| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
macsec: fix replay protection at XPN lower-PN wrap
In macsec_post_decrypt(), when pn is U32_MAX, pn + 1 overflows u32 to 0
and the first branch never fires. If next_pn_halves.lower is also in the
upper half, pn_same_half(pn, lower) is true and the XPN else-if does not
fire either, leaving next_pn_halves unchanged. An attacker that captures
the legitimate frame carrying pn == 0xFFFFFFFF on an XPN association
can then replay it indefinitely, since lowest_pn never rises above
the captured pn and macsec_decrypt() reconstructs the same IV.
Extend the XPN else-if to also fire when pn + 1 wraps to 0, so receipt
of pn == U32_MAX advances next_pn_halves to (upper + 1, 0). |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: exthdrs: refresh nh after handling HAO option
ip6_parse_tlv() caches skb_network_header(skb) in nh while walking
IPv6 TLVs.
ipv6_dest_hao() may call pskb_expand_head() for a cloned skb, which can
move the skb head and invalidate the cached network header pointer.
Refresh nh after ipv6_dest_hao() returns so any trailing padding or TLVs
are parsed from the current skb head.
This matches the existing pattern used in ip6_parse_tlv() after helpers
that can modify skb header storage. |
| In the Linux kernel, the following vulnerability has been resolved:
ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().
After patch 1/2 in this series, vti6_update() unlinks and relinks
the tunnel through t->net. vti6_siocdevprivate() still uses
dev_net(dev) for the collision lookup. For a tunnel moved through
IFLA_NET_NS_FD, dev_net(dev) is the new netns, not t->net.
SIOCCHGTUNNEL on a migrated tunnel then runs:
net = dev_net(dev) /* migrated netns */
t = vti6_locate(net, &p1, false) /* misses target in t->net */
...
t = netdev_priv(dev)
vti6_update(t, &p1, false) /* mutates t->net's hash */
A caller in the migrated netns picks params that match a tunnel
in the creation netns. The lookup in dev_net(dev) finds nothing.
vti6_update() prepends the migrated tunnel at the head of the
creation netns hash bucket for those params. Later lookups in
the creation netns resolve to the migrated device. xfrm receive
delivers the matched packets through a device the caller controls.
Reachable from an unprivileged user namespace (unshare --user
--map-root-user --net). Cross tenant scope on container hosts.
Switch the SIOCCHGTUNNEL path on a non fallback device to use
t->net for the lookup. The lookup now matches the netns
vti6_update() operates on.
Also add ns_capable(self->net->user_ns, CAP_NET_ADMIN) before
the lookup. The check at the top of the case is against
dev_net(dev)->user_ns, which after migration is the attacker's
netns. A caller there can pick params absent from self->net,
the lookup returns NULL, t becomes self, and vti6_update()
inserts the device into the creation netns hash. The new check
requires CAP_NET_ADMIN in the creation netns user_ns too.
SIOCADDTUNNEL and SIOCCHGTUNNEL on the fallback device keep
dev_net(dev), which equals init_net there. |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: input: hold netns during deferred transport reinjection
Transport-mode reinjection stores a struct net pointer in skb->cb and
uses it later from xfrm_trans_reinject(). That pointer must stay valid
until the deferred callback runs.
Take a netns reference when queueing deferred reinjection work and drop
it after the callback completes. Use maybe_get_net() so the queueing
path does not revive a namespace that is already being torn down.
This keeps the existing workqueue design and fixes the netns lifetime
handling in one place for all users of xfrm_trans_queue_net(). |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: route MIGRATE notifications to caller's netns
xfrm_send_migrate() in net/xfrm/xfrm_user.c and pfkey_send_migrate()
in net/key/af_key.c both hardcode &init_net for the multicast that
announces a successful XFRM_MSG_MIGRATE / SADB_X_MIGRATE.
XFRM_MSG_MIGRATE arrives on a per-netns NETLINK_XFRM socket, and the
rest of the xfrm/af_key netlink path was made netns-aware in 2008.
