From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF43A2459DD; Thu, 28 May 2026 20:48:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780001288; cv=none; b=oLU5496oUg4y/4qe1KzG7PY8/d7vd2lmLf1pUmE4JRHUyFg9BzRmT2Hze/v79YLGNU9yUFbFiYAC5gJ0s1lH9jByihZ5HZCWbVyAHVX0ejnv2z0APIMt/Xx0zrnqyxcUTjp/9ooagJGEjksB/zE+61mdNAfVH8NKdPxQUK8ZAm4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780001288; c=relaxed/simple; bh=smTPM2gYAWckIC0AdfME/7XGKQAUO6FLBvvxyRDID6c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L0yQlEqL/aWCth6btEiXwxuU+DXEI2ZOjpsROvPCoPGzP2OlcDhDDiS5uFXQlrhwo+5KdnmTQ3uv5fyrc9OBXwmiIMFQI9tsGvBjXOAWVtG2VtFbiLfDIr8r4/8I1monsq2pPqtJtC/hV/pOhtp3QGxD9Ht/H/4IUwUi4lvByLQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qTarjUti; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qTarjUti" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 185321F000E9; Thu, 28 May 2026 20:48:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780001287; bh=nDMCSWD0I13XQdSKGzyMStp1EePF8sFxJaFPKq8hBMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qTarjUtiHS0Niy+yQoZmUCGRhyoqHf7HxJe0gCW/gpMW9MN4fWTJtUefSbVPbp8kq F2ZlhoYMSaj6Y1+uWv3QhNPWoL/+fDUdmTXmvotDnCAW8cgF9g/h7F2Y0+0G4Prizf ly3ge9jE1/C9W1GW09r9NCzE/8174EPl926KODBU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alex Hung , Harry Wentland , Ivan Lipski , Dan Wheeler , Alex Deucher Subject: [PATCH 6.6 075/186] drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async Date: Thu, 28 May 2026 21:49:15 +0200 Message-ID: <20260528194930.963304854@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194928.941004471@linuxfoundation.org> References: <20260528194928.941004471@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harry Wentland commit 6c92f6d9600efa3ef0d9e560a2b52776d9803c29 upstream. [Why&How] dc_process_dmub_aux_transfer_async() copies payload->length bytes into a 16-byte stack buffer (dpaux.data[16]) guarded only by an ASSERT(), which is a no-op in release builds. If a caller ever passes length > 16 this results in a stack buffer overflow via memcpy. Additionally, link_index is used to dereference dc->links[] without bounds checking against dc->link_count, risking an out-of-bounds access. Replace the ASSERT with a hard runtime check that returns false when payload->length exceeds the destination buffer size, and add a bounds check for link_index before it is used. Assisted-by: GitHub Copilot:Claude claude-4-opus Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ba4caa9fecdf7a38f98c878ad05a8a64148b6881) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/dc/core/dc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/amd/display/dc/core/dc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c @@ -4965,7 +4965,11 @@ bool dc_process_dmub_aux_transfer_async( uint8_t action; union dmub_rb_cmd cmd = {0}; - ASSERT(payload->length <= 16); + if (link_index >= dc->link_count || !dc->links[link_index]) + return false; + + if (payload->length > sizeof(cmd.dp_aux_access.aux_control.dpaux.data)) + return false; cmd.dp_aux_access.header.type = DMUB_CMD__DP_AUX_ACCESS; cmd.dp_aux_access.header.payload_bytes = 0;