Security Vulnerabilities - CVEs Published In May 2024
In the Linux kernel, the following vulnerability has been resolved:
netfilter: bridge: confirm multicast packets before passing them up the stack
conntrack nf_confirm logic cannot handle cloned skbs referencing
the same nf_conn entry, which will happen for multicast (broadcast)
frames on bridges.
Example:
macvlan0
|
br0
/ \
ethX ethY
ethX (or Y) receives a L2 multicast or broadcast packet containing
an IP packet, flow is not yet in conntrack table.
1. skb passes through bridge and fake-ip (br_netfilter)Prerouting.
-> skb->_nfct now references a unconfirmed entry
2. skb is broad/mcast packet. bridge now passes clones out on each bridge
interface.
3. skb gets passed up the stack.
4. In macvlan case, macvlan driver retains clone(s) of the mcast skb
and schedules a work queue to send them out on the lower devices.
The clone skb->_nfct is not a copy, it is the same entry as the
original skb. The macvlan rx handler then returns RX_HANDLER_PASS.
5. Normal conntrack hooks (in NF_INET_LOCAL_IN) confirm the orig skb.
The Macvlan broadcast worker and normal confirm path will race.
This race will not happen if step 2 already confirmed a clone. In that
case later steps perform skb_clone() with skb->_nfct already confirmed (in
hash table). This works fine.
But such confirmation won't happen when eb/ip/nftables rules dropped the
packets before they reached the nf_confirm step in postrouting.
Pablo points out that nf_conntrack_bridge doesn't allow use of stateful
nat, so we can safely discard the nf_conn entry and let inet call
conntrack again.
This doesn't work for bridge netfilter: skb could have a nat
transformation. Also bridge nf prevents re-invocation of inet prerouting
via 'sabotage_in' hook.
Work around this problem by explicit confirmation of the entry at LOCAL_IN
time, before upper layer has a chance to clone the unconfirmed entry.
The downside is that this disables NAT and conntrack helpers.
Alternative fix would be to add locking to all code parts that deal with
unconfirmed packets, but even if that could be done in a sane way this
opens up other problems, for example:
-m physdev --physdev-out eth0 -j SNAT --snat-to 1.2.3.4
-m physdev --physdev-out eth1 -j SNAT --snat-to 1.2.3.5
For multicast case, only one of such conflicting mappings will be
created, conntrack only handles 1:1 NAT mappings.
Users should set create a setup that explicitly marks such traffic
NOTRACK (conntrack bypass) to avoid this, but we cannot auto-bypass
them, ruleset might have accept rules for untracked traffic already,
so user-visible behaviour would change.
CVSS Score
4.7
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Fixed overflow check in mi_enum_attr()
CVSS Score
8.4
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
CVSS Score
4.7
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: dw-edma: HDMA: Add sync read before starting the DMA transfer in remote setup
The Linked list element and pointer are not stored in the same memory as
the HDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: reject iftype change with mesh ID change
It's currently possible to change the mesh ID when the
interface isn't yet in mesh mode, at the same time as
changing it into mesh mode. This leads to an overwrite
of data in the wdev->u union for the interface type it
currently has, causing cfg80211_change_iface() to do
wrong things when switching.
We could probably allow setting an interface to mesh
while setting the mesh ID at the same time by doing a
different order of operations here, but realistically
there's no userspace that's going to do this, so just
disallow changes in iftype when setting mesh ID.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: keep DMA buffers required for suspend/resume
Nouveau deallocates a few buffers post GPU init which are required for GPU suspend/resume to function correctly.
This is likely not as big an issue on systems where the NVGPU is the only GPU, but on multi-GPU set ups it leads to a regression where the kernel module errors and results in a system-wide rendering freeze.
This commit addresses that regression by moving the two buffers required for suspend and resume to be deallocated at driver unload instead of post init.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_flow_offload: reset dst in route object after setting up flow
dst is transferred to the flow object, route object does not own it
anymore. Reset dst in route object, otherwise if flow_offload_add()
fails, error path releases dst twice, leading to a refcount underflow.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
mptcp: fix data races on remote_id
Similar to the previous patch, address the data race on
remote_id, adding the suitable ONCE annotations.
CVSS Score
4.7
EPSS Score
0.0
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs
It is observed sometimes when tethering is used over NCM with Windows 11
as host, at some instances, the gadget_giveback has one byte appended at
the end of a proper NTB. When the NTB is parsed, unwrap call looks for
any leftover bytes in SKB provided by u_ether and if there are any pending
bytes, it treats them as a separate NTB and parses it. But in case the
second NTB (as per unwrap call) is faulty/corrupt, all the datagrams that
were parsed properly in the first NTB and saved in rx_list are dropped.
Adding a few custom traces showed the following:
[002] d..1 7828.532866: dwc3_gadget_giveback: ep1out:
req 000000003868811a length 1025/16384 zsI ==> 0
[002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb toprocess: 1025
[002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb seq: 0xce67
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x400
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb ndp_len: 0x10
[002] d..1 7828.532869: ncm_unwrap_ntb: K: Parsed NTB with 1 frames
In this case, the giveback is of 1025 bytes and block length is 1024.
The rest 1 byte (which is 0x00) won't be parsed resulting in drop of
all datagrams in rx_list.
Same is case with packets of size 2048:
[002] d..1 7828.557948: dwc3_gadget_giveback: ep1out:
req 0000000011dfd96e length 2049/16384 zsI ==> 0
[002] d..1 7828.557949: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342
[002] d..1 7828.557950: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x800
Lecroy shows one byte coming in extra confirming that the byte is coming
in from PC:
Transfer 2959 - Bytes Transferred(1025) Timestamp((18.524 843 590)
- Transaction 8391 - Data(1025 bytes) Timestamp(18.524 843 590)
--- Packet 4063861
Data(1024 bytes)
Duration(2.117us) Idle(14.700ns) Timestamp(18.524 843 590)
--- Packet 4063863
Data(1 byte)
Duration(66.160ns) Time(282.000ns) Timestamp(18.524 845 722)
According to Windows driver, no ZLP is needed if wBlockLength is non-zero,
because the non-zero wBlockLength has already told the function side the
size of transfer to be expected. However, there are in-market NCM devices
that rely on ZLP as long as the wBlockLength is multiple of wMaxPacketSize.
To deal with such devices, it pads an extra 0 at end so the transfer is no
longer multiple of wMaxPacketSize.
CVSS Score
7.5
EPSS Score
0.002
Published
2024-05-17
In the Linux kernel, the following vulnerability has been resolved:
lib/Kconfig.debug: TEST_IOV_ITER depends on MMU
Trying to run the iov_iter unit test on a nommu system such as the qemu
kc705-nommu emulation results in a crash.
KTAP version 1
# Subtest: iov_iter
# module: kunit_iov_iter
1..9
BUG: failure at mm/nommu.c:318/vmap()!
Kernel panic - not syncing: BUG!
The test calls vmap() directly, but vmap() is not supported on nommu
systems, causing the crash. TEST_IOV_ITER therefore needs to depend on
MMU.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-17