CVE-2024-26903: Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security
First published: Wed Apr 17 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel | <4.19.311 | 4.19.311 |
| redhat/kernel | <5.4.273 | 5.4.273 |
| redhat/kernel | <5.10.214 | 5.10.214 |
| redhat/kernel | <5.15.153 | 5.15.153 |
| redhat/kernel | <6.1.83 | 6.1.83 |
| redhat/kernel | <6.6.23 | 6.6.23 |
| redhat/kernel | <6.7.11 | 6.7.11 |
| redhat/kernel | <6.8 | 6.8 |
| Linux Kernel | <4.19.311 | |
| Linux Kernel | >=4.20<5.4.273 | |
| Linux Kernel | >=5.5<5.10.214 | |
| Linux Kernel | >=5.11<5.15.153 | |
| Linux Kernel | >=5.16<6.1.83 | |
| Linux Kernel | >=6.2<6.6.23 | |
| Linux Kernel | >=6.7<6.7.11 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.123-1 6.1.119-1 6.12.10-1 6.12.11-1 |
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Reference Links
- https://git.kernel.org/stable/c/2535b848fa0f42ddff3e5255cf5e742c9b77bb26
- https://git.kernel.org/stable/c/369f419c097e82407dd429a202cde9a73d3ae29b
- https://git.kernel.org/stable/c/3ead59bafad05f2967ae2438c0528d53244cfde5
- https://git.kernel.org/stable/c/567c0411dc3b424fc7bd1e6109726d7ba32d4f73
- https://git.kernel.org/stable/c/5f369efd9d963c1f711a06c9b8baf9f5ce616d85
- https://git.kernel.org/stable/c/5f9fe302dd3a9bbc50f4888464c1773f45166bfd
- https://git.kernel.org/stable/c/81d7d920a22fd58ef9aedb1bd0a68ee32bd23e96
- https://git.kernel.org/stable/c/8d1753973f598531baaa2c1033cf7f7b5bb004b0
- https://launchpad.net/bugs/cve/CVE-2024-26903
- https://access.redhat.com/security/cve/CVE-2024-26903
- https://lore.kernel.org/linux-cve-announce/2024041745-CVE-2024-26903-de5c@gregkh/T
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2275642
- https://access.redhat.com/errata/RHSA-2024:9315
- https://bugzilla.redhat.com/show_bug.cgi?id=2275641
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-26903
- https://nvd.nist.gov/vuln/detail/CVE-2024-26903
- https://security-tracker.debian.org/tracker/CVE-2024-26903
- https://ubuntu.com/security/CVE-2024-26903
- https://git.kernel.org/linus/2535b848fa0f42ddff3e5255cf5e742c9b77bb26
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html
Frequently Asked Questions
What is the severity of CVE-2024-26903?
CVE-2024-26903 is classified as a high severity vulnerability in the Linux kernel affecting Bluetooth RFCOMM.
How do I fix CVE-2024-26903?
To fix CVE-2024-26903, update your Linux kernel to versions 4.19.311, 5.4.273, 5.10.214, 5.15.153, 6.1.83, 6.6.23, 6.7.11, or 6.8 as applicable.
What systems are affected by CVE-2024-26903?
CVE-2024-26903 affects various versions of the Linux kernel across distributions such as Red Hat and Debian.
What component of Linux is impacted by CVE-2024-26903?
CVE-2024-26903 impacts the Bluetooth RFCOMM layer in the Linux kernel.
Is CVE-2024-26903 being actively exploited?
There is no current evidence of active exploitation for CVE-2024-26903, but users are encouraged to apply updates promptly.
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