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authorEric Dumazet <edumazet@google.com>2017-03-21 19:22:28 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-30 09:41:22 +0200
commit62e85fe590721acf19dfc7f8fcdd0f3eb8fc6ac5 (patch)
treec2e7df47d2bcf8400c0a267ff0cfa79b1f350e4e /net/ipv4
parent2f94dd54cfe64a9f49e49c0856640c11fd1c9bc0 (diff)
ipv4: provide stronger user input validation in nl_fib_input()
[ Upstream commit c64c0b3cac4c5b8cb093727d2c19743ea3965c0b ] 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>
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 5b03d7f3b255..6789e48b7085 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1081,7 +1081,8 @@ 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;