In the Linux kernel, the following vulnerability has been resolved:
ip_gre: test csum_start instead of transport header
GRE with TUNNEL_CSUM will apply local checksum offload on
CHECKSUM_PARTIAL packets.
ipgre_xmit must validate csum_start after an optional skb_pull,
else lco_csum may trigger an overflow. The original check was
if (csum && skb_checksum_start(skb) < skb->data)
return -EINVAL;
This had false positives when skb_checksum_start is undefined:
when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement
was straightforward
if (csum && skb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_start(skb) < skb->data)
return -EINVAL;
But was eventually revised more thoroughly:
- restrict the check to the only branch where needed, in an
uncommon GRE path that uses header_ops and calls skb_pull.
- test skb_transport_header, which is set along with csum_start
in skb_partial_csum_set in the normal header_ops datapath.
Turns out skbs can arrive in this branch without the transport
header set, e.g., through BPF redirection.
Revise the check back to check csum_start directly, and only if
CHECKSUM_PARTIAL. Do leave the check in the updated location.
Check field regardless of whether TUNNEL_CSUM is configured.
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Redhat |
|
No data.
| Package | CPE | Advisory | Released Date |
|---|---|---|---|
| Red Hat Enterprise Linux 9 | |||
| kernel-0:5.14.0-162.6.1.el9_1 | cpe:/a:redhat:enterprise_linux:9 | RHSA-2022:8267 | 2022-11-15T00:00:00Z |
| kernel-0:5.14.0-162.6.1.el9_1 | cpe:/o:redhat:enterprise_linux:9 | RHSA-2022:8267 | 2022-11-15T00:00:00Z |
References
History
Sat, 07 Jun 2025 03:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat
Redhat enterprise Linux |
|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
|
| Vendors & Products |
Redhat
Redhat enterprise Linux |
Fri, 28 Feb 2025 01:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Wed, 26 Feb 2025 02:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ip_gre: test csum_start instead of transport header GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets. ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was if (csum && skb_checksum_start(skb) < skb->data) return -EINVAL; This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) < skb->data) return -EINVAL; But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath. Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection. Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured. | |
| Title | ip_gre: test csum_start instead of transport header | |
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2025-02-26T02:10:57.322Z
Updated: 2025-05-04T12:44:28.114Z
Reserved: 2025-02-26T02:08:31.541Z
Link: CVE-2022-49340
Vulnrichment
No data.
NVD
Status : Received
Published: 2025-02-26T07:01:10.753
Modified: 2025-02-26T07:01:10.753
Link: CVE-2022-49340
Redhat