From 4039ce7ef40474d5ba46f414c50cc7020b9cf8ae Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 7 Aug 2025 15:49:59 +0200 Subject: netfilter: nf_tables: Introduce NFTA_DEVICE_PREFIX This new attribute is supposed to be used instead of NFTA_DEVICE_NAME for simple wildcard interface specs. It holds a NUL-terminated string representing an interface name prefix to match on. While kernel code to distinguish full names from prefixes in NFTA_DEVICE_NAME is simpler than this solution, reusing the existing attribute with different semantics leads to confusion between different versions of kernel and user space though: * With old kernels, wildcards submitted by user space are accepted yet silently treated as regular names. * With old user space, wildcards submitted by kernel may cause crashes since libnftnl expects NUL-termination when there is none. Using a distinct attribute type sanitizes these situations as the receiving part detects and rejects the unexpected attribute nested in *_HOOK_DEVS attributes. Fixes: 6d07a289504a ("netfilter: nf_tables: Support wildcard netdev hook specs") Signed-off-by: Phil Sutter Signed-off-by: Florian Westphal --- include/uapi/linux/netfilter/nf_tables.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 2beb30be2c5f..8e0eb832bc01 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -1784,10 +1784,12 @@ enum nft_synproxy_attributes { * enum nft_device_attributes - nf_tables device netlink attributes * * @NFTA_DEVICE_NAME: name of this device (NLA_STRING) + * @NFTA_DEVICE_PREFIX: device name prefix, a simple wildcard (NLA_STRING) */ enum nft_devices_attributes { NFTA_DEVICE_UNSPEC, NFTA_DEVICE_NAME, + NFTA_DEVICE_PREFIX, __NFTA_DEVICE_MAX }; #define NFTA_DEVICE_MAX (__NFTA_DEVICE_MAX - 1) -- cgit v1.2.3