Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix slab-use-after-free in __inet_lookup_established The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot have their slab caches created with this flag via proto_register(). However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init() (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point, tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently. This causes MPTCP v6 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so when these sockets are freed without SOCK_RCU_FREE (which is cleared for child sockets by design), the memory can be immediately reused. Concurrent ehash lookups under rcu_read_lock can then access freed memory, triggering a slab-use-after-free in __inet_lookup_established. Fix this by splitting the IPv6-specific initialization out of mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called from mptcp_proto_v6_init() before protocol registration. This ensures tcpv6_prot_override.slab correctly inherits the SLAB_TYPESAFE_BY_RCU slab cache.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected b19bc2945b40b9fd38e835700907ffe8534ef0de before f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before fb1f54b7d16f393b8b65d328410f78b4beea8fcc; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before 3fd6547f5b8ac99687be6d937a0321efda760597; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before eb9c6aeb512f877cf397deb1e4526f646c70e4a7; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before 15fa9ead4d5e6b6b9c794e84144146c917f2cb62; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before b313e9037d98c13938740e5ebda7852929366dff; affected b19bc2945b40b9fd38e835700907ffe8534ef0de before 9b55b253907e7431210483519c5ad711a37dafa1 |
| Linux / Linux | affected 5.12; unaffected 0 before 5.12; unaffected 5.15.203 through 5.15.*; unaffected 6.1.169 through 6.1.*; unaffected 6.6.135 through 6.6.*; unaffected 6.12.82 through 6.12.*; unaffected 6.18.23 through 6.18.*; unaffected 6.19.13 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47
- https://git.kernel.org/stable/c/fb1f54b7d16f393b8b65d328410f78b4beea8fcc
- https://git.kernel.org/stable/c/3fd6547f5b8ac99687be6d937a0321efda760597
- https://git.kernel.org/stable/c/eb9c6aeb512f877cf397deb1e4526f646c70e4a7
- https://git.kernel.org/stable/c/15fa9ead4d5e6b6b9c794e84144146c917f2cb62
- https://git.kernel.org/stable/c/b313e9037d98c13938740e5ebda7852929366dff
- https://git.kernel.org/stable/c/9b55b253907e7431210483519c5ad711a37dafa1
ADP enrichment
No English description supplied.
No English description supplied.
No references supplied.