66 lines
2.7 KiB
Diff
66 lines
2.7 KiB
Diff
From 4bdf131363bf22e4cfb8dbaaf0cf38ae0e18dfe7 Mon Sep 17 00:00:00 2001
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From: David Marlin <dmarlin@redhat.com>
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Date: Thu, 7 May 2026 18:01:01 -0500
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Subject: [PATCH] Bluetooth: hci_sync: fix stack buffer overflow in
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hci_le_big_create_sync
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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JIRA: https://issues.redhat.com/browse/RHEL-172460
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JIRA: https://issues.redhat.com/browse/RHEL-172865
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CVE: CVE-2026-31772
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commit bc39a094730ce062fa034a529c93147c096cb488
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Author: hkbinbin <hkbinbinbin@gmail.com>
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Date: Tue Mar 31 05:39:16 2026 +0000
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Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync
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hci_le_big_create_sync() uses DEFINE_FLEX to allocate a
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struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)
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BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31)
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entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller
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hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31,
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the memcpy that copies conn->bis into cp->bis writes up to 14 bytes
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past the stack buffer, corrupting adjacent stack memory.
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This is trivially reproducible: binding an ISO socket with
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bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will
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eventually trigger hci_le_big_create_sync() from the HCI command
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sync worker, causing a KASAN-detectable stack-out-of-bounds write:
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BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0
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Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71
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Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to
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HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that
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conn->bis can actually carry.
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Fixes: 42ecf1947135 ("Bluetooth: ISO: Do not emit LE BIG Create Sync if previous is pending")
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Cc: stable@vger.kernel.org
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Signed-off-by: hkbinbin <hkbinbinbin@gmail.com>
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Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
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Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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Signed-off-by: David Marlin <dmarlin@redhat.com>
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diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
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index 092118b12e18..9096f6ba940b 100644
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--- a/net/bluetooth/hci_sync.c
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+++ b/net/bluetooth/hci_sync.c
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@@ -7241,7 +7241,8 @@ static void create_big_complete(struct hci_dev *hdev, void *data, int err)
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static int hci_le_big_create_sync(struct hci_dev *hdev, void *data)
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{
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- DEFINE_FLEX(struct hci_cp_le_big_create_sync, cp, bis, num_bis, 0x11);
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+ DEFINE_FLEX(struct hci_cp_le_big_create_sync, cp, bis, num_bis,
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+ HCI_MAX_ISO_BIS);
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struct hci_conn *conn = data;
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struct bt_iso_qos *qos = &conn->iso_qos;
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int err;
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--
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2.50.1 (Apple Git-155)
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