| 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-2024-56640: net/smc: fix LGR and link use-after-free issue |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net/smc: fix LGR and link use-after-free issue |
| |
| We encountered a LGR/link use-after-free issue, which manifested as |
| the LGR/link refcnt reaching 0 early and entering the clear process, |
| making resource access unsafe. |
| |
| refcount_t: addition on 0; use-after-free. |
| WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140 |
| Workqueue: events smc_lgr_terminate_work [smc] |
| Call trace: |
| refcount_warn_saturate+0x9c/0x140 |
| __smc_lgr_terminate.part.45+0x2a8/0x370 [smc] |
| smc_lgr_terminate_work+0x28/0x30 [smc] |
| process_one_work+0x1b8/0x420 |
| worker_thread+0x158/0x510 |
| kthread+0x114/0x118 |
| |
| or |
| |
| refcount_t: underflow; use-after-free. |
| WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140 |
| Workqueue: smc_hs_wq smc_listen_work [smc] |
| Call trace: |
| refcount_warn_saturate+0xf0/0x140 |
| smcr_link_put+0x1cc/0x1d8 [smc] |
| smc_conn_free+0x110/0x1b0 [smc] |
| smc_conn_abort+0x50/0x60 [smc] |
| smc_listen_find_device+0x75c/0x790 [smc] |
| smc_listen_work+0x368/0x8a0 [smc] |
| process_one_work+0x1b8/0x420 |
| worker_thread+0x158/0x510 |
| kthread+0x114/0x118 |
| |
| It is caused by repeated release of LGR/link refcnt. One suspect is that |
| smc_conn_free() is called repeatedly because some smc_conn_free() from |
| server listening path are not protected by sock lock. |
| |
| e.g. |
| |
| Calls under socklock | smc_listen_work |
| ------------------------------------------------------- |
| lock_sock(sk) | smc_conn_abort |
| smc_conn_free | \- smc_conn_free |
| \- smcr_link_put | \- smcr_link_put (duplicated) |
| release_sock(sk) |
| |
| So here add sock lock protection in smc_listen_work() path, making it |
| exclusive with other connection operations. |
| |
| The Linux kernel CVE team has assigned CVE-2024-56640 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.18 with commit 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 and fixed in 5.15.174 with commit f502a88fdd415647a1f2dc45fac71b9c522a052b |
| Issue introduced in 4.18 with commit 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 and fixed in 6.1.120 with commit 0cf598548a6c36d90681d53c6b77d52363f2f295 |
| Issue introduced in 4.18 with commit 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 and fixed in 6.6.66 with commit 673d606683ac70bc074ca6676b938bff18635226 |
| Issue introduced in 4.18 with commit 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 and fixed in 6.12.5 with commit 6f0ae06a234a78ae137064f2c89135ac078a00eb |
| Issue introduced in 4.18 with commit 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 and fixed in 6.13 with commit 2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 |
| |
| 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-2024-56640 |
| 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: |
| net/smc/af_smc.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/f502a88fdd415647a1f2dc45fac71b9c522a052b |
| https://git.kernel.org/stable/c/0cf598548a6c36d90681d53c6b77d52363f2f295 |
| https://git.kernel.org/stable/c/673d606683ac70bc074ca6676b938bff18635226 |
| https://git.kernel.org/stable/c/6f0ae06a234a78ae137064f2c89135ac078a00eb |
| https://git.kernel.org/stable/c/2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 |
