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Mon, 17 Jun 2024 15:59:30 +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 HaUuNWJdcGawdQAAD6G6ig (envelope-from ); Mon, 17 Jun 2024 15:59:30 +0000 Date: Mon, 17 Jun 2024 17:59:30 +0200 From: Michal Hocko To: Greg Kroah-Hartman Cc: cve@kernel.org, linux-kernel@vger.kernel.org, Eric Dumazet , linux-cve-announce@vger.kernel.org Subject: Re: CVE-2024-35840: mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect() Message-ID: References: <2024051756-CVE-2024-35840-99fa@gregkh> <2024061750-glade-overstep-7759@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2024061750-glade-overstep-7759@gregkh> X-Spam-Score: -3.80 X-Spam-Level: X-Spam-Flag: NO X-Spamd-Result: default: False [-3.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_RHS_NOT_FQDN(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FROM_HAS_DN(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_TLS_ALL(0.00)[]; MISSING_XM_UA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_FIVE(0.00)[5] On Mon 17-06-24 17:43:10, Greg KH wrote: > On Thu, Jun 06, 2024 at 10:03:54AM +0200, Michal Hocko wrote: > > Hi, > > what is the actual security threat here? As far as I can see, the > > problem that the commit requested here addresses seems to be rather > > functional, rather than responding to an unexpected packet options with > > a reset, we actually establish a connection with some garbage parameters > > (likely unpredictable). Which is unfortunate but I do not see any > > security implications. > > Sorry for the delay. I'm pretty sure this is a data leak as the > "garbage" is coming from other kernel data, and as such, was reviewed by > us as a vulnerability. This is not my area so bear with me, but isn't the garbage coming from a remote side of the connection so it is just a garbage? I would understand that a misbehavior on the receiving end could be considered problematic but I still do not see this happening. Or am I wrong? -- Michal Hocko SUSE Labs