From a4d258036ed9b2a1811c3670c6099203a0f284a0 Mon Sep 17 00:00:00 2001 From: Tom Marshall Date: Mon, 20 Sep 2010 15:42:05 -0700 Subject: tcp: Fix race in tcp_poll If a RST comes in immediately after checking sk->sk_err, tcp_poll will return POLLIN but not POLLOUT. Fix this by checking sk->sk_err at the end of tcp_poll. Additionally, ensure the correct order of operations on SMP machines with memory barriers. Signed-off-by: Tom Marshall Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp.c') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3fb1428e526..95d75d44392 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -386,8 +386,6 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) */ mask = 0; - if (sk->sk_err) - mask = POLLERR; /* * POLLHUP is certainly not done right. But poll() doesn't @@ -457,6 +455,11 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) if (tp->urg_data & TCP_URG_VALID) mask |= POLLPRI; } + /* This barrier is coupled with smp_wmb() in tcp_reset() */ + smp_rmb(); + if (sk->sk_err) + mask |= POLLERR; + return mask; } EXPORT_SYMBOL(tcp_poll); -- cgit v1.2.3-70-g09d2 From 01db403cf99f739f86903314a489fb420e0e254f Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 27 Sep 2010 20:24:54 -0700 Subject: tcp: Fix >4GB writes on 64-bit. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reported-by: Daniel Büse Reported-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/socket.h | 2 +- net/core/iovec.c | 5 +++-- net/ipv4/tcp.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) (limited to 'net/ipv4/tcp.c') diff --git a/include/linux/socket.h b/include/linux/socket.h index a2fada9becb..a8f56e1ec76 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, 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 1cd98df412d..e6b133b77cc 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 95d75d44392..f115ea68a4e 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 = 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++; -- cgit v1.2.3-70-g09d2