Re: [nf PATCH 1/2] netfilter: nf_tables: Audit log setelem reset

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, Aug 29, 2023 at 07:51:57PM +0200, Phil Sutter wrote:
> Since set element reset is not integrated into nf_tables' transaction
> logic, an explicit log call is needed, similar to NFT_MSG_GETOBJ_RESET
> handling.
> 
> For the sake of simplicity, catchall element reset will always generate
> a dedicated log entry. This relieves nf_tables_dump_set() from having to
> adjust the logged element count depending on whether a catchall element
> was found or not.
> 
> Cc: Richard Guy Briggs <rgb@redhat.com>
> Fixes: 079cd633219d7 ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> ---
>  include/linux/audit.h         |  1 +
>  kernel/auditsc.c              |  1 +
>  net/netfilter/nf_tables_api.c | 31 ++++++++++++++++++++++++++++---
>  3 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 6a3a9e122bb5e..192bf03aacc52 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -117,6 +117,7 @@ enum audit_nfcfgop {
>  	AUDIT_NFT_OP_OBJ_RESET,
>  	AUDIT_NFT_OP_FLOWTABLE_REGISTER,
>  	AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,
> +	AUDIT_NFT_OP_SETELEM_RESET,
>  	AUDIT_NFT_OP_INVALID,
>  };
>  
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index addeed3df15d3..38481e3181975 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -143,6 +143,7 @@ static const struct audit_nfcfgop_tab audit_nfcfgs[] = {
>  	{ AUDIT_NFT_OP_OBJ_RESET,		"nft_reset_obj"		   },
>  	{ AUDIT_NFT_OP_FLOWTABLE_REGISTER,	"nft_register_flowtable"   },
>  	{ AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,	"nft_unregister_flowtable" },
> +	{ AUDIT_NFT_OP_SETELEM_RESET,		"nft_reset_setelem"        },
>  	{ AUDIT_NFT_OP_INVALID,			"nft_invalid"		   },
>  };
>  
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index 1ddbdca4e47d6..a1218ea4e0c3d 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -102,6 +102,7 @@ static const u8 nft2audit_op[NFT_MSG_MAX] = { // enum nf_tables_msg_types
>  	[NFT_MSG_NEWFLOWTABLE]	= AUDIT_NFT_OP_FLOWTABLE_REGISTER,
>  	[NFT_MSG_GETFLOWTABLE]	= AUDIT_NFT_OP_INVALID,
>  	[NFT_MSG_DELFLOWTABLE]	= AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,
> +	[NFT_MSG_GETSETELEM_RESET] = AUDIT_NFT_OP_SETELEM_RESET,
>  };
>  
>  static void nft_validate_state_update(struct nft_table *table, u8 new_validate_state)
> @@ -5661,13 +5662,25 @@ static int nf_tables_dump_setelem(const struct nft_ctx *ctx,
>  	return nf_tables_fill_setelem(args->skb, set, elem, args->reset);
>  }
>  
> +static void audit_log_nft_set_reset(const struct nft_table *table,
> +				    unsigned int base_seq,
> +				    unsigned int nentries)
> +{
> +	char *buf = kasprintf(GFP_ATOMIC, "%s:%u", table->name, base_seq);

No check for NULL?

I can see we have more like this in the tree.