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authorParthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>2017-08-24 16:31:23 +0200
committerDavid S. Miller <davem@davemloft.net>2017-08-24 21:54:34 -0700
commit60d1d93664a0bb3d5af722ed38c57ee165a45bf7 (patch)
tree0e5ebe511f6f2e52e852c90dedcc24461515cfee /net/tipc/msg.c
parent27163138b4d80e36f2006273d66b6c122d241f30 (diff)
downloadlinux-60d1d93664a0bb3d5af722ed38c57ee165a45bf7.tar.gz
tipc: reassign pointers after skb reallocation / linearization
In tipc_msg_reverse(), we assign skb attributes to local pointers
in stack at startup. This is followed by skb_linearize() and for
cloned buffers we perform skb relocation using pskb_expand_head().
Both these methods may update the skb attributes and thus making
the pointers incorrect.

In this commit, we fix this error by ensuring that the pointers
are re-assigned after any of these skb operations.

Fixes: 29042e19f2c60 ("tipc: let function tipc_msg_reverse() expand header
when needed")
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/msg.c')
-rw-r--r--net/tipc/msg.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index dcd90e6fa7c3..6ef379f004ac 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -479,13 +479,14 @@ bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 {
 	struct sk_buff *_skb = *skb;
-	struct tipc_msg *hdr = buf_msg(_skb);
+	struct tipc_msg *hdr;
 	struct tipc_msg ohdr;
-	int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
+	int dlen;
 
 	if (skb_linearize(_skb))
 		goto exit;
 	hdr = buf_msg(_skb);
+	dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
 	if (msg_dest_droppable(hdr))
 		goto exit;
 	if (msg_errcode(hdr))
@@ -511,6 +512,8 @@ bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 	    pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
 		goto exit;
 
+	/* reassign after skb header modifications */
+	hdr = buf_msg(_skb);
 	/* Now reverse the concerned fields */
 	msg_set_errcode(hdr, err);
 	msg_set_non_seq(hdr, 0);