| 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-2023-52582: netfs: Only call folio_start_fscache() one time for each folio |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfs: Only call folio_start_fscache() one time for each folio |
| |
| If a network filesystem using netfs implements a clamp_length() |
| function, it can set subrequest lengths smaller than a page size. |
| |
| When we loop through the folios in netfs_rreq_unlock_folios() to |
| set any folios to be written back, we need to make sure we only |
| call folio_start_fscache() once for each folio. |
| |
| Otherwise, this simple testcase: |
| |
| mount -o fsc,rsize=1024,wsize=1024 127.0.0.1:/export /mnt/nfs |
| dd if=/dev/zero of=/mnt/nfs/file.bin bs=4096 count=1 |
| 1+0 records in |
| 1+0 records out |
| 4096 bytes (4.1 kB, 4.0 KiB) copied, 0.0126359 s, 324 kB/s |
| echo 3 > /proc/sys/vm/drop_caches |
| cat /mnt/nfs/file.bin > /dev/null |
| |
| will trigger an oops similar to the following: |
| |
| page dumped because: VM_BUG_ON_FOLIO(folio_test_private_2(folio)) |
| ------------[ cut here ]------------ |
| kernel BUG at include/linux/netfs.h:44! |
| ... |
| CPU: 5 PID: 134 Comm: kworker/u16:5 Kdump: loaded Not tainted 6.4.0-rc5 |
| ... |
| RIP: 0010:netfs_rreq_unlock_folios+0x68e/0x730 [netfs] |
| ... |
| Call Trace: |
| netfs_rreq_assess+0x497/0x660 [netfs] |
| netfs_subreq_terminated+0x32b/0x610 [netfs] |
| nfs_netfs_read_completion+0x14e/0x1a0 [nfs] |
| nfs_read_completion+0x2f9/0x330 [nfs] |
| rpc_free_task+0x72/0xa0 [sunrpc] |
| rpc_async_release+0x46/0x70 [sunrpc] |
| process_one_work+0x3bd/0x710 |
| worker_thread+0x89/0x610 |
| kthread+0x181/0x1c0 |
| ret_from_fork+0x29/0x50 |
| |
| The Linux kernel CVE team has assigned CVE-2023-52582 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.13 with commit 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd and fixed in 6.1.56 with commit df9950d37df113db59495fa09d060754366a2b7c |
| Issue introduced in 5.13 with commit 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd and fixed in 6.5.6 with commit d9f5537479d4ec97ea92ff24e81a517d5772581a |
| Issue introduced in 5.13 with commit 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd and fixed in 6.6 with commit df1c357f25d808e30b216188330e708e09e1a412 |
| |
| 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-2023-52582 |
| 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/buffered_read.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/df9950d37df113db59495fa09d060754366a2b7c |
| https://git.kernel.org/stable/c/d9f5537479d4ec97ea92ff24e81a517d5772581a |
| https://git.kernel.org/stable/c/df1c357f25d808e30b216188330e708e09e1a412 |
