CVE-2022-49869
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix possible crash in bnxt_hwrm_set_coal() During the error recovery sequence, the rtnl_lock is not held for the entire duration and some datastructures may be freed during the sequence. Check for the BNXT_STATE_OPEN flag instead of netif_running() to ensure that the device is fully operational before proceeding to reconfigure the coalescing settings. This will fix a possible crash like this: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 10 PID: 181276 Comm: ethtool Kdump: loaded Tainted: G IOE --------- - - 4.18.0-348.el8.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/0F9N89, BIOS 2.3.10 08/15/2019 RIP: 0010:bnxt_hwrm_set_coal+0x1fb/0x2a0 [bnxt_en] Code: c2 66 83 4e 22 08 66 89 46 1c e8 10 cb 00 00 41 83 c6 01 44 39 b3 68 01 00 00 0f 8e a3 00 00 00 48 8b 93 c8 00 00 00 49 63 c6 <48> 8b 2c c2 48 8b 85 b8 02 00 00 48 85 c0 74 2e 48 8b 74 24 08 f6 RSP: 0018:ffffb11c8dcaba50 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8d168a8b0ac0 RCX: 00000000000000c5 RDX: 0000000000000000 RSI: ffff8d162f72c000 RDI: ffff8d168a8b0b28 RBP: 0000000000000000 R08: b6e1f68a12e9a7eb R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000037 R12: ffff8d168a8b109c R13: ffff8d168a8b10aa R14: 0000000000000000 R15: ffffffffc01ac4e0 FS: 00007f3852e4c740(0000) GS:ffff8d24c0080000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000041b3ee003 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ethnl_set_coalesce+0x3ce/0x4c0 genl_family_rcv_msg_doit.isra.15+0x10f/0x150 genl_family_rcv_msg+0xb3/0x160 ? coalesce_fill_reply+0x480/0x480 genl_rcv_msg+0x47/0x90 ? genl_family_rcv_msg+0x160/0x160 netlink_rcv_skb+0x4c/0x120 genl_rcv+0x24/0x40 netlink_unicast+0x196/0x230 netlink_sendmsg+0x204/0x3d0 sock_sendmsg+0x4c/0x50 __sys_sendto+0xee/0x160 ? syscall_trace_enter+0x1d3/0x2c0 ? __audit_syscall_exit+0x249/0x2a0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x5b/0x1a0 entry_SYSCALL_64_after_hwframe+0x65/0xca RIP: 0033:0x7f38524163bb
Statement
NULL Pointer Dereference in bnxt_en via ethtool Coalesce Settings (CVE Pending). A race condition in the Broadcom NetXtreme Ethernet (bnxt_en) driver allows a privileged user to crash the kernel using ethtool -C during a device recovery sequence. The bug stems from a premature dereference of a freed data structure when the device is not fully operational. Local user with CAP_NET_ADMIN or access to ethtool can trigger it.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | 5.5 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
