nfsd: prevent panic for nfsv4.0 closed files in nfs4_show_open

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: prevent panic for nfsv4.0 closed files in nfs4_show_open Prior to commit 3f29cc82a84c ("nfsd: split sc_status out of sc_type") states_show() relied on sc_type field to be of valid type before calling into a subfunction to show content of a particular stateid. From that commit, we split the validity of the stateid into sc_status and no longer changed sc_type to 0 while unhashing the stateid. This resulted in kernel oopsing for nfsv4.0 opens that stay around and in nfs4_show_open() would derefence sc_file which was NULL. Instead, for closed open stateids forgo displaying information that relies of having a valid sc_file. To reproduce: mount the server with 4.0, read and close a file and then on the server cat /proc/fs/nfsd/clients/2/states [ 513.590804] Call trace: [ 513.590925] _raw_spin_lock+0xcc/0x160 [ 513.591119] nfs4_show_open+0x78/0x2c0 [nfsd] [ 513.591412] states_show+0x44c/0x488 [nfsd] [ 513.591681] seq_read_iter+0x5d8/0x760 [ 513.591896] seq_read+0x188/0x208 [ 513.592075] vfs_read+0x148/0x470 [ 513.592241] ksys_read+0xcc/0x178

Timeline

1. Sep 13, 2024, 5:29 AM UTCCVE published
2. Sep 29, 2024, 3:09 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 21, 2026, 12:35 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 3f29cc82a84c23cfd12b903029dd26002ca825f5 · fixed in ba0b697de298285301c71c258598226e06494236; From 3f29cc82a84c23cfd12b903029dd26002ca825f5 · fixed in a204501e1743d695ca2930ed25a2be9f8ced96d3; From 6.6.160 · fixed in 6.7

• Linux Linux

  6.9

• KernelLinux

  From 6.9.0 · fixed in 6.10.8

References 2