CVE-2024-35894

Summary

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

mptcp: prevent BPF accessing lowat from a subflow socket.

Alexei reported the following splat:

WARNING: CPU: 32 PID: 3276 at net/mptcp/subflow.c:1430 subflow_data_ready+0x147/0x1c0 Modules linked in: dummy bpf_testmod(O) [last unloaded: bpf_test_no_cfi(O)] CPU: 32 PID: 3276 Comm: test_progs Tainted: GO 6.8.0-12873-g2c43c33bfd23 Call Trace: <TASK> mptcp_set_rcvlowat+0x79/0x1d0 sk_setsockopt+0x6c0/0x1540 __bpf_setsockopt+0x6f/0x90 bpf_sock_ops_setsockopt+0x3c/0x90 bpf_prog_509ce5db2c7f9981_bpf_test_sockopt_int+0xb4/0x11b bpf_prog_dce07e362d941d2b_bpf_test_socket_sockopt+0x12b/0x132 bpf_prog_348c9b5faaf10092_skops_sockopt+0x954/0xe86 __cgroup_bpf_run_filter_sock_ops+0xbc/0x250 tcp_connect+0x879/0x1160 tcp_v6_connect+0x50c/0x870 mptcp_connect+0x129/0x280 __inet_stream_connect+0xce/0x370 inet_stream_connect+0x36/0x50 bpf_trampoline_6442491565+0x49/0xef inet_stream_connect+0x5/0x50 __sys_connect+0x63/0x90 __x64_sys_connect+0x14/0x20

The root cause of the issue is that bpf allows accessing mptcp-level proto_ops from a tcp subflow scope.

Fix the issue detecting the problematic call and preventing any action.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux124a4885b55f3039c697feb53edc5ad88bf21161 < ee3c845787b621cfe82c2e52c513024a9d7a78f5affected
LinuxLinux5684ab1a0effbfeb706f47d85785f653005b97b1 < 3ffb1ab698376f09cc33101c07c1be229389fe29affected
LinuxLinux5684ab1a0effbfeb706f47d85785f653005b97b1 < fcf4692fa39e86a590c14a4af2de704e1d20a3b5affected
LinuxLinux6.7affected
LinuxLinux0 < 6.7unaffected
LinuxLinux6.8.5 <= 6.8.*unaffected
LinuxLinux6.9 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

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

CVE Program Container

Additional References

References