CVE-2023-53333: linux kernel Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one Eric Dumazet says: nf_conntrack_dccp_packet() has an unique: dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh); And nothing more is 'pulled' from the packet, depending on the content. dh->dccph_doff, and/or dh->dccph_x ...) So dccp_ack_seq() is happily reading stuff past the _dh buffer. BUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0 Read of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371 [..] Fix this by increasing the stack buffer to also include room for the extra sequence numbers and all the known dccp packet type headers, then pull again after the initial validation of the basic header. While at it, mark packets invalid that lack 48bit sequence bit but where RFC says the type MUST use them. Compile tested only. v2: first skb_header_pointer() now needs to adjust the size to only pull the generic header. (Eric) Heads-up: I intend to remove dccp conntrack support later this year.

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.26 — 5.4.251
linux	linux_kernel	5.5 — 5.10.188
linux	linux_kernel	5.11 — 5.15.121
linux	linux_kernel	5.16 — 6.1.39
linux	linux_kernel	6.2 — 6.3.13
linux	linux_kernel	6.4 — 6.4.4

References

Advisories & Patches

https://git.kernel.org/stable/c/26bd1f210d3783a691052c51d76bb8a8bbd24c67 https://git.kernel.org/stable/c/337fdce450637ea663bc816edc2ba81e5cdad02e https://git.kernel.org/stable/c/5c618daa5038712c4a4ef8923905a2ea1b8836a1 https://git.kernel.org/stable/c/8c0980493beed3a80d6329c44ab293dc8c032927 https://git.kernel.org/stable/c/9bdcda7abaf22f6453e5b5efb7eb4e524095d5d8 https://git.kernel.org/stable/c/c052797ac36813419ad3bfa54cb8615db4b41f15 https://git.kernel.org/stable/c/ff0a3a7d52ff7282dbd183e7fc29a1fe386b0c30

Frequently Asked Questions

What is CVE-2023-53333? +

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one Eric Dumazet says: nf_conntrack_dccp_packet() has an unique: dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh); And nothing more is 'pulled' from the packet, depending on the content. dh->dccph_doff, and/or dh->dccph_x ...) So dccp_ack_seq() is happily reading stuff past the _dh buffer. BUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0 Read of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371 [..] Fix this by increasing the stack buffer to also include room for the extra sequence numbers and all the known dccp packet type headers, then pull again after the initial validation of the basic header. While at it, mark packets invalid that lack 48bit sequence bit but where RFC says the type MUST use them. Compile tested only. v2: first skb_header_pointer() now needs to adjust the size to only pull the generic header. (Eric) Heads-up: I intend to remove dccp conntrack support later this year. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2023-53333? +

CVE-2023-53333 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2023-53333? +

CVE-2023-53333 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-53333? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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