| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate compound request size before reading StructureSize2
When ksmbd validates a compound (chained) SMB2 request,
ksmbd_smb2_check_message() reads pdu->StructureSize2 without first
checking that the compound element is large enough to contain it.
StructureSize2 is a 2-byte field at offset 64
(__SMB2_HEADER_STRUCTURE_SIZE) from the start of each element.
The compound-walking logic only guarantees that a full 64-byte SMB2
header is present for the trailing element: when NextCommand is 0, len is
reduced to the number of bytes remaining after next_smb2_rcv_hdr_off. A
remote client can craft a compound request whose last element has exactly
64 bytes, so the 2-byte StructureSize2 read at offset 64 extends one byte
past the receive buffer, producing a slab-out-of-bounds read.
BUG: KASAN: slab-out-of-bounds in ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402)
Read of size 2 at addr ffff888012ae31ac by task kworker/0:1/14
The buggy address is located 172 bytes inside of allocated 173-byte region
Workqueue: ksmbd-io handle_ksmbd_work
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402)
handle_ksmbd_work (fs/smb/server/server.c:119)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
Reject any compound element that is too small to hold StructureSize2
before dereferencing it. |
| In the Linux kernel, the following vulnerability has been resolved:
gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its
caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +
gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For
a 16-19 byte echo request the pull fails and returns NULL without
advancing skb->data; execution continues, and the following skb_push()
plus the IP header pushed by iptunnel_xmit() move skb->data below
skb->head, tripping skb_under_panic().
Fix it by dropping the packet when skb_pull_data() fails.
skbuff: skb_under_panic: ...
kernel BUG at net/core/skbuff.c:214!
Call Trace:
skb_push (net/core/skbuff.c:2648)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)
gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)
udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)
...
Kernel panic - not syncing: Fatal exception in interrupt |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: tcp: fix double sock release on batch realloc
bpf_iter_tcp_batch() releases the current batch via
bpf_iter_tcp_put_batch(), which drops the socket refs and rewrites
each slot with the socket cookie, then grows the batch. cur_sk/end_sk
are kept for bpf_iter_tcp_resume(), but on realloc failure the function
returns ERR_PTR() before resume runs, leaving cur_sk < end_sk over
slots that now hold cookies rather than sock pointers.
bpf_iter_tcp_seq_stop() then calls bpf_iter_tcp_put_batch() again and
dereferences a cookie as a struct sock.
Empty the batch on the failure path so stop() does not release it
again. The sockets were already freed by the first
bpf_iter_tcp_put_batch(), so nothing leaks, and a later read() rescans
the bucket from the start instead of skipping it. The sibling
GFP_NOWAIT failure path still holds real socket references and is left
for stop() to release.
BUG: KASAN: null-ptr-deref in __sock_gen_cookie
Read of size 8 at addr 0000000000000059 by task exploit
...
__sock_gen_cookie (net/core/sock_diag.c:28)
bpf_iter_tcp_put_batch (net/ipv4/tcp_ipv4.c:2918)
bpf_iter_tcp_seq_stop (net/ipv4/tcp_ipv4.c:3270)
bpf_seq_read (kernel/bpf/bpf_iter.c:205)
vfs_read (fs/read_write.c:572)
ksys_read (fs/read_write.c:716)
do_syscall_64
entry_SYSCALL_64_after_hwframe
Kernel panic - not syncing: Fatal exception |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: qca: fix NVM tag length underflow in TLV parser
In the TLV_TYPE_NVM branch of qca_tlv_check_data() the tag loop bound is
"while (idx < length - sizeof(struct tlv_type_nvm))". "length" is a signed
int from the firmware TLV header and sizeof(struct tlv_type_nvm) is a
size_t (12), so "length" is converted to size_t and any firmware-supplied
"length" < 12 makes the subtraction wrap to a huge value. The loop body
then reads a 12-byte struct tlv_type_nvm past the end of the short
vmalloc'd firmware buffer (and the EDL_TAG_ID_* handlers can write past it).
Rewrite the bound as "idx + sizeof(struct tlv_type_nvm) <= length"; both
operands are non-negative, so it no longer underflows and a "length" too
small for one record correctly skips the loop.
