CVE-2024-26633 ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()

2024-03-1810:07:49

Linux

www.cve.org

linux kernel

vulnerability resolved

nexthdr_fragment

ip6_tunnel

skb->head

bug

uninit-value

syzbot

kmsan

7.7 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

13.1%

JSON

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

ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()

syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.

Reading frag_off can only be done if we pulled enough bytes
to skb->head. Currently we might access garbage.

[1]
BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3564
__dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
dst_output include/net/dst.h:451 [inline]
ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
__kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:1027
kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
__pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655
pskb_may_pull_reason include/linux/skbuff.h:2673 [inline]
pskb_may_pull include/linux/skbuff.h:2681 [inline]
ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0 net/ipv6/ip6_tunnel.c:408
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3564
__dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
dst_output include/net/dst.h:451 [inline]
ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
inet_sendmsg+0x105/0x190 net/ipv4/af_inet.c:847
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendms
—truncated—

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/ip6_tunnel.c"
    ],
    "versions": [
      {
        "version": "fbfa743a9d2a",
        "lessThan": "135414f300c5",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "3f15ba3dc14e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "da23bd709b46",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "4329426cf6b8",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "62a1fedeb14c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "687c5d52fe53",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "ba8d904c2742",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fbfa743a9d2a",
        "lessThan": "d375b98e0248",
        "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/ip6_tunnel.c"
    ],
    "versions": [
      {
        "version": "4.10",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.10",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.306",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.268",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.209",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.148",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.75",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.14",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.7.2",
        "lessThanOrEqual": "6.7.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]