| 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-2024-40962: btrfs: zoned: allocate dummy checksums for zoned NODATASUM writes |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: zoned: allocate dummy checksums for zoned NODATASUM writes |
| |
| Shin'ichiro reported that when he's running fstests' test-case |
| btrfs/167 on emulated zoned devices, he's seeing the following NULL |
| pointer dereference in 'btrfs_zone_finish_endio()': |
| |
| Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] PREEMPT SMP KASAN NOPTI |
| KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f] |
| CPU: 4 PID: 2332440 Comm: kworker/u80:15 Tainted: G W 6.10.0-rc2-kts+ #4 |
| Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020 |
| Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] |
| RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs] |
| |
| RSP: 0018:ffff88867f107a90 EFLAGS: 00010206 |
| RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff893e5534 |
| RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088 |
| RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1081696028 |
| R10: ffff88840b4b0143 R11: ffff88834dfff600 R12: ffff88840b4b0000 |
| R13: 0000000000020000 R14: 0000000000000000 R15: ffff888530ad5210 |
| FS: 0000000000000000(0000) GS:ffff888e3f800000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 00007f87223fff38 CR3: 00000007a7c6a002 CR4: 00000000007706f0 |
| DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 |
| PKRU: 55555554 |
| Call Trace: |
| <TASK> |
| ? __die_body.cold+0x19/0x27 |
| ? die_addr+0x46/0x70 |
| ? exc_general_protection+0x14f/0x250 |
| ? asm_exc_general_protection+0x26/0x30 |
| ? do_raw_read_unlock+0x44/0x70 |
| ? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs] |
| btrfs_finish_one_ordered+0x5d9/0x19a0 [btrfs] |
| ? __pfx_lock_release+0x10/0x10 |
| ? do_raw_write_lock+0x90/0x260 |
| ? __pfx_do_raw_write_lock+0x10/0x10 |
| ? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs] |
| ? _raw_write_unlock+0x23/0x40 |
| ? btrfs_finish_ordered_zoned+0x5a9/0x850 [btrfs] |
| ? lock_acquire+0x435/0x500 |
| btrfs_work_helper+0x1b1/0xa70 [btrfs] |
| ? __schedule+0x10a8/0x60b0 |
| ? __pfx___might_resched+0x10/0x10 |
| process_one_work+0x862/0x1410 |
| ? __pfx_lock_acquire+0x10/0x10 |
| ? __pfx_process_one_work+0x10/0x10 |
| ? assign_work+0x16c/0x240 |
| worker_thread+0x5e6/0x1010 |
| ? __pfx_worker_thread+0x10/0x10 |
| kthread+0x2c3/0x3a0 |
| ? trace_irq_enable.constprop.0+0xce/0x110 |
| ? __pfx_kthread+0x10/0x10 |
| ret_from_fork+0x31/0x70 |
| ? __pfx_kthread+0x10/0x10 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| |
| Enabling CONFIG_BTRFS_ASSERT revealed the following assertion to |
| trigger: |
| |
| assertion failed: !list_empty(&ordered->list), in fs/btrfs/zoned.c:1815 |
| |
| This indicates, that we're missing the checksums list on the |
| ordered_extent. As btrfs/167 is doing a NOCOW write this is to be |
| expected. |
| |
| Further analysis with drgn confirmed the assumption: |
| |
| >>> inode = prog.crashed_thread().stack_trace()[11]['ordered'].inode |
| >>> btrfs_inode = drgn.container_of(inode, "struct btrfs_inode", \ |
| "vfs_inode") |
| >>> print(btrfs_inode.flags) |
| (u32)1 |
| |
| As zoned emulation mode simulates conventional zones on regular devices, |
| we cannot use zone-append for writing. But we're only attaching dummy |
| checksums if we're doing a zone-append write. |
| |
| So for NOCOW zoned data writes on conventional zones, also attach a |
| dummy checksum. |
| |
| The Linux kernel CVE team has assigned CVE-2024-40962 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.5 with commit cbfce4c7fbde23cc8bcba44822a58c728caf6ec9 and fixed in 6.6.36 with commit 082b3d4e788953a3ff42ecdb70c4210149076285 |
| Issue introduced in 6.5 with commit cbfce4c7fbde23cc8bcba44822a58c728caf6ec9 and fixed in 6.9.7 with commit 25cfe59f4470a051d1b80f51fa0ca3a5048e4a19 |
| Issue introduced in 6.5 with commit cbfce4c7fbde23cc8bcba44822a58c728caf6ec9 and fixed in 6.10 with commit cebae292e0c32a228e8f2219c270a7237be24a6a |
| |
| 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-2024-40962 |
| 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/btrfs/bio.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/082b3d4e788953a3ff42ecdb70c4210149076285 |
| https://git.kernel.org/stable/c/25cfe59f4470a051d1b80f51fa0ca3a5048e4a19 |
| https://git.kernel.org/stable/c/cebae292e0c32a228e8f2219c270a7237be24a6a |