The other 14 multicast paths in xfrm_user.c route their event using
xs_net(x), xp_net(xp) or sock_net(skb->sk); only the migrate path
was missed.
Two consequences of the init_net hardcoding:
1. The notification (selector, old/new endpoint addresses, and the
km_address) is delivered to listeners on init_net's
XFRMNLGRP_MIGRATE / pfkey BROADCAST_ALL groups rather than on
the issuing netns. An IKE daemon running in init_net therefore
receives migration notifications originating from any other
netns on the host.
2. An IKE daemon running inside a non-init netns and subscribed
to its own XFRMNLGRP_MIGRATE / pfkey groups never receives the
notification of its own migration. IKEv2 MOBIKE / address-update
handling inside a netns is silently broken.
Thread struct net through km_migrate() and the xfrm_mgr.migrate
function pointer, drop the &init_net override in xfrm_send_migrate()
and pfkey_send_migrate(), and pass the caller's net (already in
scope in xfrm_migrate() via sock_net(skb->sk)) all the way down.
struct xfrm_mgr is in-tree only and not exported as a stable API,
so the function-pointer signature change is internal.
pfkey_broadcast() is already netns-aware via net_generic(net,
pfkey_net_id) since the pernet conversion. The five other
pfkey_broadcast() callers in af_key.c already pass xs_net(x),
sock_net(sk) or a per-netns net, so this only removes the
&init_net outlier. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check
An unintended behavior in the TCP conntrack state machine allows a
connection to be forced into the CLOSE state using an RST packet with an
invalid sequence number.
Specifically, after a SYN packet is observed, an RST with an invalid SEQ
can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of
whether the RST corresponds to the expected reply direction. The relevant
code path assumes the RST is a response to an outgoing SYN, but does not
validate packet direction or ensure that a matching SYN was actually sent
in the opposite direction.
As a result, a crafted packet sequence consisting of a SYN followed by an
invalid-sequence RST can prematurely terminate an active NAT entry. This
makes connection teardown easier than intended.
So, tighten the state transition logic to ensure that RST-triggered
CLOSE transitions only occur when the RST is a valid response to a
previously observed SYN in the correct direction. |
| In the Linux kernel, the following vulnerability has been resolved:
arm64: tlb: Flush walk cache when unsharing PMD tables
When huge_pmd_unshare() is called to unshare a PMD table, the
tlb_unshare_pmd_ptdesc() function sets tlb->unshared_tables=true
but the aarch64 tlb_flush() only checked tlb->freed_tables to
determine whether to use TLBF_NONE (vae1is, invalidates walk
cache) or TLBF_NOWALKCACHE (vale1is, leaf-only).
This caused the stale PMD page table entry to remain in the walk cache
after unshare, potentially leading to incorrect page table walks.
Fix by including unshared_tables in the check, so that when
unsharing tables, TLBF_NONE is used and the walk cache is properly
invalidated.
Here is the detailed distinction between vae1is and vale1is:
| Instruction Combination | Actual Invalidation Scope |
| ------------------------ | --------------------------------------------------|
| `VAE1IS` + TTL=`0` | All entries at all levels (full invalidation) |
| `VAE1IS` + TTL=`2` (L2) | Non-leaf at Level 0/1 + leaf at Level 2 |
| `VALE1IS` + TTL=`0` | Leaf entries at all levels (non-leaf not cleared) |
| `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only | |
| In the Linux kernel, the following vulnerability has been resolved:
drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()
There is a unbalanced lock/unlock to gpusvm notifier lock:
[ 931.045868] =====================================
[ 931.046509] WARNING: bad unlock balance detected!
[ 931.047149] 6.19.0-rc6+xe-**************** #9 Tainted: G U
[ 931.048150] -------------------------------------
[ 931.048790] kworker/u5:0/51 is trying to release lock (&gpusvm->notifier_lock) at:
[ 931.049801] [<ffffffffa090c0d8>] drm_gpusvm_scan_mm+0x188/0x460 [drm_gpusvm_helper]
[ 931.050802] but there are no more locks to release!
