[PATCH 6.1 506/609] bpf: tcp: Use bpf_tcp_iter_batch_item for bpf_tcp_iter_state batch items

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jordan Rife <[email protected]>

[ Upstream commit efeb820951ebf3778830256496ff72d00d135310 ]

Prepare for the next patch that tracks cookies between iterations by
converting struct sock **batch to union bpf_tcp_iter_batch_item *batch
inside struct bpf_tcp_iter_state.

Signed-off-by: Jordan Rife <[email protected]>
Signed-off-by: Martin KaFai Lau <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Acked-by: Stanislav Fomichev <[email protected]>
Stable-dep-of: e5fd3f514e27 ("bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()")
Signed-off-by: Sasha Levin <[email protected]>
---
 net/ipv4/tcp_ipv4.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index fb975e8f55ae5..9843e05343565 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2725,12 +2725,16 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
 }
 
 #ifdef CONFIG_BPF_SYSCALL
+union bpf_tcp_iter_batch_item {
+	struct sock *sk;
+};
+
 struct bpf_tcp_iter_state {
 	struct tcp_iter_state state;
 	unsigned int cur_sk;
 	unsigned int end_sk;
 	unsigned int max_sk;
-	struct sock **batch;
+	union bpf_tcp_iter_batch_item *batch;
 };
 
 struct bpf_iter__tcp {
@@ -2756,13 +2760,13 @@ static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
 	unsigned int cur_sk = iter->cur_sk;
 
 	while (cur_sk < iter->end_sk)
-		sock_gen_put(iter->batch[cur_sk++]);
+		sock_gen_put(iter->batch[cur_sk++].sk);
 }
 
 static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
 				      unsigned int new_batch_sz, gfp_t flags)
 {
-	struct sock **new_batch;
+	union bpf_tcp_iter_batch_item *new_batch;
 
 	new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
 			     flags | __GFP_NOWARN);
@@ -2786,7 +2790,7 @@ static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
 	struct sock *sk;
 
 	sock_hold(*start_sk);
-	iter->batch[iter->end_sk++] = *start_sk;
+	iter->batch[iter->end_sk++].sk = *start_sk;
 
 	sk = sk_nulls_next(*start_sk);
 	*start_sk = NULL;
@@ -2794,7 +2798,7 @@ static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
 		if (seq_sk_match(seq, sk)) {
 			if (iter->end_sk < iter->max_sk) {
 				sock_hold(sk);
-				iter->batch[iter->end_sk++] = sk;
+				iter->batch[iter->end_sk++].sk = sk;
 			} else if (!*start_sk) {
 				/* Remember where we left off. */
 				*start_sk = sk;
@@ -2815,7 +2819,7 @@ static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
 	struct sock *sk;
 
 	sock_hold(*start_sk);
-	iter->batch[iter->end_sk++] = *start_sk;
+	iter->batch[iter->end_sk++].sk = *start_sk;
 
 	sk = sk_nulls_next(*start_sk);
 	*start_sk = NULL;
@@ -2823,7 +2827,7 @@ static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
 		if (seq_sk_match(seq, sk)) {
 			if (iter->end_sk < iter->max_sk) {
 				sock_hold(sk);
-				iter->batch[iter->end_sk++] = sk;
+				iter->batch[iter->end_sk++].sk = sk;
 			} else if (!*start_sk) {
 				/* Remember where we left off. */
 				*start_sk = sk;
@@ -2927,7 +2931,7 @@ static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
 	WARN_ON_ONCE(iter->end_sk != expected);
 done:
 	bpf_iter_tcp_unlock_bucket(seq);
-	return iter->batch[0];
+	return iter->batch[0].sk;
 }
 
 static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
@@ -2962,11 +2966,11 @@ static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 		 * st->bucket.  See tcp_seek_last_pos().
 		 */
 		st->offset++;
-		sock_gen_put(iter->batch[iter->cur_sk++]);
+		sock_gen_put(iter->batch[iter->cur_sk++].sk);
 	}
 
 	if (iter->cur_sk < iter->end_sk)
-		sk = iter->batch[iter->cur_sk];
+		sk = iter->batch[iter->cur_sk].sk;
 	else
 		sk = bpf_iter_tcp_batch(seq);
 
-- 
2.53.0