BUG: KASAN: vmalloc-out-of-bounds in qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421)
Read of size 2 at addr ffffc900000e5004 by task kworker/u9:0/52
Workqueue: hci0 hci_power_on
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421 drivers/bluetooth/btqca.c:617)
qca_uart_setup (drivers/bluetooth/btqca.c:948)
qca_setup (drivers/bluetooth/hci_qca.c:2029)
hci_uart_setup (drivers/bluetooth/hci_ldisc.c:438)
hci_dev_open_sync (net/bluetooth/hci_sync.c:5227)
hci_power_on (net/bluetooth/hci_core.c:920)
process_one_work (kernel/workqueue.c:3322)
worker_thread (kernel/workqueue.c:3486)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245) |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: fib: free fib_alias with kfree_rcu() on insert error path
fib_table_insert() publishes new_fa into the leaf's fa_list with
fib_insert_alias() before calling the fib entry notifiers. When a
notifier fails, the error path removes new_fa with fib_remove_alias()
(hlist_del_rcu) and frees it right away with kmem_cache_free().
fib_table_lookup() walks that list under rcu_read_lock() only, so a
concurrent lookup that already reached new_fa keeps reading it after the
free:
BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601)
Read of size 1 at addr ffff88810676d4eb by task exploit/297
Call Trace:
fib_table_lookup (net/ipv4/fib_trie.c:1601)
ip_route_output_key_hash_rcu (net/ipv4/route.c:2814)
ip_route_output_key_hash (net/ipv4/route.c:2705)
__ip4_datagram_connect (net/ipv4/datagram.c:49)
udp_connect (net/ipv4/udp.c:2144)
__sys_connect (net/socket.c:2167)
__x64_sys_connect (net/socket.c:2173)
do_syscall_64
entry_SYSCALL_64_after_hwframe
which belongs to the cache ip_fib_alias of size 56
Triggering the error path needs CAP_NET_ADMIN and a registered fib
notifier that can reject a route; a netdevsim device whose IPv4 FIB
resource is exhausted is enough.
Free new_fa with alias_free_mem_rcu(), as fib_table_delete() already
does for a fib_alias removed from the trie. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: p54: validate RX frame length in p54_rx_eeprom_readback()
p54_rx_eeprom_readback() copies the requested EEPROM slice out of a
device-supplied readback frame without checking that the skb actually holds
that many bytes. Commit da1b9a55ff11 ("wifi: p54: prevent buffer-overflow in
p54_rx_eeprom_readback()") closed the destination overflow by copying a
fixed priv->eeprom_slice_size (and rejecting a mismatched advertised len),
but the source side is still unbounded: nothing verifies the frame is long
enough to supply that many bytes.
A malicious USB device can send a short frame whose advertised len matches
priv->eeprom_slice_size while the payload is truncated. The equality check
passes and memcpy() reads past the end of the skb, leaking adjacent heap:
BUG: KASAN: slab-out-of-bounds in p54_rx (drivers/net/wireless/intersil/p54/txrx.c:507)
Read of size 1016 at addr ffff88800f077114 by task swapper/0/0
Call Trace:
<IRQ>
...
__asan_memcpy (mm/kasan/shadow.c:105)
p54_rx (drivers/net/wireless/intersil/p54/txrx.c:507)
p54u_rx_cb (drivers/net/wireless/intersil/p54/p54usb.c:163)
__usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657)
dummy_timer (drivers/usb/gadget/udc/dummy_hcd.c:2005)
...
</IRQ>
The buggy address belongs to the object at ffff88800f0770c0
which belongs to the cache skbuff_small_head of size 704
The buggy address is located 84 bytes inside of
allocated 704-byte region [ffff88800f0770c0, ffff88800f077380)
Check that the slice fits in the skb before copying. |
| In the Linux kernel, the following vulnerability has been resolved:
mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n
On CONFIG_INET=n builds, mpls_valid_fib_dump_req() walks the parsed
attribute table itself instead of calling ip_valid_fib_dump_req(). The
RTA_OIF arm passes tb[RTA_OIF] to nla_get_u32() without checking it is
present, so an RTM_GETROUTE dump for AF_MPLS with strict checking and no
RTA_OIF hits a NULL dereference.
