From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Sashiko <sashiko-bot@kernel.org>,
	Xin Long <lucien.xin@gmail.com>,
	Simon Horman <horms@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18 0584/1250] sctp: fix err_chunk memory leaks in INIT handling
Date: Thu, 17 Sep 2026 16:06:19 +0100
Message-ID: <20260917151607.715307525@linuxfoundation.org>
In-Reply-To: <20260917151551.901433442@linuxfoundation.org>
References: <20260917151551.901433442@linuxfoundation.org>
User-Agent: quilt/0.69
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

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

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

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit 9f58a0a4d6c2ed5d341bba64f058f15d1b0c36f2 ]

When sctp_verify_init() encounters unrecognized parameters, it allocates an
err_chunk to report them. However, this chunk is leaked in several code
paths:

1. In sctp_sf_do_5_1B_init(), if security_sctp_assoc_request() fails after
   sctp_verify_init() has populated err_chunk, the function returns
   immediately without freeing it.

2. In sctp_sf_do_unexpected_init(), the same leak occurs on the
   security_sctp_assoc_request() failure path.

3. In sctp_sf_do_unexpected_init(), on the success path after copying
   unrecognized parameters to the INIT-ACK, the function returns without
   freeing err_chunk, unlike sctp_sf_do_5_1B_init() which properly frees
   it.

Fix all three leaks by adding sctp_chunk_free(err_chunk) calls before
returning in the error paths and on the success path in
sctp_sf_do_unexpected_init().

Fixes: c081d53f97a1 ("security: pass asoc to sctp_assoc_request and sctp_sk_clone")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/0656704f1b0158287c98aec09ba36c83e4a537ab.1781970534.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sctp/sm_statefuns.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 1377493b0844c..3a8e16b29660c 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -416,6 +416,8 @@ enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
 	/* Update socket peer label if first association. */
 	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
 		sctp_association_free(new_asoc);
+		if (err_chunk)
+			sctp_chunk_free(err_chunk);
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 	}
 
@@ -1620,6 +1622,8 @@ static enum sctp_disposition sctp_sf_do_unexpected_init(
 	/* Update socket peer label if first association. */
 	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
 		sctp_association_free(new_asoc);
+		if (err_chunk)
+			sctp_chunk_free(err_chunk);
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 	}
 
@@ -1685,6 +1689,7 @@ static enum sctp_disposition sctp_sf_do_unexpected_init(
 		 * parameter type.
 		 */
 		sctp_addto_chunk(repl, len, unk_param);
+		sctp_chunk_free(err_chunk);
 	}
 
 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
-- 
2.53.0