[ 931.051463]
The drm_gpusvm_notifier_unlock() sits under err_free label and the
first jump to err_free is just before calling the
drm_gpusvm_notifier_lock() causing unbalanced unlock. |
| In the Linux kernel, the following vulnerability has been resolved:
vxlan: mdb: Fix source list corruption on a failed replace
When replacing the source list of an MDB remote entry, all existing
sources are first marked for deletion and vxlan_mdb_remote_srcs_add()
is then called to add the new source list. Sources present in the new
list have their deletion mark cleared, and any sources left marked
afterwards are removed.
If vxlan_mdb_remote_srcs_add() fails partway through, its error path
deletes all entries on the remote's source list. That rollback is only
correct for its other caller, vxlan_mdb_remote_add(), where the remote
was just allocated and the list contains solely entries added during
the call. On the replace path the list also holds pre-existing sources,
so a failed replace tears them down together with their (S, G)
forwarding entries instead of leaving the entry unchanged.
This is reachable from an existing (*, G) remote. An EXCLUDE filter
that loses sources starts forwarding traffic that should be blocked,
while an INCLUDE filter that loses sources drops traffic that should be
forwarded.
Mark entries created during the current pass with a new
VXLAN_SGRP_F_NEW flag. On failure, delete only those entries and clear
the deletion mark on the pre-existing ones, so a failed replace leaves
the source list untouched. Retain the flag until the whole operation
succeeds and then clear it. Also stop vxlan_mdb_remote_src_add() from
deleting a pre-existing entry it only looked up when adding that
entry's forwarding entry fails. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/core: Prefer NLA_NUL_STRING
These attributes are evaluated as c-string (passed to strcmp), but
NLA_STRING doesn't check for the presence of a \0 terminator.
Either this needs to switch to nla_strcmp() and needs to adjust printf fmt
specifier to not use plain %s, or this needs to use NLA_NUL_STRING.
As the code has been this way for long time, it seems to me that userspace
does include the terminating nul, even tough its not enforced so far, and
thus NLA_NUL_STRING use is the simpler solution. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs3: reject direct userspace writes to reserved $LX* xattrs
NTFS3 uses $LXUID, $LXGID, $LXMOD and $LXDEV as internal WSL
permission metadata and reloads them into i_uid, i_gid and i_mode
from ntfs_get_wsl_perm().
Because the empty-prefix xattr handler also lets file owners call
setxattr() on these names directly, an unprivileged writer on a
writable ntfs3 mount can plant root ownership and S_ISUID on their own
file and gain euid 0 after inode reload.
Reject direct userspace writes to the reserved $LX* names. Internal
ntfs3 metadata updates are unchanged because ntfs_save_wsl_perm()
writes them via ntfs_set_ea() directly.
[almaz.alexandrovich@paragon-software.com: added an additional check for non privileged users] |
| In the Linux kernel, the following vulnerability has been resolved:
mac802154: llsec: add skb_cow_data() before in-place crypto
llsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),
llsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform
in-place cryptographic transformations on skb data. They build a
scatterlist with sg_init_one() pointing into the skb's linear data area
and then pass the same scatterlist as both src and dst to the crypto API
(e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt).
On the RX path, __ieee802154_rx_handle_packet() clones the received skb
before handing it to each subscriber via ieee802154_subif_frame(). The
cloned skb shares the same underlying data buffer via reference
counting. When llsec_do_decrypt() subsequently modifies this shared
buffer in place, it corrupts data that other clones -- potentially
belonging to other sockets or subsystems -- still reference.
On the TX path, similar data sharing can occur when an skb's head has
been cloned (skb_cloned() returns true).
