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>
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index dcd90e6..6ef379f 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -479,13 +479,14 @@
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 @@
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);