python: T8857: replace bare except clauses with except Exception in config scripts

Bare except: catches everything derived from BaseException, including
SystemExit and KeyboardInterrupt. Config scripts must not silently
continue past sys.exit(), so replace bare except: with except Exception:
in the three config-mode scripts that contained one.

Library code (python/vyos/configverify.py, python/vyos/config.py) and
op-mode scripts are intentionally out of scope: those cases require
case-by-case design review (e.g. MTU lookups should accept defaults as
arguments rather than rely on exception handling; reset-style op-mode
scripts may legitimately want to ignore KeyboardInterrupt).

Sites changed:
- src/conf_mode/interfaces_ethernet.py (MTU adapter lookup)
- src/conf_mode/vpp_interfaces_bonding.py (MAC validation)
- src/conf_mode/container.py x2 (IPv4 / IPv6 prefix lookup)

3 files changed, 4 insertions, 4 deletions

diff --git a/src/conf_mode/container.py b/src/conf_mode/container.py
index 20ec300aa..19ff0da34 100755
--- a/src/conf_mode/container.py
+++ b/src/conf_mode/container.py
@@ -177,13 +177,13 @@ def verify(container):
                             try:
                                 network = [x for x in container['network'][network_name]['prefix'] if is_ipv4(x)][0]
                                 cnt_ipv4 += 1
-                            except:
+                            except Exception:
                                 raise ConfigError(f'Network "{network_name}" does not contain an IPv4 prefix!')
                         elif is_ipv6(address):
                             try:
                                 network = [x for x in container['network'][network_name]['prefix'] if is_ipv6(x)][0]
                                 cnt_ipv6 += 1
-                            except:
+                            except Exception:
                                 raise ConfigError(f'Network "{network_name}" does not contain an IPv6 prefix!')
 
                         # Specified container IP address must belong to network prefix
diff --git a/src/conf_mode/interfaces_ethernet.py b/src/conf_mode/interfaces_ethernet.py
index 2eb36a231..b9177cd34 100755
--- a/src/conf_mode/interfaces_ethernet.py
+++ b/src/conf_mode/interfaces_ethernet.py
@@ -159,7 +159,7 @@ def get_config(config=None):
             max_mtu = EthernetIf(ifname).get_max_mtu()
             if max_mtu < int(ethernet['mtu']):
                 ethernet['mtu'] = str(max_mtu)
-        except:
+        except Exception:
             pass
 
     if 'is_bond_member' in ethernet:
diff --git a/src/conf_mode/vpp_interfaces_bonding.py b/src/conf_mode/vpp_interfaces_bonding.py
index 51272c087..d02975e23 100644
--- a/src/conf_mode/vpp_interfaces_bonding.py
+++ b/src/conf_mode/vpp_interfaces_bonding.py
@@ -188,7 +188,7 @@ def verify(config):
         mac = config['mac']
         try:
             assert_mac(mac, test_all_zero=False)
-        except:
+        except Exception:
             raise ConfigError(
                 f'Cannot use {mac}: it is a multicast MAC address. Please provide a unicast MAC address.'
             )