diff options
| author | Willem de Bruijn <willemb@google.com> | 2019-05-15 20:29:16 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-05-16 22:17:50 +0300 |
| commit | 185ce5c38ea76f29b6bd9c7c8c7a5e5408834920 (patch) | |
| tree | 84ac1b5a0f65276f68bae561519e6568507e58d4 /include/linux/skbuff.h | |
| parent | b4e467c82f8c12af78b6f6fa5730cb7dea7af1b4 (diff) | |
| download | linux-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.h | 9 |
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); } |