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authorEric Dumazet <edumazet@google.com>2017-03-21 19:22:28 -0700
committerDavid S. Miller <davem@davemloft.net>2017-03-22 14:15:49 -0700
commitc64c0b3cac4c5b8cb093727d2c19743ea3965c0b (patch)
treecf028128aa74adefd46b05428bcc82cb132c9f43 /net/ipv4
parent8c290e60fa2a51806159522331c9ed41252a8fb3 (diff)
ipv4: provide stronger user input validation in nl_fib_input()
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>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/fib_frontend.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 42bfd08109dd..8f2133ffc2ff 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1083,7 +1083,8 @@ static void nl_fib_input(struct sk_buff *skb)
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;