From nobody Fri Dec 19 21:48:33 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6605F29618D; Sun, 24 Mar 2024 23:51:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711324317; cv=none; b=mA6DncKh9hRPmnl802d3+6b+5ZGGctuDJ0KAPIgY9Wg/LMsCJH9oWG+J3g1EMT3ce4d4z3qVj2PL5J4Bzzp1+cjnqAERCKgO05n5BYEbe7cIByAe3f7GWldENwnC5oUXtGi+sPxLoRJWKQaRJXgyM2NPl2QMuTlwThF0l9mRyRA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711324317; c=relaxed/simple; bh=xhecuLVwTF/x3m+Vd/DgeBCVK7TzpAqqQH6UaRkUs2U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=N/144OoHrBHKlcFgPYdBjQocWgdYaJ+W0weaIbIJqGea8+y/i/hCL5pRbMcIwH8+JQ6dxfRhaX+U+wyPq7UxPw0FvKvykoJKop4IAbONdhF8MqF0/DfCb3tjkW/cN7JGGML1h9KQb1eP6Hc4wu38U39nTRRsEIajIvXZr+Ay71s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UXurerOg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UXurerOg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45252C433B1; Sun, 24 Mar 2024 23:51:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711324316; bh=xhecuLVwTF/x3m+Vd/DgeBCVK7TzpAqqQH6UaRkUs2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UXurerOgJQShx5x1RX1jrlOYFDdDtTXWj+VBID/dBI10Vf5PwHpb1w7XUZINsZKTN xdapYpHR+IrguI8vaHusUpoxUQg9QE4jxtEX+RZFiuibZa0Q39WCLgun36vggHJHq8 8PgKiFTAJ6bh9GHH1WOuxKNaJH5lyxmU4wFA7r+MYucdCnXVVnavT17QVvx3146h3m OJgPillJlBOxcAiqGIvINtizAIc0j7EjFYN+jhzIwIgwcYZrbNXVTQuQYl5JyaSR7g h/Q6MqEGpF1E5l4900hCc+TJjuOgs2hYukoWCGuq/TOXNPhQlU+W/WBqb+aopB0JAS Oc00iAeLc7sIQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhipeng Lu , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 4.19 087/148] media: edia: dvbdev: fix a use-after-free Date: Sun, 24 Mar 2024 19:49:11 -0400 Message-ID: <20240324235012.1356413-88-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324235012.1356413-1-sashal@kernel.org> References: <20240324235012.1356413-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Zhipeng Lu [ Upstream commit 8c64f4cdf4e6cc5682c52523713af8c39c94e6d5 ] In dvb_register_device, *pdvbdev is set equal to dvbdev, which is freed in several error-handling paths. However, *pdvbdev is not set to NULL after dvbdev's deallocation, causing use-after-frees in many places, for example, in the following call chain: budget_register |-> dvb_dmxdev_init |-> dvb_register_device |-> dvb_dmxdev_release |-> dvb_unregister_device |-> dvb_remove_device |-> dvb_device_put |-> kref_put When calling dvb_unregister_device, dmxdev->dvbdev (i.e. *pdvbdev in dvb_register_device) could point to memory that had been freed in dvb_register_device. Thereafter, this pointer is transferred to kref_put and triggering a use-after-free. Link: https://lore.kernel.org/linux-media/20240203134046.3120099-1-alexious= @zju.edu.cn Fixes: b61901024776 ("V4L/DVB (5244): Dvbdev: fix illegal re-usage of fileo= perations struct") Signed-off-by: Zhipeng Lu Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/dvb-core/dvbdev.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbde= v.c index 35c272d77375e..f426e1bf16f0a 100644 --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -504,6 +504,7 @@ int dvb_register_device(struct dvb_adapter *adap, struc= t dvb_device **pdvbdev, dvbdevfops =3D kmemdup(template->fops, sizeof(*dvbdevfops), GFP_KERNEL); if (!dvbdevfops) { kfree(dvbdev); + *pdvbdev =3D NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -512,6 +513,7 @@ int dvb_register_device(struct dvb_adapter *adap, struc= t dvb_device **pdvbdev, if (!new_node) { kfree(dvbdevfops); kfree(dvbdev); + *pdvbdev =3D NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -545,6 +547,7 @@ int dvb_register_device(struct dvb_adapter *adap, struc= t dvb_device **pdvbdev, } list_del (&dvbdev->list_head); kfree(dvbdev); + *pdvbdev =3D NULL; up_write(&minor_rwsem); mutex_unlock(&dvbdev_register_lock); return -EINVAL; @@ -567,6 +570,7 @@ int dvb_register_device(struct dvb_adapter *adap, struc= t dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del (&dvbdev->list_head); kfree(dvbdev); + *pdvbdev =3D NULL; mutex_unlock(&dvbdev_register_lock); return ret; } @@ -585,6 +589,7 @@ int dvb_register_device(struct dvb_adapter *adap, struc= t dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del (&dvbdev->list_head); kfree(dvbdev); + *pdvbdev =3D NULL; mutex_unlock(&dvbdev_register_lock); return PTR_ERR(clsdev); } --=20 2.43.0