Message-ID: <2025070426-CVE-2025-38223-2e38@gregkh>
Date: Fri,  4 Jul 2025 15:37:52 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38223: ceph: avoid kernel BUG for encrypted inode with unaligned file size

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

ceph: avoid kernel BUG for encrypted inode with unaligned file size

The generic/397 test hits a BUG_ON for the case of encrypted inode with
unaligned file size (for example, 33K or 1K):

[ 877.737811] run fstests generic/397 at 2025-01-03 12:34:40
[ 877.875761] libceph: mon0 (2)127.0.0.1:40674 session established
[ 877.876130] libceph: client4614 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 877.991965] libceph: mon0 (2)127.0.0.1:40674 session established
[ 877.992334] libceph: client4617 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 878.017234] libceph: mon0 (2)127.0.0.1:40674 session established
[ 878.017594] libceph: client4620 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 878.031394] xfs_io (pid 18988) is setting deprecated v1 encryption policy; recommend upgrading to v2.
[ 878.054528] libceph: mon0 (2)127.0.0.1:40674 session established
[ 878.054892] libceph: client4623 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 878.070287] libceph: mon0 (2)127.0.0.1:40674 session established
[ 878.070704] libceph: client4626 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 878.264586] libceph: mon0 (2)127.0.0.1:40674 session established
[ 878.265258] libceph: client4629 fsid 19b90bca-f1ae-47a6-93dd-0b03ee637949
[ 878.374578] -----------[ cut here ]------------
[ 878.374586] kernel BUG at net/ceph/messenger.c:1070!
[ 878.375150] Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 878.378145] CPU: 2 UID: 0 PID: 4759 Comm: kworker/2:9 Not tainted 6.13.0-rc5+ #1
[ 878.378969] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 878.380167] Workqueue: ceph-msgr ceph_con_workfn
[ 878.381639] RIP: 0010:ceph_msg_data_cursor_init+0x42/0x50
[ 878.382152] Code: 89 17 48 8b 46 70 55 48 89 47 08 c7 47 18 00 00 00 00 48 89 e5 e8 de cc ff ff 5d 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 0f 0b <0f> 0b 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90
[ 878.383928] RSP: 0018:ffffb4ffc7cbbd28 EFLAGS: 00010287
[ 878.384447] RAX: ffffffff82bb9ac0 RBX: ffff981390c2f1f8 RCX: 0000000000000000
[ 878.385129] RDX: 0000000000009000 RSI: ffff981288232b58 RDI: ffff981390c2f378
[ 878.385839] RBP: ffffb4ffc7cbbe18 R08: 0000000000000000 R09: 0000000000000000
[ 878.386539] R10: 0000000000000000 R11: 0000000000000000 R12: ffff981390c2f030
[ 878.387203] R13: ffff981288232b58 R14: 0000000000000029 R15: 0000000000000001
[ 878.387877] FS: 0000000000000000(0000) GS:ffff9814b7900000(0000) knlGS:0000000000000000
[ 878.388663] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 878.389212] CR2: 00005e106a0554e0 CR3: 0000000112bf0001 CR4: 0000000000772ef0
[ 878.389921] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 878.390620] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 878.391307] PKRU: 55555554
[ 878.391567] Call Trace:
[ 878.391807] <TASK>
[ 878.392021] ? show_regs+0x71/0x90
[ 878.392391] ? die+0x38/0xa0
[ 878.392667] ? do_trap+0xdb/0x100
[ 878.392981] ? do_error_trap+0x75/0xb0
[ 878.393372] ? ceph_msg_data_cursor_init+0x42/0x50
[ 878.393842] ? exc_invalid_op+0x53/0x80
[ 878.394232] ? ceph_msg_data_cursor_init+0x42/0x50
[ 878.394694] ? asm_exc_invalid_op+0x1b/0x20
[ 878.395099] ? ceph_msg_data_cursor_init+0x42/0x50
[ 878.395583] ? ceph_con_v2_try_read+0xd16/0x2220
[ 878.396027] ? _raw_spin_unlock+0xe/0x40
[ 878.396428] ? raw_spin_rq_unlock+0x10/0x40
[ 878.396842] ? finish_task_switch.isra.0+0x97/0x310
[ 878.397338] ? __schedule+0x44b/0x16b0
[ 878.397738] ceph_con_workfn+0x326/0x750
[ 878.398121] process_one_work+0x188/0x3d0
[ 878.398522] ? __pfx_worker_thread+0x10/0x10
[ 878.398929] worker_thread+0x2b5/0x3c0
[ 878.399310] ? __pfx_worker_thread+0x10/0x10
[ 878.399727] kthread+0xe1/0x120
[ 878.400031] ? __pfx_kthread+0x10/0x10
[ 878.400431] ret_from_fork+0x43/0x70
[ 878.400771] ? __pfx_kthread+0x10/0x10
[ 878.401127] ret_from_fork_asm+0x1a/0x30
[ 878.401543] </TASK>
[ 878.401760] Modules linked in: hctr2 nhpoly1305_avx2 nhpoly1305_sse2 nhpoly1305 chacha_generic chacha_x86_64 libchacha adiantum libpoly1305 essiv authenc mptcp_diag xsk_diag tcp_diag udp_diag raw_diag inet_diag unix_diag af_packet_diag netlink_diag intel_rapl_msr intel_rapl_common intel_uncore_frequency_common skx_edac_common nfit kvm_intel kvm crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 sha1_ssse3 aesni_intel joydev crypto_simd cryptd rapl input_leds psmouse sch_fq_codel serio_raw bochs i2c_piix4 floppy qemu_fw_cfg i2c_smbus mac_hid pata_acpi msr parport_pc ppdev lp parport efi_pstore ip_tables x_tables
[ 878.407319] ---[ end trace 0000000000000000 ]---
[ 878.407775] RIP: 0010:ceph_msg_data_cursor_init+0x42/0x50
[ 878.408317] Code: 89 17 48 8b 46 70 55 48 89 47 08 c7 47 18 00 00 00 00 48 89 e5 e8 de cc ff ff 5d 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 0f 0b <0f> 0b 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90
[ 878.410087] RSP: 0018:ffffb4ffc7cbbd28 EFLAGS: 00010287
[ 878.410609] RAX: ffffffff82bb9ac0 RBX: ffff981390c2f1f8 RCX: 0000000000000000
[ 878.411318] RDX: 0000000000009000 RSI: ffff981288232b58 RDI: ffff981390c2f378
[ 878.412014] RBP: ffffb4ffc7cbbe18 R08: 0000000000000000 R09: 0000000000000000
[ 878.412735] R10: 0000000000000000 R11: 0000000000000000 R12: ffff981390c2f030
[ 878.413438] R13: ffff981288232b58 R14: 0000000000000029 R15: 0000000000000001
[ 878.414121] FS: 0000000000000000(0000) GS:ffff9814b7900000(0000) knlGS:0000000000000000
[ 878.414935] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 878.415516] CR2: 00005e106a0554e0 CR3: 0000000112bf0001 CR4: 0000000000772ef0
[ 878.416211] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 878.416907] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 878.417630] PKRU: 55555554

