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net: rework recvmsg handler msg_name and msg_namelen logic

Browse Source 
CVE-2013-7266

BugLink: http://bugs.launchpad.net/bugs/1267081

This patch now always passes msg->msg_namelen as 0. recvmsg handlers must
set msg_namelen to the proper size <= sizeof(struct sockaddr_storage)
to return msg_name to the user.

This prevents numerous uninitialized memory leaks we had in the
recvmsg handlers and makes it harder for new code to accidentally leak
uninitialized memory.

Optimize for the case recvfrom is called with NULL as address. We don't
need to copy the address at all, so set it to NULL before invoking the
recvmsg handler. We can do so, because all the recvmsg handlers must
cope with the case a plain read() is called on them. read() also sets
msg_name to NULL.

Also document these changes in include/linux/net.h as suggested by David
Miller.

Changes since RFC:

Set msg->msg_name = NULL if user specified a NULL in msg_name but had a
non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
affect sendto as it would bail out earlier while trying to copy-in the
address. It also more naturally reflects the logic by the callers of
verify_iovec.

With this change in place I could remove "
if (!uaddr || msg_sys->msg_namelen == 0)
	msg->msg_name = NULL
".

This change does not alter the user visible error logic as we ignore
msg_namelen as long as msg_name is NULL.

Also remove two unnecessary curly brackets in ___sys_recvmsg and change
comments to netdev style.

Cc: David Miller <davem@davemloft.net>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
(back ported from commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c)
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Acked-by: Andy Whitcroft <andy.whitcroft@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
This commit is contained in:
Hannes Frederic Sowa 2013-11-21 03:14:22 +01:00 committed by Willy Tarreau
parent f8e4f8fc47
commit 4485f23cb4
27 changed files with 65 additions and 96 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/isdn/mISDN/socket.c
View File

@ -115,7 +115,6 @@ mISDN_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
{
struct sk_buff *skb;
struct sock *sk = sock->sk;
struct sockaddr_mISDN *maddr;
int copied, err;
@ -133,9 +132,9 @@ mISDN_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
if (!skb)
return err;
if (msg->msg_namelen >= sizeof(struct sockaddr_mISDN)) {
msg->msg_namelen = sizeof(struct sockaddr_mISDN);
maddr = (struct sockaddr_mISDN *)msg->msg_name;
if (msg->msg_name) {
struct sockaddr_mISDN *maddr = msg->msg_name;
maddr->family = AF_ISDN;
maddr->dev = _pms(sk)->dev->id;
if ((sk->sk_protocol == ISDN_P_LAPD_TE) ||
@ -148,11 +147,7 @@ mISDN_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
maddr->sapi = _pms(sk)->ch.addr & 0xFF;
maddr->tei = (_pms(sk)->ch.addr >> 8) & 0xFF;
}
} else {
if (msg->msg_namelen)
printk(KERN_WARNING "%s: too small namelen %d\n",
__func__, msg->msg_namelen);
msg->msg_namelen = 0;
msg->msg_namelen = sizeof(*maddr);
}
copied = skb->len + MISDN_HEADER_LEN;

2
drivers/net/pppoe.c
View File

@ -992,8 +992,6 @@ static int pppoe_recvmsg(struct kiocb *iocb, struct socket *sock,
if (error < 0)
goto end;
m->msg_namelen = 0;
if (skb) {
total_len = min_t(size_t, total_len, skb->len);
error = skb_copy_datagram_iovec(skb, 0, m->msg_iov, total_len);

2
drivers/net/pppol2tp.c
View File

@ -829,8 +829,6 @@ static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
if (sk->sk_state & PPPOX_BOUND)
goto end;
msg->msg_namelen = 0;
err = 0;
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &err);

8
include/linux/net.h
View File

@ -187,6 +187,14 @@ struct proto_ops {
int optname, char __user *optval, int __user *optlen);
int (*sendmsg) (struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len);
/* Notes for implementing recvmsg:
* ===============================
* msg->msg_namelen should get updated by the recvmsg handlers
* iff msg_name != NULL. It is by default 0 to prevent
* returning uninitialized memory to user space. The recvfrom
* handlers can assume that msg.msg_name is either NULL or has
* a minimum size of sizeof(struct sockaddr_storage).
*/
int (*recvmsg) (struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len,
int flags);

