CVE-2021-47399 ixgbe: Fix NULL pointer dereference in ixgbe_xdp_setup

2024-05-2115:03:54

Linux

www.cve.org

linux kernel vulnerability

null pointer

ixgbe_xdp_setup

online cpus

num_xdp_queues

max_channels

xdp_queues

panic

6.4 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.6%

JSON

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

ixgbe: Fix NULL pointer dereference in ixgbe_xdp_setup

The ixgbe driver currently generates a NULL pointer dereference with
some machine (online cpus < 63). This is due to the fact that the
maximum value of num_xdp_queues is nr_cpu_ids. Code is in
“ixgbe_set_rss_queues”".

Here’s how the problem repeats itself:
Some machine (online cpus < 63), And user set num_queues to 63 through
ethtool. Code is in the “ixgbe_set_channels”,
adapter->ring_feature[RING_F_FDIR].limit = count;

It becomes 63.

When user use xdp, “ixgbe_set_rss_queues” will set queues num.
adapter->num_rx_queues = rss_i;
adapter->num_tx_queues = rss_i;
adapter->num_xdp_queues = ixgbe_xdp_queues(adapter);

And rss_i’s value is from
f = &adapter->ring_feature[RING_F_FDIR];
rss_i = f->indices = f->limit;

So “num_rx_queues” > “num_xdp_queues”, when run to “ixgbe_xdp_setup”,
for (i = 0; i < adapter->num_rx_queues; i++)
if (adapter->xdp_ring[i]->xsk_umem)

It leads to panic.

Call trace:
[exception RIP: ixgbe_xdp+368]
RIP: ffffffffc02a76a0 RSP: ffff9fe16202f8d0 RFLAGS: 00010297
RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000001c RDI: ffffffffa94ead90
RBP: ffff92f8f24c0c18 R8: 0000000000000000 R9: 0000000000000000
R10: ffff9fe16202f830 R11: 0000000000000000 R12: ffff92f8f24c0000
R13: ffff9fe16202fc01 R14: 000000000000000a R15: ffffffffc02a7530
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
7 [ffff9fe16202f8f0] dev_xdp_install at ffffffffa89fbbcc
8 [ffff9fe16202f920] dev_change_xdp_fd at ffffffffa8a08808
9 [ffff9fe16202f960] do_setlink at ffffffffa8a20235
10 [ffff9fe16202fa88] rtnl_setlink at ffffffffa8a20384
11 [ffff9fe16202fc78] rtnetlink_rcv_msg at ffffffffa8a1a8dd
12 [ffff9fe16202fcf0] netlink_rcv_skb at ffffffffa8a717eb
13 [ffff9fe16202fd40] netlink_unicast at ffffffffa8a70f88
14 [ffff9fe16202fd80] netlink_sendmsg at ffffffffa8a71319
15 [ffff9fe16202fdf0] sock_sendmsg at ffffffffa89df290
16 [ffff9fe16202fe08] __sys_sendto at ffffffffa89e19c8
17 [ffff9fe16202ff30] __x64_sys_sendto at ffffffffa89e1a64
18 [ffff9fe16202ff38] do_syscall_64 at ffffffffa84042b9
19 [ffff9fe16202ff50] entry_SYSCALL_64_after_hwframe at ffffffffa8c0008c

So I fix ixgbe_max_channels so that it will not allow a setting of queues
to be higher than the num_online_cpus(). And when run to ixgbe_xdp_setup,
take the smaller value of num_rx_queues and num_xdp_queues.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c",
      "drivers/net/ethernet/intel/ixgbe/ixgbe_main.c"
    ],
    "versions": [
      {
        "version": "4a9b32f30f80",
        "lessThan": "20f6c4a31a52",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4a9b32f30f80",
        "lessThan": "2744341dd52e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4a9b32f30f80",
        "lessThan": "513e605d7a9c",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c",
      "drivers/net/ethernet/intel/ixgbe/ixgbe_main.c"
    ],
    "versions": [
      {
        "version": "5.0",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.0",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.71",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14.10",
        "lessThanOrEqual": "5.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]