From 5a6f6873606e03a0a95afe40ba5e84bb6e28a26f Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 14 Jun 2023 09:04:16 +0100 Subject: ip, ip6: Fix splice to raw and ping sockets Splicing to SOCK_RAW sockets may set MSG_SPLICE_PAGES, but in such a case, __ip_append_data() will call skb_splice_from_iter() to access the 'from' data, assuming it to point to a msghdr struct with an iter, instead of using the provided getfrag function to access it. In the case of raw_sendmsg(), however, this is not the case and 'from' will point to a raw_frag_vec struct and raw_getfrag() will be the frag-getting function. A similar issue may occur with rawv6_sendmsg(). Fix this by ignoring MSG_SPLICE_PAGES if getfrag != ip_generic_getfrag as ip_generic_getfrag() expects "from" to be a msghdr*, but the other getfrags don't. Note that this will prevent MSG_SPLICE_PAGES from being effective for udplite. This likely affects ping sockets too. udplite looks like it should be okay as it expects "from" to be a msghdr. Signed-off-by: David Howells Reported-by: syzbot+d8486855ef44506fd675@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000ae4cbf05fdeb8349@google.com/ Fixes: 2dc334f1a63a ("splice, net: Use sendmsg(MSG_SPLICE_PAGES) rather than ->sendpage()") Tested-by: syzbot+d8486855ef44506fd675@syzkaller.appspotmail.com cc: David Ahern cc: Jens Axboe cc: Matthew Wilcox Reviewed-by: Willem de Bruijn Link: https://lore.kernel.org/r/1410156.1686729856@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski --- net/ipv6/ip6_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/ipv6/ip6_output.c') diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index c06ff7519f19..1e8c90e97608 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1593,7 +1593,8 @@ emsgsize: } else if ((flags & MSG_SPLICE_PAGES) && length) { if (inet_sk(sk)->hdrincl) return -EPERM; - if (rt->dst.dev->features & NETIF_F_SG) + if (rt->dst.dev->features & NETIF_F_SG && + getfrag == ip_generic_getfrag) /* We need an empty buffer to attach stuff to */ paged = true; else -- cgit