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* nft: Delete builtin chains compatiblyPhil Sutter2021-09-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Attempting to delete all chains if --delete-chain is called without argument has unwanted side-effects especially legacy iptables users are not aware of and won't expect: * Non-default policies are ignored, a previously dropping firewall may start accepting traffic. * The kernel refuses to remove non-empty chains, causing program abort even if no user-defined chain exists. Fix this by requiring a rule cache in that situation and make builtin chain deletion depend on its policy and number of rules. Since this may change concurrently, check again when having to refresh the transaction. Also, hide builtin chains from verbose output - their creation is implicit, so treat their removal as implicit, too. When deleting a specific chain, do not allow to skip the job though. Otherwise deleting a builtin chain which is still in use will succeed although not executed. Fixes: 61e85e3192dea ("iptables-nft: allow removal of empty builtin chains") Signed-off-by: Phil Sutter <phil@nwl.cc>
* ebtables: Avoid dropping policy when flushingPhil Sutter2021-09-151-1/+3
| | | | | | | | Unlike nftables, ebtables' user-defined chains have policies - ebtables-nft implements those internally as invisible last rule. In order to recreate them after a flush command, a rule cache is needed. https://bugzilla.netfilter.org/show_bug.cgi?id=1558
* iptables-nft: allow removal of empty builtin chainsFlorian Westphal2021-09-071-4/+4
| | | | | | | | | | | | The only reason why this is prohibited is that you cannot do it in iptables-legacy. This removes the artifical limitation. "iptables-nft -X" will leave the builtin chains alone; Also, deletion is only permitted if the chain is empty. Signed-off-by: Florian Westphal <fw@strlen.de>
* nft: Use xtables_{m,c}alloc() everywherePhil Sutter2021-08-311-4/+1
| | | | | | | | | | Make use of libxtables allocators where sensible to have implicit error checking. Leave library-internal calls in place to not create unexpected program exit points for users, apart from xt_xlate_alloc() as that function called xtables_error() in error case which exits by itself already. Signed-off-by: Phil Sutter <phil@nwl.cc>
* libxtables: Introduce xtables_strdup() and use it everywherePhil Sutter2021-06-071-6/+7
| | | | | | This wraps strdup(), checking for errors. Signed-off-by: Phil Sutter <phil@nwl.cc>
* nft: Avoid memleak in error path of nft_cmd_new()Phil Sutter2021-06-071-1/+3
| | | | | | | | If rule allocation fails, free the allocated 'cmd' before returning to caller. Fixes: a7f1e208cdf9c ("nft: split parsing from netlink commands") Signed-off-by: Phil Sutter <phil@nwl.cc>
* iptables-nft: fix -Z optionFlorian Westphal2021-02-241-1/+1
| | | | | | | | | it zeroes the rule counters, so it needs fully populated cache. Add a test case to cover this. Fixes: 9d07514ac5c7a ("nft: calculate cache requirements from list of commands") Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Phil Sutter <phil@nwl.cc>
* nft: Make table creation purely implicitPhil Sutter2020-07-241-5/+0
| | | | | | | | | | | | | | | | | | | While asserting a required builtin chain exists, its table is created implicitly if missing. Exploit this from xtables-restore, too: The only actions which need adjustment are chain_new and chain_restore, i.e. when restoring (either builtin or custom) chains. Note: The call to nft_table_builtin_add() wasn't sufficient as it doesn't set the table as initialized and therefore a following call to nft_xt_builtin_init() would override non-default base chain policies. Note2: The 'table_new' callback in 'nft_xt_restore_cb' is left in place as xtables-translate uses it to print an explicit 'add table' command. Note3: nft_table_new() function was already unused since a7f1e208cdf9c ("nft: split parsing from netlink commands"). Signed-off-by: Phil Sutter <phil@nwl.cc>
* xtables-restore: Fix verbose mode table flushingPhil Sutter2020-06-091-1/+6
| | | | | | | | | | When called with --verbose mode, iptables-nft-restore did not print anything when flushing the table. Fix this by adding a "manual" mode to nft_cmd_table_flush(), turning it into a wrapper around '-F' and '-X' commands, which is exactly what iptables-legacy-restore does to flush a table. This though requires a real cache, so don't set NFT_CL_FAKE then. Signed-off-by: Phil Sutter <phil@nwl.cc>
* nft: cache: Optimize caching for flush commandPhil Sutter2020-05-111-1/+4
| | | | | | | | | | | | | | | | | | When flushing all chains and verbose mode is not enabled, nft_rule_flush() uses a shortcut: It doesn't specify a chain name for NFT_MSG_DELRULE, so the kernel will flush all existing chains without user space needing to know which they are. The above allows to avoid a chain cache, but there's a caveat: nft_xt_builtin_init() will create base chains as it assumes they are missing and thereby possibly overrides any non-default chain policies. Solve this by making nft_xt_builtin_init() cache-aware: If a command doesn't need a chain cache, there's no need to bother with creating any non-existing builtin chains, either. For the sake of completeness, also do nothing if cache is not initialized (although that shouldn't happen). Signed-off-by: Phil Sutter <phil@nwl.cc>
* nft-cache: Fetch cache per tablePhil Sutter2020-05-111-29/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | Restore per-table operation of cache routines as initially implemented in commit e2883c5531e6e ("nft-cache: Support partial cache per table"). As before, this doesn't limit fetching of tables (their number is supposed to be low) but instead limits fetching of sets, chains and rules to the specified table. For this to behave correctly when restoring without flushing over multiple tables, cache must be freed fully after each commit - otherwise the previous table's cache level is reused for the current one. The exception being fake cache, used for flushing restore: NFT_CL_FAKE is set just once at program startup, so it must stay set otherwise consecutive tables cause pointless cache fetching. The sole use-case requiring a multi-table cache, iptables-save, is indicated by req->table being NULL. Therefore, req->table assignment is a bit sloppy: All calls to nft_cache_level_set() are assumed to set the same table value, collision detection exists merely to catch programming mistakes. Make nft_fini() call nft_release_cache() instead of flush_chain_cache(), the former does a full cache deinit including cache_req contents. Signed-off-by: Phil Sutter <phil@nwl.cc>
* nft: calculate cache requirements from list of commandsPablo Neira Ayuso2020-05-111-0/+66
| | | | | | | | | | | | | | | | | | | | This patch uses the new list of commands to calculate the cache requirements, the rationale after this updates is the following: #1 Parsing, that builds the list of commands and it also calculates cache level requirements. #2 Cache building. #3 Translate commands to jobs #4 Translate jobs to netlink This patch removes the pre-parsing code in xtables-restore.c to calculate the cache. After this patch, cache is calculated only once, there is no need to cancel and refetch for an in-transit transaction. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Phil Sutter <phil@nwl.cc>
* nft: split parsing from netlink commandsPablo Neira Ayuso2020-05-111-0/+327
This patch updates the parser to generate a list of command objects. This list of commands is then transformed to a list of netlink jobs. This new command object stores the rule using the nftnl representation via nft_rule_new(). To reduce the number of updates in this patch, the nft_*_rule_find() functions have been updated to restore the native representation to skip the update of the rule comparison code. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Phil Sutter <phil@nwl.cc>