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Mon, 27 Apr 2026 21:47:12 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id oGNoCmDZ72m5RgAAD6G6ig (envelope-from ); Mon, 27 Apr 2026 21:47:12 +0000 From: Gabriel Krisman Bertazi To: Ali Raza Cc: io-uring@vger.kernel.org, Jens Axboe , Pavel Begunkov Subject: Re: [PATCH v2] io_uring: add submitter_task consistency check to io_install_bpf() In-Reply-To: <20260427192400.416133-1-elirazamumtaz@gmail.com> (Ali Raza's message of "Tue, 28 Apr 2026 00:24:00 +0500") References: <12c2bec8-ffb9-4b01-8bea-819c6ec77c5e@gmail.com> <20260427192400.416133-1-elirazamumtaz@gmail.com> Date: Mon, 27 Apr 2026 17:47:10 -0400 Message-ID: <87mryom5y9.fsf@mailhost.krisman.be> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.998]; MIME_GOOD(-0.10)[text/plain]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; TAGGED_RCPT(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RCPT_COUNT_THREE(0.00)[4]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[vger.kernel.org,kernel.dk,gmail.com]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,mailhost.krisman.be:mid] X-Spam-Flag: NO Ali Raza writes: > io_uring_register() already guards against a different task touching > a SINGLE_ISSUER ring (register.c:733): > > if (ctx->submitter_task && ctx->submitter_task != current) > return -EEXIST; > > bpf_io_reg() calls io_install_bpf() without an equivalent guard. Add > the same check for consistency. The check is gated on > IORING_SETUP_SINGLE_ISSUER since submitter_task is only assigned for > that flag combination (io_uring.c:3053 and register.c:282). > > Note: io_install_bpf() is called directly from the BPF syscall path, > so `current` is the task invoking BPF_LINK_CREATE. If BPF link > registration were ever deferred to a worker thread, this check would > need revisiting. > > Signed-off-by: Ali Raza > --- > v2: Added IORING_SETUP_SINGLE_ISSUER gate; changed -EPERM to -EEXIST to > match register.c:733; removed security/exploit framing from commit > message; acknowledged that `current` may not be valid if BPF link > creation is ever deferred to a worker thread. > > io_uring/bpf-ops.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/io_uring/bpf-ops.c b/io_uring/bpf-ops.c > index 937e48bef40b..84578614cc0b 100644 > --- a/io_uring/bpf-ops.c > +++ b/io_uring/bpf-ops.c > @@ -162,6 +162,9 @@ static int io_install_bpf(struct io_ring_ctx *ctx, struct io_uring_bpf_ops *ops) > return -EOPNOTSUPP; > if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) > return -EOPNOTSUPP; > + if ((ctx->flags & IORING_SETUP_SINGLE_ISSUER) && > + ctx->submitter_task && ctx->submitter_task != current) The ctx->flags & IORING_SETUP_SINGLE_ISSUER check is redundant. IIUC, ->submitter_task can only be set if the ring is set with IORING_SETUP_SINGLE_ISSUER. > + return -EEXIST; > > if (ctx->bpf_ops) > return -EBUSY; > -- > 2.43.0 -- Gabriel Krisman Bertazi