path: root/net/ipv4
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authorEric Dumazet <edumazet@google.com>2018-09-30 11:33:39 -0700
committerDavid S. Miller <davem@davemloft.net>2018-10-02 22:32:05 -0700
commit64199fc0a46ba211362472f7f942f900af9492fd (patch)
tree35b727833c02a05799aa522edde425018b33160a /net/ipv4
parentMerge tag 'mlx5-fixes-2018-10-01' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux (diff)
ipv4: fix use-after-free in ip_cmsg_recv_dstaddr()
Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy, do not do it. Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index c0fe5ad996f2..26c36cccabdc 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -149,7 +149,6 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
struct sockaddr_in sin;
- const struct iphdr *iph = ip_hdr(skb);
__be16 *ports;
int end;
@@ -164,7 +163,7 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
ports = (__be16 *)skb_transport_header(skb);
sin.sin_family = AF_INET;
- sin.sin_addr.s_addr = iph->daddr;
+ sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
sin.sin_port = ports[1];
memset(sin.sin_zero, 0, sizeof(sin.sin_zero));