From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: [PATCH v2] net/sctp: Validate parameter size for SCTP_GET_ASSOC_STATS Date: Wed, 27 Feb 2013 12:57:31 -0800 Message-ID: <1361998651-19354-1-git-send-email-linux@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-sctp@vger.kernel.org, Vlad Yasevich , Sridhar Samudrala , Neil Horman , "David S. Miller" , Guenter Roeck To: netdev@vger.kernel.org Return-path: Received: from mail.active-venture.com ([67.228.131.205]:59789 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750955Ab3B0U5k (ORCPT ); Wed, 27 Feb 2013 15:57:40 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Building sctp may fail with: In function =E2=80=98copy_from_user=E2=80=99, inlined from =E2=80=98sctp_getsockopt_assoc_stats=E2=80=99 at net/sctp/socket.c:5656:20: arch/x86/include/asm/uaccess_32.h:211:26: error: call to =E2=80=98copy_from_user_overflow=E2=80=99 declared with attribute e= rror: copy_from_user() buffer size is not provably correct if built with W=3D1 due to a missing parameter size validation before the call to copy_from_user. Signed-off-by: Guenter Roeck --- v2: Fix by moving the existing parameter size validation up in the function instead of adding an additional one. net/sctp/socket.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index cedd9bf..9ef5c73 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -5653,6 +5653,9 @@ static int sctp_getsockopt_assoc_stats(struct soc= k *sk, int len, if (len < sizeof(sctp_assoc_t)) return -EINVAL; =20 + /* Allow the struct to grow and fill in as much as possible */ + len =3D min_t(size_t, len, sizeof(sas)); + if (copy_from_user(&sas, optval, len)) return -EFAULT; =20 @@ -5686,9 +5689,6 @@ static int sctp_getsockopt_assoc_stats(struct soc= k *sk, int len, /* Mark beginning of a new observation period */ asoc->stats.max_obs_rto =3D asoc->rto_min; =20 - /* Allow the struct to grow and fill in as much as possible */ - len =3D min_t(size_t, len, sizeof(sas)); - if (put_user(len, optlen)) return -EFAULT; =20 --=20 1.7.9.7