inet: prevent leakage of uninitialized memory to user in recv syscalls
Only update *addr_len when we actually fill in sockaddr, otherwise we can return uninitialized memory from the stack to the caller in the recvfrom, recvmmsg and recvmsg syscalls. Drop the the (addr_len == NULL) checks because we only get called with a valid addr_len pointer either from sock_common_recvmsg or inet_recvmsg. If a blocking read waits on a socket which is concurrently shut down we now return zero and set msg_msgnamelen to 0. Reported-by: mpb <mpb.mail@gmail.com> Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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committato da
David S. Miller

parent
bcd081a3ae
commit
bceaa90240
@@ -830,8 +830,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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{
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struct inet_sock *isk = inet_sk(sk);
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int family = sk->sk_family;
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struct sockaddr_in *sin;
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struct sockaddr_in6 *sin6;
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struct sk_buff *skb;
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int copied, err;
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@@ -841,13 +839,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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if (flags & MSG_OOB)
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goto out;
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if (addr_len) {
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if (family == AF_INET)
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*addr_len = sizeof(*sin);
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else if (family == AF_INET6 && addr_len)
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*addr_len = sizeof(*sin6);
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}
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if (flags & MSG_ERRQUEUE) {
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if (family == AF_INET) {
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return ip_recv_error(sk, msg, len);
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@@ -877,11 +868,13 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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/* Copy the address and add cmsg data. */
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if (family == AF_INET) {
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sin = (struct sockaddr_in *) msg->msg_name;
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struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
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sin->sin_family = AF_INET;
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sin->sin_port = 0 /* skb->h.uh->source */;
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sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
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memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
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*addr_len = sizeof(*sin);
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if (isk->cmsg_flags)
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ip_cmsg_recv(msg, skb);
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@@ -890,17 +883,19 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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} else if (family == AF_INET6) {
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struct ipv6_pinfo *np = inet6_sk(sk);
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struct ipv6hdr *ip6 = ipv6_hdr(skb);
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sin6 = (struct sockaddr_in6 *) msg->msg_name;
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struct sockaddr_in6 *sin6 =
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(struct sockaddr_in6 *)msg->msg_name;
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sin6->sin6_family = AF_INET6;
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sin6->sin6_port = 0;
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sin6->sin6_addr = ip6->saddr;
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sin6->sin6_flowinfo = 0;
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if (np->sndflow)
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sin6->sin6_flowinfo = ip6_flowinfo(ip6);
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sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
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IP6CB(skb)->iif);
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*addr_len = sizeof(*sin6);
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if (inet6_sk(sk)->rxopt.all)
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pingv6_ops.ip6_datagram_recv_ctl(sk, msg, skb);
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@@ -696,9 +696,6 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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if (flags & MSG_OOB)
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goto out;
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if (addr_len)
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*addr_len = sizeof(*sin);
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if (flags & MSG_ERRQUEUE) {
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err = ip_recv_error(sk, msg, len);
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goto out;
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@@ -726,6 +723,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
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sin->sin_port = 0;
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memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
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*addr_len = sizeof(*sin);
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}
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if (inet->cmsg_flags)
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ip_cmsg_recv(msg, skb);
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@@ -1235,12 +1235,6 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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int is_udplite = IS_UDPLITE(sk);
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bool slow;
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/*
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* Check any passed addresses
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*/
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if (addr_len)
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*addr_len = sizeof(*sin);
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if (flags & MSG_ERRQUEUE)
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return ip_recv_error(sk, msg, len);
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@@ -1302,6 +1296,7 @@ try_again:
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sin->sin_port = udp_hdr(skb)->source;
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sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
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memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
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*addr_len = sizeof(*sin);
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}
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if (inet->cmsg_flags)
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ip_cmsg_recv(msg, skb);
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