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inet: prevent leakage of uninitialized memory to user in recv syscalls
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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 <[email protected]>
Suggested-by: Eric Dumazet <[email protected]>
Signed-off-by: Hannes Frederic Sowa <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@strssndktn @davem330
strssndktn authored and davem330 committed Nov 18, 2013
1 parent bcd081a commit bceaa90
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Showing 8 changed files with 17 additions and 38 deletions.
3 changes: 1 addition & 2 deletions net/ieee802154/dgram.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -315,9 +315,8 @@ static int dgram_recvmsg(struct kiocb *iocb, struct sock *sk,
if (saddr) {
saddr->family = AF_IEEE802154;
saddr->addr = mac_cb(skb)->sa;
}
if (addr_len)
*addr_len = sizeof(*saddr);
}

if (flags & MSG_TRUNC)
copied = skb->len;
Expand Down
19 changes: 7 additions & 12 deletions net/ipv4/ping.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand All @@ -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);
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand Down
4 changes: 1 addition & 3 deletions net/ipv4/raw.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down
7 changes: 1 addition & 6 deletions net/ipv4/udp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand Down Expand Up @@ -1302,6 +1296,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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);
Expand Down
4 changes: 1 addition & 3 deletions net/ipv6/raw.c
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Original file line number Diff line number Diff line change
Expand Up @@ -465,9 +465,6 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk,
if (flags & MSG_OOB)
return -EOPNOTSUPP;

if (addr_len)
*addr_len=sizeof(*sin6);

if (flags & MSG_ERRQUEUE)
return ipv6_recv_error(sk, msg, len);

Expand Down Expand Up @@ -506,6 +503,7 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk,
sin6->sin6_flowinfo = 0;
sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
IP6CB(skb)->iif);
*addr_len = sizeof(*sin6);
}

sock_recv_ts_and_drops(msg, sk, skb);
Expand Down
5 changes: 1 addition & 4 deletions net/ipv6/udp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -392,9 +392,6 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
int is_udp4;
bool slow;

if (addr_len)
*addr_len = sizeof(struct sockaddr_in6);

if (flags & MSG_ERRQUEUE)
return ipv6_recv_error(sk, msg, len);

Expand Down Expand Up @@ -480,7 +477,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
ipv6_iface_scope_id(&sin6->sin6_addr,
IP6CB(skb)->iif);
}

*addr_len = sizeof(*sin6);
}
if (is_udp4) {
if (inet->cmsg_flags)
Expand Down
4 changes: 1 addition & 3 deletions net/l2tp/l2tp_ip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -518,9 +518,6 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
if (flags & MSG_OOB)
goto out;

if (addr_len)
*addr_len = sizeof(*sin);

skb = skb_recv_datagram(sk, flags, noblock, &err);
if (!skb)
goto out;
Expand All @@ -543,6 +540,7 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
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);
Expand Down
9 changes: 4 additions & 5 deletions net/phonet/datagram.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -139,9 +139,6 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
MSG_CMSG_COMPAT))
goto out_nofree;

if (addr_len)
*addr_len = sizeof(sa);

skb = skb_recv_datagram(sk, flags, noblock, &rval);
if (skb == NULL)
goto out_nofree;
Expand All @@ -162,8 +159,10 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,

rval = (flags & MSG_TRUNC) ? skb->len : copylen;

if (msg->msg_name != NULL)
memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
if (msg->msg_name != NULL) {
memcpy(msg->msg_name, &sa, sizeof(sa));
*addr_len = sizeof(sa);
}

out:
skb_free_datagram(sk, skb);
Expand Down

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