Description

In the Linux kernel, the following vulnerability has been resolved: tpm: Use kfree_sensitive() to free auth session in tpm_dev_release() tpm_dev_release() uses plain kfree() to free chip->auth, which contains sensitive cryptographic material including HMAC session keys, nonces, and passphrase data (struct tpm2_auth). Every other code path that frees this structure uses kfree_sensitive() to zero the memory before releasing it: both tpm2_end_auth_session() and tpm_buf_check_hmac_response() do so. The tpm_dev_release() path is the only one that does not, leaving key material in freed slab memory until it is eventually overwritten. Use kfree_sensitive() for consistency with the rest of the driver and to ensure session keys are scrubbed during device teardown.

References 4

• git.kernel.org https://git.kernel.org/stable/c/53e6d2d834df40960b655b353e7a8ff4d927e1c7
• git.kernel.org https://git.kernel.org/stable/c/84ced03172da544c9f8c0862faad48104f519352
• git.kernel.org https://git.kernel.org/stable/c/c424d2664f08c77f08b4580b5f0cbaabf7c229b2
• git.kernel.org https://git.kernel.org/stable/c/dd3ac52ea7a001406c7dbc663aae4b9f89da679a

Remediation