2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------
 syscalls

From: Hannes Frederic Sowa <[email protected]>

[ Upstream commit bceaa90240b6019ed73b49965eac7d167610be69 ]

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]>
[wt: no ieee802154, ping nor l2tp in 2.6.32]
Signed-off-by: Willy Tarreau <[email protected]>
---
 net/ipv4/raw.c        | 4 +---
 net/ipv4/udp.c        | 7 +------
 net/ipv6/raw.c        | 4 +---
 net/ipv6/udp.c        | 5 +----
 net/phonet/datagram.c | 9 ++++-----
 5 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 07ab583..c50344b 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -681,9 +681,6 @@ 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;
@@ -711,6 +708,7 @@ 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 af559e0..80487ee 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -941,12 +941,6 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, 
struct msghdr *msg,
        int err;
        int is_udplite = IS_UDPLITE(sk);
 
-       /*
-        *      Check any passed addresses
-        */
-       if (addr_len)
-               *addr_len = sizeof(*sin);
-
        if (flags & MSG_ERRQUEUE)
                return ip_recv_error(sk, msg, len);
 
@@ -1001,6 +995,7 @@ 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);
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 4f24570..df75f94 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -456,9 +456,6 @@ 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);
 
@@ -495,6 +492,7 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock 
*sk,
                sin6->sin6_scope_id = 0;
                if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
                        sin6->sin6_scope_id = IP6CB(skb)->iif;
+               *addr_len = sizeof(*sin6);
        }
 
        sock_recv_timestamp(msg, sk, skb);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index d8c0374..ce291af 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -200,9 +200,6 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
        int is_udplite = IS_UDPLITE(sk);
        int is_udp4;
 
-       if (addr_len)
-               *addr_len=sizeof(struct sockaddr_in6);
-
        if (flags & MSG_ERRQUEUE)
                return ipv6_recv_error(sk, msg, len);
 
@@ -273,7 +270,7 @@ try_again:
                        if (ipv6_addr_type(&sin6->sin6_addr) & 
IPV6_ADDR_LINKLOCAL)
                                sin6->sin6_scope_id = IP6CB(skb)->iif;
                }
-
+               *addr_len = sizeof(*sin6);
        }
        if (is_udp4) {
                if (inet->cmsg_flags)
diff --git a/net/phonet/datagram.c b/net/phonet/datagram.c
index ef5c75c..c88da73 100644
--- a/net/phonet/datagram.c
+++ b/net/phonet/datagram.c
@@ -122,9 +122,6 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
        if (flags & MSG_OOB)
                goto out_nofree;
 
-       if (addr_len)
-               *addr_len = sizeof(sa);
-
        skb = skb_recv_datagram(sk, flags, noblock, &rval);
        if (skb == NULL)
                goto out_nofree;
@@ -145,8 +142,10 @@ 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);
-- 
1.7.12.2.21.g234cd45.dirty



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