[PATCH RFC] nftables: fix surpression of "permission denied" errors

[Patrick McHardy <kaber@trash.net>]

commit 8ca6730e9c8fd59d8a03ae505777a8a6b97898b1
Author: Patrick McHardy <kaber@trash.net>
Date:   Wed Jan 8 20:57:11 2014 +0000

    nftables: fix surpression of "permission denied" errors
    
    ntroduction of batch support broke displaying of EPERM since those are
    generated by the kernel before batch processing start and thus have the
    sequence number of the NFNL_MSG_BATCH_BEGIN message instead of the
    command messages. Also only a single error message is generated for the
    entire batch.
    
    This patch fixes this by noting the batch sequence number and displaying
    the error for all commands since this is what would happen if the
    permission check was inside batch processing as every other check.
    
    Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/include/mnl.h b/include/mnl.h
index fe2fb40..a630605 100644
--- a/include/mnl.h
+++ b/include/mnl.h
@@ -18,7 +18,7 @@ void mnl_err_list_free(struct mnl_err *err);
 void mnl_batch_init(void);
 bool mnl_batch_ready(void);
 void mnl_batch_reset(void);
-void mnl_batch_begin(void);
+uint32_t mnl_batch_begin(void);
 void mnl_batch_end(void);
 int mnl_batch_talk(struct mnl_socket *nl, struct list_head *err_list);
 int mnl_nft_rule_batch_add(struct nft_rule *nlr, unsigned int flags,
diff --git a/src/main.c b/src/main.c
index 859ddaa..33a02e1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -160,9 +160,10 @@ static int nft_netlink(struct parser_state *state, struct list_head *msgs)
 	struct cmd *cmd, *next;
 	struct mnl_err *err, *tmp;
 	LIST_HEAD(err_list);
+	uint32_t batch_seqnum;
 	int ret = 0;
 
-	mnl_batch_begin();
+	batch_seqnum = mnl_batch_begin();
 	list_for_each_entry(cmd, &state->cmds, list) {
 		memset(&ctx, 0, sizeof(ctx));
 		ctx.msgs = msgs;
@@ -183,12 +184,15 @@ static int nft_netlink(struct parser_state *state, struct list_head *msgs)
 
 	list_for_each_entry_safe(err, tmp, &err_list, head) {
 		list_for_each_entry(cmd, &state->cmds, list) {
-			if (err->seqnum == cmd->seqnum) {
+			if (err->seqnum == cmd->seqnum ||
+			    err->seqnum == batch_seqnum) {
 				netlink_io_error(&ctx, &cmd->location,
 					"Could not process rule in batch: %s",
 					strerror(err->err));
-				mnl_err_list_free(err);
-				break;
+				if (err->seqnum == cmd->seqnum) {
+					mnl_err_list_free(err);
+					break;
+				}
 			}
 		}
 	}
diff --git a/src/mnl.c b/src/mnl.c
index a711b5e..a4a4c4a 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -106,7 +106,7 @@ static void mnl_batch_page_add(void)
 	batch = mnl_batch_alloc();
 }
 
-static void mnl_batch_put(int type)
+static uint32_t mnl_batch_put(int type)
 {
 	struct nlmsghdr *nlh;
 	struct nfgenmsg *nfg;
@@ -123,11 +123,13 @@ static void mnl_batch_put(int type)
 
 	if (!mnl_nlmsg_batch_next(batch))
 		mnl_batch_page_add();
+
+	return nlh->nlmsg_seq;
 }
 
-void mnl_batch_begin(void)
+uint32_t mnl_batch_begin(void)
 {
-	mnl_batch_put(NFNL_MSG_BATCH_BEGIN);
+	return mnl_batch_put(NFNL_MSG_BATCH_BEGIN);
 }
 
 void mnl_batch_end(void)