CVE-2023-52609

NameCVE-2023-52609
DescriptionIn the Linux kernel, the following vulnerability has been resolved: binder: fix race between mmput() and do_exit() Task A calls binder_update_page_range() to allocate and insert pages on a remote address space from Task B. For this, Task A pins the remote mm via mmget_not_zero() first. This can race with Task B do_exit() and the final mmput() refcount decrement will come from Task A. Task A | Task B ------------------+------------------ mmget_not_zero() | | do_exit() | exit_mm() | mmput() mmput() | exit_mmap() | remove_vma() | fput() | In this case, the work of ____fput() from Task B is queued up in Task A as TWA_RESUME. So in theory, Task A returns to userspace and the cleanup work gets executed. However, Task A instead sleep, waiting for a reply from Task B that never comes (it's dead). This means the binder_deferred_release() is blocked until an unrelated binder event forces Task A to go back to userspace. All the associated death notifications will also be delayed until then. In order to fix this use mmput_async() that will schedule the work in the corresponding mm->async_put_work WQ instead of Task A.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3840-1, DLA-3841-1, ELA-1116-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)jessie, jessie (lts)3.16.84-1vulnerable
stretch (security)4.9.320-2vulnerable
stretch (lts), stretch4.9.320-3vulnerable
buster (security), buster, buster (lts)4.19.316-1fixed
bullseye5.10.223-1fixed
bullseye (security)5.10.226-1fixed
bookworm6.1.106-3fixed
bookworm (security)6.1.112-1fixed
sid, trixie6.11.5-1fixed
linux-4.19 (PTS)jessie, jessie (lts)4.19.316-1~deb8u1fixed
stretch (security)4.19.232-1~deb9u1vulnerable
stretch (lts), stretch4.19.316-1~deb9u1fixed
linux-5.10 (PTS)buster, buster (lts)5.10.226-1~deb10u1fixed
buster (security)5.10.218-1~deb10u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcejessie(unfixed)end-of-life
linuxsourcestretch(unfixed)end-of-life
linuxsourcebuster4.19.316-1DLA-3840-1
linuxsourcebullseye5.10.209-1
linuxsourcebookworm6.1.76-1
linuxsource(unstable)6.6.15-1
linux-4.19sourcejessie4.19.316-1~deb8u1ELA-1116-1
linux-4.19sourcestretch4.19.316-1~deb9u1ELA-1116-1
linux-5.10sourcebuster5.10.209-2~deb10u1DLA-3841-1

Notes

https://git.kernel.org/linus/9a9ab0d963621d9d12199df9817e66982582d5a5 (6.8-rc1)

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