CVE-2021-47619

In the Linux kernel, the following vulnerability has been resolved:

i40e: Fix queues reservation for XDP

When XDP was configured on a system with large number of CPUs and X722 NIC there was a call trace with NULL pointer dereference.

i40e 0000:87:00.0: failed to get tracking for 256 queues for VSI 0 err -12 i40e 0000:87:00.0: setup of MAIN VSI failed

BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:i40e_xdp+0xea/0x1b0 [i40e] Call Trace: ? i40e_reconfig_rss_queues+0x130/0x130 [i40e] dev_xdp_install+0x61/0xe0 dev_xdp_attach+0x18a/0x4c0 dev_change_xdp_fd+0x1e6/0x220 do_setlink+0x616/0x1030 ? ahci_port_stop+0x80/0x80 ? ata_qc_issue+0x107/0x1e0 ? lock_timer_base+0x61/0x80 ? __mod_timer+0x202/0x380 rtnl_setlink+0xe5/0x170 ? bpf_lsm_binder_transaction+0x10/0x10 ? security_capable+0x36/0x50 rtnetlink_rcv_msg+0x121/0x350 ? rtnl_calcit.isra.0+0x100/0x100 netlink_rcv_skb+0x50/0xf0 netlink_unicast+0x1d3/0x2a0 netlink_sendmsg+0x22a/0x440 sock_sendmsg+0x5e/0x60 __sys_sendto+0xf0/0x160 ? __sys_getsockname+0x7e/0xc0 ? _copy_from_user+0x3c/0x80 ? __sys_setsockopt+0xc8/0x1a0 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f83fa7a39e0

This was caused by PF queue pile fragmentation due to flow director VSI queue being placed right after main VSI. Because of this main VSI was not able to resize its queue allocation for XDP resulting in no queues allocated for main VSI when XDP was turned on.

Fix this by always allocating last queue in PF queue pile for a flow director VSI.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/00eddb0e4ea115154581d1049507a996acfc2d3e
• https://git.kernel.org/stable/c/4b3aa858268b7b9aeef02e5f9c4cd8f8fac101c8
• https://git.kernel.org/stable/c/768eb705e6381f0c70ca29d4e66f19790d5d19a1
• https://git.kernel.org/stable/c/92947844b8beee988c0ce17082b705c2f75f0742
• https://git.kernel.org/stable/c/be6998f232b8e4ca8225029e305b8329d89bfd59
• https://git.kernel.org/stable/c/d46fa4ea9756ef6cbcf9752d0832cc66e2d7121b