The fix is to call skb_cow_data() before performing any in-place crypto
operation. skb_cow_data() ensures that the skb's data area is not
shared: if the skb head is cloned or the data spans multiple fragments,
it copies the data into a private buffer that can be safely modified in
place. This is the same pattern used by:
- ESP (net/ipv4/esp4.c, net/ipv6/esp6.c)
- MACsec (drivers/net/macsec.c)
- WireGuard (drivers/net/wireguard/receive.c)
- TIPC (net/tipc/crypto.c)
Without this guard, in-place crypto on shared skb data leads to:
- Silent data corruption of other skb clones
- Use-after-free when the crypto API scatterwalk writes through a
page that has already been freed by another clone's kfree_skb()
- Kernel crashes under concurrent 802.15.4 traffic with security
enabled (KASAN/KMSAN reports slab-use-after-free)
Found by 0sec (https://0sec.ai) using automated source analysis. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink
A tunnel changelink() operates on at most two netns, dev_net(dev) and
the tunnel link netns t->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in t->net can rewrite a tunnel that
lives in t->net.
Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in
net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is
skipped when the link netns is dev_net(dev), where the rtnl path already
checked it. The other patches in this series use the same helper.
Gate ipgre_changelink() and erspan_changelink() with it, at the top of
the op before any attribute is parsed, because the parsers update live
tunnel fields first. ipgre_netlink_parms() sets t->collect_md before
ip_tunnel_changelink() runs.
Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in
vti6_siocdevprivate().") added the same check on the ioctl path. This
adds it on RTM_NEWLINK. |
| In the Linux kernel, the following vulnerability has been resolved:
keys: Pin request_key_auth payload in instantiate paths
A: request_key() B: KEYCTL_INSTANTIATE_IOV
================ =========================
create auth key
store rka in auth key
wait for helper
get auth key
load rka from auth key
copy user payload
sleep on #PF
helper completed
detach and free rka
destroy auth key
wake up
use rka->target_key
**USE-AFTER-FREE**
Give request_key_auth payloads a refcount. Take a payload reference while
authkey->sem stabilizes the payload and revocation state. Hold that
reference across the instantiate and reject paths. Drop the auth key
owning reference from revoke and destroy.
[jarkko: Replaced the first two paragraphs of text with an actual
concurrency scenario.] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: use kvfree() for replaced sysctl write buffer
proc_sys_call_handler() allocates its temporary sysctl buffer with
kvzalloc() and passes it to __cgroup_bpf_run_filter_sysctl(). Since
kvzalloc() may fall back to vmalloc() for large allocations, freeing
that buffer with kfree() is wrong and can corrupt memory.
Use kvfree() to safely handle both kmalloc and kvzalloc()/vmalloc
allocations.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1-rc5.
Reproduced the bug based on v7.1-rc4 in a QEMU x86_64 guest booted with
KASAN and CONFIG_FAILSLAB enabled. To exercise the replacement path, the
test tree also included the accompanying fix for the stale ret == 1
check in __cgroup_bpf_run_filter_sysctl(). The reproducer confines
failslab injections to the proc_sys_call_handler() range, uses
stacktrace-depth=32, and injects fail-nth=1 while writing 8191 bytes to
/proc/sys/kernel/domainname from a task in the target cgroup. Under
that setup, fail-nth=1 triggered the fault:
BUG: unable to handle page fault for address: ffffeb0200024d48
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 SMP KASAN NOPTI
CPU: 2 UID: 0 PID: 209 Comm: repro_proc_sys_ Not tainted 7.1.0-rc4-00686-g97625979a5d4 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:kfree+0x6e/0x510
...
Call Trace:
<TASK>
? __cgroup_bpf_run_filter_sysctl+0x626/0xc30
__cgroup_bpf_run_filter_sysctl+0x74d/0xc30
? __pfx___cgroup_bpf_run_filter_sysctl+0x10/0x10
? srso_return_thunk+0x5/0x5f
? __kvmalloc_node_noprof+0x345/0x870
? proc_sys_call_handler+0x250/0x480
? srso_return_thunk+0x5/0x5f
proc_sys_call_handler+0x3a2/0x480
? __pfx_proc_sys_call_handler+0x10/0x10
? srso_return_thunk+0x5/0x5f
? selinux_file_permission+0x39f/0x500
? srso_return_thunk+0x5/0x5f
? lock_is_held_type+0x9e/0x120
vfs_write+0x98e/0x1000
...
