| 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-2024-46786: fscache: delete fscache_cookie_lru_timer when fscache exits to avoid UAF |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| fscache: delete fscache_cookie_lru_timer when fscache exits to avoid UAF |
| |
| The fscache_cookie_lru_timer is initialized when the fscache module |
| is inserted, but is not deleted when the fscache module is removed. |
| If timer_reduce() is called before removing the fscache module, |
| the fscache_cookie_lru_timer will be added to the timer list of |
| the current cpu. Afterwards, a use-after-free will be triggered |
| in the softIRQ after removing the fscache module, as follows: |
| |
| ================================================================== |
| BUG: unable to handle page fault for address: fffffbfff803c9e9 |
| PF: supervisor read access in kernel mode |
| PF: error_code(0x0000) - not-present page |
| PGD 21ffea067 P4D 21ffea067 PUD 21ffe6067 PMD 110a7c067 PTE 0 |
| Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI |
| CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G W 6.11.0-rc3 #855 |
| Tainted: [W]=WARN |
| RIP: 0010:__run_timer_base.part.0+0x254/0x8a0 |
| Call Trace: |
| <IRQ> |
| tmigr_handle_remote_up+0x627/0x810 |
| __walk_groups.isra.0+0x47/0x140 |
| tmigr_handle_remote+0x1fa/0x2f0 |
| handle_softirqs+0x180/0x590 |
| irq_exit_rcu+0x84/0xb0 |
| sysvec_apic_timer_interrupt+0x6e/0x90 |
| </IRQ> |
| <TASK> |
| asm_sysvec_apic_timer_interrupt+0x1a/0x20 |
| RIP: 0010:default_idle+0xf/0x20 |
| default_idle_call+0x38/0x60 |
| do_idle+0x2b5/0x300 |
| cpu_startup_entry+0x54/0x60 |
| start_secondary+0x20d/0x280 |
| common_startup_64+0x13e/0x148 |
| </TASK> |
| Modules linked in: [last unloaded: netfs] |
| ================================================================== |
| |
| Therefore delete fscache_cookie_lru_timer when removing the fscahe module. |
| |
| The Linux kernel CVE team has assigned CVE-2024-46786 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.17 with commit 12bb21a29c19aae50cfad4e2bb5c943108f34a7d and fixed in 6.6.51 with commit e0d724932ad12e3528f4ce97fc0f6078d0cce4bc |
| Issue introduced in 5.17 with commit 12bb21a29c19aae50cfad4e2bb5c943108f34a7d and fixed in 6.10.10 with commit 0a11262549ac2ac6fb98c7cd40a67136817e5a52 |
| Issue introduced in 5.17 with commit 12bb21a29c19aae50cfad4e2bb5c943108f34a7d and fixed in 6.11 with commit 72a6e22c604c95ddb3b10b5d3bb85b6ff4dbc34f |
| |
| 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-2024-46786 |
| 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: |
| fs/netfs/fscache_main.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/e0d724932ad12e3528f4ce97fc0f6078d0cce4bc |
| https://git.kernel.org/stable/c/0a11262549ac2ac6fb98c7cd40a67136817e5a52 |
| https://git.kernel.org/stable/c/72a6e22c604c95ddb3b10b5d3bb85b6ff4dbc34f |
