| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26903: Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security |
| |
| During our fuzz testing of the connection and disconnection process at the |
| RFCOMM layer, we discovered this bug. By comparing the packets from a |
| normal connection and disconnection process with the testcase that |
| triggered a KASAN report. We analyzed the cause of this bug as follows: |
| |
| 1. In the packets captured during a normal connection, the host sends a |
| `Read Encryption Key Size` type of `HCI_CMD` packet |
| (Command Opcode: 0x1408) to the controller to inquire the length of |
| encryption key.After receiving this packet, the controller immediately |
| replies with a Command Completepacket (Event Code: 0x0e) to return the |
| Encryption Key Size. |
| |
| 2. In our fuzz test case, the timing of the controller's response to this |
| packet was delayed to an unexpected point: after the RFCOMM and L2CAP |
| layers had disconnected but before the HCI layer had disconnected. |
| |
| 3. After receiving the Encryption Key Size Response at the time described |
| in point 2, the host still called the rfcomm_check_security function. |
| However, by this time `struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;` |
| had already been released, and when the function executed |
| `return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);`, |
| specifically when accessing `conn->hcon`, a null-ptr-deref error occurred. |
| |
| To fix this bug, check if `sk->sk_state` is BT_CLOSED before calling |
| rfcomm_recv_frame in rfcomm_process_rx. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26903 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.19.311 with commit 369f419c097e82407dd429a202cde9a73d3ae29b |
| Fixed in 5.4.273 with commit 5f369efd9d963c1f711a06c9b8baf9f5ce616d85 |
| Fixed in 5.10.214 with commit 81d7d920a22fd58ef9aedb1bd0a68ee32bd23e96 |
| Fixed in 5.15.153 with commit 8d1753973f598531baaa2c1033cf7f7b5bb004b0 |
| Fixed in 6.1.83 with commit 567c0411dc3b424fc7bd1e6109726d7ba32d4f73 |
| Fixed in 6.6.23 with commit 3ead59bafad05f2967ae2438c0528d53244cfde5 |
| Fixed in 6.7.11 with commit 5f9fe302dd3a9bbc50f4888464c1773f45166bfd |
| Fixed in 6.8 with commit 2535b848fa0f42ddff3e5255cf5e742c9b77bb26 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-26903 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/bluetooth/rfcomm/core.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/369f419c097e82407dd429a202cde9a73d3ae29b |
| https://git.kernel.org/stable/c/5f369efd9d963c1f711a06c9b8baf9f5ce616d85 |
| https://git.kernel.org/stable/c/81d7d920a22fd58ef9aedb1bd0a68ee32bd23e96 |
| https://git.kernel.org/stable/c/8d1753973f598531baaa2c1033cf7f7b5bb004b0 |
| https://git.kernel.org/stable/c/567c0411dc3b424fc7bd1e6109726d7ba32d4f73 |
| https://git.kernel.org/stable/c/3ead59bafad05f2967ae2438c0528d53244cfde5 |
| https://git.kernel.org/stable/c/5f9fe302dd3a9bbc50f4888464c1773f45166bfd |
| https://git.kernel.org/stable/c/2535b848fa0f42ddff3e5255cf5e742c9b77bb26 |
