CVE intelligence and bounded remediation
CVE-2022-48644 — Linux Linux Kernel security vulnerability
In the Linux kernel, the following vulnerability has been resolved: net/sched: taprio: avoid disabling offload when it was never enabled In an incredibly strange API design decision, qdisc->destroy() gets called even if qdisc->init() never succeeded, not exclusively since commit 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation"), but apparently also earlier (in the case of qdisc_create_dflt()). The taprio qdisc does not fully acknowledge this when it attempts full offload, because it starts off with q->flags = TAPRIO_FLAGS_INVALID in taprio_init(), then it replaces q->flags with TCA_TAPRIO_ATTR_FLAGS parsed from netlink (in taprio_change(), tail called from taprio_init()). But in taprio_destroy(), we call taprio_disable_offload(), and this determines what to do based on FULL_OFFLOAD_IS_ENABLED(q->flags). But looking at the implementation of FULL_OFFLOAD_IS_ENABLED() (a bitwise check of bit 1 in q->flags), it is invalid to call this macro on q->flags when it contains TAPRIO_FLAGS_INVALID, because that is set to U32_MAX, and therefore FULL_OFFLOAD_IS_ENABLED() will return true on an invalid set of flags. As a result, it is possible to crash the kernel if user space for…
- Severity
- Medium
- CVSS
- 5.5 (3.1)
- Published
- 2024-04-28
- CISA KEV
- Not currently listed
- Ecosystem
- linux/kernel
- Weaknesses
- CWE-476
Affected products
- linux / linux_kernel
- linux / linux_kernel / 6.0
Matched remediation archetype
Buffer bounds, memory safety, and memory corruption
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Check exposure
- Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
- Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
- Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.
Remediate safely
- Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
- Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
- Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.
Authoritative sources
Complete CVE record and remediation plan
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