In the Linux kernel, the following vulnerability has been resolved: bpf: fix end-of-list detection in cgroup_storage_get_next_key() list_next_entry() never returns NULL -- when the current element is the last entry it wraps to the list…

Overview

In the Linux kernel, the following vulnerability has been resolved:

bpf: fix end-of-list detection in cgroup_storage_get_next_key()

list_next_entry() never returns NULL -- when the current element is the last entry it wraps to the list head via container_of(). The subsequent NULL check is therefore dead code and get_next_key() never returns -ENOENT for the last element, instead reading storage->key from a bogus pointer that aliases internal map fields and copying the result to userspace.

Replace it with list_entry_is_head() so the function correctly returns -ENOENT when there are no more entries.

Affected

• linux_kernel >= 4.19, < 5.10.258
• linux_kernel >= 5.11, < 5.15.209
• linux_kernel >= 5.16, < 6.1.175
• linux_kernel >= 6.2, < 6.6.141
• linux_kernel >= 6.7, < 6.12.91
• linux_kernel >= 6.13, < 6.18.33
• linux_kernel >= 6.19, < 7.0.10

Remediation

Upgrade past the affected range:

• linux_kernel 7.0.10