nfs: fix panic when nfs4_ff_layout_prepare_ds() fails

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2024-26868
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-04-17 11:15:09 UTC
Updated2026-08-04 11:17:15 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nfs: fix panic when nfs4_ff_layout_prepare_ds() fails We've been seeing the following panic in production BUG: kernel NULL pointer dereference, address: 0000000000000065 PGD 2f485f067 P4D 2f485f067 PUD 2cc5d8067 PMD 0 RIP: 0010:ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles] Call Trace: <TASK> ? __die+0x78/0xc0 ? page_fault_oops+0x286/0x380 ? __rpc_execute+0x2c3/0x470 [sunrpc] ? rpc_new_task+0x42/0x1c0 [sunrpc] ? exc_page_fault+0x5d/0x110 ? asm_exc_page_fault+0x22/0x30 ? ff_layout_free_layoutreturn+0x110/0x110 [nfs_layout_flexfiles] ? ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles] ? ff_layout_cancel_io+0x6f/0x90 [nfs_layout_flexfiles] pnfs_mark_matching_lsegs_return+0x1b0/0x360 [nfsv4] pnfs_error_mark_layout_for_return+0x9e/0x110 [nfsv4] ? ff_layout_send_layouterror+0x50/0x160 [nfs_layout_flexfiles] nfs4_ff_layout_prepare_ds+0x11f/0x290 [nfs_layout_flexfiles] ff_layout_pg_init_write+0xf0/0x1f0 [nfs_layout_flexfiles] __nfs_pageio_add_request+0x154/0x6c0 [nfs] nfs_pageio_add_request+0x26b/0x380 [nfs] nfs_do_writepage+0x111/0x1e0 [nfs] nfs_writepages_callback+0xf/0x30 [nfs] write_cache_pages+0x17f/0x380 ? nfs_pageio_init_write+0x50/0x50 [nfs] ? nfs_writepages+0x6d/0x210 [nfs] ? nfs_writepages+0x6d/0x210 [nfs] nfs_writepages+0x125/0x210 [nfs] do_writepages+0x67/0x220 ? generic_perform_write+0x14b/0x210 filemap_fdatawrite_wbc+0x5b/0x80 file_write_and_wait_range+0x6d/0xc0 nfs_file_fsync+0x81/0x170 [nfs] ? nfs_file_mmap+0x60/0x60 [nfs] __x64_sys_fsync+0x53/0x90 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Inspecting the core with drgn I was able to pull this >>> prog.crashed_thread().stack_trace()[0] #0 at 0xffffffffa079657a (ff_layout_cancel_io+0x3a/0x84) in ff_layout_cancel_io at fs/nfs/flexfilelayout/flexfilelayout.c:2021:27 >>> prog.crashed_thread().stack_trace()[0]['idx'] (u32)1 >>> prog.crashed_thread().stack_trace()[0]['flseg'].mirror_array[1].mirror_ds (struct nfs4_ff_layout_ds *)0xffffffffffffffed This is clear from the stack trace, we call nfs4_ff_layout_prepare_ds() which could error out initializing the mirror_ds, and then we go to clean it all up and our check is only for if (!mirror->mirror_ds). This is inconsistent with the rest of the users of mirror_ds, which have if (IS_ERR_OR_NULL(mirror_ds)) to keep from tripping over this exact scenario. Fix this up in ff_layout_cancel_io() to make sure we don't panic when we get an error. I also spot checked all the other instances of checking mirror_ds and we appear to be doing the correct checks everywhere, only unconditionally dereferencing mirror_ds when we know it would be valid.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-476

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b739a5bd9d9f18cc69dced8db128ef7206e000cd 31db25e3141b20e2a76a9f219eeca52e3cab126c git Not specified
CNA Linux Linux affected b739a5bd9d9f18cc69dced8db128ef7206e000cd 7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5 git Not specified
CNA Linux Linux affected b739a5bd9d9f18cc69dced8db128ef7206e000cd 5ada9016b1217498fad876a3d5b07645cc955608 git Not specified
CNA Linux Linux affected b739a5bd9d9f18cc69dced8db128ef7206e000cd dac068f164ad05b35e7c0be13f138c3f6adca58f git Not specified
CNA Linux Linux affected b739a5bd9d9f18cc69dced8db128ef7206e000cd 719fcafe07c12646691bd62d7f8d94d657fa0766 git Not specified
CNA Linux Linux affected 6.1 Not specified
CNA Linux Linux unaffected 6.1 semver Not specified
CNA Linux Linux unaffected 6.1.83 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.23 6.6.* semver Not specified
CNA Linux Linux unaffected 6.7.11 6.7.* semver Not specified
CNA Linux Linux unaffected 6.8.2 6.8.* semver Not specified
CNA Linux Linux unaffected 6.9 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/5ada9016b1217498fad876a3d5b07645cc955608 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/dac068f164ad05b35e7c0be13f138c3f6adca58f af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/719fcafe07c12646691bd62d7f8d94d657fa0766 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/31db25e3141b20e2a76a9f219eeca52e3cab126c af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
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