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=1794336356; b=gnORUM7JGCZDpjNFG0v45Qc+WSmVupHEbXssHc2RZhIueId7ywHecMvMcttinBHJeq9B tnN+0vjiUwsVDz/4FAozwLZMMMUK5ZAKRBYce+i+j4x/3pT5woNhj/QlvcU+63tU7MuyX UA22R682wa455iDGzN/OZv3DU4jExj4ler3F/dy2rUonLH8MOljx5kNUJmBRJqcdcZ5x9 wKggoxYjb54Fnaw6UPJBlCHOG8bXthQwtaFmiojpAdgLglWfIH0XOH/xAmo6lpW1qnEgn DLA7GR6WtoMHqemKHyvAHIg4oH0363EDmV/IMs55OsolxBlofXy3gzxvIkecoY1+miw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794336356; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=TcyqcLIgUFxJIDXUK93qdHLVOYF9gDA6eecDi782dU0=; b=GNcmL++aIO1EedQuLaJNRKurL9cahDrisOsWNxFQq+x+VSALS2iZX67H1mUiLslEtBTP gHbbx0lE5M0havS5ia1ZMT0gTeryGti5A35Q7fR/sc07hCSl9wtbkMoCR4QbdsLmxWOU4 LH+rULBKnW6kAXlMKXvj35S5XzUj8iHVnDVFwu8vhM+H2OhXBt0gnxZRrjrk1ibY5eqFv mfjXZMHePupaVC8csyLwZtyeOtea0zSnjttv7oVBNJ7mjia1HIL9ClK7wcJaGEGk0JQ2U 49DjqXe7O6rlLwMJeOWKe/2UUtCJVoyqiCv46kCy+BkUHHU0500QWuhBLJ+4PfXNyJw== 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=Iv5Rk3Y7; 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 7C480606A336 for ; Tue, 10 Nov 2026 18:45:56 +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=Iv5Rk3Y7 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 697851F008A1; Tue, 10 Nov 2026 18:45:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794336356; bh=TcyqcLIgUFxJIDXUK93qdHLVOYF9gDA6eecDi782dU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Iv5Rk3Y7pMe28wNErAsNTq1Dg6twpX/2TvcYyNrL4o6gPZr2q6er2ivNF7q65byC+ xfbG74Si8dSNzr9UrA+PxlOGXfyej5HEXxhhC6kbm/Ur+w2V/dbjs1WywPff4oxhhy 08jm28o7PBFzuHLhUenRe8C/WgXqMr+wjWUVwUiVTe0oIb4mAah9514A3B/eG6kc2P zFM6PxSfV7JZkqCibhXqfK45fBLThTYlaAosJLqLcgpP1g4SgTj7ZCoKb0n1l2mcBN XtlKOwb2ZcF6G0qvTdyEv1sdF5QCblr77eju/j0Mw5602SM611TNWq91TQ8kAnKDRX s89BJ7Iumi/QQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Yehyeong Lee , Juergen Gross , Bjorn Helgaas , Sasha Levin Subject: [PATCH 5.15.y 2/2] xen/pcifront: check that an AER callback exists before calling it Date: Tue, 10 Nov 2026 13:45:53 -0500 Message-ID: <20261110184209.3328253-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261110184209.3328253-1-sashal@kernel.org> References: <20261107060339-failed-5.15-3b4854b69ee7@kernel.org> <20261110184209.3328253-1-sashal@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: Yehyeong Lee [ Upstream commit 3b4854b69ee70fffb2fa7acac09e715a7efcbae1 ] pcifront_common_process() handles an AER request from the backend by dispatching on aer_op.cmd to the bound driver's PCI error handler. It only checks that err_handler and err_handler->error_detected are present, then for the mmio_enabled, slot_reset and resume commands it calls the corresponding callback unconditionally. Those three callbacks are optional -- the PCI core NULL-checks each of them individually before use -- and many drivers (for example igb, igc, ice and ixgbevf) install error_detected without all of them. aer_op.cmd comes from the shared ring, so a malicious or buggy backend can send XEN_PCI_OP_aer_mmio (or _slotreset/_resume) for a device whose driver leaves that callback NULL and make the frontend call through a NULL pointer, crashing the guest. Check each callback before calling it. When mmio_enabled or slot_reset is absent, return PCI_ERS_RESULT_RECOVERED so recovery proceeds, as the PCI core does for a missing callback; returning PCI_ERS_RESULT_NONE would instead make xen-pciback tear the guest domain down. Fixes: 956a9202cd12 ("xen-pcifront: Xen PCI frontend driver.") Cc: stable@vger.kernel.org Signed-off-by: Yehyeong Lee Reviewed-by: Juergen Gross Acked-by: Bjorn Helgaas Signed-off-by: Juergen Gross Message-ID: <20261006023443.338194-1-yhlee@isslab.korea.ac.kr> Signed-off-by: Sasha Levin --- drivers/pci/xen-pcifront.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c index aa3b84823e686..1dac92706f1ec 100644 --- a/drivers/pci/xen-pcifront.c +++ b/drivers/pci/xen-pcifront.c @@ -612,11 +612,16 @@ static pci_ers_result_t pcifront_common_process(int cmd, case XEN_PCI_OP_aer_detected: return pdrv->err_handler->error_detected(pcidev, state); case XEN_PCI_OP_aer_mmio: - return pdrv->err_handler->mmio_enabled(pcidev); + if (pdrv->err_handler->mmio_enabled) + return pdrv->err_handler->mmio_enabled(pcidev); + return PCI_ERS_RESULT_RECOVERED; case XEN_PCI_OP_aer_slotreset: - return pdrv->err_handler->slot_reset(pcidev); + if (pdrv->err_handler->slot_reset) + return pdrv->err_handler->slot_reset(pcidev); + return PCI_ERS_RESULT_RECOVERED; case XEN_PCI_OP_aer_resume: - pdrv->err_handler->resume(pcidev); + if (pdrv->err_handler->resume) + pdrv->err_handler->resume(pcidev); return PCI_ERS_RESULT_NONE; default: dev_err(&pdev->xdev->dev, -- 2.53.0