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Thu, 30 May 2019 08:17:08 -0700 (PDT) Received: by localhost.localdomain (Postfix, from userid 1000) id B67F9C1BC5; Thu, 30 May 2019 12:17:05 -0300 (-03) Date: Thu, 30 May 2019 12:17:05 -0300 From: Marcelo Ricardo Leitner To: Neil Horman Cc: syzbot , davem@davemloft.net, linux-kernel@vger.kernel.org, linux-sctp@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, vyasevich@gmail.com Subject: Re: memory leak in sctp_process_init Message-ID: <20190530151705.GD3713@localhost.localdomain> References: <00000000000097abb90589e804fd@google.com> <20190528013600.GM5506@localhost.localdomain> <20190528111550.GA4658@hmswarspite.think-freely.org> <20190529190709.GE31099@hmswarspite.think-freely.org> <20190529233757.GC3713@localhost.localdomain> <20190530142011.GC1966@hmswarspite.think-freely.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190530142011.GC1966@hmswarspite.think-freely.org> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, May 30, 2019 at 10:20:11AM -0400, Neil Horman wrote: > On Wed, May 29, 2019 at 08:37:57PM -0300, Marcelo Ricardo Leitner wrote: > > On Wed, May 29, 2019 at 03:07:09PM -0400, Neil Horman wrote: > > > --- a/net/sctp/sm_make_chunk.c > > > +++ b/net/sctp/sm_make_chunk.c > > > @@ -2419,9 +2419,12 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk, > > > /* Copy cookie in case we need to resend COOKIE-ECHO. */ > > > cookie = asoc->peer.cookie; > > > if (cookie) { > > > + if (asoc->peer.cookie_allocated) > > > + kfree(cookie); > > > asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp); > > > if (!asoc->peer.cookie) > > > goto clean_up; > > > + asoc->peer.cookie_allocated=1; > > > } > > > > > > /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily > > > > What if we kmemdup directly at sctp_process_param(), as it's done for > > others already? Like SCTP_PARAM_RANDOM and SCTP_PARAM_HMAC_ALGO. I > > don't see a reason for SCTP_PARAM_STATE_COOKIE to be different > > here. This way it would be always allocated, and ready to be kfreed. > > > > We still need to free it after the handshake, btw. > > > > Marcelo > > > > Still untested, but something like this? > Yes, just.. > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c > index d2c7d0d2abc1..718b9917844e 100644 > --- a/net/sctp/associola.c > +++ b/net/sctp/associola.c > @@ -393,6 +393,7 @@ void sctp_association_free(struct sctp_association *asoc) > kfree(asoc->peer.peer_random); > kfree(asoc->peer.peer_chunks); > kfree(asoc->peer.peer_hmacs); > + kfree(asoc->peer.cookie); this chunk is not needed because it is freed right above the first kfree() in the context here. > > /* Release the transport structures. */ > list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > index 72e74503f9fc..ff365f22a3c1 100644 > --- a/net/sctp/sm_make_chunk.c > +++ b/net/sctp/sm_make_chunk.c > @@ -2431,14 +2431,6 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk, > /* Peer Rwnd : Current calculated value of the peer's rwnd. */ > asoc->peer.rwnd = asoc->peer.i.a_rwnd; > > - /* Copy cookie in case we need to resend COOKIE-ECHO. */ > - cookie = asoc->peer.cookie; > - if (cookie) { > - asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp); > - if (!asoc->peer.cookie) > - goto clean_up; > - } > - > /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily > * high (for example, implementations MAY use the size of the receiver > * advertised window). > @@ -2607,7 +2599,9 @@ static int sctp_process_param(struct sctp_association *asoc, > case SCTP_PARAM_STATE_COOKIE: > asoc->peer.cookie_len = > ntohs(param.p->length) - sizeof(struct sctp_paramhdr); > - asoc->peer.cookie = param.cookie->body; > + asoc->peer.cookie = kmemdup(param.cookie->body, asoc->peer.cookie_len, gfp); > + if (!asoc->peer.cookie) > + retval = 0; > break; > > case SCTP_PARAM_HEARTBEAT_INFO: Plus: --- a/net/sctp/sm_sideeffect.c +++ b/net/sctp/sm_sideeffect.c @@ -898,6 +898,11 @@ static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds, asoc->rto_initial; } + if (sctp_state(asoc, ESTABLISHED)) { + kfree(asoc->peer.cookie); + asoc->peer.cookie = NULL; + } + if (sctp_state(asoc, ESTABLISHED) || sctp_state(asoc, CLOSED) || sctp_state(asoc, SHUTDOWN_RECEIVED)) { Also untested, just sharing the idea. Marcelo