</TASK>
With this fix applied on top of the same test setup, rerunning the
reproducer with fail-nth=1 yields no corresponding Oops reports. |
| In the Linux kernel, the following vulnerability has been resolved:
exfat: fix potential use-after-free in exfat_find_dir_entry()
In exfat_find_dir_entry(), the buffer_head obtained from
exfat_get_dentry() is released with brelse(bh) before the fall-through
TYPE_EXTEND branch reads the directory entry through ep (which points
into bh->b_data):
brelse(bh);
if (entry_type == TYPE_EXTEND) {
...
len = exfat_extract_uni_name(ep, entry_uniname);
...
}
After brelse() drops our reference, nothing guarantees that the
underlying page backing bh->b_data remains valid for the subsequent
exfat_extract_uni_name() read. This is the same pattern fixed in
commit fc961522ddbd ("exfat: Fix potential use after free in
exfat_load_upcase_table()").
Move brelse(bh) so it runs after ep is no longer dereferenced on
each branch.
Confirmed on QEMU x86_64 with CONFIG_KASAN=y + CONFIG_DEBUG_PAGEALLOC=y
+ CONFIG_PAGE_POISONING=y on linux-next, using a crafted exFAT image
(long filename with same-hash collisions forcing the TYPE_EXTEND path).
With a debug-only invalidate_bdev() inserted between brelse(bh) and
the ep read to make the stale-deref window deterministic, the
unpatched kernel faults:
BUG: KASAN: use-after-free in exfat_find_dir_entry+0x133b/0x15a0
BUG: unable to handle page fault for address: ffff88801a5fa0c2
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
RIP: 0010:exfat_find_dir_entry+0x1188/0x15a0
With this patch applied, the same instrumented harness completes
cleanly under the same sanitizer stack. I have not reproduced a
crash on an uninstrumented kernel under ordinary reclaim; the
instrumented A/B establishes the lifetime violation and that the
patch closes it, not an unaided triggerability claim. |
| 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:
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:
blk-cgroup: fix UAF in __blkcg_rstat_flush()
When multiple blkgs in the same blkcg are released concurrently,
a use-after-free can occur. The race happens when one blkg's
__blkcg_rstat_flush() removes another blkg's iostat entries via
llist_del_all(). The second blkg sees an empty list and proceeds
to free itself while the first is still iterating over its entries.
Move the flush from __blkg_release() (RCU callback) to blkg_release()
(before call_rcu). This ensures the RCU grace period waits for any
concurrent flush's rcu_read_lock() section to complete before freeing. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: release layout stid on setlease failure
nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via
idr_alloc_cyclic() under cl_lock before returning to
nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then
fails, the error path frees the layout stateid directly with
kmem_cache_free() without ever calling idr_remove(), leaving the
IDR slot pointing at freed slab memory. Any subsequent IDR walker
(states_show, client teardown) dereferences the dangling pointer.
The correct teardown for an IDR-published stid is nfs4_put_stid(),
which removes the IDR slot under cl_lock, dispatches sc_free
(nfsd4_free_layout_stateid) to release ls->ls_file via
nfsd4_close_layout(), and drops the nfs4_file reference in its
tail.
A second issue blocks that switch: nfsd4_free_layout_stateid()
unconditionally inspects ls->ls_fence_work via
delayed_work_pending() under ls_lock, but
INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only
after the setlease call. On the setlease-failure path the
destructor would touch an uninitialized delayed_work.
nfsd4_alloc_layout_stateid()
nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */
nfsd4_layout_setlease() /* fails */
nfs4_put_stid()
nfsd4_free_layout_stateid()
delayed_work_pending(&ls->ls_fence_work) /* needs INIT */
nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */
put_nfs4_file()
Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK
initialization above the nfsd4_layout_setlease() call, and replace
the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup
with a single nfs4_put_stid(stp). |
