CVE-2023-53338

Summary

In the Linux kernel, the following vulnerability has been resolved:

lwt: Fix return values of BPF xmit ops

BPF encap ops can return different types of positive values, such like NET_RX_DROP, NET_XMIT_CN, NETDEV_TX_BUSY, and so on, from function skb_do_redirect and bpf_lwt_xmit_reroute. At the xmit hook, such return values would be treated implicitly as LWTUNNEL_XMIT_CONTINUE in ip(6)_finish_output2. When this happens, skbs that have been freed would continue to the neighbor subsystem, causing use-after-free bug and kernel crashes.

To fix the incorrect behavior, skb_do_redirect return values can be simply discarded, the same as tc-egress behavior. On the other hand, bpf_lwt_xmit_reroute returns useful errors to local senders, e.g. PMTU information. Thus convert its return values to avoid the conflict with LWTUNNEL_XMIT_CONTINUE.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 67f8f2bae8e7ac72e09def2b667e44704c4d1ee1affected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < a97f221651fcdc891166e9bc270e3d9bfa5a0080affected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < e3f647e4b642f9f6d32795a16f92c116c138d2afaffected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 065d5f17096ec9161180e2c890afdff4dc6125f2affected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < d68c17402442f5f494a2c3ebde5cb82f6aa9160aaffected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 65583f9e070db7bece20710cfa2e3daeb0b831d9affected
LinuxLinux3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 29b22badb7a84b783e3a4fffca16f7768fb31205affected
LinuxLinux4.10affected
LinuxLinux0 < 4.10unaffected
LinuxLinux5.4.257 <= 5.4.*unaffected
LinuxLinux5.10.195 <= 5.10.*unaffected
LinuxLinux5.15.132 <= 5.15.*unaffected
LinuxLinux6.1.53 <= 6.1.*unaffected
LinuxLinux6.4.16 <= 6.4.*unaffected
LinuxLinux6.5.3 <= 6.5.*unaffected
LinuxLinux6.6 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References