| 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-2024-26935: scsi: core: Fix unremoved procfs host directory regression |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| scsi: core: Fix unremoved procfs host directory regression |
| |
| Commit fc663711b944 ("scsi: core: Remove the /proc/scsi/${proc_name} |
| directory earlier") fixed a bug related to modules loading/unloading, by |
| adding a call to scsi_proc_hostdir_rm() on scsi_remove_host(). But that led |
| to a potential duplicate call to the hostdir_rm() routine, since it's also |
| called from scsi_host_dev_release(). That triggered a regression report, |
| which was then fixed by commit be03df3d4bfe ("scsi: core: Fix a procfs host |
| directory removal regression"). The fix just dropped the hostdir_rm() call |
| from dev_release(). |
| |
| But it happens that this proc directory is created on scsi_host_alloc(), |
| and that function "pairs" with scsi_host_dev_release(), while |
| scsi_remove_host() pairs with scsi_add_host(). In other words, it seems the |
| reason for removing the proc directory on dev_release() was meant to cover |
| cases in which a SCSI host structure was allocated, but the call to |
| scsi_add_host() didn't happen. And that pattern happens to exist in some |
| error paths, for example. |
| |
| Syzkaller causes that by using USB raw gadget device, error'ing on |
| usb-storage driver, at usb_stor_probe2(). By checking that path, we can see |
| that the BadDevice label leads to a scsi_host_put() after a SCSI host |
| allocation, but there's no call to scsi_add_host() in such path. That leads |
| to messages like this in dmesg (and a leak of the SCSI host proc |
| structure): |
| |
| usb-storage 4-1:87.51: USB Mass Storage device detected |
| proc_dir_entry 'scsi/usb-storage' already registered |
| WARNING: CPU: 1 PID: 3519 at fs/proc/generic.c:377 proc_register+0x347/0x4e0 fs/proc/generic.c:376 |
| |
| The proper fix seems to still call scsi_proc_hostdir_rm() on dev_release(), |
| but guard that with the state check for SHOST_CREATED; there is even a |
| comment in scsi_host_dev_release() detailing that: such conditional is |
| meant for cases where the SCSI host was allocated but there was no calls to |
| {add,remove}_host(), like the usb-storage case. |
| |
| This is what we propose here and with that, the error path of usb-storage |
| does not trigger the warning anymore. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26935 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.4.238 with commit 88c3d3bb6469cea929ac68fd326bdcbefcdfdd83 and fixed in 5.4.274 with commit 0053f15d50d50c9312d8ab9c11e2e405812dfcac |
| Issue introduced in 5.10.176 with commit 68c665bb185037e7eb66fb792c61da9d7151e99c and fixed in 5.10.215 with commit 5c2386ba80e779a92ec3bb64ccadbedd88f779b1 |
| Issue introduced in 5.15.104 with commit 2a764d55e938743efa7c2cba7305633bcf227f09 and fixed in 5.15.154 with commit cea234bb214b17d004dfdccce4491e6ff57c96ee |
| Issue introduced in 6.1.21 with commit 7e0ae8667fcdd99d1756922e1140cac75f5fa279 and fixed in 6.1.84 with commit 3678cf67ff7136db1dd3bf63c361650db5d92889 |
| Issue introduced in 6.3 with commit be03df3d4bfe7e8866d4aa43d62e648ffe884f5f and fixed in 6.6.24 with commit d4c34782b6d7b1e68d18d9549451b19433bd4c6c |
| Issue introduced in 6.3 with commit be03df3d4bfe7e8866d4aa43d62e648ffe884f5f and fixed in 6.7.12 with commit e293c773c13b830cdc251f155df2254981abc320 |
| Issue introduced in 6.3 with commit be03df3d4bfe7e8866d4aa43d62e648ffe884f5f and fixed in 6.8.3 with commit f4ff08fab66eb5c0b97e1a24edac052fb40bf5d7 |
| Issue introduced in 6.3 with commit be03df3d4bfe7e8866d4aa43d62e648ffe884f5f and fixed in 6.9 with commit f23a4d6e07570826fe95023ca1aa96a011fa9f84 |
| Issue introduced in 6.2.8 with commit 73f030d4ef6d1ad17f824a0a2eb637ef7a9c7d51 |
| |
| 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-2024-26935 |
| 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/scsi/hosts.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/0053f15d50d50c9312d8ab9c11e2e405812dfcac |
| https://git.kernel.org/stable/c/5c2386ba80e779a92ec3bb64ccadbedd88f779b1 |
| https://git.kernel.org/stable/c/cea234bb214b17d004dfdccce4491e6ff57c96ee |
| https://git.kernel.org/stable/c/3678cf67ff7136db1dd3bf63c361650db5d92889 |
| https://git.kernel.org/stable/c/d4c34782b6d7b1e68d18d9549451b19433bd4c6c |
| https://git.kernel.org/stable/c/e293c773c13b830cdc251f155df2254981abc320 |
| https://git.kernel.org/stable/c/f4ff08fab66eb5c0b97e1a24edac052fb40bf5d7 |
| https://git.kernel.org/stable/c/f23a4d6e07570826fe95023ca1aa96a011fa9f84 |
