| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2023-52609: binder: fix race between mmput() and do_exit() |
| |
| Description |
| =========== |
| |
| In 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. |
| |
| The Linux kernel CVE team has assigned CVE-2023-52609 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 4.19.306 with commit 95b1d336b0642198b56836b89908d07b9a0c9608 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 5.4.268 with commit 252a2a5569eb9f8d16428872cc24dea1ac0bb097 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 5.10.209 with commit 7e7a0d86542b0ea903006d3f42f33c4f7ead6918 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 5.15.148 with commit 98fee5bee97ad47b527a997d5786410430d1f0e9 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 6.1.75 with commit 6696f76c32ff67fec26823fc2df46498e70d9bf3 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 6.6.14 with commit 67f16bf2cc1698fd50e01ee8a2becc5a8e6d3a3e |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 6.7.2 with commit 77d210e8db4d61d43b2d16df66b1ec46fad2ee01 |
| Issue introduced in 2.6.29 with commit 457b9a6f09f011ebcb9b52cc203a6331a6fc2de7 and fixed in 6.8 with commit 9a9ab0d963621d9d12199df9817e66982582d5a5 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2023-52609 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/android/binder_alloc.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/95b1d336b0642198b56836b89908d07b9a0c9608 |
| https://git.kernel.org/stable/c/252a2a5569eb9f8d16428872cc24dea1ac0bb097 |
| https://git.kernel.org/stable/c/7e7a0d86542b0ea903006d3f42f33c4f7ead6918 |
| https://git.kernel.org/stable/c/98fee5bee97ad47b527a997d5786410430d1f0e9 |
| https://git.kernel.org/stable/c/6696f76c32ff67fec26823fc2df46498e70d9bf3 |
| https://git.kernel.org/stable/c/67f16bf2cc1698fd50e01ee8a2becc5a8e6d3a3e |
| https://git.kernel.org/stable/c/77d210e8db4d61d43b2d16df66b1ec46fad2ee01 |
| https://git.kernel.org/stable/c/9a9ab0d963621d9d12199df9817e66982582d5a5 |
