Description
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix TOCTOU race between smc_listen_out() and listener close smc_listen_out() reads lsmc->sk.sk_state without the listener lock, then acquires lock_sock_nested() only after the check passes. This opens a window where smc_close_active() can transition the listener to SMC_CLOSED, call smc_close_cleanup_listen() to drain the accept queue, and release the lock, all between the lockless read and the delayed lock acquisition: smc_listen_work (smc_hs_wq) smc_close_active() ------------------------------- ------------------------- release_sock(child) if (sk_state == SMC_LISTEN) TRUE lock_sock(listener) sk_state = SMC_CLOSED smc_close_cleanup_listen() release_sock(listener) flush_work(tcp_listen_work) lock_sock_nested(listener) smc_accept_enqueue(listener, child) /* child enqueued on dead listener */ smc_close_active() flushes only tcp_listen_work. Work items already dispatched onto smc_hs_wq for the CLC handshake continue running unguarded. smc_accept_enqueue() takes a sock_hold() on the child that is never released, so the child smc_sock, its clcsock, and the reference all leak. A remote peer that opens TCP connections while the server calls close() can exhaust kernel memory. Move lock_sock_nested() to before the sk_state check so that the test and the enqueue are atomic under the listener lock.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < 53c7938d8bcfde3296ec1a347ba2a9393c1fdcfaaffectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < feb71634bb1abab3e8fb5cde874b27001cc1282eaffectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < 01865e1ddb126b25ac9eba5cdd7ec49e11183a64affectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < 00f89433777236ced4771211047fb5d4cd581ceaaffectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < 78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67affectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < ff5bcd804b5bc5c64736b7d318c20e12ea9506b8affectedfd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 to < 185a4caeecabc150106deda1da170b09f2ad803faffectedd1d004585b40c212b338fc8a40cbaaf230ea4703affected4.19.299 to < 4.20affected
Linux Linux
Default version status: affected
5.1affected0 to < 5.1unaffected5.15.216 to ≤ 5.15.*unaffected6.1.183 to ≤ 6.1.*unaffected6.6.152 to ≤ 6.6.*unaffected6.12.104 to ≤ 6.12.*unaffected6.18.45 to ≤ 6.18.*unaffected7.1.9 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa ↗
- https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e ↗
- https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64 ↗
- https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea ↗
- https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67 ↗
- https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8 ↗
- https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f ↗