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authorWillem de Bruijn <willemb@google.com>2019-05-15 20:29:16 +0300
committerDavid S. Miller <davem@davemloft.net>2019-05-16 22:17:50 +0300
commit185ce5c38ea76f29b6bd9c7c8c7a5e5408834920 (patch)
tree84ac1b5a0f65276f68bae561519e6568507e58d4 /include/linux/skbuff.h
parentb4e467c82f8c12af78b6f6fa5730cb7dea7af1b4 (diff)
downloadlinux-185ce5c38ea76f29b6bd9c7c8c7a5e5408834920.tar.xz
net: test nouarg before dereferencing zerocopy pointers
Zerocopy skbs without completion notification were added for packet sockets with PACKET_TX_RING user buffers. Those signal completion through the TP_STATUS_USER bit in the ring. Zerocopy annotation was added only to avoid premature notification after clone or orphan, by triggering a copy on these paths for these packets. The mechanism had to define a special "no-uarg" mode because packet sockets already use skb_uarg(skb) == skb_shinfo(skb)->destructor_arg for a different pointer. Before deferencing skb_uarg(skb), verify that it is a real pointer. Fixes: 5cd8d46ea1562 ("packet: copy user buffers before orphan or clone") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6d58fa8a65fd..2ee5e63195c0 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1434,10 +1434,12 @@ static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
struct ubuf_info *uarg = skb_zcopy(skb);
if (uarg) {
- if (uarg->callback == sock_zerocopy_callback) {
+ if (skb_zcopy_is_nouarg(skb)) {
+ /* no notification callback */
+ } else if (uarg->callback == sock_zerocopy_callback) {
uarg->zerocopy = uarg->zerocopy && zerocopy;
sock_zerocopy_put(uarg);
- } else if (!skb_zcopy_is_nouarg(skb)) {
+ } else {
uarg->callback(uarg, zerocopy);
}
@@ -2691,7 +2693,8 @@ static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
{
if (likely(!skb_zcopy(skb)))
return 0;
- if (skb_uarg(skb)->callback == sock_zerocopy_callback)
+ if (!skb_zcopy_is_nouarg(skb) &&
+ skb_uarg(skb)->callback == sock_zerocopy_callback)
return 0;
return skb_copy_ubufs(skb, gfp_mask);
}