Re: [PATCH AUTOSEL 6.18-6.1] tls: reject the combination of TLS and sockmap

[Sabrina Dubroca <sd@queasysnail.net>]

2026-09-01, 11:09:02 -0400, Sasha Levin wrote:
> On Tue, Sep 01, 2026 at 11:36:31AM +0200, Sabrina Dubroca wrote:
> > 2026-08-31, 09:30:24 -0400, Sasha Levin wrote:
> > > From: Jakub Kicinski <kuba@kernel.org>
> > > 
> > > [ Upstream commit 460e6486617c17dd19abe8f3fc67d9a6fa25f8ca ]
> > > 
> > > TLS and sockmap (BPF psock) integration hides a lot of latent bugs.
> > > Bugs which may be more or less relevant for real users but they
> > > are definitely exploitable.
> > > 
> > > We could not find anyone actively using this integration so let's
> > > reject this config. Adding a TLS socket to a sockmap was already
> > > rejected by sk_psock_init() through the inet_csk_has_ulp() check.
> > > We need to reject the attempts to configure the TLS keys (rather
> > > than adding the ULP itself) because checking prior to the ULP
> > > installation is tricky without risking a race with sockmap getting
> > > added in parallel (sockmap does not hold the socket lock).
> > > 
> > > This patch is a minimal rejection of the feature. Subsequent patch
> > > in the series will do a light dead code removal. Full cleanup would
> > > require a major rewrite of the Tx path, we don't need skmsg any more.
> > > 
> > > Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
> > > Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
> > > Link: https://patch.msgid.link/20260614014102.461064-2-kuba@kernel.org
> > > Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> > > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > > ---
> > > 
> > > LLM Generated explanations, may be completely bogus:
> > 
> > 330L... wow.
> > 
> > > ## Phase 1: Commit Message Forensics
> > > 
> > > ### Step 1.1: Subject line
> > > **Record:** `[tls]` / `reject` — reject the unsupported TLS + sockmap
> > > (BPF psock) configuration.
> > > 
> > > ### Step 1.2: Tags
> > > **Record:**
> > > - **Reviewed-by:** Jakub Sitnicki `<jakub@cloudflare.com>`
> > > - **Reviewed-by:** Sabrina Dubroca `<sd@queasysnail.net>`
> > > - **Link:**
> > >   https://patch.msgid.link/20260614014102.461064-2-kuba@kernel.org
> > > - **Signed-off-by:** Jakub Kicinski `<kuba@kernel.org>`
> > > - No Fixes:, Reported-by:, Cc: stable@vger.kernel.org, or syzbot tags
> > 
> > Yes, this was intentionally sent to net-next without a Fixes tag,
> > because it's a "feature-level" change, so it kind of feels wrong to
> > send that to stable (even if it's removing a feature that nobody seems
> > to be using). OTOH the code is broken and not really fixable...
> 
> We have plenty of "fixes" that just drop a bunch of broken code :)
> 
> Happy to do either, just let me know.

Alright, if that's ok for you, no objection.

-- 
Sabrina