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.
History

Fri, 22 Nov 2024 12:00:00 +0000


Wed, 13 Nov 2024 02:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux

Tue, 05 Nov 2024 10:45:00 +0000


cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2024-04-17T10:27:51.673Z

Updated: 2024-11-05T09:17:56.551Z

Reserved: 2024-02-19T14:20:24.187Z

Link: CVE-2024-26903

cve-icon Vulnrichment

Updated: 2024-08-02T00:21:05.535Z

cve-icon NVD

Status : Modified

Published: 2024-04-17T11:15:11.060

Modified: 2024-11-21T09:03:20.827

Link: CVE-2024-26903

cve-icon Redhat

Severity : Low

Publid Date: 2024-04-17T00:00:00Z

Links: CVE-2024-26903 - Bugzilla