(gdb) l *ceph_msg_data_cursor_init+0x42
0xffffffff823b45a2 is in ceph_msg_data_cursor_init (net/ceph/messenger.c:1070).
1065
1066 void ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor,
1067                                struct ceph_msg *msg, size_t length)
1068 {
1069        BUG_ON(!length);
1070        BUG_ON(length > msg->data_length);
1071        BUG_ON(!msg->num_data_items);
1072
1073        cursor->total_resid = length;
1074        cursor->data = msg->data;

The issue takes place because of this:

[ 202.628853] libceph: net/ceph/messenger_v2.c:2034 prepare_sparse_read_data(): msg->data_length 33792, msg->sparse_read_total 36864

1070        BUG_ON(length > msg->data_length);

The generic/397 test (xfstests) executes such steps:
(1) create encrypted files and directories;
(2) access the created files and folders with encryption key;
(3) access the created files and folders without encryption key.

The issue takes place in this portion of code:

    if (IS_ENCRYPTED(inode)) {
            struct page **pages;
            size_t page_off;

            err = iov_iter_get_pages_alloc2(&subreq->io_iter, &pages, len,
                                            &page_off);
            if (err < 0) {
                    doutc(cl, "%llx.%llx failed to allocate pages, %d\n",
                          ceph_vinop(inode), err);
                    goto out;
            }

            /* should always give us a page-aligned read */
            WARN_ON_ONCE(page_off);
            len = err;
            err = 0;

            osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false,
                                             false);

The reason of the issue is that subreq->io_iter.count keeps unaligned
value of length:

[  347.751182] lib/iov_iter.c:1185 __iov_iter_get_pages_alloc(): maxsize 36864, maxpages 4294967295, start 18446659367320516064
[  347.752808] lib/iov_iter.c:1196 __iov_iter_get_pages_alloc(): maxsize 33792, maxpages 4294967295, start 18446659367320516064
[  347.754394] lib/iov_iter.c:1015 iter_folioq_get_pages(): maxsize 33792, maxpages 4294967295, extracted 0, _start_offset 18446659367320516064

This patch simply assigns the aligned value to subreq->io_iter.count
before calling iov_iter_get_pages_alloc2().

[ idryomov: tag the comment with FIXME to make it clear that it's only
            a workaround for netfslib not coexisting with fscrypt nicely
            (this is also noted in another pre-existing comment) ]

The Linux kernel CVE team has assigned CVE-2025-38223 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.12 with commit ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and fixed in 6.12.35 with commit 75583606aeef357a524cf6afd07f4b653ae48964
	Issue introduced in 6.12 with commit ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and fixed in 6.15.4 with commit 26725a76264b97d1ff104031b78da57f47741625
	Issue introduced in 6.12 with commit ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and fixed in 6.16-rc1 with commit 060909278cc0a91373a20726bd3d8ce085f480a9

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-2025-38223
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/ceph/addr.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/75583606aeef357a524cf6afd07f4b653ae48964
	https://git.kernel.org/stable/c/26725a76264b97d1ff104031b78da57f47741625
	https://git.kernel.org/stable/c/060909278cc0a91373a20726bd3d8ce085f480a9

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