RTM_GETROUTE is RTNL_KIND_GET, which rtnetlink_rcv_msg() permits without
CAP_NET_ADMIN, so an unprivileged user can trigger it.
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:mpls_valid_fib_dump_req (net/mpls/af_mpls.c:2189)
Call Trace:
mpls_dump_routes (net/mpls/af_mpls.c:2236)
netlink_dump (net/netlink/af_netlink.c:2331)
__netlink_dump_start (net/netlink/af_netlink.c:2446)
rtnetlink_rcv_msg (net/core/rtnetlink.c:7033)
netlink_rcv_skb (net/netlink/af_netlink.c:2556)
netlink_unicast (net/netlink/af_netlink.c:1345)
netlink_sendmsg (net/netlink/af_netlink.c:1900)
__sock_sendmsg (net/socket.c:790)
____sys_sendmsg (net/socket.c:2684)
___sys_sendmsg (net/socket.c:2738)
__sys_sendmsg (net/socket.c:2770)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Skip unset attributes, as ip_valid_fib_dump_req() does. |
| In the Linux kernel, the following vulnerability has been resolved:
Input: ims-pcu - fix heap-buffer-overflow in ims_pcu_process_data()
The `ims_pcu_process_data()` processes incoming URB data byte by byte.
However, it fails to check if the `read_pos` index exceeds
IMS_PCU_BUF_SIZE.
If a malicious USB device sends a packet larger than IMS_PCU_BUF_SIZE,
`read_pos` will increment indefinitely. Moreover, since `read_pos` is
located immediately after `read_buf`, the attacker can overwrite
`read_pos` itself to arbitrarily control the index.
This manipulated `read_pos` is subsequently used in
`ims_pcu_handle_response()` to copy data into `cmd_buf`, leading to a
heap buffer overflow.
Specifically, an attacker can overwrite the `cmd_done.wait.head` located
at offset 136 relative to `cmd_buf` in the `ims_pcu_handle_response()`.
Consequently, when the driver calls `complete(&pcu->cmd_done)`, it
triggers a control flow hijack by using the manipulated pointer.
Fix this by adding a bounds check for `read_pos` before writing to
`read_buf`. If the packet is too long, discard it, log a warning,
and reset the parser state.
[dtor: factor out resetting packet state, reset checksum as well] |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: don't free the ASCONF's own transport in DEL-IP processing
sctp_process_asconf() caches the transport the ASCONF chunk is processed
against in asconf->transport (== chunk->transport, set once in sctp_rcv()).
For an ASCONF located through its Address Parameter by
__sctp_rcv_asconf_lookup(), that cached transport corresponds to the
Address Parameter, which need not be the packet's source address.
sctp_process_asconf_param() rejects a DEL-IP for the packet source address
(ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport.
A single ASCONF can therefore carry, in order:
[Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0]
where L differs from the source. The DEL-IP for L passes the D8 check and
calls sctp_assoc_rm_peer() on the transport that asconf->transport still
points at, freeing it (RCU-deferred). The following wildcard DEL-IP then
reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and
sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed
transport (->ipaddr, ->state) and plants the dangling pointer into
asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping
only the pointer that is no longer on the list, removes every real
transport, leaving the association with a transport_count of 0 and
primary_path/active_path pointing at freed memory.
Reject a DEL-IP that targets the transport the ASCONF is being processed
against, mirroring the existing source-address guard, so the wildcard
branch can never reuse a freed transport. |
| In the Linux kernel, the following vulnerability has been resolved:
rhashtable: clear stale iter->p on table restart
rhashtable_walk_start_check() has two restart paths when resuming a walk.
When iter->walker.tbl is valid, it re-validates iter->p against the table
and sets iter->p = NULL if the object is gone. When iter->walker.tbl is
NULL (table was freed during resize), it resets slot and skip but forgets
to clear iter->p.
rhashtable_walk_next() then dereferences the stale iter->p, reading
freed memory. This is a use-after-free.
