{"uuid": "607ed559-9e39-4029-96be-4446a1a93311", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "2a075640-a300-48a4-bb44-bc6130783b9b", "vulnerability": "CVE-2025-21682", "type": "published-proof-of-concept", "source": "https://t.me/DarkWebInformer_CVEAlerts/3646", "content": "\ud83d\udd17 DarkWebInformer.com - Cyber Threat Intelligence\n\ud83d\udccc CVE ID: CVE-2025-21682\n\ud83d\udd25 CVSS Score: N/A\n\ud83d\udd39 Description: In the Linux kernel, the following vulnerability has been resolved:\n\neth: bnxt: always recalculate features after XDP clearing, fix null-deref\n\nRecalculate features when XDP is detached.\n\nBefore:\n  # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp\n  # ip li set dev eth0 xdp off\n  # ethtool -k eth0 | grep gro\n  rx-gro-hw: off [requested on]\n\nAfter:\n  # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp\n  # ip li set dev eth0 xdp off\n  # ethtool -k eth0 | grep gro\n  rx-gro-hw: on\n\nThe fact that HW-GRO doesn't get re-enabled automatically is just\na minor annoyance. The real issue is that the features will randomly\ncome back during another reconfiguration which just happens to invoke\nnetdev_update_features(). The driver doesn't handle reconfiguring\ntwo things at a time very robustly.\n\nStarting with commit 98ba1d931f61 (\"bnxt_en: Fix RSS logic in\n__bnxt_reserve_rings()\") we only reconfigure the RSS hash table\nif the \"effective\" number of Rx rings has changed. If HW-GRO is\nenabled \"effective\" number of rings is 2x what user sees.\nSo if we are in the bad state, with HW-GRO re-enablement \"pending\"\nafter XDP off, and we lower the rings by / 2 - the HW-GRO rings\ndoing 2x and the ethtool -L doing / 2 may cancel each other out,\nand the:\n\n  if (old_rx_rings != bp->hw_resc.resv_rx_rings &&\n\ncondition in __bnxt_reserve_rings() will be false.\nThe RSS map won't get updated, and we'll crash with:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000168\n  RIP: 0010:__bnxt_hwrm_vnic_set_rss+0x13a/0x1a0\n    bnxt_hwrm_vnic_rss_cfg_p5+0x47/0x180\n    __bnxt_setup_vnic_p5+0x58/0x110\n    bnxt_init_nic+0xb72/0xf50\n    __bnxt_open_nic+0x40d/0xab0\n    bnxt_open_nic+0x2b/0x60\n    ethtool_set_channels+0x18c/0x1d0\n\nAs we try to access a freed ring.\n\nThe issue is present since XDP support was added, really, but\nprior to commit 98ba1d931f61 (\"bnxt_en: Fix RSS logic in\n__bnxt_reserve_rings()\") it wasn't causing major issues.\n\ud83d\udccf Published: 2025-01-31T12:33:03Z\n\ud83d\udccf Modified: 2025-01-31T12:33:03Z\n\ud83d\udd17 References:\n1. https://nvd.nist.gov/vuln/detail/CVE-2025-21682\n2. https://git.kernel.org/stable/c/08831a894d18abfaabb5bbde7c2069a7fb41dd93\n3. https://git.kernel.org/stable/c/f0aa6a37a3dbb40b272df5fc6db93c114688adcd", "creation_timestamp": "2025-01-31T13:14:57.000000Z"}