPU: 4 UID: 1000 PID: 629 Comm: ovs_ipv6_oob Tainted: G N 7.3.0-rc3+ #348
Call Trace:
inet_proto_csum_replace16+0x445/0x470
set_ipv6_addr+0x3dd/0x460
do_execute_actions+0x6a3d/0x7c40
ovs_execute_actions+0xfd/0x480
ovs_packet_cmd_execute+0xc38/0xf20
genl_rcv_msg+0x59e/0x870
netlink_rcv_skb+0x18b/0x450
genl_rcv+0x2d/0x40
netlink_unicast+0x6bc/0xa20
The buggy address belongs to the object at ffff88810b754980
which belongs to the cache skbuff_small_head of size 704
The buggy address is located 390 bytes inside of
freed 704-byte region [ffff88810b754980, ffff88810b754c40)
Other callers use that offset too, so bound it here rather than in one
caller.
Reject a header whose declared length does not fit in the packet.
ipv6_find_hdr() already fails with -EBADMSG on a malformed chain, so this
adds no new failure mode. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: fix use-after-free and multi-container gap in kfd_dev_mapping
kfd_dev_mapping caches the address_space of the first /dev/kfd opener
so that the GPU reset path can call unmap_mapping_range() to zap all
userspace mappings of doorbell and MMIO ranges. This design has two
bugs that both manifest under SRIOV with multiple containers:
1. Use-after-free / rwsem deadlock. The cached pointer refers to an
inode owned by the first opener's container. When that container
exits and its inode is released, kfd_dev_mapping becomes a dangling
pointer. A subsequent GPU reset dereferences it inside
unmap_mapping_range(), which takes i_mmap_rwsem on the freed inode,
causing a hard hang observable as an uninterruptible rwsem wait.
2. Multi-container gap. Only the first opener's address_space is cached;
VMAs created by later openers live in a different address_space and
are never reached by unmap_mapping_range(). After a GPU reset those
stale mappings keep doorbell and MMIO pages accessible to guest
userspace with no GPU behind them, risking PCIe transaction timeouts
and NMI panics.
Fix both bugs with the same approach used by DRM core (drm_drv.c):
create a private pseudo-filesystem at module init time and allocate one
anonymous inode from it. In kfd_open() redirect every opener's
file->f_mapping to that inode's address_space. The inode is
module-owned, lives exactly as long as the amdgpu module, and collects
VMAs from all openers in one address_space. A single
unmap_mapping_range() call in the reset path then correctly reaches
every container's mappings with no dangling pointer risk.
The hang manifests as an NMI backtrace on the GPU reset workqueue stuck
spinning in rwsem_down_read_slowpath() with a corrupted i_mmap_rwsem:
Workqueue: amdgpu-reset-dev xgpu_ai_mailbox_flr_work [amdgpu]
Call Trace:
<TASK>
kvm_wait+0x1f/0x40
__pv_queued_spin_lock_slowpath+0x31d/0x3a0
_raw_spin_lock_irq+0x51/0x80
rwsem_down_read_slowpath+0xb3/0x550
down_read+0x48/0xd0
unmap_mapping_range+0x71/0x140
kfd_dev_unmap_mapping_range+0x5b/0x140 [amdgpu]
amdgpu_amdkfd_clear_kfd_mapping+0xd8/0x190 [amdgpu]
amdgpu_device_gpu_recover+0x232/0x450 [amdgpu]
xgpu_ai_mailbox_flr_work+0xb5/0xc0 [amdgpu]
process_one_work+0x18e/0x3e0
worker_thread+0x2e3/0x420
kthread+0x10a/0x230
(cherry picked from commit 1128b4a52de1572e87431de837fd9850cb99542c) |
| In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/dmem: pin VRAM for the whole registered range
Commit c32287471077 ("gpu/drm/nouveau: enable THP support for GPU memory
migration") grew the device-private region that
nouveau_dmem_chunk_alloc() registers from DMEM_CHUNK_SIZE to
DMEM_CHUNK_SIZE * NR_CHUNKS, but left the VRAM buffer object backing that
region at DMEM_CHUNK_SIZE.
nouveau_dmem_page_addr() returns chunk->bo->offset plus the page's offset
within the registered region, so every page past the first chunk resolves
to VRAM outside the buffer object.