16
net/appletalk/ddp.c
View File

@ -1703,7 +1703,6 @@ static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
size_t size, int flags)
{
struct sock *sk = sock->sk;
struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
struct ddpehdr *ddp;
int copied = 0;
int offset = 0;
@ -1728,14 +1727,13 @@ static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
}
err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);
if (!err) {
if (sat) {
sat->sat_family = AF_APPLETALK;
sat->sat_port = ddp->deh_sport;
sat->sat_addr.s_node = ddp->deh_snode;
sat->sat_addr.s_net = ddp->deh_snet;
}
msg->msg_namelen = sizeof(*sat);
if (!err && msg->msg_name) {
struct sockaddr_at *sat = msg->msg_name;
sat->sat_family = AF_APPLETALK;
sat->sat_port = ddp->deh_sport;
sat->sat_addr.s_node = ddp->deh_snode;
sat->sat_addr.s_net = ddp->deh_snet;
msg->msg_namelen = sizeof(*sat);
}
skb_free_datagram(sk, skb); /* Free the datagram. */

2
net/atm/common.c
View File

@ -473,8 +473,6 @@ int vcc_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
struct sk_buff *skb;
int copied, error = -EINVAL;
msg->msg_namelen = 0;
if (sock->state != SS_CONNECTED)
return -ENOTCONN;
if (flags & ~MSG_DONTWAIT) /* only handle MSG_DONTWAIT */

4
net/ax25/af_ax25.c
View File

@ -1648,11 +1648,11 @@ static int ax25_recvmsg(struct kiocb *iocb, struct socket *sock,
skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
if (msg->msg_namelen != 0) {
struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name;
if (msg->msg_name) {
ax25_digi digi;
ax25_address src;
const unsigned char *mac = skb_mac_header(skb);
struct sockaddr_ax25 *sax = msg->msg_name;
memset(sax, 0, sizeof(struct full_sockaddr_ax25));
ax25_addr_parse(mac + 1, skb->data - mac - 1, &src, NULL,

2
net/bluetooth/af_bluetooth.c
View File

@ -240,8 +240,6 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
if (flags & (MSG_OOB))
return -EOPNOTSUPP;
msg->msg_namelen = 0;
if (!(skb = skb_recv_datagram(sk, flags, noblock, &err))) {
if (sk->sk_shutdown & RCV_SHUTDOWN)
return 0;

2
net/bluetooth/hci_sock.c
View File

@ -370,8 +370,6 @@ static int hci_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
if (!(skb = skb_recv_datagram(sk, flags, noblock, &err)))
return err;
msg->msg_namelen = 0;
copied = skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;

3
net/bluetooth/rfcomm/sock.c
View File

@ -652,15 +652,12 @@ static int rfcomm_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
rfcomm_dlc_accept(d);
msg->msg_namelen = 0;
return 0;
}
if (flags & MSG_OOB)
return -EOPNOTSUPP;
msg->msg_namelen = 0;
BT_DBG("sk %p size %zu", sk, size);
lock_sock(sk);

3
net/compat.c
View File

@ -91,7 +91,8 @@ int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *kern_iov,
if (err < 0)
return err;
}
kern_msg->msg_name = kern_address;
if (kern_msg->msg_name)
kern_msg->msg_name = kern_address;
} else
kern_msg->msg_name = NULL;

3
net/core/iovec.c
View File

@ -47,7 +47,8 @@ int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address,
if (err < 0)
return err;
}
m->msg_name = address;
if (m->msg_name)
m->msg_name = address;
} else {
m->msg_name = NULL;
}

3
net/ipx/af_ipx.c
View File

@ -1808,8 +1808,6 @@ static int ipx_recvmsg(struct kiocb *iocb, struct socket *sock,
if (skb->tstamp.tv64)
sk->sk_stamp = skb->tstamp;
msg->msg_namelen = sizeof(*sipx);
if (sipx) {
sipx->sipx_family = AF_IPX;
sipx->sipx_port = ipx->ipx_source.sock;
@ -1817,6 +1815,7 @@ static int ipx_recvmsg(struct kiocb *iocb, struct socket *sock,
sipx->sipx_network = IPX_SKB_CB(skb)->ipx_source_net;
sipx->sipx_type = ipx->ipx_type;
sipx->sipx_zero = 0;
msg->msg_namelen = sizeof(*sipx);
}
rc = copied;

