Messages in this thread | | | Date | Fri, 24 Feb 2023 21:22:43 +0100 | From | Sabrina Dubroca <> | Subject | Re: [PATCH] net: tls: fix possible race condition between do_tls_getsockopt_conf() and do_tls_setsockopt_conf() |
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2023-02-24, 10:55:08 -0800, Jakub Kicinski wrote: > On Fri, 24 Feb 2023 13:06:06 +0100 Florian Westphal wrote: > > Hangyu Hua <hbh25y@gmail.com> wrote: > > > ctx->crypto_send.info is not protected by lock_sock in > > > do_tls_getsockopt_conf(). A race condition between do_tls_getsockopt_conf() > > > and do_tls_setsockopt_conf() can cause a NULL point dereference or > > > use-after-free read when memcpy. > > > > Its good practice to quote the relevant parts of the splat here. > > Right, the bug and the fix seem completely bogus. > Please make sure the bugs are real and the fixes you sent actually > fix them.
I suggested a change of locking in do_tls_getsockopt_conf this morning [1]. The issue reported last seemed valid, but this patch is not at all what I had in mind. [1] https://lore.kernel.org/all/Y/ht6gQL+u6fj3dG@hog/
do_tls_setsockopt_conf fills crypto_info immediately from what userspace gives us (and clears it on exit in case of failure), which getsockopt could see since it's not locking the socket when it checks TLS_CRYPTO_INFO_READY. So getsockopt would progress up to the point it finally locks the socket, but if setsockopt failed, we could have cleared TLS_CRYPTO_INFO_READY and freed iv/rec_seq.
-- Sabrina
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