Fix CVE-2021-43784: runc is a CLI tool for spawning and running
containers on Linux according to the OCI specification. In runc, netlink
is used internally as a serialization system for specifying the relevant
container configuration to the `C` portion of the code (responsible for
the based namespace setup of containers). In all versions of runc prior
to 1.0.3, the encoder did not handle the possibility of an integer
overflow in the 16-bit length field for the byte array attribute type,
meaning that a large enough malicious byte array attribute could result
in the length overflowing and the attribute contents being parsed as
netlink messages for container configuration. This vulnerability
requires the attacker to have some control over the configuration of the
container and would allow the attacker to bypass the namespace
restrictions of the container by simply adding their own netlink payload
which disables all namespaces. The main users impacted are those who
allow untrusted images with untrusted configurations to run on their
machines (such as with shared cloud infrastructure). runc version 1.0.3
contains a fix for this bug. As a workaround, one may try disallowing
untrusted namespace paths from your container. It should be noted that
untrusted namespace paths would allow the attacker to disable namespace
protections entirely even in the absence of this bug.
https://github.com/opencontainers/runc/releases/tag/v1.0.3
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
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