From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [Bugme-new] [Bug 16603] New: send of data > 4 GB fails on 64 bit systems Date: Mon, 27 Sep 2010 20:24:25 -0700 (PDT) Message-ID: <20100927.202425.71120040.davem@davemloft.net> References: <20100927161540.776f748e.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org, bugme-daemon@bugzilla.kernel.org, bono@onlinehome.de To: akpm@linux-foundation.org Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:55405 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758011Ab0I1DYG convert rfc822-to-8bit (ORCPT ); Mon, 27 Sep 2010 23:24:06 -0400 In-Reply-To: <20100927161540.776f748e.akpm@linux-foundation.org> Sender: netdev-owner@vger.kernel.org List-ID: Ok, I suspect the following is enough to fix this specific bug report, TCP sending. However, as I stated in my previous reply there are creepy crawlies all over the place. =46or example, all of the routines in net/core/iovec.c (memcpy_toiovec, memcpy_toiovecend, memcpy_fromiovec, memcpy_fromiovecend, csum_partial_copy_fromiovecend) that cast using min_t() are currently casting "down" to "unsigned int". They should probably case "up" to "size_t". Otherwise 4GB iov_len's on 64-bit will be truncated to zero just as they do in the TCP path being fixed here. If, alterntatively, we want to try and take the size_t values all the way down the code paths to the individual copies, that is a huge undertaking. It's huge because we end up getting to the architecture specific csum_copy_*() routines, which all take 'int' as the length and many are written in assembler and would need audits and potentially changes before we can make the type 'long' or 'size_t'. Anyways, this part here is simple enough and I'll push it to Linus and -stable. -------------------- tcp: Fix >4GB writes on 64-bit. =46ixes kernel bugzilla #16603 tcp_sendmsg() truncates iov_len to an 'int' which a 4GB write to write zero bytes, for example. There is also the problem higher up of how verify_iovec() works. It wants to prevent the total length from looking like an error return value. However it does this using 'int', but syscalls return 'long' (and thus signed 64-bit on 64-bit machines). So it could trigger false-positives on 64-bit as written. So fix it to use 'long'. Reported-by: Olaf Bonorden Reported-by: Daniel B=FCse Reported-by: Andrew Morton Signed-off-by: David S. Miller diff --git a/include/linux/socket.h b/include/linux/socket.h index a2fada9..a8f56e1 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -322,7 +322,7 @@ extern int csum_partial_copy_fromiovecend(unsigned = char *kdata, int offset,=20 unsigned int len, __wsum *csump); =20 -extern int verify_iovec(struct msghdr *m, struct iovec *iov, struct so= ckaddr *address, int mode); +extern long verify_iovec(struct msghdr *m, struct iovec *iov, struct s= ockaddr *address, int mode); extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int l= en); extern int memcpy_toiovecend(const struct iovec *v, unsigned char *kda= ta, int offset, int len); diff --git a/net/core/iovec.c b/net/core/iovec.c index 1cd98df..e6b133b 100644 --- a/net/core/iovec.c +++ b/net/core/iovec.c @@ -35,9 +35,10 @@ * in any case. */ =20 -int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr = *address, int mode) +long verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr= *address, int mode) { - int size, err, ct; + int size, ct; + long err; =20 if (m->msg_namelen) { if (mode =3D=3D VERIFY_READ) { diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 95d75d4..f115ea6 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -943,7 +943,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk= , struct msghdr *msg, sg =3D sk->sk_route_caps & NETIF_F_SG; =20 while (--iovlen >=3D 0) { - int seglen =3D iov->iov_len; + size_t seglen =3D iov->iov_len; unsigned char __user *from =3D iov->iov_base; =20 iov++;