CVE-2023-53516

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF<br /> <br /> The previous commit 954d1fa1ac93 ("macvlan: Add netlink attribute for<br /> broadcast cutoff") added one additional attribute named<br /> IFLA_MACVLAN_BC_CUTOFF to allow broadcast cutfoff.<br /> <br /> However, it forgot to describe the nla_policy at macvlan_policy<br /> (drivers/net/macvlan.c). Hence, this suppose NLA_S32 (4 bytes) integer<br /> can be faked as empty (0 bytes) by a malicious user, which could leads<br /> to OOB in heap just like CVE-2023-3773.<br /> <br /> To fix it, this commit just completes the nla_policy description for<br /> IFLA_MACVLAN_BC_CUTOFF. This enforces the length check and avoids the<br /> potential OOB read.