From patchwork Wed Jul 31 19:03:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 13749065 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) (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 D3B8D8BE0 for ; Wed, 31 Jul 2024 19:03:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.60.130.6 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722452642; cv=none; b=F2bjRYsBn36YZtDOHHzKNLX3yzojenv6rCeqM0FV+J7bPrMuzDTcp1XizhIiBfp5SOwnb6AnKtWZ/L4KJ3CE/m57zIpReo6Wv5C7vRtw33U+c5BOkc8DFv0e/sztgHgQXX4PwU8iGLMytGI5kcMOargb4Ut9e5Pb4Eg3nw3xHhQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722452642; c=relaxed/simple; bh=2G7+qJuP2xXW1sO134ksAIEosd1yNslO6dAxeUW9hG8=; 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bh=LY8wrhZT2/j08yzF+EkdR+9clkRxKx5d8E6tPh9GQkg=; b=MywBFxEi/hYLhq9u4gO91F2Hyq ugg2kXZrjiuMuXyIyASAjAGkCYfp04YBX9z6btvT/k60wRBq7aplkl+l6DRRT6UKQywWk9Pr2Jq3p 0iFA24+G5G5eYUp1UyduACmg/ixA/nSeAqD+BzTTwWdLJH+Zdld79jX1BftyeH+p0uA0afbD4Cic4 QlS9Rc1GdgAoNBVw4MxThZcUm6zR3CSmxmxMYZgMyyYlIHoDzrQzHz23xqGbwCmSolHUYf387KlOJ +4C3eXtWPvR/UNX02YA+wiPY5uSSlAUzvO1PPZpi0MvVEtu+0uqa5N7cV4HWALD6ihvoiLgMY6m0y JQXDXT2A==; Received: from 179-125-70-184-dinamico.pombonet.net.br ([179.125.70.184] helo=quatroqueijos.lan) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1sZEby-0067OU-3q; Wed, 31 Jul 2024 21:03:46 +0200 From: Thadeu Lima de Souza Cascardo To: linux-bluetooth@vger.kernel.org Cc: linux-mediatek@lists.infradead.org, Marcel Holtmann , Luiz Augusto von Dentz , Matthias Brugger , AngeloGioacchino Del Regno , Jing Cai , Chris Lu , Sean Wang , kernel-dev@igalia.com, Thadeu Lima de Souza Cascardo Subject: [PATCH] Bluetooth: btmtk: avoid UAF in btmtk_process_coredump Date: Wed, 31 Jul 2024 16:03:30 -0300 Message-Id: <20240731190330.1619718-1-cascardo@igalia.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 hci_devcd_append may lead to the release of the skb, so it cannot be accessed once it is called. ================================================================== BUG: KASAN: slab-use-after-free in btmtk_process_coredump+0x2a7/0x2d0 [btmtk] Read of size 4 at addr ffff888033cfabb0 by task kworker/0:3/82 CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G U 6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS Google_Yaviks_Ufs.15217.552.0 05/07/2024 Workqueue: events btusb_rx_work [btusb] Call Trace: dump_stack_lvl+0xfd/0x150 print_report+0x131/0x780 kasan_report+0x177/0x1c0 btmtk_process_coredump+0x2a7/0x2d0 [btmtk 03edd567dd71a65958807c95a65db31d433e1d01] btusb_recv_acl_mtk+0x11c/0x1a0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec] btusb_rx_work+0x9e/0xe0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 Allocated by task 82: stack_trace_save+0xdc/0x190 kasan_set_track+0x4e/0x80 __kasan_slab_alloc+0x4e/0x60 kmem_cache_alloc+0x19f/0x360 skb_clone+0x132/0xf70 btusb_recv_acl_mtk+0x104/0x1a0 [btusb] btusb_rx_work+0x9e/0xe0 [btusb] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 Freed by task 1733: stack_trace_save+0xdc/0x190 kasan_set_track+0x4e/0x80 kasan_save_free_info+0x28/0xb0 ____kasan_slab_free+0xfd/0x170 kmem_cache_free+0x183/0x3f0 hci_devcd_rx+0x91a/0x2060 [bluetooth] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 The buggy address belongs to the object at ffff888033cfab40 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 112 bytes inside of freed 232-byte region [ffff888033cfab40, ffff888033cfac28) The buggy address belongs to the physical page: page:00000000a174ba93 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33cfa head:00000000a174ba93 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x4000000000000840(slab|head|zone=1) page_type: 0xffffffff() raw: 4000000000000840 ffff888100848a00 0000000000000000 0000000000000001 raw: 0000000000000000 0000000080190019 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888033cfaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888033cfab00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888033cfab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888033cfac00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff888033cfac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Check if we need to call hci_devcd_complete before calling hci_devcd_append. That requires that we check data->cd_info.cnt >= MTK_COREDUMP_NUM instead of data->cd_info.cnt > MTK_COREDUMP_NUM, as we increment data->cd_info.cnt only once the call to hci_devcd_append succeeds. Fixes: 0b7015132878 ("Bluetooth: btusb: mediatek: add MediaTek devcoredump support") Signed-off-by: Thadeu Lima de Souza Cascardo --- drivers/bluetooth/btmtk.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c index b7c348687a77..46f605249df7 100644 --- a/drivers/bluetooth/btmtk.c +++ b/drivers/bluetooth/btmtk.c @@ -395,6 +395,7 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb) { struct btmtk_data *data = hci_get_priv(hdev); int err; + bool complete = false; if (!IS_ENABLED(CONFIG_DEV_COREDUMP)) { kfree_skb(skb); @@ -416,19 +417,22 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb) fallthrough; case HCI_DEVCOREDUMP_ACTIVE: default: + /* Mediatek coredump data would be more than MTK_COREDUMP_NUM */ + if (data->cd_info.cnt >= MTK_COREDUMP_NUM && + skb->len > MTK_COREDUMP_END_LEN) + if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN], + MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) + complete = true; + err = hci_devcd_append(hdev, skb); if (err < 0) break; data->cd_info.cnt++; - /* Mediatek coredump data would be more than MTK_COREDUMP_NUM */ - if (data->cd_info.cnt > MTK_COREDUMP_NUM && - skb->len > MTK_COREDUMP_END_LEN) - if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN], - MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) { - bt_dev_info(hdev, "Mediatek coredump end"); - hci_devcd_complete(hdev); - } + if (complete) { + bt_dev_info(hdev, "Mediatek coredump end"); + hci_devcd_complete(hdev); + } break; }