Subject: CVE-2024-49875: nfsd: map the EBADMSG to nfserr_io to avoid warning

From: Greg Kroah-Hartman <[email-masked]>

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

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

nfsd: map the EBADMSG to nfserr_io to avoid warning

Ext4 will throw -EBADMSG through ext4_readdir when a checksum error
occurs, resulting in the following WARNING.

Fix it by mapping EBADMSG to nfserr_io.

nfsd_buffered_readdir
 iterate_dir // -EBADMSG -74
  ext4_readdir // .iterate_shared
   ext4_dx_readdir
    ext4_htree_fill_tree
     htree_dirblock_to_tree
      ext4_read_dirblock
       __ext4_read_dirblock
        ext4_dirblock_csum_verify
         warn_no_space_for_csum
          __warn_no_space_for_csum
        return ERR_PTR(-EFSBADCRC) // -EBADMSG -74
 nfserrno // WARNING

[  161.115610] ------------[ cut here ]------------
[  161.116465] nfsd: non-standard errno: -74
[  161.117315] WARNING: CPU: 1 PID: 780 at fs/nfsd/nfsproc.c:878 nfserrno+0x9d/0xd0
[  161.118596] Modules linked in:
[  161.119243] CPU: 1 PID: 780 Comm: nfsd Not tainted 5.10.0-00014-g79679361fd5d #138
[  161.120684] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qe
mu.org 04/01/2014
[  161.123601] RIP: 0010:nfserrno+0x9d/0xd0
[  161.124676] Code: 0f 87 da 30 dd 00 83 e3 01 b8 00 00 00 05 75 d7 44 89 ee 48 c7 c7 c0 57 24 98 89 44 24 04 c6
 05 ce 2b 61 03 01 e8 99 20 d8 00 <0f> 0b 8b 44 24 04 eb b5 4c 89 e6 48 c7 c7 a0 6d a4 99 e8 cc 15 33
[  161.127797] RSP: 0018:ffffc90000e2f9c0 EFLAGS: 00010286
[  161.128794] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  161.130089] RDX: 1ffff1103ee16f6d RSI: 0000000000000008 RDI: fffff520001c5f2a
[  161.131379] RBP: 0000000000000022 R08: 0000000000000001 R09: ffff8881f70c1827
[  161.132664] R10: ffffed103ee18304 R11: 0000000000000001 R12: 0000000000000021
[  161.133949] R13: 00000000ffffffb6 R14: ffff8881317c0000 R15: ffffc90000e2fbd8
[  161.135244] FS:  0000000000000000(0000) GS:ffff8881f7080000(0000) knlGS:0000000000000000
[  161.136695] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  161.137761] CR2: 00007fcaad70b348 CR3: 0000000144256006 CR4: 0000000000770ee0
[  161.139041] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  161.140291] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  161.141519] PKRU: 55555554
[  161.142076] Call Trace:
[  161.142575]  ? __warn+0x9b/0x140
[  161.143229]  ? nfserrno+0x9d/0xd0
[  161.143872]  ? report_bug+0x125/0x150
[  161.144595]  ? handle_bug+0x41/0x90
[  161.145284]  ? exc_invalid_op+0x14/0x70
[  161.146009]  ? asm_exc_invalid_op+0x12/0x20
[  161.146816]  ? nfserrno+0x9d/0xd0
[  161.147487]  nfsd_buffered_readdir+0x28b/0x2b0
[  161.148333]  ? nfsd4_encode_dirent_fattr+0x380/0x380
[  161.149258]  ? nfsd_buffered_filldir+0xf0/0xf0
[  161.150093]  ? wait_for_concurrent_writes+0x170/0x170
[  161.151004]  ? generic_file_llseek_size+0x48/0x160
[  161.151895]  nfsd_readdir+0x132/0x190
[  161.152606]  ? nfsd4_encode_dirent_fattr+0x380/0x380
[  161.153516]  ? nfsd_unlink+0x380/0x380
[  161.154256]  ? override_creds+0x45/0x60
[  161.155006]  nfsd4_encode_readdir+0x21a/0x3d0
[  161.155850]  ? nfsd4_encode_readlink+0x210/0x210
[  161.156731]  ? write_bytes_to_xdr_buf+0x97/0xe0
[  161.157598]  ? __write_bytes_to_xdr_buf+0xd0/0xd0
[  161.158494]  ? lock_downgrade+0x90/0x90
[  161.159232]  ? nfs4svc_decode_voidarg+0x10/0x10
[  161.160092]  nfsd4_encode_operation+0x15a/0x440
[  161.160959]  nfsd4_proc_compound+0x718/0xe90
[  161.161818]  nfsd_dispatch+0x18e/0x2c0
[  161.162586]  svc_process_common+0x786/0xc50
[  161.163403]  ? nfsd_svc+0x380/0x380
[  161.164137]  ? svc_printk+0x160/0x160
[  161.164846]  ? svc_xprt_do_enqueue.part.0+0x365/0x380
[  161.165808]  ? nfsd_svc+0x380/0x380
[  161.166523]  ? rcu_is_watching+0x23/0x40
[  161.167309]  svc_process+0x1a5/0x200
[  161.168019]  nfsd+0x1f5/0x380
[  161.168663]  ? nfsd_shutdown_threads+0x260/0x260
[  161.169554]  kthread+0x1c4/0x210
[  161.170224]  ? kthread_insert_work_sanity_check+0x80/0x80
[  161.171246]  ret_from_fork+0x1f/0x30

The Linux kernel CVE team has assigned CVE-2024-49875 to this issue.

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

	Fixed in 5.10.227 with commit 0ea4333c679f
	Fixed in 5.15.168 with commit 825789ca9460
	Fixed in 6.1.113 with commit 6fe058502f88
	Fixed in 6.6.55 with commit f7d8ee9db943
	Fixed in 6.10.14 with commit c76005adfa93
	Fixed in 6.11.3 with commit e9cfecca22a3
	Fixed in 6.12-rc1 with commit 340e61e44c1d

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-2024-49875
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/nfsd/vfs.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/0ea4333c679f333e23956de743ad17387819d3f2
	https://git.kernel.org/stable/c/825789ca94602543101045ad3aad19b2b60c6b2a
	https://git.kernel.org/stable/c/6fe058502f8864649c3d614b06b2235223798f48
	https://git.kernel.org/stable/c/f7d8ee9db94372b8235f5f22bb24381891594c42
	https://git.kernel.org/stable/c/c76005adfa93d1a027433331252422078750321f
	https://git.kernel.org/stable/c/e9cfecca22a36b927a440abc6307efb9e138fed5
	https://git.kernel.org/stable/c/340e61e44c1d2a15c42ec72ade9195ad525fd048