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net: test nouarg before dereferencing zerocopy pointers
[ Upstream commit185ce5c38e
] 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:5cd8d46ea1
("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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00b0f63783
commit
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1 changed files with 6 additions and 3 deletions
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@ -1310,10 +1310,12 @@ static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
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struct ubuf_info *uarg = skb_zcopy(skb);
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if (uarg) {
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if (uarg->callback == sock_zerocopy_callback) {
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if (skb_zcopy_is_nouarg(skb)) {
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/* no notification callback */
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} else if (uarg->callback == sock_zerocopy_callback) {
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uarg->zerocopy = uarg->zerocopy && zerocopy;
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sock_zerocopy_put(uarg);
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} else if (!skb_zcopy_is_nouarg(skb)) {
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} else {
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uarg->callback(uarg, zerocopy);
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}
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@ -2572,7 +2574,8 @@ static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
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{
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if (likely(!skb_zcopy(skb)))
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return 0;
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if (skb_uarg(skb)->callback == sock_zerocopy_callback)
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if (!skb_zcopy_is_nouarg(skb) &&
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skb_uarg(skb)->callback == sock_zerocopy_callback)
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return 0;
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return skb_copy_ubufs(skb, gfp_mask);
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}
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