8754e1379e
This patch fixed 2 issues with the usage of skb_cow in LAPB drivers
"lapbether" and "hdlc_x25":
1) After skb_cow fails, kfree_skb should be called to drop a reference
to the skb. But in both drivers, kfree_skb is not called.
2) skb_cow should be called before skb_push so that is can ensure the
safety of skb_push. But in "lapbether", it is incorrectly called after
skb_push.
More details about these 2 issues:
1) The behavior of calling kfree_skb on failure is also the behavior of
netif_rx, which is called by this function with "return netif_rx(skb);".
So this function should follow this behavior, too.
2) In "lapbether", skb_cow is called after skb_push. This results in 2
logical issues:
a) skb_push is not protected by skb_cow;
b) An extra headroom of 1 byte is ensured after skb_push. This extra
headroom has no use in this function. It also has no use in the
upper-layer function that this function passes the skb to
(x25_lapb_receive_frame in net/x25/x25_dev.c).
So logically skb_cow should instead be called before skb_push.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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| .. | ||
| lmc | ||
| .gitignore | ||
| c101.c | ||
| cosa.c | ||
| cosa.h | ||
| dlci.c | ||
| farsync.c | ||
| farsync.h | ||
| fsl_ucc_hdlc.c | ||
| fsl_ucc_hdlc.h | ||
| hd64570.c | ||
| hd64570.h | ||
| hd64572.c | ||
| hd64572.h | ||
| hdlc_cisco.c | ||
| hdlc_fr.c | ||
| hdlc_ppp.c | ||
| hdlc_raw_eth.c | ||
| hdlc_raw.c | ||
| hdlc_x25.c | ||
| hdlc.c | ||
| hostess_sv11.c | ||
| ixp4xx_hss.c | ||
| Kconfig | ||
| lapbether.c | ||
| Makefile | ||
| n2.c | ||
| pc300too.c | ||
| pci200syn.c | ||
| sbni.c | ||
| sbni.h | ||
| sdla.c | ||
| sealevel.c | ||
| slic_ds26522.c | ||
| slic_ds26522.h | ||
| wanxl.c | ||
| wanxl.h | ||
| wanxlfw.inc_shipped | ||
| wanxlfw.S | ||
| x25_asy.c | ||
| x25_asy.h | ||
| z85230.c | ||
| z85230.h | ||