From nobody Fri Dec 19 22:02:08 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 1B50420DD56; Sun, 24 Mar 2024 23:07:36 +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=1711321657; cv=none; b=DBuHHcblmmxfs6wy8Cr1Fymkzx90+cKTRCSDU/cWaK9NZUMwtan1t5Dhxgr1f8nHn5Vnsxd7JdRGqQ452SD6TSiIR3JEI4e4tzsQ32FMExqdIt4PtKHAzTjImdSVC+Eqpf5o/SfR6zW0gRfkyNpYJSSUfICioKpkmw4KLZbv8HY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321657; c=relaxed/simple; bh=ScxSW6UgPUsVoztvMsj+KZEAdBvd7VPwubsif2s549w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XR/03zSpXM3bo5XmzNoXZpjBM5MNAw4HorrlkyVqde7AqRFfzFmx34QSHC1PrGzc6izewjYwKu0gqZK+Ne+Ir8S4CY2up+AHNzihk97x2OQdibaHpWDMDnPoeqyUM8coW18ZVayA74wRrjy5TZmjsqfyg6Hzpttu5uZuwQjJvfs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IbZxKwRy; 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="IbZxKwRy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5AF91C43394; Sun, 24 Mar 2024 23:07:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321656; bh=ScxSW6UgPUsVoztvMsj+KZEAdBvd7VPwubsif2s549w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IbZxKwRyCBTrQqQYHxNDHJfmqjqI4+6vyZrdkV2HxhciMVGOhO6us9rXp32JSWPP8 dCaNvjz37L74qlCf4o+VWA3t+oFCa2LahM45lyq7EsamWEmKTjxepXFgTBgfUBRLFd 75cPujZY9B6OT1uZzQy8d7ssiag5CL8ZkoCxS0hfwVsty94XDcwII0Hthrluuf7zIH OMzhv2P8j/BeiuoTBy16uoyQrC73y776QK9153xoA/vrp6gDjqSlhV0Hn6Zi/Z9vkK eCSsymiM+B1dNy3eRdNJogRVZF5+aX7SNSjpxld4MAKgnyhuzCDkRA2Eg0WT8R6ZT9 WExR1peD+HlMw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhipeng Lu , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 6.6 385/638] media: edia: dvbdev: fix a use-after-free Date: Sun, 24 Mar 2024 18:57:02 -0400 Message-ID: <20240324230116.1348576-386-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324230116.1348576-1-sashal@kernel.org> References: <20240324230116.1348576-1-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 49f0eb7d0b9d3..733d0bc4b4cc3 100644 --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -490,6 +490,7 @@ 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; } @@ -498,6 +499,7 @@ 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; } @@ -531,6 +533,7 @@ 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; @@ -553,6 +556,7 @@ 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; } @@ -571,6 +575,7 @@ 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