On Thu, 1 May 2025 11:54:07 +0200 Janne Grunau wrote:

Commit 59cc89f ("udp, udp_flow: Track our specific address on socket interfaces") added a getsockname() call in udp_flow_new(). This requires getattr. Fixes "Flow 0 (UDP flow): Unable to determine local address: Permission denied" errors in muvm/passt on Fedora Linux 42 with SELinux.

The SELinux audit message is

| type=AVC msg=audit(1746083799.606:235): avc: denied { getattr } for | pid=2961 comm="passt" laddr=127.0.0.1 lport=49221 | faddr=127.0.0.53 fport=53 | scontext=unconfined_u:unconfined_r:passt_t:s0-s0:c0.c1023 | tcontext=unconfined_u:unconfined_r:passt_t:s0-s0:c0.c1023 | tclass=udp_socket permissive=0

Fixes: 59cc89f ("udp, udp_flow: Track our specific address on socket interfaces") Signed-off-by: Janne Grunau

Whoops. Applied. Thanks for fixing this, and welcome to the git log! By the way, if somebody is wondering:

--- contrib/selinux/passt.te | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/contrib/selinux/passt.te b/contrib/selinux/passt.te index f8ea672..eb9ce72 100644 --- a/contrib/selinux/passt.te +++ b/contrib/selinux/passt.te @@ -49,7 +49,7 @@ require { type proc_net_t; type node_t; class tcp_socket { create accept listen name_bind name_connect getattr ioctl }; - class udp_socket { create accept listen }; + class udp_socket { create accept listen getattr }; class icmp_socket { bind create name_bind node_bind setopt read write }; class sock_file { create unlink write };

@@ -133,7 +133,7 @@ allow passt_t node_t:icmp_socket { name_bind node_bind }; allow passt_t port_t:icmp_socket name_bind;

allow passt_t self:tcp_socket { create getopt setopt connect bind listen accept shutdown read write getattr ioctl }; -allow passt_t self:udp_socket { create getopt setopt connect bind read write }; +allow passt_t self:udp_socket { create getopt setopt connect bind read write getattr };

...this already works with pasta's (pasta_t) profile because there we need a bunch of other things (for "spliced" sockets) and I used the create_stream_socket_perms macro instead, which already includes getattr. But including getattr here is enough for passt, no need to allow everything else.

allow passt_t self:icmp_socket { bind create setopt read write };

allow passt_t user_tmp_t:dir { add_name write };

-- Stefano