This is a note to let you know that I've just added the patch titled
net, sunrpc: Remap EPERM in case of connection failure in xs_tcp_setup_socket
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sunrpc-remap-eperm-in-case-of-connection-failure.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ee9ebc917de2779e3ed584d061d283ea30fafe41
Author: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Date: Thu Jul 4 08:41:57 2024 +0200
net, sunrpc: Remap EPERM in case of connection failure in xs_tcp_setup_socket
[ Upstream commit 626dfed5fa3bfb41e0dffd796032b555b69f9cde ]
When using a BPF program on kernel_connect(), the call can return -EPERM. This
causes xs_tcp_setup_socket() to loop forever, filling up the syslog and causing
the kernel to potentially freeze up.
Neil suggested:
This will propagate -EPERM up into other layers which might not be ready
to handle it. It might be safer to map EPERM to an error we would be more
likely to expect from the network system - such as ECONNREFUSED or ENETDOWN.
ECONNREFUSED as error seems reasonable. For programs setting a different error
can be out of reach (see handling in 4fbac77d2d09) in particular on kernels
which do not have f10d05966196 ("bpf: Make BPF_PROG_RUN_ARRAY return -err
instead of allow boolean"), thus given that it is better to simply remap for
consistent behavior. UDP does handle EPERM in xs_udp_send_request().
Fixes: d74bad4e74ee ("bpf: Hooks for sys_connect")
Fixes: 4fbac77d2d09 ("bpf: Hooks for sys_bind")
Co-developed-by: Lex Siegel <usiegl00@xxxxxxxxx>
Signed-off-by: Lex Siegel <usiegl00@xxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Trond Myklebust <trondmy@xxxxxxxxxx>
Cc: Anna Schumaker <anna@xxxxxxxxxx>
Link: https://github.com/cilium/cilium/issues/33395
Link: https://lore.kernel.org/bpf/171374175513.12877.8993642908082014881@xxxxxxxxxxxxxxxxxxxxx
Link: https://patch.msgid.link/9069ec1d59e4b2129fc23433349fd5580ad43921.1720075070.git.daniel@xxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index c3007f3e16f8c..c1fe2a6ea7976 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2422,6 +2422,13 @@ static void xs_tcp_setup_socket(struct work_struct *work)
transport->srcport = 0;
status = -EAGAIN;
break;
+ case -EPERM:
+ /* Happens, for instance, if a BPF program is preventing
+ * the connect. Remap the error so upper layers can better
+ * deal with it.
+ */
+ status = -ECONNREFUSED;
+ fallthrough;
case -EINVAL:
/* Happens, for instance, if the user specified a link
* local IPv6 address without a scope-id.
