pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmocom-bb/+/31109 )

Change subject: trxcon: Fix heap-use-after-free in l1ctl_client ......................................................................

trxcon: Fix heap-use-after-free in l1ctl_client

If the peer connected to trxcon restarts the process, read() on the unix socket in trxcon fails, and triggers closing the conn (l1ctl_client), which ends up freeing the struct. This all happens during read_cb() of the l1ctl_client wqueue. If the kernel also flags WRITE event in the same main loop iteration, the wqueue code would end up using the freed struct again when running the write_cb.

Make sure the read_cb returns -EBADF in the code branch closing the conn in read_cb, since it makes no sense to handle a write_cb after that. This saves the code from accessing the potentially freed struct.

Related: OS#5872 Change-Id: I100a8ba056a09b4e52675e3539640da0c0f8d837 --- M src/host/trxcon/src/l1ctl_server.c 1 file changed, 1 insertion(+), 1 deletion(-)

git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/09/31109/1

diff --git a/src/host/trxcon/src/l1ctl_server.c b/src/host/trxcon/src/l1ctl_server.c index bfbd997..c0f1015 100644 --- a/src/host/trxcon/src/l1ctl_server.c +++ b/src/host/trxcon/src/l1ctl_server.c @@ -61,7 +61,7 @@ rc = -EIO; } l1ctl_client_conn_close(client); - return rc; + return -EBADF; /* client fd is gone, avoid processing any other events. */ }

/* Check message length */