Security Vulnerabilities
- CVEs Published In May 2024
In the Linux kernel, the following vulnerability has been resolved:
net: mctp: take ownership of skb in mctp_local_output
Currently, mctp_local_output only takes ownership of skb on success, and
we may leak an skb if mctp_local_output fails in specific states; the
skb ownership isn't transferred until the actual output routing occurs.
Instead, make mctp_local_output free the skb on all error paths up to
the route action, so it always consumes the passed skb.
In the Linux kernel, the following vulnerability has been resolved:
netrom: Fix data-races around sysctl_net_busy_read
We need to protect the reader reading the sysctl value because the
value can be changed concurrently.
In the Linux kernel, the following vulnerability has been resolved:
power: supply: bq27xxx-i2c: Do not free non existing IRQ
The bq27xxx i2c-client may not have an IRQ, in which case
client->irq will be 0. bq27xxx_battery_i2c_probe() already has
an if (client->irq) check wrapping the request_threaded_irq().
But bq27xxx_battery_i2c_remove() unconditionally calls
free_irq(client->irq) leading to:
[ 190.310742] ------------[ cut here ]------------
[ 190.310843] Trying to free already-free IRQ 0
[ 190.310861] WARNING: CPU: 2 PID: 1304 at kernel/irq/manage.c:1893 free_irq+0x1b8/0x310
Followed by a backtrace when unbinding the driver. Add
an if (client->irq) to bq27xxx_battery_i2c_remove() mirroring
probe() to fix this.
In the Linux kernel, the following vulnerability has been resolved:
efi/capsule-loader: fix incorrect allocation size
gcc-14 notices that the allocation with sizeof(void) on 32-bit architectures
is not enough for a 64-bit phys_addr_t:
drivers/firmware/efi/capsule-loader.c: In function 'efi_capsule_open':
drivers/firmware/efi/capsule-loader.c:295:24: error: allocation of insufficient size '4' for type 'phys_addr_t' {aka 'long long unsigned int'} with size '8' [-Werror=alloc-size]
295 | cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL);
| ^
Use the correct type instead here.
In the Linux kernel, the following vulnerability has been resolved:
rtnetlink: fix error logic of IFLA_BRIDGE_FLAGS writing back
In the commit d73ef2d69c0d ("rtnetlink: let rtnl_bridge_setlink checks
IFLA_BRIDGE_MODE length"), an adjustment was made to the old loop logic
in the function `rtnl_bridge_setlink` to enable the loop to also check
the length of the IFLA_BRIDGE_MODE attribute. However, this adjustment
removed the `break` statement and led to an error logic of the flags
writing back at the end of this function.
if (have_flags)
memcpy(nla_data(attr), &flags, sizeof(flags));
// attr should point to IFLA_BRIDGE_FLAGS NLA !!!
Before the mentioned commit, the `attr` is granted to be IFLA_BRIDGE_FLAGS.
However, this is not necessarily true fow now as the updated loop will let
the attr point to the last NLA, even an invalid NLA which could cause
overflow writes.
This patch introduces a new variable `br_flag` to save the NLA pointer
that points to IFLA_BRIDGE_FLAGS and uses it to resolve the mentioned
error logic.
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.
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Fixed overflow check in mi_enum_attr()
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.
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.
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.