KEYS: trusted: Fix TPM teardown ordering

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89763
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:20:07 UTC
Updated2026-09-11 20:20:07 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: KEYS: trusted: Fix TPM teardown ordering trusted_tpm_exit() drops the TPM chip reference and frees the digest array before unregistering the trusted key type. key_type_lookup() holds key_types_sem for reading until the key operation finishes, while unregister_key_type() takes it for writing. It therefore provides the synchronization point that must precede backend teardown. The current order permits this interleaving: CPU 0 CPU 1 trusted_tpm_exit() key_type_lookup("trusted") put_device(&chip->dev) trusted_tpm_seal() kfree(digests) pcrlock() unregister_key_type() tpm_pcr_extend(..., digests) CPU 1 can consequently dereference the freed digest array. The chip can also be released before callbacks stop using it. KASAN reported: BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200 Read of size 2 at addr ffff88810872d000 by task poc/89 Call Trace: tpm_pcr_extend+0x1f0/0x200 pcrlock+0x42/0x70 [trusted] trusted_tpm_seal+0x1b6/0x570 [trusted] trusted_instantiate+0x293/0x340 [trusted] __key_instantiate_and_link+0xb2/0x2b0 __key_create_or_update+0x61e/0xb50 __do_sys_add_key+0x1b8/0x310 Allocated by task 88: __kmalloc_noprof+0x1a7/0x490 do_one_initcall+0xa1/0x390 do_init_module+0x2df/0x840 Freed by task 90: kfree+0x131/0x3c0 trusted_tpm_exit+0x59/0xa0 [trusted] __do_sys_delete_module+0x346/0x510 Move unregister_key_type() before releasing either resource. This stops new lookups and waits for in-flight key operations to finish before the backend state is destroyed.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 753c978f2400f9783eb524842a975d3ac950d511 git Not specified
CNA Linux Linux affected 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 2f7541afbc57fe9d26769a22c31d8ce8790c9a19 git Not specified
CNA Linux Linux affected 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 5e2d672280d97d83de43031d93761b12dadd7b8a git Not specified
CNA Linux Linux affected 5.1 Not specified
CNA Linux Linux unaffected 5.1 semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/5e2d672280d97d83de43031d93761b12dadd7b8a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2f7541afbc57fe9d26769a22c31d8ce8790c9a19 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/753c978f2400f9783eb524842a975d3ac950d511 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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