Any caller that does multi-fragment rhashtable walks across
walk_stop/walk_start boundaries is affected. Concrete cases include
netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC
(tipc_nl_sk_walk in net/tipc/socket.c).
Crash stack (netlink_diag):
BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0
Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)
Call Trace:
rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)
__netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)
netlink_diag_dump+0xc2/0x240
netlink_dump+0x5bc/0x1270
netlink_recvmsg+0x7a3/0x980
sock_recvmsg+0x1bc/0x200
__sys_recvfrom+0x1d4/0x2c0 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Hide shadow VMCS right after VMCLEAR
free_nested() frees the shadow VMCS while vmcs01 still points to it. But
because it is asynchronous with respect to loaded_vmcs_clear(), the vCPU
might migrate before the pointer is cleared and __loaded_vmcs_clear()
may then execute VMCLEAR.
The VMCS needs to stay attached until its explicit VMCLEAR completes, but
then it can be hidden and the page safely freed. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: ndisc: fix NULL deref in accept_untracked_na()
accept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev)
and dereferences idev->cnf.accept_untracked_na without a NULL check,
even though its only caller ndisc_recv_na() already fetched and
NULL-checked idev for the same device.
Both reads of dev->ip6_ptr run in the same RCU read-side critical
section, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr
between them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown()
without the synchronize_net() that orders the unregister path, so the
re-fetch returns NULL and oopses:
BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974)
Read of size 4 at addr 0000000000000364
Call Trace:
<IRQ>
ndisc_recv_na (net/ipv6/ndisc.c:974)
icmpv6_rcv (net/ipv6/icmp.c:1193)
ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479)
ip6_input_finish (net/ipv6/ip6_input.c:534)
ip6_input (net/ipv6/ip6_input.c:545)
ip6_mc_input (net/ipv6/ip6_input.c:635)
ipv6_rcv (net/ipv6/ip6_input.c:351)
</IRQ>
It is reachable by an unprivileged user via a network namespace.
Pass the caller's already validated idev instead of re-fetching it; the
idev stays alive for the whole RCU critical section, so it is safe even
after dev->ip6_ptr has been cleared. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Support for hardening against JIT spraying
The BPF JIT allocator packs many small programs into larger executable
allocations and reuses space within those allocations as programs are
loaded and freed. When fresh code is written into space that a previous
program occupied, an indirect jump into the new program can reuse a branch
prediction left behind by the old one.
Flush the indirect branch predictors before reusing JIT memory so that
indirect jumps into a newly written program don't reuse predictions from an
old program that occupied the same space.
Introduce bpf_arch_pred_flush_enabled static key and bpf_arch_pred_flush
static call for flushing the branch predictors on JIT memory reuse.
Architectures that need a flush, can update it to a predictor flush
function. By default, its a NOP and does not emit any CALL.
Allocations larger than a pack are not covered by this flush. That is safe
because cBPF programs (the unprivileged attack surface) are bounded well
below a pack size. Issue a warning if this assumption is ever violated
while the flush is active. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/bugs: Enable IBPB flush on BPF JIT allocation
Enable hardening against JIT spraying when Spectre-v2 mitigations are in
use. Specifically, issue an IBPB flush on BPF JIT memory reuse. Skip
enabling the IBPB flush if the BPF dispatcher is already using a retpoline
sequence.
This hardening applies only when BPF-JIT is in use. Guard the enabling
under CONFIG_BPF_JIT so that bugs.c still builds with CONFIG_BPF_JIT=n. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix ld_{abs,ind} failure path analysis in subprogs
Usage of ld_{abs,ind} instructions got extended into subprogs some time
ago via commit 09b28d76eac4 ("bpf: Add abnormal return checks."). These
are only allowed in subprograms when the latter are BTF annotated and
have scalar return types.
The code generator in bpf_gen_ld_abs() has an abnormal exit path (r0=0 +
exit) from legacy cBPF times. While the enforcement is on scalar return
types, the verifier must also simulate the path of abnormal exit if the
packet data load via ld_{abs,ind} failed.
