Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: release page in error path to avoid BUG_ON Consider the following sequence of events: 1. Userspace issues a UFFD ioctl, which ends up calling into shmem_mfill_atomic_pte(). We successfully account the blocks, we shmem_alloc_page(), but then the copy_from_user() fails. We return -ENOENT. We don't release the page we allocated. 2. Our caller detects this error code, tries the copy_from_user() after dropping the mmap_lock, and retries, calling back into shmem_mfill_atomic_pte(). 3. Meanwhile, let's say another process filled up the tmpfs being used. 4. So shmem_mfill_atomic_pte() fails to account blocks this time, and immediately returns - without releasing the page. This triggers a BUG_ON in our caller, which asserts that the page should always be consumed, unless -ENOENT is returned. To fix this, detect if we have such a "dangling" page when accounting fails, and if so, release it before returning.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected cb658a453b9327ce96ce5222c24d162b5b65b564 before 319116227e52d49eee671f0aa278bac89b3c1b69; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before 07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before 140cfd9980124aecb6c03ef2e69c72d0548744de; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before ad53127973034c63b5348715a1043d0e80ceb330; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before 2d59a0ed8b26b8f3638d8afc31f839e27759f1f6; affected cb658a453b9327ce96ce5222c24d162b5b65b564 before 7ed9d238c7dbb1fdb63ad96a6184985151b0171c |
| Linux / Linux | affected 4.11; unaffected 0 before 4.11; unaffected 4.14.233 through 4.14.*; unaffected 4.19.191 through 4.19.*; unaffected 5.4.120 through 5.4.*; unaffected 5.10.38 through 5.10.*; unaffected 5.11.22 through 5.11.*; unaffected 5.12.5 through 5.12.*; unaffected 5.13 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/319116227e52d49eee671f0aa278bac89b3c1b69
- https://git.kernel.org/stable/c/07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f
- https://git.kernel.org/stable/c/b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43
- https://git.kernel.org/stable/c/140cfd9980124aecb6c03ef2e69c72d0548744de
- https://git.kernel.org/stable/c/ad53127973034c63b5348715a1043d0e80ceb330
- https://git.kernel.org/stable/c/2d59a0ed8b26b8f3638d8afc31f839e27759f1f6
- https://git.kernel.org/stable/c/7ed9d238c7dbb1fdb63ad96a6184985151b0171c
ADP enrichment
No English description supplied.
No references supplied.
No English description supplied.
- https://git.kernel.org/stable/c/319116227e52d49eee671f0aa278bac89b3c1b69
- https://git.kernel.org/stable/c/07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f
- https://git.kernel.org/stable/c/b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43
- https://git.kernel.org/stable/c/140cfd9980124aecb6c03ef2e69c72d0548744de
- https://git.kernel.org/stable/c/ad53127973034c63b5348715a1043d0e80ceb330
- https://git.kernel.org/stable/c/2d59a0ed8b26b8f3638d8afc31f839e27759f1f6
- https://git.kernel.org/stable/c/7ed9d238c7dbb1fdb63ad96a6184985151b0171c