[PATCH 6.12.y 3/4] mptcp: use sock_kmemdup for address entry

[Sasha Levin <sashal@kernel.org>]

From: Geliang Tang <tanggeliang@kylinos.cn>

[ Upstream commit 52f83c0b5f857dbe24f66fc9a7f035523e9ffbc9 ]

Instead of using sock_kmalloc() to allocate an address
entry "e" and then immediately duplicate the input "entry"
to it, the newly added sock_kmemdup() helper can be used in
mptcp_userspace_pm_append_new_local_addr() to simplify the code.

More importantly, the code "*e = *entry;" that assigns "entry"
to "e" is not easy to implemented in BPF if we use the same code
to implement an append_new_local_addr() helper of a BFP path
manager. This patch avoids this type of memory assignment
operation.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/3e5a307aed213038a87e44ff93b5793229b16279.1740735165.git.tanggeliang@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: f9f0068e8813 ("mptcp: pm: userspace: fix address ID overflow")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mptcp/pm_userspace.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 708cc81e707e7..da39a2e396661 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -68,13 +68,12 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 		/* Memory for the entry is allocated from the
 		 * sock option buffer.
 		 */
-		e = sock_kmalloc(sk, sizeof(*e), GFP_ATOMIC);
+		e = sock_kmemdup(sk, entry, sizeof(*entry), GFP_ATOMIC);
 		if (!e) {
 			ret = -ENOMEM;
 			goto append_err;
 		}
 
-		*e = *entry;
 		if (!e->addr.id && needs_id)
 			e->addr.id = find_next_zero_bit(id_bitmap,
 							MPTCP_PM_MAX_ADDR_ID + 1,
-- 
2.53.0