Size the buffer object to the region it backs. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: fix double-free in nvif_vmm_dtor
On failure, nouveau_cli_init() calls nouveau_cli_fini() to tear
the client down. Then, nouveau_drm_open() also enters into its
cleanup path and calls nouveau_cli_fini() AGAIN. nouveau_cli_fini()
calls nouveau_vmm_fini():
void
nouveau_vmm_fini(struct nouveau_vmm *vmm)
{
nouveau_svmm_fini(&vmm->svmm);
nvif_vmm_dtor(&vmm->vmm);
vmm->cli = NULL;
}
Inside nvif_vmm_dtor(), vmm->page is freed unconditionally:
void
nvif_vmm_dtor(struct nvif_vmm *vmm)
{
kfree(vmm->page);
nvif_object_dtor(&vmm->object);
}
vmm->page is never cleared after being freed, so the second call of
nvif_vmm_dtor() will cause a double-free.
Found by fuzzing the nouveau driver with a modified Syzkaller:
BUG: KASAN: double-free in nvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194
Free of addr ffff888010fcdc30 by task syz.0.173/2567
CPU: 1 UID: 0 PID: 2567 Comm: syz.0.173 Not tainted 7.2.0 #24 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x95/0xe0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcb/0x5a0 mm/kasan/report.c:482
kasan_report_invalid_free+0xaa/0xd0 mm/kasan/report.c:557
check_slab_allocation+0xe4/0x110 mm/kasan/common.c:235
kasan_slab_pre_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:2622 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x192/0x590 mm/slub.c:6692
nvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194
nouveau_vmm_fini+0x16/0x50 drivers/gpu/drm/nouveau/nouveau_vmm.c:127
nouveau_cli_fini+0x10e/0x210 drivers/gpu/drm/nouveau/nouveau_drm.c:225
nouveau_drm_open+0x24e/0x740 drivers/gpu/drm/nouveau/nouveau_drm.c:1255
drm_file_alloc+0x5f2/0xad0 drivers/gpu/drm/drm_file.c:176
drm_open_helper+0x1d7/0x4a0 drivers/gpu/drm/drm_file.c:335
drm_open+0x190/0x3d0 drivers/gpu/drm/drm_file.c:388
drm_stub_open+0x1f2/0x460 drivers/gpu/drm/drm_drv.c:1211
chrdev_open+0x21c/0x660 fs/char_dev.c:411
do_dentry_open+0x59d/0x12b0 fs/open.c:947
vfs_open+0x82/0x390 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2345/0x3420 fs/namei.c:4863
do_file_open+0x207/0x460 fs/namei.c:4892
do_sys_openat2+0xd1/0x1d0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x144/0x200 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x690 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6d687594d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc6d5295008 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc6d6b06180 RCX: 00007fc6d687594d
RDX: 0000000000022501 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fc6d691c303 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6d6b06218 R14: 00007fc6d6b06180 R15: 00007ffd9451d760
</TASK>
Allocated by task 2567 on cpu 1 at 163.593900s:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:57
kasan_save_track+0x17/0x60 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kmalloc_noprof+0x304/0x7c0 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
nvif_vmm_ctor+0x3c0/0x7e0 drivers/gpu/drm/nouveau/nvif/vmm.c:237
nouveau_vmm_init+0x40/0x90 drivers/gpu/drm/nouveau/nouveau_vmm.c:134
nouveau_cli_init+0x7b9/0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: RCU-free the scheduler-containing nouveau_sched
struct nouveau_sched embeds a struct drm_gpu_scheduler (base).
nouveau_sched_destroy() calls nouveau_sched_fini() (which does
drm_sched_fini(&sched->base)) and then frees the object with plain
kfree(sched).
drm_sched_fence_get_timeline_name() returns fence->sched->name, and the
scheduler fence keeps a .release callback so it is not ops-detached on
signalling. A finished fence exported to userspace via drm_syncobj /
sync_file therefore keeps pointing at &sched->base after nouveau_sched_destroy(),
and a later get_timeline_name() -- reachable unprivileged through
SYNC_IOC_FILE_INFO -- dereferences freed memory (KASAN slab-use-after-free
read).
Per the dma-fence lifetime contract the exporter must keep the data backing a
signalled fence alive for an RCU grace period. Free the scheduler-containing
object with kfree_rcu() instead of kfree(). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/xe/vm: nuke PTs only after unlinking contested VMAs
In xe_vm_close_and_put(), external-BO VMAs are queued on the contested
list for deferred destruction via xe_vma_destroy_unlocked(). However,
xe_vm_pt_destroy() was previously invoked before processing contested
VMAs, destroying vm->pt_root while those VMAs were still linked to their
respective buffer objects (vm_bo->list.gpuva).
If a concurrent thread evicts one of those shared buffer objects,
xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in
fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because
vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a
NULL ptr deref.
Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until
after all contested VMAs have been unlinked and destroyed.
User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which
could be explained by this race.
(cherry picked from commit c2863648959489767f08892fd6e90577d2ea0b6a) |
| In the Linux kernel, the following vulnerability has been resolved:
HID: wacom: fix OOB read in wacom_wac_pen_serial_enforce()
The 'wacom_wac_pen_serial_enforce()' function may calculate and pass an
invalid offset to hid_field_extract(), resulting in memory reads at
incorrect addresses -- possibly beyond the end of the report. If a
field in the HID descriptor lists more usages than its Report Count
actually reserves space for, the function's inner 'j' will walk past
the end of the field:
for (i = 0; i < report->maxfield; i++) {
for (j = 0; j < report->field[i]->maxusage; j++) {
...
value = hid_field_extract(hdev, raw_data + 1,
offset + j * size, size);
A descriptor listing 12288 usages against Report Count 1 has the loop
extract the usage at index 12287 from bit offset 98296 -- about 12 KB
past a 2-byte received report. The value is stored in
wacom_wac->serial[0] and can reach userspace as an MSC_SERIAL event,
making this an information disclosure.
Clamp the loop to field->report_count, the number of value slots the
report holds. Value slots past the last declared usage are still
scanned; they reuse that usage (HID 1.11, 6.2.2.8).
Verified on v6.12.105 with a UHID reproducer: a 2-byte report from
such a descriptor trips KASAN before the patch and not after it. |
| In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry
In a case where skb with an unconfirmed ct entry gets cloned, we may
end up committing both but with different sets of extensions.
The series of events:
1. The first clone wants to commit and runs the helpers wiring up
the extension pointer into the expectation list.
2. Then it looses the confirmation keeping the entry unconfirmed.
3. Second clone now wants to commit labels and adds the new extension
for that breaking the pointer in the expectation list causing
UAF on the destruction path later.
While this is possible to trigger, there should be no practical
network pipeline where committing both clones without modifications
into the same zone is needed. So, let's just reset the entry in case
for some reason we got an skb with a shared one during commit. This
doesn't affect any known use cases, but avoids any potential problems
with sharing and modification of the unconfirmed ct entry.
The fixes tag points to the introduction of helpers, since that's the
main UAF trigger for the sharing. |
| In the Linux kernel, the following vulnerability has been resolved:
net: bridge: mdb: restart port group walk after deletion
br_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking
mp->ports. br_multicast_del_pg() can re-enter the same MDB entry through
br_multicast_sg_del_exclude_ports() and unlink other port groups. If the
cursor points into one of those groups, the next iteration dereferences a
stale cursor and can leave mp->ports pointing at freed memory.
A following RTM_GETMDB exposes the dangling pointer:
BUG: KASAN: slab-use-after-free in br_mdb_dump
Read of size 8
br_mdb_dump
rtnl_mdb_dump
rtnl_dumpit
netlink_dump
Reset the cursor to mp->ports after every deletion. The deletion removes at
least the selected group, so the restarted walk always makes progress. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read
rt_mt6_check() permits rules to be configured with rtinfo->addrnr == 0
even when address matching (IP6T_RT_FST_MASK) is requested.
In the IP6T_RT_FST_NSTRICT path, rt_mt6() evaluates packet routing
addresses against rtinfo->addrs[i] and terminates backwards at the bottom
of the loop:
if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
i++;
}
if (i == rtinfo->addrnr)
break;
When addrnr is 0, if the first packet address matches rtinfo->addrs[0],
i is incremented to 1. Because i is now strictly greater than addrnr (0),
the loop termination condition (i == rtinfo->addrnr) is bypassed and will
never be satisfied.
If a crafted IPv6 packet contains matching routing addresses, i will
advance past IP6T_RT_HOPS (16). The subsequent call to ipv6_addr_equal()
reads beyond struct ip6t_rt, triggering UBSAN/KASAN out-of-bounds warnings
or kernel panics.
Fix this by:
1. Rejecting rules in rt_mt6_check() where IP6T_RT_FST_MASK is set but
rtinfo->addrnr is zero.
2. In rt_mt6(), moving the termination condition (i < rtinfo->addrnr)
into the for-loop header condition and removing the backwards break
at the end of the loop body. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Do cache maintenance on the source VM during intra-host migration
Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.
Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Fix AArch32 DBGBXVR<n> handling
The consolidation of the breakpoint and watchpoint register accessors
switched DBGBXVR<n> from trap_bvr() to trap_dbg_wb_reg(). The latter
selects backing storage with demux_wb_reg(), which only handles Op2 values
4 through 7. Since DBGBXVR<n> uses Op2 1, an AArch32 guest access hits
KVM_BUG_ON() and marks the VM dead.
