CVE-2024-40957 seg6: fix parameter passing when calling NF_HOOK() in End.DX4 and End.DX6 behaviors

2024-07-1212:31:59

Linux

www.cve.org

linux kernel

vulnerability resolved

nf_hook

prerouting hook

null pointer dereference

rpfilter_mt

EPSS

Percentile

5.1%

JSON

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

seg6: fix parameter passing when calling NF_HOOK() in End.DX4 and End.DX6 behaviors

input_action_end_dx4() and input_action_end_dx6() are called NF_HOOK() for
PREROUTING hook, in PREROUTING hook, we should passing a valid indev,
and a NULL outdev to NF_HOOK(), otherwise may trigger a NULL pointer
dereference, as below:

[74830.647293] BUG: kernel NULL pointer dereference, address: 0000000000000090
[74830.655633] #PF: supervisor read access in kernel mode
[74830.657888] #PF: error_code(0x0000) - not-present page
[74830.659500] PGD 0 P4D 0
[74830.660450] Oops: 0000 [#1] PREEMPT SMP PTI
...
[74830.664953] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[74830.666569] RIP: 0010:rpfilter_mt+0x44/0x15e [ipt_rpfilter]
...
[74830.689725] Call Trace:
[74830.690402]  &lt;IRQ&gt;
[74830.690953]  ? show_trace_log_lvl+0x1c4/0x2df
[74830.692020]  ? show_trace_log_lvl+0x1c4/0x2df
[74830.693095]  ? ipt_do_table+0x286/0x710 [ip_tables]
[74830.694275]  ? __die_body.cold+0x8/0xd
[74830.695205]  ? page_fault_oops+0xac/0x140
[74830.696244]  ? exc_page_fault+0x62/0x150
[74830.697225]  ? asm_exc_page_fault+0x22/0x30
[74830.698344]  ? rpfilter_mt+0x44/0x15e [ipt_rpfilter]
[74830.699540]  ipt_do_table+0x286/0x710 [ip_tables]
[74830.700758]  ? ip6_route_input+0x19d/0x240
[74830.701752]  nf_hook_slow+0x3f/0xb0
[74830.702678]  input_action_end_dx4+0x19b/0x1e0
[74830.703735]  ? input_action_end_t+0xe0/0xe0
[74830.704734]  seg6_local_input_core+0x2d/0x60
[74830.705782]  lwtunnel_input+0x5b/0xb0
[74830.706690]  __netif_receive_skb_one_core+0x63/0xa0
[74830.707825]  process_backlog+0x99/0x140
[74830.709538]  __napi_poll+0x2c/0x160
[74830.710673]  net_rx_action+0x296/0x350
[74830.711860]  __do_softirq+0xcb/0x2ac
[74830.713049]  do_softirq+0x63/0x90

input_action_end_dx4() passing a NULL indev to NF_HOOK(), and finally
trigger a NULL dereference in rpfilter_mt()->rpfilter_is_loopback():

static bool
rpfilter_is_loopback(const struct sk_buff *skb,
      	       const struct net_device *in)
{
        // in is NULL
        return skb-&gt;pkt_type == PACKET_LOOPBACK ||
      	 in-&gt;flags & IFF_LOOPBACK;
}

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/seg6_local.c"
    ],
    "versions": [
      {
        "version": "7a3f5b0de364",
        "lessThan": "af90e3d73dc4",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "7a3f5b0de364",
        "lessThan": "ec4d970b597e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "7a3f5b0de364",
        "lessThan": "d62df86c1720",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "7a3f5b0de364",
        "lessThan": "561475d53aa7",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "7a3f5b0de364",
        "lessThan": "9a3bc8d16e0a",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/seg6_local.c"
    ],
    "versions": [
      {
        "version": "5.15",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.15",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.162",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.96",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.36",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9.7",
        "lessThanOrEqual": "6.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]