| 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-2024-41023: sched/deadline: Fix task_struct reference leak |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| sched/deadline: Fix task_struct reference leak |
| |
| During the execution of the following stress test with linux-rt: |
| |
| stress-ng --cyclic 30 --timeout 30 --minimize --quiet |
| |
| kmemleak frequently reported a memory leak concerning the task_struct: |
| |
| unreferenced object 0xffff8881305b8000 (size 16136): |
| comm "stress-ng", pid 614, jiffies 4294883961 (age 286.412s) |
| object hex dump (first 32 bytes): |
| 02 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .@.............. |
| 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| debug hex dump (first 16 bytes): |
| 53 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 S............... |
| backtrace: |
| [<00000000046b6790>] dup_task_struct+0x30/0x540 |
| [<00000000c5ca0f0b>] copy_process+0x3d9/0x50e0 |
| [<00000000ced59777>] kernel_clone+0xb0/0x770 |
| [<00000000a50befdc>] __do_sys_clone+0xb6/0xf0 |
| [<000000001dbf2008>] do_syscall_64+0x5d/0xf0 |
| [<00000000552900ff>] entry_SYSCALL_64_after_hwframe+0x6e/0x76 |
| |
| The issue occurs in start_dl_timer(), which increments the task_struct |
| reference count and sets a timer. The timer callback, dl_task_timer, |
| is supposed to decrement the reference count upon expiration. However, |
| if enqueue_task_dl() is called before the timer expires and cancels it, |
| the reference count is not decremented, leading to the leak. |
| |
| This patch fixes the reference leak by ensuring the task_struct |
| reference count is properly decremented when the timer is canceled. |
| |
| The Linux kernel CVE team has assigned CVE-2024-41023 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.10 with commit feff2e65efd8d84cf831668e182b2ce73c604bbb and fixed in 6.9.10 with commit 7a54d31face626f62de415ebe77b43f76c3ffaf4 |
| Issue introduced in 5.10 with commit feff2e65efd8d84cf831668e182b2ce73c604bbb and fixed in 6.10 with commit b58652db66c910c2245f5bee7deca41c12d707b9 |
| Issue introduced in 4.19.257 with commit f0e1c1d8ff908a39dd42e723d08f104505dfa601 |
| Issue introduced in 5.4.212 with commit 184c8ab5342450c4ae6fc5d937f9bb06c620dcf1 |
| |
| 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-2024-41023 |
| 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: |
| kernel/sched/deadline.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/7a54d31face626f62de415ebe77b43f76c3ffaf4 |
| https://git.kernel.org/stable/c/b58652db66c910c2245f5bee7deca41c12d707b9 |