DBGBXVR<n> aliases DBGBVR<n>_EL1[63:32], and its AA32(HI) descriptor
already selects the upper half. Map Op2 1 to dbg_bvr[] alongside Op2 4,
restoring the pre-regression behavior. |
| In the Linux kernel, the following vulnerability has been resolved:
RISC-V: KVM: Serialize IMSIC attributes with vCPU migration
KVM device ioctls are not serialized against KVM_RUN. As a result,
kvm_riscv_aia_imsic_rw_attr() can snapshot the physical CPU and HGEI of
an IMSIC VS-file before a concurrent vCPU migration releases it.
The HGEI can then be allocated to another vCPU before imsic_vsfile_rw()
uses the stale tuple. A GET or SET attribute may consequently access the
new owner's interrupt file.
Serialize the entire IMSIC attribute operation with the target vCPU
mutex. This prevents the VS-file from being migrated and recycled until
the attribute access completes. Acquire the mutex killably so that the
device ioctl remains interruptible while waiting for KVM_RUN to finish. |
| In the Linux kernel, the following vulnerability has been resolved:
RISC-V: KVM: Synchronize hrtimer callback during teardown
The non-Sstc hrtimer callback clears next_set before its final uses of
the enclosing vCPU. If teardown observes next_set as false while the
callback is still running, kvm_riscv_vcpu_timer_cancel() skips
hrtimer_cancel() and kvm_destroy_vcpus() can free the vCPU before the
callback enters kvm_riscv_vcpu_set_interrupt().
A guest can arm the timer with SBI TIME and request shutdown with SBI
legacy shutdown or SRST. A VMM that honors KVM_EXIT_SYSTEM_EVENT and
destroys the VM supplies the teardown side of the race; no post-launch
host ioctl is needed to arm or request teardown.
On upstream master 62cc90241548, generic KASAN reported:
BUG: KASAN: slab-use-after-free in do_raw_spin_lock
Write of size 4 at addr ff60000005e58898
kvm_riscv_vcpu_set_interrupt
kvm_riscv_vcpu_hrtimer_expired
__hrtimer_run_queues
hrtimer_interrupt
The object was allocated by KVM_CREATE_VCPU and freed concurrently by:
kvm_destroy_vcpus
kvm_arch_destroy_vm
kvm_destroy_vm
__fput
For deterministic validation, I added mdelay(1000) immediately after
the existing next_set = false assignment. This only widens the
existing post-clear callback window. A no-delay trace build naturally
reached the callback-after-teardown-start/before-deinit ordering in 12
of 200 runs, but 1,500 stock-kernel stress iterations did not produce a
KASAN report, so natural reproduction is timing-sensitive.
Always invoke hrtimer_cancel() for an initialized timer. Preserve the
existing -EINVAL result when the timer is no longer set, but only after
synchronizing with a running callback.
With this patch, hrtimer_cancel() blocked for the full widened callback
window before vCPU destruction. KASAN reported no error in 100
fixed-and-widened runs or 200 fix-only timing-sweep runs. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_ct: fix helper UAF due to extensions realloc
While calling the helpers, a raw pointer to the extensions area is
wired into expectations list:
-> nf_ct_helper()
-> helper->help()
-> nf_ct_expect_related_report()
-> nf_ct_expect_insert()
-> hlist_add_head_rcu(&exp->lnode, &master_help->expectations)
In case the connection is not confirmed yet, more extensions can be
added afterwards with *_ext_add() calls reallocating the extension
space and leaving the now invalid pointer in the expectations list
that is later accessed while removing the expectation.
Make sure that helpers are called at the end after all the other
extensions are already added.
Note that the helper rejection now leaves the mark and labels set,
but that's not different from how the NAT was handled before or how
the mark and the labels were handled on confirmation failure. And
there are no atomicity guarantees provided by the API anyway. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_ct: avoid modifying shared unconfirmed ct entry
In a case where skb with an unconfirmed ct entry gets cloned, we may
end up processing both again but with different sets of extensions.
The series of events:
1. The first clone wants to commit and runs the helpers wiring up
the extension pointer into the expectation list.
2. Then it looses the confirmation keeping the entry unconfirmed.
3. Second clone now wants to commit labels or run NAT and adds the
new extension for that breaking the pointer in the expectation
list causing UAF on the destruction path later.
