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. Signed-off-by: Parthasarathy Bhuvaragan <[email protected]> --- net/tipc/msg.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/tipc/msg.c b/net/tipc/msg.c index ab3087687a32..98edfa6d3b2d 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -479,13 +479,15 @@ 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 +513,8 @@ 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_origport(hdr, msg_destport(&ohdr)); -- 2.1.4 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ tipc-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/tipc-discussion