This is currently not the case. Fix it by having the verifier simulate
both success and failure paths, and extend it in similar ways as we do
for tail calls. The success path (r0=unknown, continue to next insn) is
pushed onto stack for later validation and the r0=0 and return to the
caller is done on the fall-through side. |
| In the Linux kernel, the following vulnerability has been resolved:
futex: Prevent lockup in requeue-PI during signal/ timeout wakeup
During wait-requeue-pi (task A) and requeue-PI (task B) the following
race can happen:
Task A Task B
futex_wait_requeue_pi()
futex_setup_timer()
futex_do_wait()
futex_requeue()
CLASS(hb, hb1)(&key1);
CLASS(hb, hb2)(&key2);
*timeout*
futex_requeue_pi_wakeup_sync()
requeue_state = Q_REQUEUE_PI_IGNORE
*blocks on hb->lock*
futex_proxy_trylock_atomic()
futex_requeue_pi_prepare()
Q_REQUEUE_PI_IGNORE => -EAGAIN
double_unlock_hb(hb1, hb2)
*retry*
Task B acquires both hb locks and attempts to acquire the PI-lock of the
top most waiter (task B). Task A is leaving early due to a signal/
timeout and started removing itself from the queue. It updates its
requeue_state but can not remove it from the list because this requires
the hb lock which is owned by task B.
Usually task A is able to swoop the lock after task B unlocked it.
However if task B is of higher priority then task A may not be able to
wake up in time and acquire the lock before task B gets it again.
Especially on a UP system where A is never scheduled.
As a result task A blocks on the lock and task B busy loops, trying to
make progress but live locks the system instead. Tragic.
This can be fixed by removing the top most waiter from the list in this
case. This allows task B to grab the next top waiter (if any) in the
next iteration and make progress.
Remove the top most waiter if futex_requeue_pi_prepare() fails.
Let the waiter conditionally remove itself from the list in
handle_early_requeue_pi_wakeup(). |
| In the Linux kernel, the following vulnerability has been resolved:
net: qrtr: ns: Limit the maximum server registration per node
Current code does no bound checking on the number of servers added per
node. A malicious client can flood NEW_SERVER messages and exhaust memory.
Fix this issue by limiting the maximum number of server registrations to
256 per node. If the NEW_SERVER message is received for an old port, then
don't restrict it as it will get replaced. While at it, also rate limit
the error messages in the failure path of qrtr_ns_worker().
Note that the limit of 256 is chosen based on the current platform
requirements. If requirement changes in the future, this limit can be
increased. |
| In the Linux kernel, the following vulnerability has been resolved:
af_unix: Give up GC if MSG_PEEK intervened.
Igor Ushakov reported that GC purged the receive queue of
an alive socket due to a race with MSG_PEEK with a nice repro.
This is the exact same issue previously fixed by commit
cbcf01128d0a ("af_unix: fix garbage collect vs MSG_PEEK").
After GC was replaced with the current algorithm, the cited
commit removed the locking dance in unix_peek_fds() and
reintroduced the same issue.
The problem is that MSG_PEEK bumps a file refcount without
interacting with GC.
Consider an SCC containing sk-A and sk-B, where sk-A is
close()d but can be recv()ed via sk-B.
The bad thing happens if sk-A is recv()ed with MSG_PEEK from
sk-B and sk-B is close()d while GC is checking unix_vertex_dead()
for sk-A and sk-B.
GC thread User thread
--------- -----------
unix_vertex_dead(sk-A)
-> true <------.
\
`------ recv(sk-B, MSG_PEEK)
invalidate !! -> sk-A's file refcount : 1 -> 2
close(sk-B)
-> sk-B's file refcount : 2 -> 1
unix_vertex_dead(sk-B)
-> true
Initially, sk-A's file refcount is 1 by the inflight fd in sk-B
recvq. GC thinks sk-A is dead because the file refcount is the
same as the number of its inflight fds.
However, sk-A's file refcount is bumped silently by MSG_PEEK,
which invalidates the previous evaluation.
At this moment, sk-B's file refcount is 2; one by the open fd,
and one by the inflight fd in sk-A. The subsequent close()
releases one refcount by the former.