4
net/irda/af_irda.c
View File

@ -1338,8 +1338,6 @@ static int irda_recvmsg_dgram(struct kiocb *iocb, struct socket *sock,
if ((err = sock_error(sk)) < 0)
return err;
msg->msg_namelen = 0;
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &err);
if (!skb)
@ -1402,8 +1400,6 @@ static int irda_recvmsg_stream(struct kiocb *iocb, struct socket *sock,
target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
timeo = sock_rcvtimeo(sk, noblock);
msg->msg_namelen = 0;
do {
int chunk;
struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);

2
net/iucv/af_iucv.c
View File

@ -1160,8 +1160,6 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
struct sk_buff *skb, *rskb, *cskb;
int err = 0;
msg->msg_namelen = 0;
if ((sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED) &&
skb_queue_empty(&iucv->backlog_skb_q) &&
skb_queue_empty(&sk->sk_receive_queue) &&

1
net/key/af_key.c
View File

@ -3597,7 +3597,6 @@ static int pfkey_recvmsg(struct kiocb *kiocb,
if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT))
goto out;
msg->msg_namelen = 0;
skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
if (skb == NULL)
goto out;

2
net/llc/af_llc.c
View File

@ -674,8 +674,6 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
int target; /* Read at least this many bytes */
long timeo;
msg->msg_namelen = 0;
lock_sock(sk);
copied = -ENOTCONN;
if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))

2
net/netlink/af_netlink.c
View File

@ -1400,8 +1400,6 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
}
#endif
msg->msg_namelen = 0;
copied = data_skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;

3
net/netrom/af_netrom.c
View File

@ -1184,10 +1184,9 @@ static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
sax->sax25_family = AF_NETROM;
skb_copy_from_linear_data_offset(skb, 7, sax->sax25_call.ax25_call,
AX25_ADDR_LEN);
msg->msg_namelen = sizeof(*sax);
}
msg->msg_namelen = sizeof(*sax);
skb_free_datagram(sk, skb);
release_sock(sk);

32
net/packet/af_packet.c
View File

@ -1423,7 +1423,6 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
struct sock *sk = sock->sk;
struct sk_buff *skb;
int copied, err;
struct sockaddr_ll *sll;
err = -EINVAL;
if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT))
@ -1455,22 +1454,10 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
if (skb == NULL)
goto out;
/*
* If the address length field is there to be filled in, we fill
* it in now.
/* You lose any data beyond the buffer you gave. If it worries
* a user program they can ask the device for its MTU
* anyway.
*/
sll = &PACKET_SKB_CB(skb)->sa.ll;
if (sock->type == SOCK_PACKET)
msg->msg_namelen = sizeof(struct sockaddr_pkt);
else
msg->msg_namelen = sll->sll_halen + offsetof(struct sockaddr_ll, sll_addr);
/*
* You lose any data beyond the buffer you gave. If it worries a
* user program they can ask the device for its MTU anyway.
*/
copied = skb->len;
if (copied > len) {
copied = len;
@ -1483,9 +1470,20 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
sock_recv_timestamp(msg, sk, skb);
if (msg->msg_name)
if (msg->msg_name) {
/* If the address length field is there to be filled
* in, we fill it in now.
*/
if (sock->type == SOCK_PACKET) {
msg->msg_namelen = sizeof(struct sockaddr_pkt);
} else {
struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
msg->msg_namelen = sll->sll_halen +
offsetof(struct sockaddr_ll, sll_addr);
}
memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa,
msg->msg_namelen);
}
if (pkt_sk(sk)->auxdata) {
struct tpacket_auxdata aux;

2
net/rds/recv.c
View File

@ -410,8 +410,6 @@ int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
msg->msg_namelen = 0;
if (msg_flags & MSG_OOB)
goto out;

8
net/rose/af_rose.c
View File

@ -1238,7 +1238,6 @@ static int rose_recvmsg(struct kiocb *iocb, struct socket *sock,
{
struct sock *sk = sock->sk;
struct rose_sock *rose = rose_sk(sk);
struct sockaddr_rose *srose = (struct sockaddr_rose *)msg->msg_name;
size_t copied;
unsigned char *asmptr;
struct sk_buff *skb;
@ -1274,8 +1273,11 @@ static int rose_recvmsg(struct kiocb *iocb, struct socket *sock,
skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
if (srose != NULL) {
memset(srose, 0, msg->msg_namelen);
if (msg->msg_name) {
struct sockaddr_rose *srose;
memset(msg->msg_name, 0, sizeof(struct full_sockaddr_rose));
srose = msg->msg_name;
srose->srose_family = AF_ROSE;
srose->srose_addr = rose->dest_addr;
srose->srose_call = rose->dest_call;

