CVE-2021-47562 ice: fix vsi->txq_map sizing
A null pointer dereference in the Intel ice network driver can cause a kernel crash when configuring XDP rings with mismatched queue counts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-47562?
CVE-2021-47562 is a medium-severity vulnerability in Linux kernel, published on 24 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ice: fix vsi->txq_map sizing
The approach of having XDP queue per CPU regardless of user's setting exposed a hidden bug that could occur in case when Rx queue count differ from Tx queue count. Currently vsi->txq_map's size is equal to the doubled vsi->alloc_txq, which is not correct due to the fact that XDP rings were previously based on the Rx queue count. Below splat can be seen when ethtool -L is used and XDP rings are configured:
[ 682.875339] BUG: kernel NULL pointer dereference, address: 000000000000000f [ 682.883403] #PF: supervisor read access in kernel mode [ 682.889345] #PF: error_code(0x0000) - not-present page [ 682.895289] PGD 0 P4D 0 [ 682.898218] Oops: 0000 [#1] PREEMPT SMP PTI [ 682.903055] CPU: 42 PID: 2878 Comm: ethtool Tainted: G OE 5.15.0-rc5+ #1 [ 682.912214] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 [ 682.923380] RIP: 0010:devres_remove+0x44/0x130 [ 682.928527] Code: 49 89 f4 55 48 89 fd 4c 89 ff 53 48 83 ec 10 e8 92 b9 49 00 48 8b 9d a8 02 00 00 48 8d 8d a0 02 00 00 49 89 c2 48 39 cb 74 0f <4c> 3b 63 10 74 25 48 8b 5b 08 48 39 cb 75 f1 4c 89 ff 4c 89 d6 e8 [ 682.950237] RSP: 0018:ffffc90006a679f0 EFLAGS: 00010002 [ 682.956285] RAX: 0000000000000286 RBX: ffffffffffffffff RCX: ffff88908343a370 [ 682.964538] RDX: 0000000000000001 RSI: ffffffff81690d60 RDI: 0000000000000000 [ 682.972789] RBP: ffff88908343a0d0 R08: 0000000000000000 R09: 0000000000000000 [ 682.981040] R10: 0000000000000286 R11: 3fffffffffffffff R12: ffffffff81690d60 [ 682.989282] R13: ffffffff81690a00 R14: ffff8890819807a8 R15: ffff88908343a36c [ 682.997535] FS: 00007f08c7bfa740(0000) GS:ffff88a03fd00000(0000) knlGS:0000000000000000 [ 683.006910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 683.013557] CR2: 000000000000000f CR3: 0000001080a66003 CR4: 00000000003706e0 [ 683.021819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 683.030075] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 683.038336] Call Trace: [ 683.041167] devm_kfree+0x33/0x50 [ 683.045004] ice_vsi_free_arrays+0x5e/0xc0 [ice] [ 683.050380] ice_vsi_rebuild+0x4c8/0x750 [ice] [ 683.055543] ice_vsi_recfg_qs+0x9a/0x110 [ice] [ 683.060697] ice_set_channels+0x14f/0x290 [ice] [ 683.065962] ethnl_set_channels+0x333/0x3f0 [ 683.070807] genl_family_rcv_msg_doit+0xea/0x150 [ 683.076152] genl_rcv_msg+0xde/0x1d0 [ 683.080289] ? channels_prepare_data+0x60/0x60 [ 683.085432] ? genl_get_cmd+0xd0/0xd0 [ 683.089667] netlink_rcv_skb+0x50/0xf0 [ 683.094006] genl_rcv+0x24/0x40 [ 683.097638] netlink_unicast+0x239/0x340 [ 683.102177] netlink_sendmsg+0x22e/0x470 [ 683.106717] sock_sendmsg+0x5e/0x60 [ 683.110756] __sys_sendto+0xee/0x150 [ 683.114894] ? handle_mm_fault+0xd0/0x2a0 [ 683.119535] ? do_user_addr_fault+0x1f3/0x690 [ 683.134173] __x64_sys_sendto+0x25/0x30 [ 683.148231] do_syscall_64+0x3b/0xc0 [ 683.161992] entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix this by taking into account the value that num_possible_cpus() yields in addition to vsi->alloc_txq instead of doubling the latter.
Weakness: CWE-476
Which versions are affected by CVE-2021-47562?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47562?
Apply the vendor's patch.
Is CVE-2021-47562 being exploited?
There is no known exploitation of CVE-2021-47562 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47562, UBUNTU-CVE-2021-47562.