| 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-2024-56555: binder: fix OOB in binder_add_freeze_work() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| binder: fix OOB in binder_add_freeze_work() |
| |
| In binder_add_freeze_work() we iterate over the proc->nodes with the |
| proc->inner_lock held. However, this lock is temporarily dropped to |
| acquire the node->lock first (lock nesting order). This can race with |
| binder_deferred_release() which removes the nodes from the proc->nodes |
| rbtree and adds them into binder_dead_nodes list. This leads to a broken |
| iteration in binder_add_freeze_work() as rb_next() will use data from |
| binder_dead_nodes, triggering an out-of-bounds access: |
| |
| ================================================================== |
| BUG: KASAN: global-out-of-bounds in rb_next+0xfc/0x124 |
| Read of size 8 at addr ffffcb84285f7170 by task freeze/660 |
| |
| CPU: 8 UID: 0 PID: 660 Comm: freeze Not tainted 6.11.0-07343-ga727812a8d45 #18 |
| Hardware name: linux,dummy-virt (DT) |
| Call trace: |
| rb_next+0xfc/0x124 |
| binder_add_freeze_work+0x344/0x534 |
| binder_ioctl+0x1e70/0x25ac |
| __arm64_sys_ioctl+0x124/0x190 |
| |
| The buggy address belongs to the variable: |
| binder_dead_nodes+0x10/0x40 |
| [...] |
| ================================================================== |
| |
| This is possible because proc->nodes (rbtree) and binder_dead_nodes |
| (list) share entries in binder_node through a union: |
| |
| struct binder_node { |
| [...] |
| union { |
| struct rb_node rb_node; |
| struct hlist_node dead_node; |
| }; |
| |
| Fix the race by checking that the proc is still alive. If not, simply |
| break out of the iteration. |
| |
| The Linux kernel CVE team has assigned CVE-2024-56555 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.12 with commit d579b04a52a183db47dfcb7a44304d7747d551e1 and fixed in 6.12.4 with commit 6b1be1da1f8279cf091266e71b5153c5b02aaff6 |
| Issue introduced in 6.12 with commit d579b04a52a183db47dfcb7a44304d7747d551e1 and fixed in 6.13 with commit 011e69a1b23011c0db3af4b8293fdd4522cc97b0 |
| |
| 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-2024-56555 |
| 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.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/6b1be1da1f8279cf091266e71b5153c5b02aaff6 |
| https://git.kernel.org/stable/c/011e69a1b23011c0db3af4b8293fdd4522cc97b0 |
