Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: mm/vma: do not try to unmap a VMA if mmap_prepare() invoked from mmap() The mmap_prepare hook functionality includes the ability to invoke mmap_prepare() from the mmap() hook of existing 'stacked' drivers, that is ones which are capable of calling the mmap hooks of other drivers/file systems (e.g. overlayfs, shm). As part of the mmap_prepare action functionality, we deal with errors by unmapping the VMA should one arise. This works in the usual mmap_prepare case, as we invoke this action at the last moment, when the VMA is established in the maple tree. However, the mmap() hook passes a not-fully-established VMA pointer to the caller (which is the motivation behind the mmap_prepare() work), which is detached. So attempting to unmap a VMA in this state will be problematic, with the most obvious symptom being a warning in vma_mark_detached(), because the VMA is already detached. It's also unncessary - the mmap() handler will clean up the VMA on error. So to fix this issue, this patch propagates whether or not an mmap action is being completed via the compatibility layer or directly. If the former, then we do not attempt VMA cleanup, if the latter, then we do. This patch also updates the userland VMA tests to reflect the change.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected ac0a3fc9c07df79dc8a4ce9d274df00afc7bf12d before 5394bcb746503f2ae4b206212416dccea78e3773; affected ac0a3fc9c07df79dc8a4ce9d274df00afc7bf12d before 619eab23e1ce7c97e54bfc5a417306d94b3f6f13 |
| Linux / Linux | affected 6.19; unaffected 0 before 6.19; unaffected 7.0.9 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.