From bceaa90240b6019ed73b49965eac7d167610be69 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Mon, 18 Nov 2013 04:20:45 +0100 Subject: 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 Suggested-by: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv4/ping.c | 19 +++++++------------ net/ipv4/raw.c | 4 +--- net/ipv4/udp.c | 7 +------ 3 files changed, 9 insertions(+), 21 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 9afbdb19f4a..aacefa0caa3 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -830,8 +830,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, { struct inet_sock *isk = inet_sk(sk); int family = sk->sk_family; - struct sockaddr_in *sin; - struct sockaddr_in6 *sin6; struct sk_buff *skb; int copied, err; @@ -841,13 +839,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, if (flags & MSG_OOB) goto out; - if (addr_len) { - if (family == AF_INET) - *addr_len = sizeof(*sin); - else if (family == AF_INET6 && addr_len) - *addr_len = sizeof(*sin6); - } - if (flags & MSG_ERRQUEUE) { if (family == AF_INET) { return ip_recv_error(sk, msg, len); @@ -877,11 +868,13 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, /* Copy the address and add cmsg data. */ if (family == AF_INET) { - sin = (struct sockaddr_in *) msg->msg_name; + struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name; + sin->sin_family = AF_INET; sin->sin_port = 0 /* skb->h.uh->source */; sin->sin_addr.s_addr = ip_hdr(skb)->saddr; memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); + *addr_len = sizeof(*sin); if (isk->cmsg_flags) ip_cmsg_recv(msg, skb); @@ -890,17 +883,19 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, } else if (family == AF_INET6) { struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6hdr *ip6 = ipv6_hdr(skb); - sin6 = (struct sockaddr_in6 *) msg->msg_name; + struct sockaddr_in6 *sin6 = + (struct sockaddr_in6 *)msg->msg_name; + sin6->sin6_family = AF_INET6; sin6->sin6_port = 0; sin6->sin6_addr = ip6->saddr; - sin6->sin6_flowinfo = 0; if (np->sndflow) sin6->sin6_flowinfo = ip6_flowinfo(ip6); sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr, IP6CB(skb)->iif); + *addr_len = sizeof(*sin6); if (inet6_sk(sk)->rxopt.all) pingv6_ops.ip6_datagram_recv_ctl(sk, msg, skb); diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 41e1d2845c8..5cb8ddb505e 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -696,9 +696,6 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, if (flags & MSG_OOB) goto out; - if (addr_len) - *addr_len = sizeof(*sin); - if (flags & MSG_ERRQUEUE) { err = ip_recv_error(sk, msg, len); goto out; @@ -726,6 +723,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, sin->sin_addr.s_addr = ip_hdr(skb)->saddr; sin->sin_port = 0; memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); + *addr_len = sizeof(*sin); } if (inet->cmsg_flags) ip_cmsg_recv(msg, skb); diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 89909dd730d..998431cd471 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1235,12 +1235,6 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, int is_udplite = IS_UDPLITE(sk); bool slow; - /* - * Check any passed addresses - */ - if (addr_len) - *addr_len = sizeof(*sin); - if (flags & MSG_ERRQUEUE) return ip_recv_error(sk, msg, len); @@ -1302,6 +1296,7 @@ try_again: sin->sin_port = udp_hdr(skb)->source; sin->sin_addr.s_addr = ip_hdr(skb)->saddr; memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); + *addr_len = sizeof(*sin); } if (inet->cmsg_flags) ip_cmsg_recv(msg, skb); -- cgit v1.2.3-70-g09d2