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af_iucv: fix recvmsg by replacing skb_pull() function 

When receiving data messages, the "BUG_ON(skb->len < skb->data_len)" in
the skb_pull() function triggers a kernel panic.

Replace the skb_pull logic by a per skb offset as advised by
Eric Dumazet.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ursula Braun 2013-04-07 22:19:26 +00:00 committed by David S. Miller
parent 88c5b5ce5c
commit f9c41a62bb
2 changed files with 24 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/net/iucv/af_iucv.h
View File

@ -130,6 +130,14 @@ struct iucv_sock {
enum iucv_tx_notify n);
};
struct iucv_skb_cb {
u32 class; /* target class of message */
u32 tag; /* tag associated with message */
u32 offset; /* offset for skb receival */
};
#define IUCV_SKB_CB(__skb) ((struct iucv_skb_cb *)&((__skb)->cb[0]))
/* iucv socket options (SOL_IUCV) */
#define SO_IPRMDATA_MSG 0x0080 /* send/recv IPRM_DATA msgs */
#define SO_MSGLIMIT 0x1000 /* get/set IUCV MSGLIMIT */

34
net/iucv/af_iucv.c
View File

@ -49,12 +49,6 @@ static const u8 iprm_shutdown[8] =
#define TRGCLS_SIZE (sizeof(((struct iucv_message *)0)->class))
/* macros to set/get socket control buffer at correct offset */
#define CB_TAG(skb) ((skb)->cb) /* iucv message tag */
#define CB_TAG_LEN (sizeof(((struct iucv_message *) 0)->tag))
#define CB_TRGCLS(skb) ((skb)->cb + CB_TAG_LEN) /* iucv msg target class */
#define CB_TRGCLS_LEN (TRGCLS_SIZE)
#define __iucv_sock_wait(sk, condition, timeo, ret) \
do { \
DEFINE_WAIT(__wait); \
@ -1141,7 +1135,7 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
/* increment and save iucv message tag for msg_completion cbk */
txmsg.tag = iucv->send_tag++;
memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN);
IUCV_SKB_CB(skb)->tag = txmsg.tag;
if (iucv->transport == AF_IUCV_TRANS_HIPER) {
atomic_inc(&iucv->msg_sent);
@ -1224,7 +1218,7 @@ static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len)
return -ENOMEM;
/* copy target class to control buffer of new skb */
memcpy(CB_TRGCLS(nskb), CB_TRGCLS(skb), CB_TRGCLS_LEN);
IUCV_SKB_CB(nskb)->class = IUCV_SKB_CB(skb)->class;
/* copy data fragment */
memcpy(nskb->data, skb->data + copied, size);
@ -1256,7 +1250,7 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
/* store msg target class in the second 4 bytes of skb ctrl buffer */
/* Note: the first 4 bytes are reserved for msg tag */
memcpy(CB_TRGCLS(skb), &msg->class, CB_TRGCLS_LEN);
IUCV_SKB_CB(skb)->class = msg->class;
/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
@ -1292,6 +1286,7 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
}
}
IUCV_SKB_CB(skb)->offset = 0;
if (sock_queue_rcv_skb(sk, skb))
skb_queue_head(&iucv_sk(sk)->backlog_skb_q, skb);
}
@ -1327,6 +1322,7 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
unsigned int copied, rlen;
struct sk_buff *skb, *rskb, *cskb;
int err = 0;
u32 offset;
msg->msg_namelen = 0;
@ -1348,13 +1344,14 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
return err;
}
rlen = skb->len; /* real length of skb */
offset = IUCV_SKB_CB(skb)->offset;
rlen = skb->len - offset; /* real length of skb */
copied = min_t(unsigned int, rlen, len);
if (!rlen)
sk->sk_shutdown = sk->sk_shutdown | RCV_SHUTDOWN;
cskb = skb;
if (skb_copy_datagram_iovec(cskb, 0, msg->msg_iov, copied)) {
if (skb_copy_datagram_iovec(cskb, offset, msg->msg_iov, copied)) {
if (!(flags & MSG_PEEK))
skb_queue_head(&sk->sk_receive_queue, skb);
return -EFAULT;
@ -1372,7 +1369,8 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
* get the trgcls from the control buffer of the skb due to
* fragmentation of original iucv message. */
err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
CB_TRGCLS_LEN, CB_TRGCLS(skb));
sizeof(IUCV_SKB_CB(skb)->class),
(void *)&IUCV_SKB_CB(skb)->class);
if (err) {
if (!(flags & MSG_PEEK))
skb_queue_head(&sk->sk_receive_queue, skb);
@ -1384,9 +1382,8 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
/* SOCK_STREAM: re-queue skb if it contains unreceived data */
if (sk->sk_type == SOCK_STREAM) {
skb_pull(skb, copied);
if (skb->len) {
skb_queue_head(&sk->sk_receive_queue, skb);
if (copied < rlen) {
IUCV_SKB_CB(skb)->offset = offset + copied;
goto done;
}
}
@ -1405,6 +1402,7 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
spin_lock_bh(&iucv->message_q.lock);
rskb = skb_dequeue(&iucv->backlog_skb_q);
while (rskb) {
IUCV_SKB_CB(rskb)->offset = 0;
if (sock_queue_rcv_skb(sk, rskb)) {
skb_queue_head(&iucv->backlog_skb_q,
rskb);
@ -1832,7 +1830,7 @@ static void iucv_callback_txdone(struct iucv_path *path,
spin_lock_irqsave(&list->lock, flags);
while (list_skb != (struct sk_buff *)list) {
if (!memcmp(&msg->tag, CB_TAG(list_skb), CB_TAG_LEN)) {
if (msg->tag != IUCV_SKB_CB(list_skb)->tag) {
this = list_skb;
break;
}
@ -2093,6 +2091,7 @@ static int afiucv_hs_callback_rx(struct sock *sk, struct sk_buff *skb)
skb_pull(skb, sizeof(struct af_iucv_trans_hdr));
skb_reset_transport_header(skb);
skb_reset_network_header(skb);
IUCV_SKB_CB(skb)->offset = 0;
spin_lock(&iucv->message_q.lock);
if (skb_queue_empty(&iucv->backlog_skb_q)) {
if (sock_queue_rcv_skb(sk, skb)) {
@ -2197,8 +2196,7 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
/* fall through and receive zero length data */
case 0:
/* plain data frame */
memcpy(CB_TRGCLS(skb), &trans_hdr->iucv_hdr.class,
CB_TRGCLS_LEN);
IUCV_SKB_CB(skb)->class = trans_hdr->iucv_hdr.class;
err = afiucv_hs_callback_rx(sk, skb);
break;
default: