fkie_cve-2021-47515
Vulnerability from fkie_nvd
Published
2024-05-24 15:15
Modified
2024-11-21 06:36
Severity ?
Summary
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nseg6: fix the iif in the IPv6 socket control block\n\nWhen an IPv4 packet is received, the ip_rcv_core(...) sets the receiving\ninterface index into the IPv4 socket control block (v5.16-rc4,\nnet/ipv4/ip_input.c line 510):\n\n IPCB(skb)-\u003eiif = skb-\u003eskb_iif;\n\nIf that IPv4 packet is meant to be encapsulated in an outer IPv6+SRH\nheader, the seg6_do_srh_encap(...) performs the required encapsulation.\nIn this case, the seg6_do_srh_encap function clears the IPv6 socket control\nblock (v5.16-rc4 net/ipv6/seg6_iptunnel.c line 163):\n\n memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));\n\nThe memset(...) was introduced in commit ef489749aae5 (\"ipv6: sr: clear\nIP6CB(skb) on SRH ip4ip6 encapsulation\") a long time ago (2019-01-29).\n\nSince the IPv6 socket control block and the IPv4 socket control block share\nthe same memory area (skb-\u003ecb), the receiving interface index info is lost\n(IP6CB(skb)-\u003eiif is set to zero).\n\nAs a side effect, that condition triggers a NULL pointer dereference if\ncommit 0857d6f8c759 (\"ipv6: When forwarding count rx stats on the orig\nnetdev\") is applied.\n\nTo fix that issue, we set the IP6CB(skb)-\u003eiif with the index of the\nreceiving interface once again."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: seg6: corrige el iif en el bloque de control del socket IPv6 Cuando se recibe un paquete IPv4, ip_rcv_core(...) establece el \u00edndice de la interfaz de recepci\u00f3n en el bloque de control del socket IPv4 (v5 .16-rc4, net/ipv4/ip_input.c l\u00ednea 510): IPCB(skb)-\u0026gt;iif = skb-\u0026gt;skb_iif; Si ese paquete IPv4 debe encapsularse en un encabezado IPv6+SRH externo, seg6_do_srh_encap(...) realiza la encapsulaci\u00f3n requerida. En este caso, la funci\u00f3n seg6_do_srh_encap borra el bloque de control del socket IPv6 (v5.16-rc4 net/ipv6/seg6_iptunnel.c l\u00ednea 163): memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); El memset(...) se introdujo en El commit ef489749aae5 (\"ipv6: sr: clear IP6CB(skb) en la encapsulaci\u00f3n SRH ip4ip6\") hace mucho tiempo (29 de enero de 2019). Dado que el bloque de control del socket IPv6 y el bloque de control del socket IPv4 comparten la misma \u00e1rea de memoria (skb-\u0026gt;cb), la informaci\u00f3n del \u00edndice de la interfaz de recepci\u00f3n se pierde (IP6CB(skb)-\u0026gt;iif se establece en cero). Como efecto secundario, esa condici\u00f3n desencadena una desreferencia del puntero NULL si se aplica el commit 0857d6f8c759 (\"ipv6: al reenviar estad\u00edsticas de recuento de rx en el netdev original\"). Para solucionar ese problema, configuramos IP6CB(skb)-\u0026gt;iif con el \u00edndice de la interfaz de recepci\u00f3n una vez m\u00e1s."
}
],
"id": "CVE-2021-47515",
"lastModified": "2024-11-21T06:36:24.957",
"metrics": {},
"published": "2024-05-24T15:15:12.937",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.