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tipc: move message validation function to msg.c

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The function link_buf_validate() is in reality re-entrant and context
independent, and will in later commits be called from several locations.
Therefore, we move it to msg.c, make it outline and rename the it to
tipc_msg_validate().

We also redesign the function to make proper use of pskb_may_pull()

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy 2015-03-13 16:08:06 -04:00 committed by David S. Miller
parent 7764d6e83d
commit cf2157f88a
3 changed files with 47 additions and 60 deletions
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58
net/tipc/link.c
View File

@ -1047,61 +1047,6 @@ static void link_retrieve_defq(struct tipc_link *link,
skb_queue_splice_tail_init(&link->deferred_queue, list);
}
/**
* link_recv_buf_validate - validate basic format of received message
*
* This routine ensures a TIPC message has an acceptable header, and at least
* as much data as the header indicates it should. The routine also ensures
* that the entire message header is stored in the main fragment of the message
* buffer, to simplify future access to message header fields.
*
* Note: Having extra info present in the message header or data areas is OK.
* TIPC will ignore the excess, under the assumption that it is optional info
* introduced by a later release of the protocol.
*/
static int link_recv_buf_validate(struct sk_buff *buf)
{
static u32 min_data_hdr_size[8] = {
SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
};
struct tipc_msg *msg;
u32 tipc_hdr[2];
u32 size;
u32 hdr_size;
u32 min_hdr_size;
/* If this packet comes from the defer queue, the skb has already
* been validated
*/
if (unlikely(TIPC_SKB_CB(buf)->deferred))
return 1;
if (unlikely(buf->len < MIN_H_SIZE))
return 0;
msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
if (msg == NULL)
return 0;
if (unlikely(msg_version(msg) != TIPC_VERSION))
return 0;
size = msg_size(msg);
hdr_size = msg_hdr_sz(msg);
min_hdr_size = msg_isdata(msg) ?
min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
if (unlikely((hdr_size < min_hdr_size) ||
(size < hdr_size) ||
(buf->len < size) ||
(size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
return 0;
return pskb_may_pull(buf, hdr_size);
}
/**
* tipc_rcv - process TIPC packets/messages arriving from off-node
* @net: the applicable net namespace
@ -1127,7 +1072,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
while ((skb = __skb_dequeue(&head))) {
/* Ensure message is well-formed */
if (unlikely(!link_recv_buf_validate(skb)))
if (unlikely(!tipc_msg_validate(skb)))
goto discard;
/* Ensure message data is a single contiguous unit */
@ -1398,7 +1343,6 @@ static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
if (tipc_link_defer_pkt(&l_ptr->deferred_queue, buf)) {
l_ptr->stats.deferred_recv++;
TIPC_SKB_CB(buf)->deferred = true;
if ((skb_queue_len(&l_ptr->deferred_queue) % 16) == 1)
tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
} else {

44
net/tipc/msg.c
View File

@ -1,7 +1,7 @@
/*
* net/tipc/msg.c: TIPC message header routines
*
* Copyright (c) 2000-2006, 2014, Ericsson AB
* Copyright (c) 2000-2006, 2014-2015, Ericsson AB
* Copyright (c) 2005, 2010-2011, Wind River Systems
* All rights reserved.
*
@ -181,6 +181,48 @@ err:
return 0;
}
/* tipc_msg_validate - validate basic format of received message
*
* This routine ensures a TIPC message has an acceptable header, and at least
* as much data as the header indicates it should. The routine also ensures
* that the entire message header is stored in the main fragment of the message
* buffer, to simplify future access to message header fields.
*
* Note: Having extra info present in the message header or data areas is OK.
* TIPC will ignore the excess, under the assumption that it is optional info
* introduced by a later release of the protocol.
*/
bool tipc_msg_validate(struct sk_buff *skb)
{
struct tipc_msg *msg;
int msz, hsz;
if (unlikely(TIPC_SKB_CB(skb)->validated))
return true;
if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
return false;
hsz = msg_hdr_sz(buf_msg(skb));
if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
return false;
if (unlikely(!pskb_may_pull(skb, hsz)))
return false;
msg = buf_msg(skb);
if (unlikely(msg_version(msg) != TIPC_VERSION))
return false;
msz = msg_size(msg);
if (unlikely(msz < hsz))
return false;
if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
return false;
if (unlikely(skb->len < msz))
return false;
TIPC_SKB_CB(skb)->validated = true;
return true;
}
/**
* tipc_msg_build - create buffer chain containing specified header and data

5
net/tipc/msg.h
View File

@ -1,7 +1,7 @@
/*
* net/tipc/msg.h: Include file for TIPC message header routines
*
* Copyright (c) 2000-2007, 2014, Ericsson AB
* Copyright (c) 2000-2007, 2014-2015 Ericsson AB
* Copyright (c) 2005-2008, 2010-2011, Wind River Systems
* All rights reserved.
*
@ -92,7 +92,7 @@ struct plist;
struct tipc_skb_cb {
void *handle;
struct sk_buff *tail;
bool deferred;
bool validated;
bool wakeup_pending;
bool bundling;
u16 chain_sz;
@ -758,6 +758,7 @@ static inline u32 msg_tot_origport(struct tipc_msg *m)
}
struct sk_buff *tipc_buf_acquire(u32 size);
bool tipc_msg_validate(struct sk_buff *skb);
bool tipc_msg_reverse(u32 own_addr, struct sk_buff *buf, u32 *dnode,
int err);
void tipc_msg_init(u32 own_addr, struct tipc_msg *m, u32 user, u32 type,