[patch 15/31] Fix length validation in rawv6_sendmsg()

Greg KH
2007-04-11T22:55:33Z

[-- Attachment #1: fix-length-validation-in-rawv6_sendmsg.patch --]
[-- Type: text/plain, Size: 2073 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------
From: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

[IPv6]: Fix incorrect length check in rawv6_sendmsg()

In article <20070329.142644.70222545.davem@davemloft.net> (at Thu, 29 Mar 2007 14:26:44 -0700 (PDT)), David Miller <davem@davemloft.net> says:

> From: Sridhar Samudrala <sri@us.ibm.com>
> Date: Thu, 29 Mar 2007 14:17:28 -0700
>
> > The check for length in rawv6_sendmsg() is incorrect.
> > As len is an unsigned int, (len < 0) will never be TRUE.
> > I think checking for IPV6_MAXPLEN(65535) is better.
> >
> > Is it possible to send ipv6 jumbo packets using raw
> > sockets? If so, we can remove this check.
>
> I don't see why such a limitation against jumbo would exist,
> does anyone else?
>
> Thanks for catching this Sridhar. A good compiler should simply
> fail to compile "if (x < 0)" when 'x' is an unsigned type, don't
> you think :-)

Dave, we use "int" for returning value,
so we should fix this anyway, IMHO;
we should not allow len > INT_MAX.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
net/ipv6/raw.c | 4 ++--
net/ipv6/udp.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -688,9 +688,9 @@ static int rawv6_sendmsg(struct kiocb *i
int err;

/* Rough check on arithmetic overflow,
- better check is made in ip6_build_xmit
+ better check is made in ip6_append_data().
*/
- if (len < 0)
+ if (len > INT_MAX)
return -EMSGSIZE;

/* Mirror BSD error message compatibility */
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -616,7 +616,7 @@ do_udp_sendmsg:
return udp_sendmsg(iocb, sk, msg, len);

/* Rough check on arithmetic overflow,
- better check is made in ip6_build_xmit
+ better check is made in ip6_append_data().
*/
if (len > INT_MAX - sizeof(struct udphdr))
return -EMSGSIZE;

--