9
net/rxrpc/ar-recvmsg.c
View File

@ -142,10 +142,13 @@ int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
/* copy the peer address and timestamp */
if (!continue_call) {
if (msg->msg_name && msg->msg_namelen > 0)
if (msg->msg_name) {
size_t len =
sizeof(call->conn->trans->peer->srx);
memcpy(msg->msg_name,
&call->conn->trans->peer->srx,
sizeof(call->conn->trans->peer->srx));
&call->conn->trans->peer->srx, len);
msg->msg_namelen = len;
}
sock_recv_timestamp(msg, &rx->sk, skb);
}

19
net/socket.c
View File

@ -1744,8 +1744,10 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
msg.msg_iov = &iov;
iov.iov_len = size;
iov.iov_base = ubuf;
msg.msg_name = (struct sockaddr *)&address;
msg.msg_namelen = sizeof(address);
/* Save some cycles and don't copy the address if not needed */
msg.msg_name = addr ? (struct sockaddr *)&address : NULL;
/* We assume all kernel code knows the size of sockaddr_storage */
msg.msg_namelen = 0;
if (sock->file->f_flags & O_NONBLOCK)
flags |= MSG_DONTWAIT;
err = sock_recvmsg(sock, &msg, size, flags);
@ -2033,18 +2035,16 @@ SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg,
goto out_put;
}
/*
* Save the user-mode address (verify_iovec will change the
* kernel msghdr to use the kernel address space)
/* Save the user-mode address (verify_iovec will change the
* kernel msghdr to use the kernel address space)
*/
uaddr = (__force void __user *)msg_sys.msg_name;
uaddr_len = COMPAT_NAMELEN(msg);
if (MSG_CMSG_COMPAT & flags) {
if (MSG_CMSG_COMPAT & flags)
err = verify_compat_iovec(&msg_sys, iov,
(struct sockaddr *)&addr,
VERIFY_WRITE);
} else
else
err = verify_iovec(&msg_sys, iov,
(struct sockaddr *)&addr,
VERIFY_WRITE);
@ -2055,6 +2055,9 @@ SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg,
cmsg_ptr = (unsigned long)msg_sys.msg_control;
msg_sys.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
/* We assume all kernel code knows the size of sockaddr_storage */
msg_sys.msg_namelen = 0;
if (sock->file->f_flags & O_NONBLOCK)
flags |= MSG_DONTWAIT;
err = sock_recvmsg(sock, &msg_sys, total_len, flags);

6
net/tipc/socket.c
View File

@ -917,9 +917,6 @@ static int recv_msg(struct kiocb *iocb, struct socket *sock,
goto exit;
}
/* will be updated in set_orig_addr() if needed */
m->msg_namelen = 0;
restart:
/* Look for a message in receive queue; wait if necessary */
@ -1053,9 +1050,6 @@ static int recv_stream(struct kiocb *iocb, struct socket *sock,
goto exit;
}
/* will be updated in set_orig_addr() if needed */
m->msg_namelen = 0;
restart:
/* Look for a message in receive queue; wait if necessary */

5
net/unix/af_unix.c
View File

@ -1682,7 +1682,6 @@ static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
{
struct unix_sock *u = unix_sk(sk);
msg->msg_namelen = 0;
if (u->addr) {
msg->msg_namelen = u->addr->len;
memcpy(msg->msg_name, u->addr->name, u->addr->len);
@ -1705,8 +1704,6 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
if (flags&MSG_OOB)
goto out;
msg->msg_namelen = 0;
mutex_lock(&u->readlock);
skb = skb_recv_datagram(sk, flags, noblock, &err);
@ -1832,8 +1829,6 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
msg->msg_namelen = 0;
/* Lock the socket to prevent queue disordering
* while sleeps in memcpy_tomsg
*/

3
net/x25/af_x25.c
View File

@ -1294,10 +1294,9 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
if (sx25) {
sx25->sx25_family = AF_X25;
sx25->sx25_addr = x25->dest_addr;
msg->msg_namelen = sizeof(*sx25);
}
msg->msg_namelen = sizeof(struct sockaddr_x25);
lock_sock(sk);
x25_check_rbuf(sk);
release_sock(sk);