[34-longterm 193/260] tcp: Fix >4GB writes on 64-bit.

Paul Gortmaker
2011-01-02T07:41:33Z

From: David S. Miller <davem@davemloft.net>

commit 01db403cf99f739f86903314a489fb420e0e254f upstream.

Fixes 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 <bono@onlinehome.de>
Reported-by: Daniel Büse <dbuese@gmx.de>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
include/linux/socket.h | 2 +-
net/core/iovec.c | 5 +++--
net/ipv4/tcp.c | 2 +-
3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 354cc56..1b5034a 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -314,7 +314,7 @@ extern int csum_partial_copy_fromiovecend(unsigned char *kdata,
int offset,
unsigned int len, __wsum *csump);

-extern int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode);
+extern long verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode);
extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int len);
extern int memcpy_toiovecend(const struct iovec *v, unsigned char *kdata,
int offset, int len);
diff --git a/net/core/iovec.c b/net/core/iovec.c
index 1e7f4e9..b5b28f0 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -35,9 +35,10 @@
* in any case.
*/

-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;

if (m->msg_namelen) {
if (mode == VERIFY_READ) {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4a638f0..1b40924 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -938,7 +938,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
sg = sk->sk_route_caps & NETIF_F_SG;

while (--iovlen >= 0) {
- int seglen = iov->iov_len;
+ size_t seglen = iov->iov_len;
unsigned char __user *from = iov->iov_base;

iov++;
--
1.7.3.3