In the Linux kernel, the following vulnerability has been resolved:
seg6: fix the iif in the IPv6 socket control block
When an IPv4 packet is received, the ip_rcv_core(…) sets the receiving
interface index into the IPv4 socket control block (v5.16-rc4,
net/ipv4/ip_input.c line 510):
IPCB(skb)->iif = skb->skb_iif;
If that IPv4 packet is meant to be encapsulated in an outer IPv6+SRH
header, the seg6_do_srh_encap(…) performs the required encapsulation.
In this case, the seg6_do_srh_encap function clears the IPv6 socket control
block (v5.16-rc4 net/ipv6/seg6_iptunnel.c line 163):
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
The memset(…) was introduced in commit ef489749aae5 (“ipv6: sr: clear
IP6CB(skb) on SRH ip4ip6 encapsulation”) a long time ago (2019-01-29).
Since the IPv6 socket control block and the IPv4 socket control block share
the same memory area (skb->cb), the receiving interface index info is lost
(IP6CB(skb)->iif is set to zero).
As a side effect, that condition triggers a NULL pointer dereference if
commit 0857d6f8c759 (“ipv6: When forwarding count rx stats on the orig
netdev”) is applied.
To fix that issue, we set the IP6CB(skb)->iif with the index of the
receiving interface once again.
Vendor | Product | Version | CPE |
---|---|---|---|
linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/ipv6/seg6_iptunnel.c"
],
"versions": [
{
"version": "c630ec8bdada",
"lessThan": "b16d412e5f79",
"status": "affected",
"versionType": "git"
},
{
"version": "2f704348c93f",
"lessThan": "6431e71093f3",
"status": "affected",
"versionType": "git"
},
{
"version": "ef489749aae5",
"lessThan": "ef8804e47c0a",
"status": "affected",
"versionType": "git"
},
{
"version": "ef489749aae5",
"lessThan": "666521b3852d",
"status": "affected",
"versionType": "git"
},
{
"version": "ef489749aae5",
"lessThan": "98adb2bbfa40",
"status": "affected",
"versionType": "git"
},
{
"version": "ef489749aae5",
"lessThan": "ae68d93354e5",
"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_iptunnel.c"
],
"versions": [
{
"version": "5.0",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.0",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.14.258",
"lessThanOrEqual": "4.14.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.19.221",
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.4.165",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.85",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.8",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.16",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]
git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e
git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831
git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1
git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c
git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3
git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9