1. 24 Nov, 2016 39 commits
  2. 19 Nov, 2016 1 commit
    • Eric Dumazet's avatar
      udp: properly support MSG_PEEK with truncated buffers · 69335972
      Eric Dumazet authored
      [ Upstream commit 197c949e ]
      
      Backport of this upstream commit into stable kernels :
      89c22d8c ("net: Fix skb csum races when peeking")
      exposed a bug in udp stack vs MSG_PEEK support, when user provides
      a buffer smaller than skb payload.
      
      In this case,
      skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr),
                                       msg->msg_iov);
      returns -EFAULT.
      
      This bug does not happen in upstream kernels since Al Viro did a great
      job to replace this into :
      skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
      This variant is safe vs short buffers.
      
      For the time being, instead reverting Herbert Xu patch and add back
      skb->ip_summed invalid changes, simply store the result of
      udp_lib_checksum_complete() so that we avoid computing the checksum a
      second time, and avoid the problematic
      skb_copy_and_csum_datagram_iovec() call.
      
      This patch can be applied on recent kernels as it avoids a double
      checksumming, then backported to stable kernels as a bug fix.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      69335972