While this is possible to trigger, there should be no practical
network pipeline where we need to process both clones without
modifications in the same zone. So, let's just reset the entry in
case for some reason we got an skb with a shared one. This doesn't
affect any known use cases, but avoids any potential problems with
sharing and modification of the unconfirmed ct entry.
Unlike openvswitch module, act_ct allows for NAT without commit.
Changing that would be a uAPI break. So, act_ct needs to reset on NAT
regardless of the commit flag to avoid reallocation of the extension
space. This, however, doesn't really change the picture for sensible
networking cases as there should be no need to run the same packet
twice (before and after the clone) through conntrack without packet
header or zone changes and without commit.
The fixes tag points to the introduction of helpers, since that's the
main UAF trigger for the sharing. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Delay freeing of shadow S2 structures until VM destruction
We free the shadow S2 structures from kvm_arch_flush_shadow_all(), which
is a Bad Idea(tm). Freeing the page tables is fair game (this is what
this callback is for), but freeing the container that could still be
referenced by another part of the system is not great.
Instead, grow separate destructors that gets called when we tear the VM
down for good. From there, we can nuke both the individual MMUs as well
as the global array that points to them, safe in the knowledge that the
vcpus themselves have been destroyed already. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix missing iov bounds check in parse_posix_sids()
In parse_posix_sids(), sidsbuf_end is calculated using the server-supplied
out_len without being validated against the actual length of the received
iov (iov_len).
If a server provides an inflated out_len, sidsbuf_end will point past the
end of the iov. This defeats the bounds guards in posix_info_sid_size(),
allowing out-of-bounds reads into adjacent kernel memory.
Fix this by rejecting responses where the calculated sidsbuf_end would
exceed the received iov boundaries or cause pointer wraparound. |
| In the Linux kernel, the following vulnerability has been resolved:
net: iptunnel: fix stale transport header during tunnel decapsulation
Syzbot reported a crash in qdisc_pkt_len_segs_init() caused by a stale
transport_header offset after tunnel decapsulation.
BUG: unable to handle page fault for address: ffffed102091a42e
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 340 Comm: qdisc_uaf_repro Not tainted 7.2.0-rc4-00061-g248951ddc14d #256 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__asan_load2
<IRQ>
qdisc_pkt_len_segs_init (net/core/dev.c:4145)
__dev_queue_xmit (net/core/dev.c:4787)
br_dev_queue_push_xmit (net/bridge/br_forward.c:53)
br_handle_frame_finish (net/bridge/br_input.c:229)
br_handle_frame (net/bridge/br_input.c:315)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6099)
__netif_receive_skb_list_core (net/core/dev.c:6287)
netif_receive_skb_list_internal (net/core/dev.c:6445)
napi_complete_done (net/core/dev.c:6813)
gro_cell_poll (net/core/gro_cells.c:74)
__napi_poll (net/core/dev.c:7735)
net_rx_action (net/core/dev.c:7798 net/core/dev.c:7955)
handle_softirqs (kernel/softirq.c:622)
do_softirq (kernel/softirq.c:523 kernel/softirq.c:510 )
__local_bh_enable_ip (kernel/softirq.c:450)
tun_get_user (drivers/net/tun.c:1986 (discriminator 1))
tun_chr_write_iter (drivers/net/tun.c:2032)
The issue is completely latent until qdisc read transport header in
commit 7fb4c1967011 ("net: pull headers in qdisc_pkt_len_segs_init()").
The crash requires four conditions to line up:
1. The incoming packet is encapsulated and carries GSO metadata. The outer
transport header offset is stored in skb->transport_header while the
packet is still in the outer tunnel context.
2. The tunnel receiver strips the outer headers. skb->data is advanced to
the inner frame, but skb->transport_header is left pointing to the
now-removed outer L4 header, so it becomes a negative offset relative to
the new data.
3. The inner frame is not delivered to the local IP stack. Instead, it
is forwarded at L2 by a bridge or HSR, so ip_rcv_core() never runs and
the transport header is not reset to the inner L4 offset.
4. The forwarding path calls __dev_queue_xmit(), which enters
qdisc_pkt_len_segs_init(). That function computes the GSO header length
from skb_transport_offset(skb). Because the offset is negative, the
unsigned cast overflows and pskb_may_pull(skb, hdr_len +
sizeof(struct tcphdr)) reads past the end of the skb, triggering a
KASAN fault or page fault.
The issue specifically requires GSO packets (shinfo->gso_size != 0), which
are processed/aggregated through gro_cells. Fix this by clearing
transport_header to the ~0U sentinel in gro_cell for all tunnnel driver.
GTP does not support GRO/GSO, drop the evil GSO packets in GTP directly. |
