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authorBen Pfaff <blp@nicira.com>2014-07-09 10:31:22 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-28 08:00:05 -0700
commitc29503e9c04e142bdc14f25df4569486c9e67bd1 (patch)
tree5d2d25b4db0852c48dd9ec2d0e59e59fd6a748bb
parentba502e1e236f4043c849cd11c159ca783643a4de (diff)
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netlink: Fix handling of error from netlink_dump().
[ Upstream commit ac30ef832e6af0505b6f0251a6659adcfa74975e ] netlink_dump() returns a negative errno value on error. Until now, netlink_recvmsg() directly recorded that negative value in sk->sk_err, but that's wrong since sk_err takes positive errno values. (This manifests as userspace receiving a positive return value from the recv() system call, falsely indicating success.) This bug was introduced in the commit that started checking the netlink_dump() return value, commit b44d211 (netlink: handle errors from netlink_dump()). Multithreaded Netlink dumps are one way to trigger this behavior in practice, as described in the commit message for the userspace workaround posted here: http://openvswitch.org/pipermail/dev/2014-June/042339.html This commit also fixes the same bug in netlink_poll(), introduced in commit cd1df525d (netlink: add flow control for memory mapped I/O). Signed-off-by: Ben Pfaff <blp@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/netlink/af_netlink.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index be34adde692..5ed562dfe74 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -500,7 +500,7 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock,
while (nlk->cb != NULL && netlink_dump_space(nlk)) {
err = netlink_dump(sk);
if (err < 0) {
- sk->sk_err = err;
+ sk->sk_err = -err;
sk->sk_error_report(sk);
break;
}
@@ -2272,7 +2272,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
ret = netlink_dump(sk);
if (ret) {
- sk->sk_err = ret;
+ sk->sk_err = -ret;
sk->sk_error_report(sk);
}
}