From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794326863; b=DrbTXgn79YuC7m/MonQZmzOXLS93Rgn3s2fee2ryof8RMZm3xxncVEwYp8MqoPzVFqWP Pj5gjLmW8S4pUj1HrxfViT+2FyA6ZGE3pd9gaCuRDvAH0dgBnv0ZJwP9vO68m/uKd+IsV VzWxXjyKju7WIkGuCrQyqgETeIhX+4wiUFi5XL+OL4d9Q5KrNHAUNKJ6gaw9lCBQ0+QpJ TaI3IFvdOB+R5CEy7UQBzyxqCoYk5/9J+IdV2T8KFf5wo9Q11aRUJiVBrS9ErmqyX3lOw pLR3n3Ki83nEdt8W9yKKACHcV2eAM3QPNrpMI1FD+oKRauer9IdEJfzzspepHooXvCg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794326863; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=T8yh6Ka5cFqopKfHtWbOI0HW3UuBrB7gJugcnlazU7U=; b=KFPqS/RRz6OA3NdoQ17rF0f0shBuvrrMQ/Jm/wHhHvWT8AvTGx2wOVB0UDOqvOkkn/Wt iea3Mp4CG8cmoyfiRLwUoq/urFwULgSsNpqxqbH6zRHEssiJ98nVDXRsFq2jfgYZfxL15 PjNKXhbOOaFA1/ewYYYBHoaPKw0+nZf4LN7yTKEEGy6qeMHjwwBh+pjDWTuuycxVPmtY2 tb13JxfxPlyjLZkVVmVIo1kxySnJyBa5V1FCen8FZJgWi6zHI3U3AWZaB+o7PbA/GwtSX MbjJinQpabe5oYTK5KXQZbPphw16XuKzjGLXsJQE+aCjyQ8Uaz1f8KkolMjYGjVt2Uw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ZBpp0X2i; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2BBF4606A320 for ; Tue, 10 Nov 2026 16:07:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ZBpp0X2i Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27FE81F0089F; Tue, 10 Nov 2026 16:07:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794326862; bh=T8yh6Ka5cFqopKfHtWbOI0HW3UuBrB7gJugcnlazU7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZBpp0X2iNf93OKzsNGZM915SMzS3ngnTKeu4DJULjKz3xA39D3mIgaAwz0gTD7RlX Vr91NoUEqiqdbe/5GoTz5AqnT88s1uQsr6KD2P3dXsx/FeKVIWPZ+6j3pVDOI6JzKI QX1FcHjZ5rE4fRfJPDEFM525HpwPXnfiGfLIcsrr/Wa6P068+THDRca9qBAKpjWGEV 521nkrdWTI8cxRZtTc1yzeG1jzDPkIrQzdYGI1daFnv24LsXR/97C1J5Xt64pHNRF0 HWxm/XCOtR4ivm3Q60ebN4X3NrRxG/ndLvKQ75EoYoRijzSuETjnhS7hKqrwFbBSrH UZvHvfRwFXFhQ== From: Sasha Levin To: stable@vger.kernel.org Cc: David Lee , Kyle Zeng , Xin Long , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y 1/2] sctp: hold shkey across socket migration Date: Tue, 10 Nov 2026 11:07:39 -0500 Message-ID: <20261110160731.2394436-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107053553-failed-6.6-52ffeaa358d1@kernel.org> References: <20261107053553-failed-6.6-52ffeaa358d1@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: David Lee [ Upstream commit ad1320865b1826ffa2e81e37c49535751e81335c ] sctp_sock_migrate() transfers queued DATA skbs from the old socket to the new one. skb_orphan() invokes sctp_wfree() during that transfer and drops the skb-owned shared-key reference. If userspace has removed that key from the association, this can be the final reference. The following sctp_set_owner_w() then dereferences the freed chunk->shkey while trying to take the new owner reference. Take a temporary shared-key reference before orphaning the skb and release it after the new owner has taken its reference. This preserves the selected authentication key throughout the ownership transfer. Bug found and triaged by OpenAI Security Research and validated by Trail of Bits. Fixes: 1b1e0bc99474 ("sctp: add refcnt support for sh_key") Signed-off-by: Kyle Zeng Signed-off-by: David Lee Acked-by: Xin Long Link: https://patch.msgid.link/20261009074244.3718-2-juny24602@gmail.com Signed-off-by: Jakub Kicinski Stable-dep-of: 52ffeaa358d1 ("sctp: re-point retained control chunks on association migration") Signed-off-by: Sasha Levin --- net/sctp/socket.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 4f9978e4f268d..d974d5d147771 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -148,9 +148,19 @@ static inline void sctp_set_owner_w(struct sctp_chunk *chunk) static void sctp_clear_owner_w(struct sctp_chunk *chunk) { + /* Keep the shkey alive until the new owner takes its reference. */ + if (chunk->shkey) + sctp_auth_shkey_hold(chunk->shkey); skb_orphan(chunk->skb); } +static void sctp_set_owner_w_migrate(struct sctp_chunk *chunk) +{ + sctp_set_owner_w(chunk); + if (chunk->shkey) + sctp_auth_shkey_release(chunk->shkey); +} + #define traverse_and_process() \ do { \ msg = chunk->msg; \ @@ -9700,7 +9710,7 @@ static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, lock_sock_nested(newsk, SINGLE_DEPTH_NESTING); sctp_for_each_tx_datachunk(assoc, true, sctp_clear_owner_w); sctp_assoc_migrate(assoc, newsk); - sctp_for_each_tx_datachunk(assoc, false, sctp_set_owner_w); + sctp_for_each_tx_datachunk(assoc, false, sctp_set_owner_w_migrate); /* If the association on the newsk is already closed before accept() * is called, set RCV_SHUTDOWN flag. -- 2.53.0