Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: l2tp: prevent possible tunnel refcount underflow When a session is created, it sets a backpointer to its tunnel. When the session refcount drops to 0, l2tp_session_free drops the tunnel refcount if session->tunnel is non-NULL. However, session->tunnel is set in l2tp_session_create, before the tunnel refcount is incremented by l2tp_session_register, which leaves a small window where session->tunnel is non-NULL when the tunnel refcount hasn't been bumped. Moving the assignment to l2tp_session_register is trivial but l2tp_session_create calls l2tp_session_set_header_len which uses session->tunnel to get the tunnel's encap. Add an encap arg to l2tp_session_set_header_len to avoid using session->tunnel. If l2tpv3 sessions have colliding IDs, it is possible for l2tp_v3_session_get to race with l2tp_session_register and fetch a session which doesn't yet have session->tunnel set. Add a check for this case.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 3953ae7b218df4d1e544b98a393666f9ae58a78c before 98691b2e28a6c3dac0680914493d54c77f215755; affected 3953ae7b218df4d1e544b98a393666f9ae58a78c before f7415e60c25a6108cd7955a20b2e66b6251ffe02; affected 3953ae7b218df4d1e544b98a393666f9ae58a78c before 24256415d18695b46da06c93135f5b51c548b950; affected b102bfc2a90d14f342580285782a9a51c74f7369; affected 10c15ddabbcf888922adbdd44ca3fecf6eab19d9; affected 8d1c650d452c53fcb3f02a7b1d772741639f89a4; affected 12b5fb58ac993c24210cf8cbc72d407d3a4e6490; affected aef37401b467a0b1a9517c69924a1d66937e0789; affected 3.2.99 before 3.3; affected 3.16.54 before 3.17; affected 4.4.225 before 4.5; affected 4.9.225 before 4.10; affected 4.14.182 before 4.15 |
| Linux / Linux | affected 4.15; unaffected 0 before 4.15; unaffected 6.6.160 through 6.6.*; unaffected 6.11.3 through 6.11.*; unaffected 6.12 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/98691b2e28a6c3dac0680914493d54c77f215755
- https://git.kernel.org/stable/c/f7415e60c25a6108cd7955a20b2e66b6251ffe02
- https://git.kernel.org/stable/c/24256415d18695b46da06c93135f5b51c548b950
ADP enrichment
No English description supplied.
No references supplied.