Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: net/9p: fix race condition on rdma->state in trans_rdma.c The rdma->state field is modified without holding req_lock in both recv_done() and p9_cm_event_handler(), while rdma_request() accesses the same field under the req_lock spinlock. This inconsistent locking creates a race condition: - recv_done() running in softirq completion context sets rdma->state = P9_RDMA_FLUSHING without acquiring req_lock - p9_cm_event_handler() modifies rdma->state at multiple points (ADDR_RESOLVED, ROUTE_RESOLVED, ESTABLISHED, CLOSED) without req_lock - rdma_request() uses spin_lock_irqsave(&rdma->req_lock, flags) to protect the read-modify-write of rdma->state The race can cause lost state transitions: recv_done() or the CM event handler could set state to FLUSHING/CLOSED while rdma_request() is concurrently checking or modifying state under the lock, leading to the FLUSHING transition being silently overwritten by CLOSING. This corrupts the connection state machine and can cause use-after-free on RDMA request objects during teardown. Fix by adding req_lock protection to all rdma->state modifications in recv_done() and p9_cm_event_handler(), matching the pattern already used in rdma_request(). Use spin_lock_irqsave/spin_unlock_irqrestore in the CM event handler since it can race with recv_done() which runs in softirq context. Tested with a kernel module that races two threads (simulating rdma_request and recv_done/CM handler) on rdma->state with proper locking: 5.5M+ FLUSHING writes over 27M iterations with 0 lost transitions.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 4cee2b8766045059d5e0b8114837b4a8efe827ac; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 5424138848eb7d7d8a7196676e90a2cbf2142454; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 3970a19a80de530b801b6256354d4a529a9a2d6c; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 151f8cf5b23d8a534d884432a82a6d54d5a61989; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 13bf9879b778b2f4b260b45bed18f31806120d1e; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before ebbcbe5c0db215feecc17def06178da443f4eea6; affected 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b before 7d54894a1ee265a72d70f7cae1da6cc774cccc71; affected 3479b3c35e82ed10aa0ca2ee9e78c4eded06ba62; affected c01ddaa54d7411e964ffd250c018d8469c5852f2; affected 9e69c673fe077b8dc491cd8406c9bdcb1f76dee2; affected e48e7e27e4dfd00c81e0381e7cee610cce021452; affected 4.4.185 before 4.5; affected 4.9.185 before 4.10; affected 4.14.132 before 4.15; affected 4.19.57 before 4.20 |
| Linux / Linux | affected 4.20; unaffected 0 before 4.20; unaffected 5.10.261 through 5.10.*; unaffected 5.15.212 through 5.15.*; unaffected 6.1.178 through 6.1.*; unaffected 6.6.145 through 6.6.*; unaffected 6.12.97 through 6.12.*; unaffected 6.18.40 through 6.18.*; unaffected 7.1.5 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/4cee2b8766045059d5e0b8114837b4a8efe827ac
- https://git.kernel.org/stable/c/5424138848eb7d7d8a7196676e90a2cbf2142454
- https://git.kernel.org/stable/c/3970a19a80de530b801b6256354d4a529a9a2d6c
- https://git.kernel.org/stable/c/8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b
- https://git.kernel.org/stable/c/151f8cf5b23d8a534d884432a82a6d54d5a61989
- https://git.kernel.org/stable/c/13bf9879b778b2f4b260b45bed18f31806120d1e
- https://git.kernel.org/stable/c/ebbcbe5c0db215feecc17def06178da443f4eea6
- https://git.kernel.org/stable/c/7d54894a1ee265a72d70f7cae1da6cc774cccc71
ADP enrichment
No English description supplied.
No references supplied.