CVE - CVE-2024-35884

CVE-ID
CVE-2024-35884	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: udp: do not accept non-tunnel GSO skbs landing in a tunnel When rx-udp-gro-forwarding is enabled UDP packets might be GROed when being forwarded. If such packets might land in a tunnel this can cause various issues and udp_gro_receive makes sure this isn't the case by looking for a matching socket. This is performed in udp4/6_gro_lookup_skb but only in the current netns. This is an issue with tunneled packets when the endpoint is in another netns. In such cases the packets will be GROed at the UDP level, which leads to various issues later on. The same thing can happen with rx-gro-list. We saw this with geneve packets being GROed at the UDP level. In such case gso_size is set; later the packet goes through the geneve rx path, the geneve header is pulled, the offset are adjusted and frag_list skbs are not adjusted with regard to geneve. When those skbs hit skb_fragment, it will misbehave. Different outcomes are possible depending on what the GROed skbs look like; from corrupted packets to kernel crashes. One example is a BUG_ON[1] triggered in skb_segment while processing the frag_list. Because gso_size is wrong (geneve header was pulled) skb_segment thinks there is "geneve header size" of data in frag_list, although it's in fact the next packet. The BUG_ON itself has nothing to do with the issue. This is only one of the potential issues. Looking up for a matching socket in udp_gro_receive is fragile: the lookup could be extended to all netns (not speaking about performances) but nothing prevents those packets from being modified in between and we could still not find a matching socket. It's OK to keep the current logic there as it should cover most cases but we also need to make sure we handle tunnel packets being GROed too early. This is done by extending the checks in udp_unexpected_gso: GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits and landing in a tunnel must be segmented. [1] kernel BUG at net/core/skbuff.c:4408! RIP: 0010:skb_segment+0xd2a/0xf70 __udp_gso_segment+0xaa/0x560
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/3001e7aa43d6691db2a878b0745b854bf12ddd19 URL:https://git.kernel.org/stable/c/3001e7aa43d6691db2a878b0745b854bf12ddd19 MISC:https://git.kernel.org/stable/c/3391b157780bbedf8ef9f202cbf10ee90bf6b0f8 URL:https://git.kernel.org/stable/c/3391b157780bbedf8ef9f202cbf10ee90bf6b0f8 MISC:https://git.kernel.org/stable/c/35fe0e0b5c00bef7dde74842a2564c43856fbce4 URL:https://git.kernel.org/stable/c/35fe0e0b5c00bef7dde74842a2564c43856fbce4 MISC:https://git.kernel.org/stable/c/3d010c8031e39f5fa1e8b13ada77e0321091011f URL:https://git.kernel.org/stable/c/3d010c8031e39f5fa1e8b13ada77e0321091011f MISC:https://git.kernel.org/stable/c/d12245080cb259d82b34699f6cd4ec11bdb688bd URL:https://git.kernel.org/stable/c/d12245080cb259d82b34699f6cd4ec11bdb688bd MISC:https://git.kernel.org/stable/c/d49ae15a5767d4e9ef8bbb79e42df1bfebc94670 URL:https://git.kernel.org/stable/c/d49ae15a5767d4e9ef8bbb79e42df1bfebc94670
Assigning CNA
kernel.org
Date Record Created
20240517	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240517)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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