| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 076/124] ipv4: provide stronger user input validation in nl_fib_input() | Date | Thu, 20 Apr 2017 08:35:51 +0200 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
commit c64c0b3cac4c5b8cb093727d2c19743ea3965c0b upstream.
Alexander reported a KMSAN splat caused by reads of uninitialized field (tb_id_in) from user provided struct fib_result_nl
It turns out nl_fib_input() sanity tests on user input is a bit wrong :
User can pretend nlh->nlmsg_len is big enough, but provide at sendmsg() time a too small buffer.
Reported-by: Alexander Potapenko <glider@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/ipv4/fib_frontend.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -961,7 +961,8 @@ static void nl_fib_input(struct sk_buff net = sock_net(skb->sk); nlh = nlmsg_hdr(skb); - if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len || + if (skb->len < nlmsg_total_size(sizeof(*frn)) || + skb->len < nlh->nlmsg_len || nlmsg_len(nlh) < sizeof(*frn)) return;
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