On 3/21/23 11:45 AM, Aditi Ghag wrote:
Previously, UDP listening sockets that bind'ed to a port
weren't getting properly destroyed via udp_abort.
Specifically, the sockets were left in the UDP hash table with
unset source port.
Fix the issue by unconditionally unhashing and resetting source
port for sockets that are getting destroyed. This would mean
that in case of sockets listening on wildcarded address and
on a specific address with a common port, users would have to
explicitly select the socket(s) they intend to destroy.
Signed-off-by: Aditi Ghag <aditi.ghag@xxxxxxxxxxxxx>
---
net/ipv4/udp.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 02d357713838..a495ac88fcee 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1965,6 +1965,25 @@ int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
}
EXPORT_SYMBOL(udp_pre_connect);
+int __udp_disconnect_with_abort(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+
+ sk->sk_state = TCP_CLOSE;
+ inet->inet_daddr = 0;
+ inet->inet_dport = 0;
+ sock_rps_reset_rxhash(sk);
+ sk->sk_bound_dev_if = 0;
+ inet_reset_saddr(sk);
+ inet->inet_sport = 0;
+ sk_dst_reset(sk);
+ /* (TBD) In case of sockets listening on wildcard and specific address
+ * with a common port, socket will be removed from {hash, hash2} table.
+ */
+ sk->sk_prot->unhash(sk);
hmm... not sure if I understand the use case. The idea is to enforce the user
space to bind() again when it gets error from read(fd) because the source
ip/port needs to change when sending to another dst IP/port? Does it have a
usage example in the selftests?
+ return 0;
+}
+
int __udp_disconnect(struct sock *sk, int flags)
{
struct inet_sock *inet = inet_sk(sk);
@@ -2937,7 +2956,7 @@ int udp_abort(struct sock *sk, int err)
sk->sk_err = err;
sk_error_report(sk);
- __udp_disconnect(sk, 0);
+ __udp_disconnect_with_abort(sk);
out:
if (!has_current_bpf_ctx())