Finally, GC incorrectly concludes that both sk-A and sk-B are dead.
One option is to restore the locking dance in unix_peek_fds(),
but we can resolve this more elegantly thanks to the new algorithm.
The point is that the issue does not occur without the subsequent
close() and we actually do not need to synchronise MSG_PEEK with
the dead SCC detection.
When the issue occurs, close() and GC touch the same file refcount.
If GC sees the refcount being decremented by close(), it can just
give up garbage-collecting the SCC.
Therefore, we only need to signal the race during MSG_PEEK with
a proper memory barrier to make it visible to the GC.
Let's use seqcount_t to notify GC when MSG_PEEK occurs and let
it defer the SCC to the next run.
This way no locking is needed on the MSG_PEEK side, and we can
avoid imposing a penalty on every MSG_PEEK unnecessarily.
Note that we can retry within unix_scc_dead() if MSG_PEEK is
detected, but we do not do so to avoid hung task splat from
abusive MSG_PEEK calls. |
| In the Linux kernel, the following vulnerability has been resolved:
exfat: validate cluster allocation bits of the allocation bitmap
syzbot created an exfat image with cluster bits not set for the allocation
bitmap. exfat-fs reads and uses the allocation bitmap without checking
this. The problem is that if the start cluster of the allocation bitmap
is 6, cluster 6 can be allocated when creating a directory with mkdir.
exfat zeros out this cluster in exfat_mkdir, which can delete existing
entries. This can reallocate the allocated entries. In addition,
the allocation bitmap is also zeroed out, so cluster 6 can be reallocated.
This patch adds exfat_test_bitmap_range to validate that clusters used for
the allocation bitmap are correctly marked as in-use. |
| In the Linux kernel, the following vulnerability has been resolved:
i40e: remove read access to debugfs files
The 'command' and 'netdev_ops' debugfs files are a legacy debugging
interface supported by the i40e driver since its early days by commit
02e9c290814c ("i40e: debugfs interface").
Both of these debugfs files provide a read handler which is mostly useless,
and which is implemented with questionable logic. They both use a static
256 byte buffer which is initialized to the empty string. In the case of
the 'command' file this buffer is literally never used and simply wastes
space. In the case of the 'netdev_ops' file, the last command written is
saved here.
On read, the files contents are presented as the name of the device
followed by a colon and then the contents of their respective static
buffer. For 'command' this will always be "<device>: ". For 'netdev_ops',
this will be "<device>: <last command written>". But note the buffer is
shared between all devices operated by this module. At best, it is mostly
meaningless information, and at worse it could be accessed simultaneously
as there doesn't appear to be any locking mechanism.
We have also recently received multiple reports for both read functions
about their use of snprintf and potential overflow that could result in
reading arbitrary kernel memory. For the 'command' file, this is definitely
impossible, since the static buffer is always zero and never written to.
For the 'netdev_ops' file, it does appear to be possible, if the user
carefully crafts the command input, it will be copied into the buffer,
which could be large enough to cause snprintf to truncate, which then
causes the copy_to_user to read beyond the length of the buffer allocated
by kzalloc.
A minimal fix would be to replace snprintf() with scnprintf() which would
cap the return to the number of bytes written, preventing an overflow. A
more involved fix would be to drop the mostly useless static buffers,
saving 512 bytes and modifying the read functions to stop needing those as
input.
Instead, lets just completely drop the read access to these files. These
are debug interfaces exposed as part of debugfs, and I don't believe that
dropping read access will break any script, as the provided output is
pretty useless. You can find the netdev name through other more standard
interfaces, and the 'netdev_ops' interface can easily result in garbage if
you issue simultaneous writes to multiple devices at once.
In order to properly remove the i40e_dbg_netdev_ops_buf, we need to
refactor its write function to avoid using the static buffer. Instead, use
the same logic as the i40e_dbg_command_write, with an allocated buffer.
Update the code to use this instead of the static buffer, and ensure we
free the buffer on exit. This fixes simultaneous writes to 'netdev_ops' on
multiple devices, and allows us to remove the now unused static buffer
along with removing the read access. |
