CVE-2024-26611

Published Mar 11, 2024

Last updated 2 years ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: xsk: fix usage of multi-buffer BPF helpers for ZC XDP Currently when packet is shrunk via bpf_xdp_adjust_tail() and memory type is set to MEM_TYPE_XSK_BUFF_POOL, null ptr dereference happens: [1136314.192256] BUG: kernel NULL pointer dereference, address: 0000000000000034 [1136314.203943] #PF: supervisor read access in kernel mode [1136314.213768] #PF: error_code(0x0000) - not-present page [1136314.223550] PGD 0 P4D 0 [1136314.230684] Oops: 0000 [#1] PREEMPT SMP NOPTI [1136314.239621] CPU: 8 PID: 54203 Comm: xdpsock Not tainted 6.6.0+ #257 [1136314.250469] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [1136314.265615] RIP: 0010:__xdp_return+0x6c/0x210 [1136314.274653] Code: ad 00 48 8b 47 08 49 89 f8 a8 01 0f 85 9b 01 00 00 0f 1f 44 00 00 f0 41 ff 48 34 75 32 4c 89 c7 e9 79 cd 80 ff 83 fe 03 75 17 <f6> 41 34 01 0f 85 02 01 00 00 48 89 cf e9 22 cc 1e 00 e9 3d d2 86 [1136314.302907] RSP: 0018:ffffc900089f8db0 EFLAGS: 00010246 [1136314.312967] RAX: ffffc9003168aed0 RBX: ffff8881c3300000 RCX: 0000000000000000 [1136314.324953] RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffffc9003168c000 [1136314.336929] RBP: 0000000000000ae0 R08: 0000000000000002 R09: 0000000000010000 [1136314.348844] R10: ffffc9000e495000 R11: 0000000000000040 R12: 0000000000000001 [1136314.360706] R13: 0000000000000524 R14: ffffc9003168aec0 R15: 0000000000000001 [1136314.373298] FS: 00007f8df8bbcb80(0000) GS:ffff8897e0e00000(0000) knlGS:0000000000000000 [1136314.386105] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1136314.396532] CR2: 0000000000000034 CR3: 00000001aa912002 CR4: 00000000007706f0 [1136314.408377] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1136314.420173] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1136314.431890] PKRU: 55555554 [1136314.439143] Call Trace: [1136314.446058] <IRQ> [1136314.452465] ? __die+0x20/0x70 [1136314.459881] ? page_fault_oops+0x15b/0x440 [1136314.468305] ? exc_page_fault+0x6a/0x150 [1136314.476491] ? asm_exc_page_fault+0x22/0x30 [1136314.484927] ? __xdp_return+0x6c/0x210 [1136314.492863] bpf_xdp_adjust_tail+0x155/0x1d0 [1136314.501269] bpf_prog_ccc47ae29d3b6570_xdp_sock_prog+0x15/0x60 [1136314.511263] ice_clean_rx_irq_zc+0x206/0xc60 [ice] [1136314.520222] ? ice_xmit_zc+0x6e/0x150 [ice] [1136314.528506] ice_napi_poll+0x467/0x670 [ice] [1136314.536858] ? ttwu_do_activate.constprop.0+0x8f/0x1a0 [1136314.546010] __napi_poll+0x29/0x1b0 [1136314.553462] net_rx_action+0x133/0x270 [1136314.561619] __do_softirq+0xbe/0x28e [1136314.569303] do_softirq+0x3f/0x60 This comes from __xdp_return() call with xdp_buff argument passed as NULL which is supposed to be consumed by xsk_buff_free() call. To address this properly, in ZC case, a node that represents the frag being removed has to be pulled out of xskb_list. Introduce appropriate xsk helpers to do such node operation and use them accordingly within bpf_xdp_adjust_tail().
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362