CVE-2025-38590
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Remove skb secpath if xfrm state is not found Hardware returns a unique identifier for a decrypted packet's xfrm state, this state is looked up in an xarray. However, the state might have been freed by the time of this lookup. Currently, if the state is not found, only a counter is incremented. The secpath (sp) extension on the skb is not removed, resulting in sp->len becoming 0. Subsequently, functions like __xfrm_policy_check() attempt to access fields such as xfrm_input_state(skb)->xso.type (which dereferences sp->xvec[sp->len - 1]) without first validating sp->len. This leads to a crash when dereferencing an invalid state pointer. This patch prevents the crash by explicitly removing the secpath extension from the skb if the xfrm state is not found after hardware decryption. This ensures downstream functions do not operate on a zero-length secpath. BUG: unable to handle page fault for address: ffffffff000002c8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 282e067 P4D 282e067 PUD 0 Oops: Oops: 0000 [#1] SMP CPU: 12 UID: 0 PID: 0 Comm: swapper/12 Not tainted 6.15.0-rc7_for_upstream_min_debug_2025_05_27_22_44 #1 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:__xfrm_policy_check+0x61a/0xa30 Code: b6 77 7f 83 e6 02 74 14 4d 8b af d8 00 00 00 41 0f b6 45 05 c1 e0 03 48 98 49 01 c5 41 8b 45 00 83 e8 01 48 98 49 8b 44 c5 10 <0f> b6 80 c8 02 00 00 83 e0 0c 3c 04 0f 84 0c 02 00 00 31 ff 80 fa RSP: 0018:ffff88885fb04918 EFLAGS: 00010297 RAX: ffffffff00000000 RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000000 RBP: ffffffff8311af80 R08: 0000000000000020 R09: 00000000c2eda353 R10: ffff88812be2bbc8 R11: 000000001faab533 R12: ffff88885fb049c8 R13: ffff88812be2bbc8 R14: 0000000000000000 R15: ffff88811896ae00 FS: 0000000000000000(0000) GS:ffff8888dca82000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff000002c8 CR3: 0000000243050002 CR4: 0000000000372eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> ? try_to_wake_up+0x108/0x4c0 ? udp4_lib_lookup2+0xbe/0x150 ? udp_lib_lport_inuse+0x100/0x100 ? __udp4_lib_lookup+0x2b0/0x410 __xfrm_policy_check2.constprop.0+0x11e/0x130 udp_queue_rcv_one_skb+0x1d/0x530 udp_unicast_rcv_skb+0x76/0x90 __udp4_lib_rcv+0xa64/0xe90 ip_protocol_deliver_rcu+0x20/0x130 ip_local_deliver_finish+0x75/0xa0 ip_local_deliver+0xc1/0xd0 ? ip_protocol_deliver_rcu+0x130/0x130 ip_sublist_rcv+0x1f9/0x240 ? ip_rcv_finish_core+0x430/0x430 ip_list_rcv+0xfc/0x130 __netif_receive_skb_list_core+0x181/0x1e0 netif_receive_skb_list_internal+0x200/0x360 ? mlx5e_build_rx_skb+0x1bc/0xda0 [mlx5_core] gro_receive_skb+0xfd/0x210 mlx5e_handle_rx_cqe_mpwrq+0x141/0x280 [mlx5_core] mlx5e_poll_rx_cq+0xcc/0x8e0 [mlx5_core] ? mlx5e_handle_rx_dim+0x91/0xd0 [mlx5_core] mlx5e_napi_poll+0x114/0xab0 [mlx5_core] __napi_poll+0x25/0x170 net_rx_action+0x32d/0x3a0 ? mlx5_eq_comp_int+0x8d/0x280 [mlx5_core] ? notifier_call_chain+0x33/0xa0 handle_softirqs+0xda/0x250 irq_exit_rcu+0x6d/0xc0 common_interrupt+0x81/0xa0 </IRQ>
Statement
This bug in the mlx5 IPsec receive offload path could trigger a kernel crash when hardware reported a decrypted packet with an already freed xfrm state. The driver failed to clear the secpath extension on the skb, leaving sp->len at zero, which later caused __xfrm_policy_check() to dereference an invalid state pointer. For the Red Hat Enterprise Linux (all versions) the Kernel config param CONFIG_MLX5_EN_MACSEC disabled, so this bug not actual (not affected).
Mitigation
To mitigate this issue, prevent module mlx5_core from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
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 | 7.5 | 5.5 | 7.5 |
| Attack Vector | Network | Local | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | Low | None |
| 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:N/AC:L/PR:N/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:N/AC:L/PR:N/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.
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